Article

Temporal variations in the primary energy use and greenhouse gas emissions of electricity provided by the Swiss grid

July 2018
Energy 161(15 october 2018):573-582

DOI:10.1016/j.energy.2018.07.087

Authors:

Didier A.S. Vuarnoz

Swiss Federal Laboratories for Materials Science and Technology

Thomas Jusselme

HES-SO University of Applied Sciences and Arts Western Switzerland

It is a frequent practice nowadays to use mean annual conversion factors (CFs) when performing life-cycle assessment (LCA) of processes and products that use electricity supplied by the grid. In this paper, we conduct an hourly assessment of the greenhouse gas (GHG) emission factor, along with the conversion factors for the cumulative energy demand (CED) and its non-renewable part (CEDnr), of electricity supplied by the Swiss grid and its direct neighboring countries (France, Germany, and Austria; Italy being neglected). Based on an hourly inventory of energy flows during a one-year period (2015-2016), this attributional approach allows performance of various certification procedures of process or product manufacturing, and comparison of energy and carbon intensities of different national mixes. Hourly calculation allows evaluation of the order of magnitude of errors made when considering an annual mix. Visualization techniques are used to better understand the obtained data and to detect when strategies involving timing optimization of electricity use may be efficient. A case study is chosen to illustrate the relevance of hourly CFs when performing LCA associated to the exploitation of a given building. Moreover, mean annual CFs of interest are discriminated by electricity end-use sectors. This could be of great help for system designers willing to improve the assessment accuracy when hourly CFs are not readily available.

Novel quantification of hourly GHG emissions in cold-climate buildings for mixed-grid environments

Thesis

Full-text available

Apr 2024

Max St-Jacques

This thesis introduces novel methodologies and tools for calculating greenhouse gas (GHG) emissions, emphasizing Scope 2 emissions in cold-climate mixed-grid setting. It aims to refine the precision of GHG emission estimations, paving the way for more informed and effective emissions mitigation strategies. By evaluating existing practices and pioneering methods for calculating and forecasting GHG emission factors (EFs), this work addresses the unique spatial and temporal challenges associated with such environments. A key advancement presented is a novel methodology for calculating Consumption-based Hourly Emission Factors (CHEFs) that considers the electrical grid's spatial and temporal sensitivity. Applied in Ontario, Canada, this approach not only demonstrated potential savings of $13.3M in over-taxation for Ontario but also a significant 44% reduction in GHG emissions for a case study building compared to conventional methods. Further analysis comparing average EFs (AEFs) and CHEFs across archetype buildings showcased the superior accuracy of CHEFs, especially during peak grid demand. This led to the recommendation of a zonal approach to building codes, aligning electrification strategies with GHG savings across various scenarios in Ontario. Moreover, the thesis evaluates the discrepancy between AEFs and CHEFs in building operations, noting a significant 61% misjudgment in GHG savings estimation. This highlights the urgent need for temporally aligned and adaptable EF models. Innovative tools such as Emission Duration Curves (EDCs) and Emission Event Duration Curves (EEDCs) were introduced, revealing a moderate correlation between hourly energy use and GHG emissions. This suggests that peak energy loads and emissions peaks do not always align, advocating for custom sustainable building management strategies. Additionally, the efficacy of ARIMA models in forecasting CHEFs was examined, showing that these models, particularly for 1-hour and 24-hour forecasts, offer high predictive accuracy. This could greatly enhance operational planning and emissions management. This thesis contributes to the understanding and improvement of GHG emissions calculations in the building sector. It demonstrates the critical need for methodologies that are sensitive to both the spatial and temporal dimensions of electrical grid use, advocating for a shift towards more dynamic and precise approaches in environmental management.

Sustainable Power Grid Expansion: Life Cycle Assessment, Modeling Approaches, Challenges, and Opportunities

Article

Full-text available

May 2023

Electric demand is steadily increasing, hence requiring continuous investments in modernizing, and expanding power grids worldwide. Traditionally, power system planning projects have considered minimizing the costs of capacity expansion and minimizing the amount of energy not served as the main objectives. With climate change policies enforcing the decommissioning of fossil-fuel-based generation, new clean and renewable generation technologies are being considered for power system capacity expansion projects. However, the environmental impacts of energy resources are not limited to carbon emissions and their contribution to global warming. In fact, every power generation technology can result in undesired impacts during its entire life cycle, which could negatively affect air quality, water resources, material resources, and/or human health. This paper provides an overview of how to assess the sustainability of power systems and power generation technologies based on life cycle assessment (LCA). A review of LCA, as applied to power systems and generation technologies, is presented with a discussion of general findings, challenges, and limitations. A review of the literature is then provided related to how sustainability objectives are currently incorporated in power grid design and capacity expansion models. Finally, shortcomings of the current models are discussed, along with opportunities for future research.

Open-data based carbon emission intensity signals for electricity generation in European countries – top down vs. bottom up approach

Article

Full-text available

Sep 2022

Dynamic grid emission factors provide a temporally resolved signal about the carbon intensity of electricity generation in the power system. Since actual carbon dioxide emission measurements are usually lacking, such a signal must be derived from system-specific emission factors combined with power generation time series. We present a bottom-up method that allows deriving per country and per technology emission factors for European countries based on plant specific power generation time series and reported emissions from the European emissions trading mechanism. We have matched, 595 fossil generation units and their respective annual emissions. In 2018, these power plants supplied 717 TWh of electricity to the grid, representing approximately 50 % of power generation from fossil fuels. Based on this dataset, 42 individual technology and country-specific emission factors are derived. The resulting values for historical per country carbon intensity of electricity generation are compared with corresponding results from a top-down approach, which uses statistical data on emissions and power generation on national scales. All calculations are based on publicly available data, such that the analysis is transparent and the method can be replicated, adjusted and expanded in a flexible way.

Open-data based carbon emission intensity signals for electricity generation in European countries -- top down vs. bottom up approach

Preprint

Full-text available

Oct 2021

Dynamic grid emission factors provide a temporally resolved signal about the carbon intensity of electricity generation in the power system. Since actual carbon dioxide emission measurements are usually lacking, such a signal has to be derived from system-specific emission factors combined with power generation time series. We present a bottom-up method which allows deriving per country and per technology emission factors for European countries based on power generation time series and reported emissions from the European emissions trading mechanism. The resulting values for historical per country carbon intensity of electricity generation are compared with corresponding results from a top-down approach, which uses statistical data on emissions and power generation on national scales. All calculations are based on publicly available data, so that the analysis is transparent and the method can be replicated, adjusted and expanded in a flexible way.

Dynamic Prospective Average and Marginal GHG Emission Factors—Scenario-Based Method for the German Power System until 2050

Article

Full-text available

Apr 2021

Due to the continuous diurnal, seasonal, and annual changes in the German power supply, prospective dynamic emission factors are needed to determine greenhouse gas (GHG) emissions from hybrid and flexible electrification measures. For the calculation of average emission factors (AEF) and marginal emission factors (MEF), detailed electricity market data are required to represent electricity trading, energy storage, and the partial load behavior of the power plant park on a unit-by-unit, hourly basis. Using two normative scenarios up to 2050, different emission factors of electricity supply with regard to the degree of decarbonization of power production were developed in a linear optimization model through different GHG emission caps (Business-As-Usual, BAU: −74%; Climate-Action-Plan, CAP: −95%). The mean hourly German AEF drops to 182 gCO2eq/kWhel (2018: 468 gCO2eq/kWhel) in the BAU scenario by the year 2050 and even to 29 gCO2eq/kWhel in the CAP scenario with 3700 almost emission-free hours from power supply per year. The overall higher MEF decreases to 475 and 368 gCO2eq/kWhel, with a stricter emissions cap initially leading to a higher MEF through more gas-fired power plants providing base load. If the emission intensity of the imported electricity differs substantially and a storage factor is implemented, the AEF is significantly affected. Hence, it is not sufficient to use the share of RES in net electricity generation as an indicator of emission intensity. With these emission factors it is possible to calculate lifetime GHG emissions and determine operating times of sector coupling technologies to mitigate GHG emissions in a future flexible energy system. This is because it is decisive when lower-emission electricity can be used to replace fossil energy sources.

The use of primary energy factors and CO2 intensities -- reviewing the state of play in academic literature

Preprint

Full-text available

Feb 2021

******* PUBLISHED VERSION: http://dx.doi.org/10.1016/j.rser.2021.111182 ******* Reaching the 2030 targets for the EU primary energy use (PE) and CO2eq emissions (CE) requires an accurate assessment of how different technologies perform on these two fronts. In this regard, the focus in academia is increasingly shifting from traditional technologies to electricity consuming alternatives. Calculating and comparing their performance with respect to traditional technologies requires conversion factors (CFs) like a primary energy factor and a CO2eq intensity. These reflect the PE and CE associated with each unit of electricity consumed. Previous work has shown that the calculation and use of CFs is a contentious and multifaceted issue. However, this has mostly remained a theoretical discussion. A stock-taking of how CFs are actually calculated and used in academic literature has so far been missing, impeding insight into what the contemporary trends and challenges are. Therefore, we structurally review 65 publications across six methodological aspects. We find that 72% of the publications consider only a single country, 86% apply a purely retrospective perspective, 54% apply a yearly temporal resolution, 65% apply a purely operational (instead of a life-cycle) perspective, 91% make use of average (rather than marginal) CFs, and 75% ignore electricity imports from surrounding countries. We conclude that there is a strong need in the literature for a publicly available, transparently calculated dataset of CFs, which avoids the shortcomings found in the literature. This would enable more accurate and transparent PE and CE calculations, and support the development of new building energy performance assessment methods and smart grid algorithms.

Increasing temporal resolution in greenhouse gas accounting of electricity consumption divided into Scopes 2 and 3: case study of Germany

Article

Full-text available

Oct 2023
INT J LIFE CYCLE ASS

Purpose As renewable energy sources (RES) experience short-term variability, electricity greenhouse gas (GHG) emissions also fluctuate. Increasing temporal resolution in electricity emissions accounting allows capturing these fluctuations. However, existing time-resolved models either neglect indirect impacts, adopt a generation perspective, or are based on non-public country-specific data. We provide an approach for calculating time-resolved GHG emission factors (EFs) of electricity consumption based on open access data for European countries and examine the temporal variability of German EFs. Methods Time-resolved electricity GHG EFs are calculated within the framework of attributional life cycle assessment (LCA) with up to quarter-hourly resolution. The approach involves top-down calculation of annual combustion emissions, validation and scaling of time-resolved electricity generation data, as well as calculation of inland consumption EFs for each interval throughout a year. The EFs are divided by the stages of net generation, consumption by hydro-pumped storage (HPS), and transmission and distribution (T&D) losses, as well as Scopes 2 and 3, enabling GHG Protocol Corporate Standard-compliant reporting. The approach is exemplarily applied to Germany and its transmission system operator zones at quarter-hourly resolution for the years from 2017 to 2020 to investigate the relation between grid mix composition and temporal variability of EFs. Results and discussion The annual average EF of the German consumption mix, encompassing direct and upstream emissions, declined from 499 (2017) to 377 g CO2e/kWh (2020), while quarter-hourly variability increased by 12%. Neglecting upstream emissions and intermediate steps between generation and consumption in Germany in 2020 resulted in an underestimation of 13% on an annual level, while quarter-hourly Scope 3 EFs reached up to 100 g CO2e/kWh. On a sub-national level, annual average EFs varied between 157 g CO2e/kWh (TenneT zone) and 505 g CO2e/kWh (50Hertz zone) in 2020. Temporal variability is the greatest in electricity systems with both fossil-fuel and renewable capacity sufficient to dominate short-term electricity generation. At an advanced level of RES integration, the fluctuations of EFs start declining, as demonstrated by the TenneT case. Conclusion An increased temporal resolution in electricity emissions accounting can enhance a posteriori LCA results’ accuracy during the energy transition phase. The provided EFs link the life cycle-based perspective with time-resolved emissions accounting. With increasing reliance on RES, indirect emissions, including those related to energy storage, will gain in significance. The next step should focus on integrating physical cross-border electricity exchanges to complete the consumption perspective, as well as examining practical implementation to other countries.

Evaluation of solar photovoltaic carport canopy with electric vehicle charging potential

Article

Full-text available

Feb 2023

While sustainable mobility and decarbonization of transportation sector are among the most comprehensive solutions to the problem of climate change, electric vehicles (EV) are becoming increasingly popular as the future mode of transport. In this study, the integration of a solar carport canopy to a potential EV charging station is analyzed using various operating conditions. A detailed analysis has been provided for the carport located in southern Taiwan, Kaohsiung city, where electricity generation, emission impacts, and financial analysis of the solar EV charging station are discussed. The results of a case study showed a potential of 140 MWh/year of solar energy yield, which could provide solar electricity of more than 3000 vehicles per month with 1-h parking time, generating 94% lower total carbon dioxide emission than the electricity produced from traditional grid methods. Taken into account the impact of carbon tax implementation on driver economics, the results demonstrated the viability of such photovoltaic (PV)-based charging stations, particularly for possible higher carbon tax scenarios in the future. The presented results can be implemented on a larger scale, offering guidelines and tools for constructing solar-powered EV charging station infrastructure.

Decarbonization strategies for Switzerland considering embedded greenhouse gas emissions in electricity imports

Article

Full-text available

Jan 2022
ENERG POLICY

Decarbonizing the energy system by electrification of heat and transport is only effective when using low-carbon electricity sources. As many countries such as Switzerland rely on imported electricity to meet their demand, the greenhouse gas (GHG) content of electricity imports must be correctly accounted for. By assuming an average GHG content for each amount imported, impacts of electricity required in peak periods are underestimated because additional (marginal) demand is primarily met with fossil power plants. This study employs a model to capture marginal GHG contents of imported electricity from a direct and indirect (life-cycle) perspective at an hourly resolution. Implications on GHG are explored for various electricity demand and supply scenarios including electrification of heat and transport, large-scale expansion of renewables, and nuclear phase-out. We find that depending on the scenario, the average GHG intensity of consumed electricity may double, while diurnal and seasonal variations are even larger. Nonetheless, results show substantial GHG mitigation of up to 45% with electrification in case of deploying a diversified electricity generation portfolio including photovoltaics and wind. For optimal GHG mitigation, short-term flexibility as provided by hydropower is necessary to manage electricity surpluses. The main challenge, however, surrounds seasonal energy storage including sector coupling.

The use of primary energy factors and CO2 intensities for electricity in the European context - A systematic methodological review and critical evaluation of the contemporary literature

Article

Aug 2021
RENEW SUST ENERG REV

Reaching the European Union's 2030 targets for primary energy use (PE) and CO2 emissions (CE) requires an accurate assessment of how different technologies perform on these two fronts. To calculate the PE and CE associated with the consumption of electricity (e.g. by an electric vehicle or a heat pump) conversion factors (CFs) are required, namely a primary energy factor and a CO2 intensity factor. Previous theoretical work has shown that the calculation and use of CFs is a contentious and multifaceted issue, but a review of the actual practice in academic literature has so far been missing. 110 recent studies have been systematically reviewed across six methodological aspects, to find that 75% of the studies consider only a single country, 79% apply a purely retrospective perspective, 66% apply a yearly temporal resolution, 75% apply a purely operational (instead of a life-cycle) perspective, 85% make use of average (rather than marginal) CFs, and 77% ignore electricity imports from surrounding countries. Future research in which CFs are used should more carefully consider each of these methodological aspects and explicitly justify the choices that are being made on this front. There is also a strong need in the literature for a publicly available and methodologically transparent database of up-to-date CFs, which would not only enable more accurate and transparent PE and CE calculations, but also support the further development of building energy performance assessment methods and smart grid algorithms.

Dynamic life cycle assessment of European electricity generation based on a retrospective approach

Article

Full-text available

Jul 2024
ENERG CONVERS MANAGE

The composition of electricity varies significantly throughout the year. As a result, the environmental impact of the electricity mix is also highly variable. However, most LCA studies assume a static annual average electricity mix and neglect these fluctuations. Therefore, this study examines the time-varying environmental impacts of electricity generation in Germany, France, Italy, Spain, and Poland using a dynamic life cycle assessment. It shows that the impacts of environmental categories vary considerably depending on when the electricity is generated, resulting from the different energy generation patterns throughout the day and year. In particular, the integration of renewable energy sources such as photovoltaic systems and wind turbines leads to significant fluctuations of environmental impacts. To determine the magnitude of the variation, coefficients of variation are calculated for each environmental impact category for a representative year. High coefficients of variation of more than 20% can be observed for several environmental impact categories. In addition, both a production-based and a consumption-based approach were used for the dynamic life cycle assessment. Comparing these two approaches shows significant differences in impact category results, for example, for Italy, with an average of 15%. These differences highlight the importance of including cross-border electricity flows in assessing the environmental profile of electricity. Overall, the results of the study emphasize the need to implement dynamic electricity mix models in life cycle assessments, especially for systems with time-varying electricity consumption. The provided Excel spreadsheet files with hourly time profiles of environmental impacts for the countries studied facilitate the adoption of the developed models by other practitioners and provide a valuable tool for assessing environmental impacts.

Spatio-temporal electrical grid emission factors effects on calculated GHG emissions of buildings in mixed-grid environments

Article

Full-text available

Jan 2024

This study compares the calculated greenhouse gas (GHG) emissions of buildings using two different methodologies in mixed-grid environments. Simulations were conducted using virtual models of 25 buildings and actual meteorological data over 2016-2018. The "Annual Method" using yearly average emission factors (AEFs) and the "Hourly Method" using consumption-based hourly emission factors (CHEFs) were used to calculate GHG emissions. The study found that the hourly method provided a more accurate representation of GHG emissions, especially during peak grid demand. Furthermore, the study recommends using a zonal approach to building codes in terms of electrical grids similar to climate zones in current codes and standards while also prioritizing building types with the largest potential for emissions reductions. A case study in Ontario, Canada found that electrification via heat pump always results in GHG savings independent of year, building model, and city if keeping the calculation method the same between fuel-switching models. Future research is needed to improve the accuracy of GHG emissions calculations and understand the relationship between electrical load and GHG emissions.

A Quantitative Positive Energy District Definition with Contextual Targets

Article

Full-text available

May 2023

This paper presents the goals and components of a quantitative energy balance assessment framework to define Positive Energy Districts (PEDs) flexibly in three important contexts: the context of the district’s density and local renewable energy supply (RES) potential, the context of a district’s location and induced mobility, and the context of the district’s future environment and its decarbonized energy demand or supply. It starts by introducing the practical goals of this definition approach: achievable, yet sufficiently ambitious, to be inline with Paris 2050 for most urban and rural Austrian district typologies. It goes on to identify the main design parts of the definition—system boundaries, balancing weights, and balance targets—and argues how they can be linked to the definition goals in detail. In particular, we specify three levels of system boundaries and argue their individual necessity: operation, mobility, and embodied energy and emissions. It argues that all three pillars of PEDs, energy efficiency, onsite renewables, and energy flexibility, can be assessed with the single metric of a primary energy balance when using carefully designed, time-dependent conversion factors. Finally, it is discussed how balance targets can be interpreted as information and requirements from the surrounding energy system, which we identify as a “context factor”. Three examples of such context factors, each corresponding to the balance target of one of the previously defined system boundaries, operation, mobility, and embodied emissions, are presented: density (as a context for operation), sectoral energy balances and location (as a context for mobility), and an outlook on personal emission budgets (as a context for embodied emissions). Finally, the proposed definition framework is applied to seven distinct district typologies in Austria and discussed in terms of its design goals.

A Quantitative Poisitive Energy District Definition with Contextual Targets

Preprint

Full-text available

Apr 2023

This paper presents the goals and components of a quantitative energy balance assessment framework to define PEDs flexibly in three important contexts: the context of the district's density and RES potential, the context of a district's location, induced mobility and the context of the dis-trict's future environment and its decarbonized energy demand or supply. It starts by introducing the practical goals of this definition approach: achievable, yet sufficiently ambitious to be inline with Paris 2050 for most urban and rural Austrian district typologies. It goes on to identify the main design parts of the definition: system boundaries, balancing weights and balance targets and argue how they can be linked to the definition goals in detail. In particular we specify three levels of system boundaries and argue their individual necessity: operation, including everyday mobili-ty, including embodied energy and emissions. It argues that all three pillars of PEDs, energy effi-ciency, onsite renewables and energy flexibility can be assessed with the single metric of a prima-ry energy balance when using carefully designed, time-dependent conversion factors. Finally, it is discussed how balance targets can be interpreted as information and requirements from the sur-rounding energy system, which we identify as a "context factor". Three examples of such context factors, each corresponding to the balance target of one of the previously defined system bounda-ries operation, mobility and embodied emissions are presented: Density (as a context of opera-tion), sectoral energy balances and location (as a context for mobility) and an outlook of a person-al emission budgets (as a context for embodied emissions). Finally, the proposed definition framework is applied to seven distinct district typologies in Austria and discussed in terms of its design goals.

A Quantitative PED Definition with Contextual Targets

Preprint

Full-text available

Apr 2023

Shaping future low-carbon energy and transportation systems: Digital technologies and applications

Article

Sep 2022

Digitalization and decarbonization are projected to be two major trends in the coming decades. As the already widespread process of digitalization continues to progress, especially in energy and transportation systems, massive data will be produced, and how these data could support and promote decarbonization has become a pressing concern. This paper presents a comprehensive review of digital technologies and their potential applications in low-carbon energy and transportation systems from the perspectives of infrastructure, common mechanisms and algorithms, and system-level impacts, as well as the application of digital technologies to coupled energy and transportation systems with electric vehicles. This paper also identifies corresponding challenges and future research directions, such as in the field of blockchain, digital twin, vehicle-to-grid, low-carbon computing, and data security and privacy, especially in the context of integrated energy and transportation systems.

Impact Landscapes: Supporting the Interpretation and Communication of Life Cycle Assessments with Interactive Voronoi Treemaps

Thesis

Full-text available

Jun 2022

Martijn Scheve

In recent years, the relevance of sustainable decision-making has continuously increased in solving society’s environmental challenges. Such decision-making should take a facts-based life cycle perspective to prevent burden-shifting and effectively tackle these challenges. Life Cycle Assessment (LCA) is an internationally standardized four-phase framework that aims to facilitate this by quantifying sustainability via various environmental impact indicators. While LCA has seen increased adoption since the 1990s, the visualization of its results does often not capture the complex underlying hierarchical structure and has predominantly been geared towards LCA experts. Consequently, LCA results are often hard to understand for, and communicate to, non-LCA experts like policy and decision-makers. Therefore, this thesis aims to answer how the hierarchical decomposition of LCA results, called contribution trees, can be visualized to support sustainable decision-making by improving interpretability and communication to a broader range of stakeholders? Munzner's (2014) four-level nested model for visualization design was followed to answer this question. Six expert interviews were conducted to demarcate the LCA domain situation and create a data and task abstraction that formed the basis for the visualization design. It was determined that contribution trees are hierarchical network/tree data used to explore, present, and identify extremes, i.e., environmental hotspots, and compare distributions, i.e., impacts of whole product systems. Ultimately, an interactive visualization system was designed. The system, named Impact Landscapes, is based on Voronoi treemaps that resemble aerial views of agricultural fields. It was released under the Mozilla Public License 2.0 to match the licensing of openLCA, the open-source LCA software that was used during parts of Impact Landscapes’ development. Furthermore, the system was implemented as a single web page application and validated through five user tests. They revealed that Impact Landscapes succeeded in answering the main research question while also revealing several potential areas of improvement. Among other identified directions, future research could focus on implementing these improvements while expanding the design process with more comprehensive validation. A live demo version of Impact Landscapes is hosted at: https://mscheve.github.io/ImpactLandscapes/

Hourly marginal electricity mixes and their relevance for assessing the environmental performance of installations with variable load or power

Article

Full-text available

Jun 2022
SCI TOTAL ENVIRON

The ongoing energy transition is causing rapid changes in the electricity system and, in consequence, the environmental impacts associated with electricity generation. In parallel, the daily variability of generation increases with higher shares of renewable energies. This affects the potential environmental impacts or benefits of devices with variable load or power, such as electric vehicles, storage systems or photovoltaic home systems. However, recent environmental assessments of the actual benefit of such systems are scarce, with existing assessments majorly using average grid mixes that are frequently outdated and disregard the dynamic nature of renewable generation. This article provides detailed hourly average and marginal electricity mixes for each month of the year, determined for Spain as an illustrative country with a diversified (renewable) power generation portfolio that experienced a rapid change in the last years. These are combined with specific life-cycle emission factors for each generation technology. Main drivers for the impacts of the marginal mix turn out to be natural gas plants and imports, but also pumped hydropower due to its comparably low storage efficiency. Applied to a hypothetical photovoltaic rooftop installation, the differences between environmental assessments on hourly and on annual basis are found to be surprisingly low when assuming that the generated electricity replaces the average grid mix, but substantial when considering the marginal generation mix (i.e., the generation technologies that respond to a change in demand at a given time). This highlights the importance of considering the dynamics of the electricity system and the corresponding marginal electricity mixes when optimizing flexible load or generation technologies under environmental aspects.

Visual tool for sustainable buildings: A design approach with various data visualisation techniques

Article

Jun 2022

To tackle sustainability, the building sector has to take into account the life cycle impacts of buildings. However, due to the complexity of life cycle assessment (LCA) and life cycle costing (LCC), architects still have a huge hurdle to integrate LCA and LCC in their design processes and even more in the first design stage where the most important decisions are taken. To overcome the complexity, this research aims to develop a comprehensive visual approach in line with an architectural design process. Firstly, environmental impacts are translated into cost so that they can be integrated with financial cost in a life cycle costing approach. Secondly, various visualisations of this single unit result are selected, and a visual approach is elaborated, which supports an integration of life cycle approach in a design process. This paper demonstrates via a theoretical simplified case of dwellings in the Belgian context how the approach can support making more desirable design decisions. The proposed approach with a combined use of visualisations can be expected to enable architects integrating LCA and LCC results in their design loop thinking and easily overview the effect of their design decisions for sustainable dwellings.

Time-evolution and forecasting of environmental and energy performance of electricity production system at national and at bidding zone level

Article

Aug 2022
ENERG CONVERS MANAGE

The electricity generation system has faced exceptional change lately because of several aspects: the electrification of heating and transport sectors, the spread of distributed energy generation, and the increase of renewable share in the electricity production mix. All these factors have contributed to exacerbate the variability of power system operation. This work aims to present hourly data analysis of the electricity production (from fossil fuels and renewables) at the country level (Italy) and at the bidding zone level in the period 2015–2019. Based on different time-resolution, several datasets have been examined and a reproducible method has been defined to overcome the temporal resolution misalignment. Subsequently, the data has been used to define and calculate the time-dependent energy efficiency and environmental indicators for the electricity system with an hourly timestep both for Italy and related bidding zones. The results have demonstrated that these parameters are extremely variable year by year and hour by hour both at the national and bidding zones level. For example, one of the analysed energy efficiency indicators referred to Italy ranges from 0.4 in the hours in which the renewable share is lower than 10% to 1.8 when the renewable share reaches 80%. At the bidding zone level, the electric efficiency indicators, and carbon dioxide emission factor for electricity show a pattern depending on the specific electricity production mix in each zone evidencing a great difference compared to outcomes related to the whole of Italy. The findings of this work evidence the need of accurate knowledge of these operational indexes in the evaluation of electric-driven energy conversion systems performance, energy planning, and in the improvements of electricity market efficiency.

Life cycle assessment of a residential building in China accounting for spatial and temporal variations of electricity production

Article

Apr 2022

Life cycle assessment (LCA) is widely used to reduce a building's environmental impacts in the design phase. Buildings consume a lot of electricity, and heat pumps are often proposed as a way to reduce greenhouse gases emissions. The electricity production mix is therefore an important aspect in building's LCA. Many studies use a static national average mix, ignoring its variations in space and time. This might be questioned in a large country undergoing energy transition such as China. A comprehensive study on this topic for China is lacking, therefore this article aims at filling this gap by investigating how the variations of the energy mix at spatial (five regions in five climate zones) and temporal (four future energy mix scenarios) scales influence the LCA results. A model is proposed to evaluate local future energy mixes. The life cycle inventory (LCI) database was contextualised considering different local energy mixes. Environmental impacts calculated using the local energy mixes and the national average energy mix were compared in the static approach and the dynamic approach (future scenarios are considered) for a residential building. The results indicated that using a national average mix instead of a local mix in the static approach brought non-negligible differences for most provinces, e.g. the overestimation of global warming potential (GWP) reached 500% in Yunnan. Similarly, differences between the static and dynamic approaches are large for most environmental impact indicators, e.g. the difference in GWP could reach around 900% in Guangdong. The differences highly depend on the prospective future scenarios and showed regional features. This paper highlights the importance of the choice of energy mix in buildings' LCA in China regarding both spatial and temporal scales, which is beneficial for more reasonable decisions.

Hourly accounting of carbon emissions from electricity consumption

Article

Full-text available

Apr 2022
ENVIRON RES LETT

Carbon accounting is important for quantifying the sources of greenhouse gas (GHG) emissions that are driving climate change, and is increasingly being used to guide policy, investment, business, and regulatory decisions. The current practice for accounting emissions from consumed electricity, guided by standards like the GHG Protocol, uses annual-average grid emission factors, although previous studies have shown that grid carbon intensity varies across seasons and hours of the day. Previous case studies have shown that annual-average carbon accounting can bias emission inventories, but none have shown that this bias is substantial or widespread. This study addresses this gap by calculating emission inventories for thousands of residential, commercial, industrial, and agricultural facilities across the U.S., and explores the magnitude and direction of this bias compared to hourly accounting of emissions. Our results show that annual-average accounting can over- or under-estimate carbon inventories as much as 35% in certain settings but result in effectively no bias in others. Bias will be greater in regions with high variation in carbon intensity, and for end-users with high variation in their electricity consumption across hours and seasons. As variation in carbon intensity continues to grow with growing shares of variable and intermittent renewable generation, these biases will only continue to worsen in the future. In most cases, using monthly-average emission factors does not substantially reduce bias compared to annual averages. Thus, the authors recommend that hourly accounting be adopted as the best practice for emissions inventories of consumed electricity.

Modelling long-term and short-term temporal variation and uncertainty of electricity production in the life cycle assessment of Buildings

Article

Nov 2021
APPL ENERG

The building stock is a major contributor to energy consumption and greenhouse gases emissions (GHG), which can be evaluated using life cycle assessment (LCA). Electrification of buildings, e.g. replacing fuel and gas boilers with heat pumps, in order to reduce these emissions is often seen as an option, but this will have short term effects by increasing peak demand, and long term effects by requiring more electricity production capacities. In this paper, a methodology to account for such interaction in LCA is presented. It connects three models addressing: market allocation on a national scale over a long term period, short term variation (i.e. seasonal, daily and hourly) of the electricity mix also on a national scale, and building energy simulation at the scale of one building. This methodology has been applied to a case study including a sample of buildings in the French context, but it can be used in other countries. Six buildings have been studied over 100 years considering 50 energy transition scenarios. Results show that the environmental impacts vary more depending on the scenarios than on the types of the building. Marginal mixes considered in consequential LCA are mainly composed of coal, gas, nuclear and peak technology production which explains the highest values of the different impacts compared to average mixes used in attributional LCA. This approach allows to address uncertainties related to electricity production.

Enerji Verimli Bina Tasarımı için Yapay Sinir Ağları ile Isıtma Soğutma Yükünün Belirlenmesi

Article

Full-text available

Oct 2021

Binalar tüketilen enerjinin yaklaşık %40’ından sorumludur. Binaların konfor koşulları gözetilerek, ihtiyaç duyacağı enerji talebinin karşılanması önemlidir. Tasarım sürecinde alınan kararlar, binaların enerji verimliliği düzeylerini etkilemektedir. Enerji simülasyon programlarının çoğu zaman alıcı yöntemler içermektedir. Daha hızlı çözüm yöntemlerine duyulan ihtiyaç bağlamında, binaların ısıtma ve soğutma yüklerinin yapay sinir ağları tabanlı yöntemlerle modellenerek enerji verimliliğinin arttırılması amaçlanmıştır. Literatürden elde edilen, binaların duvar ve çatı alanları ile toplam yükseklik, yönelim, cam yüzeylerin alanı ve dağılımı parametrelerinden oluşan 768 veri seti, eğitim ve test olmak üzere iki parçaya ayrılmış, yapay sinir ağları ile ısıtma ve soğutma yüklerinin hesabı için iki ayrı model oluşturulmuştur. Isıtma ve soğutma yüklerinin enerji talebini belirlemek için geliştirilen modellerin R performans değeri sırasıyla 0,99 ve 0,99 olarak tespit edilmiştir. Yapay sinir ağları tabanlı modelin, binalarda ısıtma ve soğutma yükü için ihtiyaç duyulan enerji talebinin hesaplanmasında simülasyon programları yerine kullanılabileceği göstermektedir.

Life Cycle Assessment of Electricity Generation: a systematic review of spatiotemporal methods

Article

Full-text available

Jul 2021

Life cycle assessments (LCAs) of electricity generation are increasingly incorporating more granular spatial and temporal information, enhancing the accuracy of both inventories and results. This systematic review determined contributions to LCA that improved spatial, temporal, or spatiotemporal resolution from 2009-2018. We analyzed 251 articles screened from an initial review of 6,519 to identify such contributions and determine areas in need of research. The geographic focus of the studies leans towards Europe, Asia, and North America, suggesting many regions remain understudied. As the impact categories were heavily weighted towards greenhouse gas emissions, the impacts that may benefit most from more granular analyses reflecting local environmental conditions were less studied (e.g., land use and eutrophication). While studies tend to focus more on spatial rather than temporal information, those that examine the most granular spatial and temporal scales (for this review, site and hourly) can result in more effective interventions that improve both environmental and economic outcomes. The two most common analysis tools used in the screened articles were optimization and Geographic Information Systems. The increasing use of these tools supported diverse improvements in LCA, such as more detailed investigations of grid interactions, enhanced characterization of impacts, and improved evaluation of resource availability. Analyses conducted at more refined spatiotemporal resolutions can provide more realistic representations of electricity generation, grid operations, and environmental impacts, supporting more effective interventions.

Réduction des émissions de gaz à effet de serre générée par un incrément de puissance de 1 MW du parc éolien domestique

Technical Report

Full-text available

Nov 2020

Soucieux de mieux connaitre l’impact d’une capacité domestique de 1 MW éolien sur les importations d’électricité et l’empreinte carbone du mix de consommation électrique suisse, l’Office Fédéral de l’Énergie a mandaté l’UNIGE afin de quantifier l’impact du développement de l’énergie éolienne sur la réduction des besoins d’électricité́ importée, et ainsi valoriser les gains environnementaux qui en résultent. L’objet du présent rapport est de quantifier des économies de carbone liées à un incrément de puissance de la production éolienne domestique. Pour ce faire, ce rapport examine l’impact d’une capacité de 1MW sur les besoins d’importations et le mix de production domestique. De cet examen, les émissions de carbone adossées sont évaluées. Ainsi, pour une production de 1842 MWh issue d’une capacité de 1MW, la production permettrait une réduction de 698t CO2-eq/an, soit l’équivalent 378 g CO2-eq/kWh, un chiffre très proche des émissions induites par la production d’une centrale de production d’électricité au gaz (CCGT) de dernière génération. A noter que l’impact environnemental de ce 1 MW éolien incrémental ne peut pas être appliqué de manière linéaire à une capacité de plus grande importance, car ceci nécessiterait un examen des interactions au niveau des imports/exports d’électricité.

Emissions of electric vehicle charging in future scenarios: The effects of time of charging

Article

Full-text available

May 2021
J IND ECOL

Electrification of transport is an important option to reduce greenhouse gas emissions. Although many studies have analyzed emission implications of electric vehicle charging, time‐specific emission effects of charging are inadequately understood. Here, we combine climate protection scenarios for Europe for the year 2050, detailed power system simulation at hourly time steps, and life cycle assessment of electricity in order to explore the influence of time on the greenhouse gas emissions associated with electric vehicle charging for representative days. We consider both average and short‐term marginal emissions. We find that the mix of electricity generation technologies, and thus, also the emissions of charging, vary appreciably across the 24‐h day. In our estimates for Europe for 2050, an assumed day‐charging regime yields one‐third‐to‐one‐half lower average emissions than an assumed night‐charging regime. This is owing to high fractions of solar PV in the electricity mix during daytime and more reliance on natural gas electricity in the late evening and night. The effect is stronger during summer months than during winter months, with day charging causing one‐half‐to‐two‐thirds lower emissions than night charging during summer. Also, when short‐term marginal electricity is assumed, emissions tend to be lower with day charging because of contributions from nuclear electricity during the day. However, the results for short‐term marginal electricity have high uncertainty. Overall, our results suggest a need for electric vehicle charging policies and emission assessments to take into consideration variations in electricity mixes and time profiles of vehicle charging over the 24‐h day.

Assessment models and dynamic variables for dynamic life cycle assessment of buildings: a review

Article

Full-text available

Jun 2021
ENVIRON SCI POLLUT R

Life cycle assessment (LCA) is widely used to quantify the environmental performance of buildings. Recently, the potential temporal variations in the lifetime of buildings and their influences on assessment results have attracted considerable attention. Dynamic LCA (DLCA) is an emerging research topic. This study provides an overview of the current scenario of DLCA studies in the building field. A literature survey was conducted by searching through scientific literature databases; 48 articles met the inclusion criteria. Eleven dynamic variables as well as their addressing approaches were summarized and analyzed. A few typical dynamic assessment models were synthesized and compared to present the methodology progress. Finally, considering the existing limitations, a few research directions were recommended: setting cutoff criteria for dynamic variables, developing a dynamic database, and considering the interactions between dynamic variables. The analyses in this study indicate that research on the DLCA of buildings needs interdisciplinary cooperation. This review promotes in-depth understanding about DLCA research of buildings and offers valuable implications for environmental practice. The highlighted future research directions facilitate further explorations in this research area.

Clustering dark energy imprints on cosmological observables of the gravitational field

Article

Dec 2020
MON NOT R ASTRON SOC

We study cosmological observables on the past light-cone of a fixed observer in the context of clustering dark energy. We focus on observables that probe the gravitational field directly, namely the integrated Sachs–Wolfe and non-linear Rees–Sciama effect (ISW-RS), weak gravitational lensing, gravitational redshift, and Shapiro time delay. With our purpose-built N-body code ‘k-evolution’ that tracks the coupled evolution of dark matter particles and the dark energy field, we are able to study the regime of low speed of sound cs where dark energy perturbations can become quite large. Using ray tracing, we produce two-dimensional sky maps for each effect and we compute their angular power spectra. It turns out that the ISW-RS signal is the most promising probe to constrain clustering dark energy properties coded in

w-c_\mathrm{ s}^2

, as the linear clustering of dark energy would change the angular power spectrum by

{\sim}30{{\ \rm per\ cent}}

at low ℓ when comparing two different speeds of sound for dark energy. Weak gravitational lensing, Shapiro time delay, and gravitational redshift are less sensitive probes of clustering dark energy, showing variations of only a few per cent. The effect of dark energy non-linearities in all the power spectra is negligible at low ℓ, but reaches about

2{{\ \rm per\ cent}}

and

3{{\ \rm per\ cent}}

, respectively, in the convergence and ISW-RS angular power spectra at multipoles of a few hundred when observed at redshift ∼0.85. Future cosmological surveys achieving per cent precision measurements will allow us to probe the clustering of dark energy to a high degree of confidence.

Observing relativistic features in large-scale structure surveys – I: Multipoles of the power spectrum

Article

Full-text available

Dec 2020
MON NOT R ASTRON SOC

Planned efforts to probe the largest observable distance scales in future cosmological surveys are motivated by a desire to detect relic correlations left over from inflation, and the possibility of constraining novel gravitational phenomena beyond General Relativity (GR). On such large scales, the usual Newtonian approaches to modelling summary statistics like the power spectrum and bispectrum are insufficient, and we must consider a fully relativistic and gauge-independent treatment of observables such as galaxy number counts in order to avoid subtle biases, e.g. in the determination of the fNL parameter. In this work, we present an initial application of an analysis pipeline capable of accurately modelling and recovering relativistic spectra and correlation functions. As a proof of concept, we focus on the non-zero dipole of the redshift-space power spectrum that arises in the cross-correlation of different mass bins of dark matter halos, using strictly gauge-independent observable quantities evaluated on the past light cone of a fully relativistic N-body simulation in a redshift bin 1.7 ≤ z ≤ 2.9. We pay particular attention to the correct estimation of power spectrum multipoles, comparing different methods of accounting for complications such as the survey geometry (window function) and evolution/bias effects on the past light cone, and discuss how our results compare with previous attempts at extracting novel GR signatures from relativistic simulations.

Observing relativistic features in large-scale structure surveys -- I: Multipoles of the power spectrum

Preprint

Full-text available

Sep 2020

f_{\rm NL}

parameter. In this work, we present an initial application of an analysis pipeline capable of accurately modelling and recovering relativistic spectra and correlation functions. As a proof of concept, we focus on the non-zero dipole of the redshift-space power spectrum that arises in the cross-correlation of different mass bins of dark matter halos, using strictly gauge-independent observable quantities evaluated on the past light cone of a fully relativistic N-body simulation in a redshift bin

1.7 \le z \le 2.9

. We pay particular attention to the correct estimation of power spectrum multipoles, comparing different methods of accounting for complications such as the survey geometry (window function) and evolution/bias effects on the past light cone, and discuss how our results compare with previous attempts at extracting novel GR signatures from relativistic simulations.

Revealing temporal and spatial variations in CO2 emission factor of electricity generation in Japan

Article

Apr 2025
ENERGY

Environmental, Redistributive and Revenue Effects of Policies Promoting Fuel Efficient and Electric Vehicles

Article

Dec 2024

Dynamic Life Cycle Assessment of Electric Power Dispatch with Different Temporal Precision Levels

Conference Paper

Sep 2024

Applying trade mechanisms to quantify dynamic GHG emissions of electricity consumption in an open economy - The case of Switzerland

Article

Oct 2024
ENERGY

Do Peak Energy Loads and Peak GHG Emissions Correlate in Buildings? Insights from Emission Duration Curves and Emission Event Duration Curves Analysis

Article

Full-text available

May 2024
J CLEAN PROD

This research proposes and applies emission duration curves (EDCs) and emission event duration curves (EEDCs) in a novel way for comprehensive analysis of greenhouse gas (GHG) emissions in correlation with building energy consumption. Examining a 2018 high-rise building in Ottawa, we found a moderate Pearson correlation of 0.3 between hourly energy and GHG emissions, despite a significant p-value. This indicates that peak energy loads and emissions peaks do not necessarily align, underscoring the need for a new operational strategy. The EDC and Load Duration Curve (LDC) patterns further accentuated these differences, suggesting that electrical emissions are more concentrated in specific periods compared to electrical loads. For our case study, 12.04% of yearly GHG emissions occurred within just 1% of the year, contrasting with only 2.14% of the annual energy use. The study also highlighted the potential of a demand response event through a simulated voluntary outage during peak emission intervals as a viable GHG mitigation strategy. Collectively, these insights stress the importance of a comprehensive perspective on building operations, their interactions with the grid, and the necessity for tailored sustainable building management strategies moving forward.

High-resolution electricity generation mixes in building operation: A methodological framework for energy and environmental impacts and the case study of an Italian net zero energy building

Article

Apr 2024
SCI TOTAL ENVIRON

Towards Standardized Grid Emission Factors: Methodological Insights and Best Practices

Article

Full-text available

Jan 2024

Inconsistent calculation of grid emission factors (EF) can result in widely divergent corporate greenhouse gas (GHG) emissions reports. We dissect this issue through a comprehensive literature review, identifying nine key...

A review of dynamic life cycle assessment methods in the field of water and wastewater

Conference Paper

Full-text available

Dec 2023

Mohammadamin Ganji

EcoDynElec: Open Python package to create historical profiles of environmental impacts from regional electricity mixes

Article

Jul 2023

This article presents the EcoDynElec python package that creates temporal historical profiles of various potential environmental impacts for electricity mixes in different regions. The profiles are evaluated with the same electricity modeling structure that is used in life cycle assessment databases, simplifying their consistent combination in studies. The open access information from the ENTSO-E platform is used as an input that enables the creation of profiles that can reach temporal precision of 15 min for the last five years. EcoDynElec is shared to open its use in environmental studies that can be substantially affected by the temporal variability of electricity uses.

Energy-saving mechanisms for evaluating efficiency improvement and losses reduction scenarios in the thermal power plants sector of Iran

Article

May 2023

Comparative Life Cycle Assessment (LCA) on battery electric and combustion engine motorcycles in Taiwan

Article

Apr 2023
J CLEAN PROD

Plus minus zero: carbon dioxide emissions of plus energy buildings in operation under consideration of hourly German carbon dioxide emission factors for past, present and future

Article

Full-text available

Sep 2022

The energy supply of private household buildings accounted for 16 % of the total German CO 2 -emission in 2020. To fulfil the targets of a climate neutral building sector in 2045, both, energy efficiency as well as on-site use of Renewable Energies in buildings are needed. One concept of a climate neutral building is the so-called Efficiency House Plus, that features large photovoltaic systems making it seemingly energy self-sufficient and CO 2 -negative by feeding in more electric energy into the grid than needed for its operation on a yearly basis. In fact, houses of this type are highly grid dependent especially during winter months due to their solely electrically based energy supply and a missing long term energy storage. This paper analyses the CO 2 -emission of Energy Efficiency Plus houses more in detail on a timely resolved basis for the German electric supply system of the year 2013, 2021 and a perspective one 2030. An alternative calculation approach for simplified normative evaluation of such buildings is proposed.

Systematic Literature Review on Dynamic Life Cycle Inventory: Towards Industry 4.0 Applications

Article

Full-text available

May 2022

Life cycle assessment (LCA) is a well-established methodology to quantify the environmental impacts of products, processes, and services. An advanced branch of this methodology, dynamic LCA, is increasingly used to reflect the variation in such potential impacts over time. The most common form of dynamic LCA focuses on the dynamism of the life cycle inventory (LCI) phase, which can be enabled by digital models or sensors for a continuous data collection. We adopt a systematic literature review with the aim to support practitioners looking to apply dynamic LCI, particularly in Industry 4.0 applications. We select 67 publications related to dynamic LCI studies to analyze their goal and scope phase and how the dynamic element is integrated in the studies. We describe and discuss methods and applications for dynamic LCI, particularly those involving continuous data collection. Electricity consumption and/or electricity technology mixes are the most used dynamic components in the LCI, with 39 publications in total. This interest can be explained by variability over time and the relevance of electricity consumption as a driver of environmental impacts. Finally, we highlight eight research gaps that, when successfully addressed, could benefit the diffusion and development of sound dynamic LCI studies.

Effectiveness of building stock sustainability measures in a low-carbon energy system: A scenario analysis for Finland until 2050

Article

Jul 2021
ENERGY

Energy systems are in a state of transition due to national energy and climate policies. The Finnish Government has declared a national target of achieving carbon neutrality by 2035. This will require further reductions in carbon intensity of the Finnish energy generation mix. Some of the energy related emission reductions could simultaneously be achieved through effective energy efficiency measures in the buildings sector. In this paper, the effectiveness of these measures is studied in alternative long-term energy system scenarios with varying CO2 reduction targets for the energy supply sector until 2050. The results show that initial carbon intensity of energy mix has a significant effect on the achievable CO2 emission reductions of demand-side measures. Moreover, assigned system boundaries can significantly affect the results, especially in a low-carbon energy system, where energy savings mostly reduce the use of wood-based biomass in the energy production. Furthermore, long-term perspective for identifying the environmental effects of an energy efficiency measure is recommended, since they often have a long economic lifetime and due to structural changes in the energy system, the marginal energy production unit changes over its lifetime. Consequently, the CO2 emission reduction potential of an energy efficiency measure can vary over its lifetime.

Integrating temporal changes in the Belgian electricity mix in the environmental impact assessment of buildings

Article

Mar 2021
J CLEAN PROD

The operational energy use of buildings contributes significantly to their environmental impact. In most environmental impact assessments, operational energy consumption and associated impacts are kept unchanged throughout the life cycle of the building. In addition to climate change, the energy mix is also changing over the building life cycle and influences the impact of the operational energy use. With the aim for climate neutrality by 2050, electricity will play an important role through the electrification of heating and the expected increase in energy consumption for cooling. The overall aim of this paper is to consider a changing electricity mix in the calculation of the life cycle environmental impact of buildings. This paper focuses on three aspects in particular. First, it analyses future scenarios for the Belgian electricity mix. Next, the environmental impact of each of these mixes is calculated and analysed using the Belgian MMG LCIA method considering a broad set of indicators. Finally, it is investigated how this changing mix over the life cycle of a building can be included in the calculation of the environmental impact of the operational phase of the building and how this influences the overall environmental impact of the operational phase. Within this study, three dynamic scenarios are defined and compared with a static scenario. Differences in the total environmental impact over the life cycle of the building were found between -29% and +34% compared to the static scenario. The importance of a holistic approach is furthermore emphasized, as this can lead to different choices compared to decisions based on climate change solely. In general, a major challenge for the next decade seems to be the phasing out of nuclear power, without increasing the environmental impact of the electricity mix.

Review of visualising LCA results in the design process of buildings

Article

Full-text available

Mar 2021
BUILD ENVIRON

Life Cycle Assessment (LCA) is increasingly used for decision-making in the design process of buildings and neighbourhoods. Therefore, visualisation of LCA results to support interpretation and decision-making becomes more important. The number of building LCA tools and the published literature has increased substantially in recent years. Most of them include some type of visualisation. However, there are currently no clear guidelines and no harmonised way of presenting LCA results. In this paper, we review the current state of the art in vis-ualising LCA results to provide a structured overview. Furthermore, we discuss recent and potential future developments. The review results show a great variety in visualisation options. By matching them with common LCA goals we provide a structured basis for future developments. Case studies combining different kinds of visualisations within the design environment, interactive dashboards, and immersive technologies, such as virtual reality, show a big potential for facilitating the interpretation of LCA results and collaborative design processes. The overview and recommendations presented in this paper provide a basis for future development of intuitive and design-integrated visualisation of LCA results to support decision-making.

The Optimal Reorder Policy in an Inventory System with Spares and Periodic Review

Chapter

Full-text available

Sep 2020

We analyze the window fill rate in an inventory system with constant lead times under a periodic review policy. The window fill rate is the probability that a random customer gets serviced within a predefined time window. It is an extension of the traditional fill rate that takes into account that customers generally tolerate a certain waiting time. We analyze the impact of the reorder-cycle on the window fill rate and present an inventory model that finds the optimal spares allocation and the optimal reorder cycle with the objective of minimizing the total costs. Furthermore, we present a numerical example and find that the number of spares increase almost linearly when the reorder-cycle time increases. Finally, we show how managers can find the optimal spares allocation and the optimal reorder-cycle time and show how they can estimate the cost of changing the required window fill rate and the reorder-cycle time.

Time-Dependent Emission Minimization in Sustainable Flow Shop Scheduling

Chapter

Sep 2020

It is generally accepted that global warming is caused by greenhouse gas emissions. Consequently, ecological aspects, such as emissions, should also be integrated into operative planning. The amount of pollutants emitted strongly depends on the energy mix and thus on the respective time period the energy is used. In this contribution we analyse the influence of fluctuating carbon dioxide emissions on emission minimization in flow shop scheduling. Therefore, we propose a new multi-objective MIP formulation which considers makespan and time-depending carbon dioxide emissions as objectives. Epsilon constraint method is used to solve the problem in a computational study, where we show that emissions can reduced by up to 10% if loads are shifted at times of lower CO2 emissions.

Weak-lensing observables in relativistic N-body simulations

Article

Full-text available

Sep 2020
MON NOT R ASTRON SOC

We present a numerical weak-lensing analysis that is fully relativistic and non-perturbative for the scalar part of the gravitational potential and first order in the vector part, frame dragging. Integrating the photon geodesics backwards from the observer to the emitters, we solve the Sachs optical equations and study in detail the weak-lensing convergence, ellipticity and rotation. For the first time, we apply such an analysis to a high-resolution relativistic N-body simulation, which consistently includes the leading-order corrections due to general relativity on both large and small scales. These are related to the question of gauge choice and to post-Newtonian corrections, respectively. We present the angular power spectra and one-point probability distribution functions for the weak-lensing variables, which we find are broadly in agreement with comparable Newtonian simulations. Our geometric approach, however, is more robust and flexible, and can therefore be applied consistently to non-standard cosmologies and modified theories of gravity.

Studying the Dynamic Relationship between Energy Supply Carbon Content and Building Energy Demand

Conference Paper

Full-text available

Jul 2016

Due to different temporal combinations of energy generation processes, the global warming potential (GWP) of energy supply evolves constantly. Despite this, the greenhouse gas (GHG) emissions related to the energy consumption in buildings are commonly assessed with yearly averaged carbon content of the energy supply. The knowledge of the hourly carbon content of the energy supply, would allow a more realistic assessment of the GHG emissions. Moreover, a temporal relationship between the GWP energy supply and building energy demand for reducing carbon footprint could be addressed. In this study, different methods to evaluate the hourly carbon contents of the on-site available energies are presented. The potential of load shifting for GHG emission mitigation is also investigated. To test the methodology, an application to a case study where the energy is supplied from the electrical grid and on-site renewables is proposed. The chosen case study is the smart living building, currently being designed and expected to be built by 2020 in Fribourg, Switzerland. This study points out significant differences between a yearly average and an hourly dynamic carbon emission assessment. Carbon footprint benefits by load shifting at day scale are found to be very limited in the context of the smart living building.

Life Cycle Inventories of Electricity Mixes and Grid

Technical Report

Full-text available

Jul 2012

Do smart grids offer a new incentive for SME carbon reduction?

Article

Full-text available

Feb 2014

Collectively small and medium sized enterprises (SMEs) are significant energy users although many are unregulated by existing policies due to their low carbon emissions. Carbon reduction is often not a priority but smart grids may create a new opportunity. A smart grid will give electricity suppliers a picture of real-time energy flows and the opportunity for consumers to receive financial incentives for engaging in demand side management. In addition to creating incentives for local carbon reduction, engaging SMEs with smart grids has potential for contributing to wider grid decarbonisation. Modelling of buildings, business activities and technology solutions is needed to identify opportunities for carbon reduction. The diversity of the SME sector complicates strategy development. SMEs are active in almost every business area and occupy the full range of property types. This paper reviews previous modelling work, exposing valuable data on floor space and energy consumption associated with different business activities. Limitations are seen with the age of this data and an inability to distinguish SME energy use. By modelling SME energy use, electrical loads are identified which could be shifted on demand, in a smart network. Initial analysis of consumption, not constrained by existing policies, identifies heating and cooling in retail and commercial offices as having potential for demand response. Hot water in hotel and catering and retail sectors may also be significant because of the energy storage potential. Areas to consider for energy efficiency schemes are also indicated.

EnergyPlus: Creating a New-Generation Building Energy Simulation Program

Article

Full-text available

Apr 2001
ENERG BUILDINGS

Many of the popular building energy simulation programs around the world are reaching maturity — some use simulation methods (and even code) that originated in the 1960s. For more than two decades, the US government supported development of two hourly building energy simulation programs, BLAST and DOE-2. Designed in the days of mainframe computers, expanding their capabilities further has become difficult, time-consuming, and expensive. At the same time, the 30 years have seen significant advances in analysis and computational methods and power — providing an opportunity for significant improvement in these tools.In 1996, a US federal agency began developing a new building energy simulation tool, EnergyPlus, building on development experience with two existing programs: DOE-2 and BLAST. EnergyPlus includes a number of innovative simulation features — such as variable time steps, user-configurable modular systems that are integrated with a heat and mass balance-based zone simulation — and input and output data structures tailored to facilitate third party module and interface development. Other planned simulation capabilities include multizone airflow, and electric power and solar thermal and photovoltaic simulation. Beta testing of EnergyPlus began in late 1999 and the first release is scheduled for early 2001.

Integrating hourly life-cycle energy and carbon emissions of energy supply in buildings

Article

Aug 2018

Huge amount of energy resources greenhouse gas (GHG) emissions is devoted to the built environment. Therefore, an accurate assessment method of these indicators is compulsory. To take advantage of the temporal variation in the primary energy use and associated GHG emissions of the energy supply, we propose two ways of integrating hourly life-cycle conversion factors in building energy systems. First, to appraise the energy system design, we developed a versatile modelling and performance assessment framework using a multi-criteria approach. The simulated performances of possible energy systems are compared, and help designers systematically choose appropriate energy production and storage systems. Second, for the operation of the building, we propose an energy management procedure (EMP) that always feeds in the energy source with the least global warming potential (GWP). These two developments are tested on a case study consisting in an architectural project that should respect the 2000 W society targets. The running conditions of several energy systems are simulated and compared. The most promising scenario is identified. Compared to traditional methods, the assessment framework has a promising future but the GWP-based energy management procedure offers, in the context of the case study, limited GHG emissions mitigation at very high primary energy cost.

A framework for water and carbon footprint analysis of national electricity production scenarios

Article

Jul 2017

While carbon footprint reduction potential and energy security aspects of renewable and non-renewable resources are widely considered in energy policy, their effects on water resources are mostly overlooked. This research aims to develop a framework for water and carbon footprint analysis to estimate the current and future trends of water consumption and withdrawal by electricity production sectors for national energy development plans – alongside carbon emissions from various electricity sources. With this motivation, the Turkish electric power industry is selected as a case study and a decision support tool is developed to determine the water consumption, withdrawal and carbon emissions from energy mixes under three different scenarios, namely Business-As-Usual (BAU), Official Governmental Plan (OGP), and Renewable Energy-Focused Development Plan (REFDP). The results indicate that water is used substantially even by renewable resources, such as hydroelectricity and biomass, which are generally considered to be more environmental friendly than other energy sources. The average water consumption of the OGP energy mix in 2030 is estimated to be about 8.1% and 9.6% less than that of the BAU and REFDP scenarios, respectively. On the other hand, it is found that the water withdrawal of the energy mix in 2030 under the REFDP scenario is about 46.3% and 16.9% less than that of BAU and OGP scenarios. Carbon emissions from BAU are projected to be 24% higher than OGP and 39% higher than REFDP in 2030. Carbon emissions and water usage are strongly correlated in BAU scenario as compared with OGP and REFDP, thus carbon friendly energy sources will result in fewer water consumptions and withdrawals, particularly under REFDP.

Balancing the carbon and water footprints of the Ontario energy mix

Article

Mar 2017

With climate change being the current most pressing environmental issue, clean energy projects are emerging with a focus on reducing our carbon footprint while meeting our energy demands. There are several intersecting challenges surrounding climate change, energy demand, and water scarcity. The movement towards a less carbon-intensive energy supply could result in an increase or decrease in water demand, depending on the choice of technology. Ontario has made great progress in mitigating climate change by phasing out coal from their energy supply mix and further changes are expected over the next decade as the province shifts towards more renewable generation. This shift, however, will significantly increase the amount of water consumed to fuel demand. Carbon and water footprints for Ontario’s energy supply mix, based on present day as well as on future projections, are presented. Cases studies illustrate how these footprints could change in likely, as well as extreme scenarios. Comparisons are also presented for California, where water scarcity is a more urgent concern. These findings stress the need for a balance between our water usage and carbon footprint and for a nexus approach to be in place to ensure a sustainable relationship between energy and water resources.

Coupling of cleaner production with a day-ahead electricity market: A hypothetical case study

Article

Dec 2016
J CLEAN PROD

During the last 25 years day-ahead electricity markets are continuously expanding and the amount of energy being traded through them is increasing. Moreover, there is a possibility for production facilities to act directly on a day-ahead market as independent market players. The aim of this paper is to analyse the potential for reduction of variable costs of an arbitrary production facility consisting of high-efficient combined heat and power (CHP), grid connection and production unit, thermal and products storage and photovoltaic (PV) panels. Costs are reduced by offsetting the expensive electricity with the use of thermal and products storage and optimization of power flows. Variable costs are, together with the costs of a raw material, directly related to input costs of energy in the form of a fossil fuel derivatives and/or electricity. Two hypothetical cases will be analysed: (1) production facility with installed PV acting as a prosumer and (2) production facility without the installed PV acting only as a consumer from the market point of view. Mathematical model consists of two sub-models which are solved in a coupled manner: the optimization of cost-reduction by retaining the output product distribution and model for obtaining the day-ahead market clearing price of electricity. The results show that coupling of market modelling with optimization of running costs for an arbitrary production facility can be used for estimation of market clearing price and optimization of power flows within the production facility.

Optimisation of costs and carbon savings in relation to the economic dispatch problem as associated with power system operation

Article

Nov 2016
ELECTR POW SYST RES

In this paper, the costs and carbon savings in the economic dispatch (ED) problem of the power system operation are optimised. Energy demands and generation are forecast and assimilated using ensemble Kalman filter (EnKF). Optimisation is performed using the ensemble-based closed-loop production optimisation scheme (EnOpt). The real energy parameters of thermal units with green generators (wind farm) are used to test the methodology. The ability of the EnKF to predict, and the robustness of the EnOpt to optimise costs and the resultant carbon emissions are demonstrated. The proposed approach addresses the complexity and diversity of the power system and may be implemented in operational conditions of energy suppliers.

Overview and methodology

Article

Jan 2007

Entwicklung der spezifischen Kohlendioxid-Emissionen des deutschen Strommix in den Jahren 1990 bis 2013

Article

Jan 2014

Peter Ichavida Icha

Accounting for temporal variation of electricity production and consumption in the LCA of an energy-efficient house

Article

Dec 2015
J CLEAN PROD

The development of on-site renewable energy production and demand management in buildings calls for a deeper understanding of the interaction between building operation and the electricity grid. Electricity consumption in buildings varies in terms of seasons (heating and cooling), day of the week (professional activities) and hour of the day, which is also the case of on-site electricity production (e.g. photovoltaic systems). Centralised electricity production varies as well according to the demand (e.g. during peak hours). This research aims at improving the evaluation of potential environmental impacts of an energy efficient house attributable to electricity consumption and production by taking into account the temporal variation of the electricity production. Electricity end-uses and on-site electricity production were evaluated on an hourly basis in the case of an energy-efficient house. Another objective was to investigate the sources of errors in the assessment. Life cycle assessment was used to evaluate potential environmental impacts based on electricity production data for the year 2013 in France. Results were compared using an annual average electricity supply mix versus hourly data. This case study demonstrates that the use of an annual average mix instead of hourly mix data can lead to underestimation of potential impacts up to 39% for Abiotic Depletion Potential (ADP) and 36% for Global warming potential (GWP) when combining all end-uses. Increase of GWP and ADP when using hourly mix data is mainly explained by higher share of coal and gas power plant in the electricity mix in winter. This coincides with a higher electricity consumption of the studied house in this season due to space heating, electric back-up of the solar water heating system and a lower onsite production (photovoltaic system).

Hourly-Based Greenhouse Gas Emissions of Electricity Possibilities for Households and Companies to Decrease Their Emissions

Article

Jan 2014

The various emissions, including GHG emissions, from electricity production are a crucial part of environmental impact assessments of any kinds of products, services and consumption. Usually average annual emissions are used, but electricity market has lately increased interest in daily-based and hourly-based emission coefficients for electricity. In such markets, where technology mixture of the production includes technologies with widely different emission factors, there is potential for large variation in hourly based emission factors and consequently this offers potential for decreasing GHG emissions by efficient real-time based demand management. In this paper, we determine hourly based GHG emission factors and give examples how GHG emissions may be decreased in households and companies by changing the use patterns, and consequently timing of electricity use, the total amount of electricity consumption being unchanged. Electricity production in Finland, as well as the electricity consumption in Finnish households and companies are used as the cases. The examples from households and companies indicate the potential of managing hourly based demand loads and resulting GHG emissions. So far hourly-based emission coefficients have not been used (at least in significant amounts) in demand management in order to reduce emissions and mitigate climate change.

Increasing Precision in Greenhouse Gas Accounting Using Real-Time Emission Factors: A Case Study of Electricity in Spain

Article

Oct 2014
J IND ECOL

For many companies, the greenhouse gas (GHG) emissions associated with their purchased and consumed electricity form one of the largest contributions to the GHG emissions that result from their activities. Currently, hourly variations in electricity grid emissions are not considered by standard GHG accounting protocols, which apply a national grid emission factor (EF), potentially resulting in erred estimates for the GHG emissions. In this study, a method is developed that calculates GHG emissions based on real-time data, and it is shown that the use of hourly electricity grid EFs can significantly improve the accuracy of the GHG emissions that are attributed to the purchased and consumed electricity of a company. A model analysis for the electricity delivered to the Spanish grid in 2012 reveals that, for companies operating during the day, GHG emissions calculated by the real-time method are estimated to be up to 5% higher (and in some special cases up to 9% higher) than the emissions calculated by the conventional method in which a national grid EF is applied, whereas for companies operating during nightly hours, GHG emissions are estimated to be as low as 3% below the GHG emissions determined by the conventional method. A significant error can therefore occur in the organizational carbon footprint (CF) of a company and, consequently, also in the product CF. It is recommended that hourly EFs be developed for other countries and power grids.

The hourly life cycle carbon footprint of electricity generation in Belgium, bringing a temporal resolution in life cycle assessment

Article

Dec 2014
APPL ENERG

Need for an embodied energy measurement protocol for buildings: A review paper

Article

Aug 2012
RENEW SUST ENERG REV

Carbon and environmental footprinting of low carbon UK electricity futures to 2050

Article

Dec 2012

Electricity generation contributes a large proportion of the total greenhouse gas emissions in the United Kingdom (UK), due to the predominant use of fossil fuel (coal and natural gas) combustion for this purpose. A range of future UK energy scenarios has been employed to determine their resulting environmental and carbon footprints. Methodologies have been established to calculate these footprints for the UK electricity supply industry on both a historic timescale and in accordance with the three selected scenarios. The latter scenarios, developed by the UK SUPERGEN Consortium on ‘Highly Distributed Power Systems’ (HDPS), were characterised as ‘Business As Usual’ (BAU), ‘Low Carbon’ (LC) and ‘Deep Green’ (DG) futures, and yielded possible electricity demands out to 2050. It was found that the environmental footprint of the current power network is 41 million (M) global hectares (gha). If future trends follow a ‘Business As Usual’ scenario, then this footprint is observed to fall to about 25 Mgha in 2050. The LC scenario implies an extensive penetration of micro-generators in the home to satisfy heat and power demands. However, these energy requirements are minimised by way of improved insulation of the building fabric and other demand reduction measures. In contrast, the DG scenario presupposes a network where centralised renewable energy technologies – mainly large-scale onshore and offshore wind turbines - have an important role in the power generation. However, both the LC and DG scenarios were found to lead to footprints of less than 4 Mgha by 2050. These latter two scenarios were found to give rise to quite similar trajectories over the period 2010–2050. They are therefore more likely to reflect an effective transition pathway in terms of meeting the 2050 UK CO2 reduction targets associated with decarbonisation of its power network. However, this appears unlikely to be achieved by 2030–2040 as advocated by the UK Government's advisory Committee on Climate Change in order to meet overall national carbon reduction targets.

Greenhouse gas emission mitigation in the Sri Lanka power sector supply side and demand side options

Article

Dec 2003
ENERG CONVERS MANAGE

Sri Lanka has had a hydropower dominated electricity generation sector for many years with a gradually decreasing percentage contribution from hydroresources. At the same time, the thermal generation share has been increasing over the years. Therefore, the expected fuel mix in the future in the large scale thermal generation system would be dominated by petroleum products and coal. This will result in a gradual increase in greenhouse gas (GHG) and other environmental emissions in the power sector and, hence, require special attention to possible mitigation measures.This paper analyses both the supply side and demand side (DSM) options available in the Sri Lanka power sector in mitigating emissions in the sector considering the technical feasibility and potential of such options. Further, the paper examines the carbon abatement costs associated with such supply side and DSM interventions using an integrated resource planning model, which is not used in Sri Lanka at present. The sensitivities of the final generation costs and emissions to different input parameters, such as discount rates, fuel prices and capital costs, are also presented in the paper. It is concluded that while some DSM measures are economically attractive as mitigation measures, all the supply side options have a relatively high cost of mitigation, particularly in the context of GHG emission mitigation. Further it is observed that when compared with the projected price of carbon under different global carbon trading scenarios, these supply side options cannot provide economically beneficial CO2 mitigation in countries like Sri Lanka.

The complexity and challenges of determining GHG (greenhouse gas) emissions from grid electricity consumption and conservation in LCA (life cycle assessment) - A methodological review

Article

Dec 2011

The way in which GHG (greenhouse gas) emissions associated with grid electricity consumption is handled in different LCA (life cycle assessment) studies, varies significantly. Apart from differences in actual research questions, methodological choices and data set selection have a significant impact on the outcomes. These inconsistencies result in difficulties to compare the findings of various LCA studies. This review paper explores the issue from a methodological point of view. The perspectives of ALCA (attributional life cycle assessment) and CLCA (consequential life cycle assessment) are reflected. Finally, the paper summarizes the key issues and provides suggestions on the way forward. The major challenge related to both of the LCA categories is to determine the GHG emissions of the power production technologies under consideration. Furthermore, the specific challenge in ALCA is to determine the appropriate electricity production mix, and in CLCA, to identify the marginal technologies affected and related consequences. Significant uncertainties are involved, particularly in future-related LCAs, and these should not be ignored. Harmonization of the methods and data sets for various purposes is suggested, acknowledging that selections might be subjective.

mix are impacted by 6.4 %; 17.8% and 2.0 % respectively for France, Austria, 475 and Germany. Finally, when taking into account these values when assessing the Swiss mix

Austrian French

French, Austrian, and German mix are impacted by 6.4 %; 17.8% and 2.0 % respectively for France, Austria, 475 and Germany. Finally, when taking into account these values when assessing the Swiss mix, the results is

The least accurate assessment is the one of the Austrian grid which 480 exhibits a high amount of electricity imports and important daily variations (See Fig. 7). It seems easier to 481 improve the hourly CFs assessment accuracy by integrating in the surrounding countries an hourly description of

German Mix

German mix (See CV factors in Table 2-4). The least accurate assessment is the one of the Austrian grid which 480 exhibits a high amount of electricity imports and important daily variations (See Fig. 7). It seems easier to 481 improve the hourly CFs assessment accuracy by integrating in the surrounding countries an hourly description of

Electricity-generation technology-specific emission factors for the lignite, coal, and gas depending on 510 different source of data. Black squares show the data from the KBOB database

Jan 2017

Friedli

Figure 9: Electricity-generation technology-specific emission factors for the lignite, coal, and gas depending on 510 different source of data. Black squares show the data from the KBOB database (Friedli et al., 2014); open circles 511 shows data used by the German government (Icha, 2017)' and the rectangular box shows the span of data from a 512 wide literature screening (Koffi et al., 2017).

the proposed method with the data 519 at disposal provides substantially higher results (see Table 5). The differences obtained between the annual 520 assessments performed in the frame of the present study and the KBOB database are smaller but still positive for 521 energies

Jan 2014

Friedli

It is a bit more problematic to judge the robustness of the obtained results when dealing with a sample of data 516 instead of the full amount of a given domestic production of electricity. Regarding the Swiss grid in particular, 517 when an energy-weighted annual average based on hourly data  p,y GHG is assessed for the Swiss mix, and is 518 compared with the data provided by the KBOB database (Friedli et al., 2014), the proposed method with the data 519 at disposal provides substantially higher results (see Table 5). The differences obtained between the annual 520 assessments performed in the frame of the present study and the KBOB database are smaller but still positive for 521 energies (+5.3% for CED; +8.5% for CEDnr) than for the GHG emissions.

Base Carbone V11.0, documentation des facteurs d'émission de la Base Carbone

Jan 2016
1-280

ADEME, 2016. Base Carbone V11.0, documentation des facteurs d'émission de la Base Carbone. 1-280.

ILCD International Reference Life Cycle Data System (ILCD) Handbook

Jan 2010

European Commission, 2010. ILCD International Reference Life Cycle Data System (ILCD) Handbook

Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth 710 Assessment Report of the Intergovernmental Panel on Climate Change

Jan 2013
1-1535

IPCC, 2013. Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth 710 Assessment Report of the Intergovernmental Panel on Climate Change Cambridge University Press, Cambridge, 711 United Kingdom and New York, NY, USA, 1-1535.

Step towards a sustainable development: A white book for R&D of energy-efficient

Jan 2004

M Zimmermann

Zimmermann M. 2004. Step towards a sustainable development: A white book for R&D of energy-efficient

Covenant of mayors for 727 climate and energy: default emission factors for local emission inventories

Jan 2017
1-53

B Koffi
A K Cerutti
M Duer
A Iancu
A Kona
G Janssens-Maenhour

Koffi, B., Cerutti, A.K., Duer, M., Iancu, A., Kona, A, Janssens-Maenhour, G., 2017.Covenant of mayors for 727 climate and energy: default emission factors for local emission inventories. European union, Luxembourg, 1-53.

Description of climate impact calculation methods of 734 the CO2e signal for the Active house project

Jan 2013
1-23

A R Kristinsdóttir
P Stoll
A Nilsson
N Brandt

Kristinsdóttir, A. R., Stoll, P., Nilsson, A., Brandt, N., 2013. Description of climate impact calculation methods of 734 the CO2e signal for the Active house project. KTH Royal Institute of Technology, 1-23.

Aperçu énergétique Suisse

Jan 2015

Swissgrid

Swissgrid, 2016. Aperçu énergétique Suisse 2015 & 2016. Excell worksheets. Available: 776 https://www.swissgrid.ch/fr/home/operation/grid-data/generation.html (accessed 15.02.18).

Although EEX does into consideration in this study. An estimate of missing contributors is possible by crossing data collected 195 from EEX with those coming from other sources of information

Jan 2014

Itten

Germany, and Austria at the leading energy exchanges in Central Europe EEX (EEX, 2016). Although EEX does into consideration in this study. An estimate of missing contributors is possible by crossing data collected 195 from EEX with those coming from other sources of information (Itten et al., 2014). On that basis, the 196 technologies missing from the inventory are evaluated as follows: for Austria, garbage (0.8% of the mix), oil 197 (1.3%), solar (0.03%), and wind (2.4%); for Switzerland, waste (1.6%), bio-energy (0.2%), and solar (0.02%).

CEDnr of the electricity by end-use sectors of our case study and its specific electricity consumption

Ced Cf

CF CED, and CF CEDnr of the electricity by end-use sectors of our case study and its specific electricity consumption

Temporal variations in the primary energy use and greenhouse gas emissions of electricity provided by the Swiss grid

Abstract

No full-text available

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