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... Power-to-gas technology converts power produced by renewables into hydrogen via water electrolysis, and through methanation further into synthetic natural gas. The rationales for synthesis to methane are the challenges related to distribution and use of hydrogen whereas in the case of methane the existing infrastructure can be used [2], [3]. The technology is especially suited for long-term storage because the cost of storing methane is low. ...
... They concentrated on the electrical system but district heat was also included with SNG-fired CHP and power-to-heat as heat producers. Tsupari et al [2] studied the integration of P2G with CHP plant by oxygen enriched air combustion where the oxygen from electrolysis is used to increase the heat output of the CHP plant. Brandstätt et al [6] studied the present and future economics of heat storages and P2G in a small-scale district heating network. ...
... Tsupari et al [2] assumed 1750 €/kW plus 15 % for balance of plant as the near-term investment cost of the whole P2G plant and 2 % of the investment cost as fixed operating and maintenance (O&M) costs. Jentsch et al [13] used 750 €/kW for a future 85 % renewable energy scenario. ...
Article
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Power-to-gas (P2G) technology has been suggested as one way to balance the variability of renewable power generation and decarbonize the transport sector. This paper studies the application of P2G plant in a real Finnish municipal district heating system in a future situation where the European power and district heating sectors have been decarbonized. From the point of view of the district heating company, the P2G plant can act as fuel producer, CO2 sink and heat source. The district heating unit commitment (DHUC) model was used to optimize the full-year hourly resolved operation of a CHP CCS plant, heat boilers, heat pumps, P2G plant and heat storages. Capacity optimization of most plants was also done. The hourly power price variability was obtained from regional unit commitment and economic dispatch simulation of the North European region. We find that a P2G plant may be profitable in the system, starting with SNG value of 70 €/MWh and depending on the specific investment. The regional simulations show that the market value of SNG is greater than this, and we conclude that P2G is a viable option.
... Power-to-gas technology converts power produced by renewables into hydrogen via water electrolysis, and through methanation further into synthetic natural gas. The rationales for synthesis to methane are the challenges related to distribution and use of hydrogen whereas in the case of methane the existing infrastructure can be used Tsupari et al., 2016). The technology is especially suited for long-term storage because the cost of storing methane is low. ...
... They concentrated on the electrical system but district heat was also included with SNG-fired CHP and power-to-heat as heat producers. Tsupari et al (2016) studied the integration of P2G with CHP plant by oxygen enriched air combustion where the oxygen from electrolysis is used to increase the heat output of the CHP plant. Brandstätt et al (2015) studied the present and future economics of heat storages and P2G in a small-scale district heating network. ...
... Evaluating the size of the hydrogen storage is not in the scope of this work. Tsupari et al (2016) assumed 1750 €/kW plus 15 % for balance of plant as the near-term investment cost of the whole P2G plant and 2 % of the investment cost as fixed operating and maintenance (O&M) costs. Jentsch et al (2014) used 750 €/kW for a future 85 % renewable energy scenario. ...
... Tsupari et al. [123] presented a detailed analysis of a PtG process incorporating a 10 MW electrolyzer integrated with an existing 300 MW fuel biomass co-fired (i.e., peat and forest residues) CHP plant in Finland. The CHP plant incorporated a boiler to co-fire peat and forest residues, and could flexibly handle moist feedstocks and mixed feedstocks. ...
... This CHP-PtG integration could only be profitable in less than ten years for the higher electrolysis efficiency value (70% versus 62% base case) or higher SNG price in Finland, based on local electricity prices. Analyzing several market scenarios, it was found that the same PtG concept could however lead to profitable business cases in Germany, where electricity cost is lower than in Finland [123]. ...
... This was attributed to the fuel switching directly impacting all medium and high-temperature heat supplies, and indirectly grid electricity savings. Unlike in [67], where electrolyzer heat was recovered to drive adsorption metal hydride heat pipes, and unlike in other distributed PtG deployments, particularly PtG-CHP integrations [123], no heat/material (e.g., oxygen) integration options were reported in [130,131]. In addition, economics were indirectly addressed through primary energy savings rather than monetary metrics. ...
Article
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Technical, economic and environmental assessments of projected power-to-gas (PtG) deployment scenarios at distributed- to national-scale are reviewed, as well as their extensions to nuclear-assisted renewable hydrogen. Their collective research trends, outcomes, challenges and limitations are highlighted, leading to suggested future work areas. These studies have focused on the conversion of excess wind and solar photovoltaic electricity in European-based energy systems using low-temperature electrolysis technologies. Synthetic natural gas, either solely or with hydrogen, has been the most frequent PtG product. However, the spectrum of possible deployment scenarios has been incompletely explored to date, in terms of geographical/sectorial application environment, electricity generation technology, and PtG processes, products and their end-uses to meet a given energy system demand portfolio. Suggested areas of focus include PtG deployment scenarios: (i) incorporating concentrated solar- and/or hybrid renewable generation technologies; (ii) for energy systems facing high cooling and/or water desalination/treatment demands; (iii) employing high-temperature and/or hybrid hydrogen production processes; and (iv) involving PtG material/energy integrations with other installations/sectors. In terms of PtG deployment simulation, suggested areas include the use of dynamic and load/utilization factor-dependent performance characteristics, dynamic commodity prices, more systematic comparisons between power-to-what potential deployment options and between product end-uses, more holistic performance criteria, and formal optimizations.
... Other significant process environments in biobased industries include facilities in the pulp & paper and combined heat & power (CHP) sectors. Power-to-X concepts in these environments have been studied earlier: CHP environment for example in [3] and pulp & paper in [4]. The goal in this study is to identify business candidates for near term deployment in Finland. ...
... FCR might be significant source of income at least for the first power-to-X plants. The model and the calculation routines are described in closer detail in [3]. ...
Conference Paper
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The climate change forces us to shift from fossil to renewable resources. Integrated utilisation of biogenic CO2 is a promising way to produce sustainable raw materials and fuels. CO2 capture and utilisation (CCU) enables sustainable routes for carbon-based products and guiding the development to utilising especially biogenic instead of fossil CO2 directs the investments towards sustainable targets in the long term. Integrated CCU options benefit from a local CO2 source – substantially reducing the CO2 transportation costs, energy integration, customisable CO2 purity and the possibility to utilise the produced fuels and chemicals on-site. The key objective of this paper is to find out feasible utilisation pathways for biogenic CO2 in Finnish biomass driven industry sectors. As main results operational costs and incomes as well as profitability indicators are presented for each biogenic CO2 utilisation pathway. Keywords: carbon dioxide (CO2), carbon capture and utilisation (CCU), biogenic, biobased economy, power-to-X
... Juanwei et al. (2019) put forward the need to extend reliability assessment to integrated energy systems coupling with other kinds of energies [20]. Tsupari, Karki and Vakkilainen (2016) reveal that the integration of power-to-gas with biomass-fired combined heat and power plant offers an economically feasible concept for future energy system [21]. Farahani et al. (2020) study hydrogen-based integrated energy and mobility system and find out that using hydrogen storage is much cheaper than using large battery storage system [22]. ...
... Hydrogen-fired power plants interlink hydrogen and electricity systems [36,37]. Methane-fired combined heat and power generation (CHP) [21,38], open cycle gas turbines (OCGT) [39], and combined cycle gas turbines (CCGT) [40] link electricity and methane systems. Electricity storage in the form of batteries [41][42][43], including electric vehicles, as well as underground hydrogen [44][45][46] and methane storage [47] help to decouple the instantaneous mismatch between supply and demand [43,48]. ...
Article
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The future energy system is widely expected to show increasing levels of integration across differing energy carriers. Electricity, hydrogen, methane and heat systems may become increasingly interdependent due to coupling through conversion and hybrid energy technologies. Market parties, network operators, policy makers and regulators require tools to capture implications of possible techno-economic and institutional developments in one system for the operation of others. In this article, we provide an integrated electricity, hydrogen and methane systems modelling framework focusing on interdependencies between them. The proposed integrated electricity and (renewable) gas system model is a market equilibrium model with hourly price and volume interactions, considering ramp rates of conventional units, variability of intermittent renewables, conversion, transport as well as storage of electricity, hydrogen and methane. The integrated model is formulated as a linear program under the assumption of perfect competition. As proof-of-concept, the model has been applied to a test case consisting of 34 electricity nodes, 19 hydrogen nodes and 22 methane nodes, reflecting the regional governance scenario in the Dutch Infrastructure Outlook 2050 study. The case study also includes different sensitivity analyses with regard to variable renewable capacity, energy demand and biomass prices to illustrate model response to perturbations of its main drivers. This article demonstrates that the interweaving of electricity, hydrogen and methane systems can provide the required flexibility in the future energy system.
... In addition to the effect of seasonal storage, PtG provides flexibility and stability in the electricity grid due to providing secondary control reserve [4], using surplus electricity [5][6][7] or due to coupling with energy production facilities directly, as investigated in [8,9]. PtG is also described in literature as an economic alternative to network expansion [10]. ...
... The thermal energy in the flow of a liquid media in its liquid or evaporated state are given in Eqs. (9) and (10) respectively. ...
Article
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This paper describes a generic and systematic method to calculate the efficiency and the annual performance for Power-to-Gas (PtG) systems. This approach gives the basis to analytically compare different PtG systems using different technologies under different boundary conditions. To have a comparable basis for efficiency calculations, a structured break down of the PtG system is done. Until now, there has not been a universal approach for efficiency calculations. This has resulted in a wide variety of efficiency calculations used in feasibility studies and for business-case calculations. For this, the PtG system is divided in two sub-systems: the electrolysis and the methanation. Each of the two sub-systems consists of several subsystem boundary levels. Staring from the main unit, i.e. the electrolysis stack and/or methanation reactor, further units that are required to operate complete PtG system are considered with their respective subsystem boundary conditions. The paper provides formulas how the efficiency of each level can be calculated and how efficiency deviations can be integrated which are caused by the extended energy flow calculations to and from energy users and thermal losses. By this, a sensitivity analysis of the sub-systems can be gained and comprehensive goal functions for optimizations can be defined. In a second step the annual performance of the system is calculated as the ratio of useable output and energetic input over one year. The input is the integral of the annual need of electrical and thermal energy of a PtG system, depending on the different operation states of the plant. The output is the higher heating value of the produced gas and – if applicable – heat flows that are used externally. The annual performance not only evaluates the steady-state operating efficiency under full load, but also other states of the system such as cold standby or service intervals. It is shown that for a full system operation assessment and further system concept development, the annual performance is of much higher importance than the steady-state system efficiency which is usually referred to. In a final step load profiles are defined and the annual performance is calculated for a specific system configuration. Using this example, different operation strategies are compared.
... The cost-competitiveness of electrolytic hydrogen can be improved even further by efficiently utilizing the by-products of electrolysers [9,10]. For instance, the integration of electrolysis with low-grade heat utilization has been demonstrated in small pilot projects in Germany and Denmark [11]. ...
Article
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Hydrogen is a versatile feedstock for various chemical and industrial processes, as well as an energy carrier. Dedicated hydrogen infrastructure is envisioned to conceptualize in hydrogen valleys, which link together the suppliers and consumers of hydrogen, heat, oxygen, and electricity. One potential hydrogen valley is the Bay of Bothnia, located in the northern part of the Baltic Sea between Finland and Sweden. The region is characterized as having excellent wind power potential, a strong forest cluster with numerous pulp and paper mills, and significant iron ore and steel production. The study investigates the hydrogen-related opportunities in the region, focusing on infrastructural requirements, flexibility, and co-operation of different sectors. The study found that local wind power capacity is rapidly increasing and will eventually enable the decarbonization of the steel sector in the area, along with moderate Power-to-X implementation. In such case, the heat obtained as a by-product from the electrolysis of hydrogen would greatly exceed the combined district heat demand of the major cities in the area. To completely fulfil its district heat demand, the city of Oulu was simulated to require 0.5–1.2 GW of electrolyser capacity, supported by heat pumps and optionally with heat storages.
... Both the technologies have their own advantages and disadvantages, and detail information can be found in Reference [21]. In this paper, the P2G used in CEGBCS is electric methane production, whose core principle is composed of two parts [22,23]. Firstly, hydrogen and oxygen are produced by electrolytic water. ...
Article
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The extensive use of wind power can not only reduce dependence on fossil fuels, but also reduce emissions of polluted gases. However, large-scale wind power curtailments often occur in northeast China during the heat supply season, due to the fact that most of electrical demand is covered by the electrical power of the combined heat and power (CHP) during the off-peak hours. At present, for northeast China with heating demand, most of the research only focuses on how to accommodate more wind power on the spot by using one-directional conversion of the electric and thermal energy. But it is still difficult to realize the bi-directional conversion between the electro-gas or electro-thermal energy. In this paper, a combined electro-gas bi-directional conversion system (CEGBCS) is established by adding the power to gas (P2G), fuel cell and heat storage device in CHP system. This CEGBCS can not only realize bi-directional conversion of the electricity and gas, but also decouple the two operation modes of CHP unit, which greatly improve the ability of system to accommodate additional wind power. Finally, the effectiveness of the proposed CEGBCS is verified by comparing with two traditional methods.
... African Journal of Science, Technology, Innovation and Development 3 entire system carbon-neutral. These 'power-to-X' technologies are chemical processes that act as bridging technologies, which can be applied for multiple purposes such as transforming power into synthetic materials, chemicals and fuels (Dimitriou et al. 2015;Elder, Cumming, and Mogensen 2015;Tsupari, Kärki, and Vakkilainen 2016;Barbosa et al. 2017). If electricity generated from renewables is converted through power-to-X into various energy products, fossil fuels could be fully substituted. ...
Article
Foresight is a pragmatic futures studies approach as structured debate about future-related topics. Deliberative foresight addresses stakeholders affected by specific futures. This paper goes beyond a low-carbon strategy to present the potential of futures based on renewable energy. In the neo-carbon energy system, high shares of solar, wind, and other renewables are used, and carbon dioxide from the air is used as a source for synthetic products such as plastics, chemicals and medicine. As transitions are about technological and social change, a neo-carbon energy innovation ecosystem, consisting of actors at multiple levels, is envisioned. To represent the present ‘direction’ of Kenya's energy transition, four renewable energy approaches and projects are examined. A conceptual model, which consists of deliberative foresight, innovation ecosystems thinking, transformative potential and sustainability, is then introduced. To study emerging energy transformations, historical assumptions and conventional approaches to development and scenario-making need to be challenged. This paper claims that deliberative foresight and a systemic approach to innovation can enable African countries to examine how their economies and energy systems can be transformed into emissions-free, efficient, low-cost, and sustainable. Our approach emphasizes inclusive innovation, broad-based socio-economic benefits, and minimizing environmental harm.
... Further processing of hydrogen entails energy losses. However, these may be compensated by the availability of existing infrastructure for transporting and storing methane whereas hydrogen would require new and challenging infrastructure for distribution, storage and utilization [7], [8]. ...
Preprint
Ammonia has been suggested as an energy vector which has enable energy storage and sector coupling in order to balance the variability of wind and solar power. This paper investigates the impact of the power-to-ammonia technology in the North European power and heat system. Three-stage model was built for the power-to-ammonia plant. A cost optimization model, targeting the year 2050, was used to optimize investments and the full-year hourly resolved operation of conversion plants, storages and the power-to-ammonia plants. We found that the investments into power-to-ammonia plants is strongly dependent on the global ammonia price. Renewable ammonia production is in balance with the energy sector consumption at price level slightly above 450 €/tonne. Regional ammonia storage of 6 million tonnes was sufficient to balance the variations in ammonia demand in the power sector.
... Further processing of hydrogen entails energy losses. However, these may be compensated by the availability of existing infrastructure for transporting and storing methane whereas hydrogen would require new and challenging infrastructure for distribution, storage and utilization [7], [8]. ...
Preprint
Ammonia has been suggested as an energy vector which has enable energy storage and sector coupling in order to balance the variability of wind and solar power. This paper investigates the impact of the power-to-ammonia technology in the North European power and heat system. Three-stage model was built for the power-to-ammonia plant. A cost optimization model, targeting the year 2050, was used to optimize investments and the full-year hourly resolved operation of conversion plants, storages and the power-to-ammonia plants. We found that the investments into power-to-ammonia plants is strongly dependent on the global ammonia price. Renewable ammonia production is in balance with the energy sector consumption at price level slightly above 450 €/tonne. Regional ammonia storage of 6 million tonnes was sufficient to balance the variations in ammonia demand in the power sector.
... Both add energy losses compared to pure hydrogen as energy carrier. Still, P2G has the advantage of existing infrastructure for methane transport and storage, compared to hydrogen which requires new challenging infrastructure [10,11]. ...
Article
Power-to-gas and other chemicals-based storages are often suggested for energy systems with high shares of variable renewable energy. Here we study the North European power and district heat system with alternative long-term storage, the power-to-ammonia (P2A) technology. Assuming fully renewable power and heat sectors and large-scale electrification of road transport, we perform simultaneous optimization of capacity investments and dispatch scheduling of wind, solar, hydro and thermal power, energy storages as well as transmission, focusing on year 2050. We find that P2A has three major roles: it provides renewable feedstock to fertilizer industry and it contributes significantly to system balancing over both time (energy storage) and space (energy transfer). The marginal cost of power-based ammonia production in the studied scenarios varied between 431 and 528 €/t, which is in the range of recent ammonia prices. Costs of P2A plants were dominated by electrolysis. In the power and heat sector, with our cost assumptions, P2A becomes competitive compared to fossil natural gas only if gas price or CO2 emission price rises above 70 €/MWh or 200 €/tCO2.
... Some interesting Finnish papers have already been published. Tsupari, Kärki, and Vakkilainen (2016) studied the economic feasibility of integrating PtG to a biomass fired CHP plant. Pilpola and Lund (2018) analyzed different scenarios for Finnish energy system transition and provided flexibility through PtX, including coupling through PtG. ...
Article
It is apparent that future energy systems need increased flexibility for example due to wider adoption of variable renewable production, general transition towards decarbonization, and bidirectional energy grids. When several energy sectors are considered holistically, the possible flexibility measures increase. This paper reviews potential means to increase flexibility of Finnish energy systems by comprehensively regarding both electricity and thermal systems. After introducing renewable energy data from Finland, the authors discuss how flexibility is defined. Then, several technological options to meet the increased flexibility needs are described and Finnish examples are given. These key technologies and solutions include energy storage, district heating and cooling, electric vehicles, smart meters, demand response, and ICT solutions. In addition, energy markets provide important flexibility means. Therefore, aspects related to electricity market design and heat trading are also assessed.
... Coupled with catalytic CO 2 reduction, power-tomethanol technologies can be established [24]. Biomass-based combined heat and power plants can be integrated with power-to-gas technology [25]. The steel manufacturing process could also utilize the hydrogen produced from power-to-gas technologies [26]. ...
Article
The massive implementation of renewable energy requires sophisticated assessments considering the combination of feasible technology options. In this study, a techno-economic analysis was conducted for hydrogen production from photovoltaic power generation (PV) utilizing a battery-assisted electrolyzer. The installed capacity of each component technology was optimized for the wide range of unit costs of electricity from the PV, battery, and proton-exchange membrane electrolyzer. Leveling of PV output by battery, the necessary capacity of electrolyzer is suppressed and the operating ratio of electrolyzer increases. The battery-assist will result in a lower hydrogen production cost when the benefit associated with the smaller capacity and higher operation ratio of the electrolyzer exceeds the necessary investment for battery installation. The results from this study indicated the cost of hydrogen as low as 17 to 27 JPY/Nm³ using a combination of technologies and the achievement of ambitious individual cost targets for batteries, PV, and electrolyzers.
... First, a variety of different efficiency definitions results from different system boundaries. In particular, there is no consensus on (i) whether to use the LHV or the HHV efficiency, 39 (ii) to what extent heat integration is applied, 79 (iii) whether materials or heat from other processes are included, [80][81][82] and (iv) whether the CO 2 supply is considered. 83,84 Second, the PtF efficiency strongly depends on the efficiency of the electrolysis. ...
Article
Polyoxymethylene dimethyl ethers (OME) are promising electricity-based fuels (e-fuels). They enable low emissions of particulate matters and nitrogen (di)oxide. In this work the energetic efficiency of the OME production from CO2 and electrical energy is calculated. CO2 capture is included in the analysis by considering direct air capture and post combustion capture technologies. CO2 is converted to methanol using hydrogen produced by electrolysis. Two routes for OME synthesis are studied: OME synthesis directly from methanol and formaldehyde and OME synthesis via the two intermediates methylal and trioxane. The energetic efficiency is evaluated for different levels of heat integration. The efficiency of the OME production was calculated for variable electrolysis efficiencies. For an electrolysis efficiency of 60 %, it ranks between 24.3 - 36.7 %. The production of 1 kg OME3-5 (LHV of 18.9 MJ per kg) has an energy demand of 51.6 - 78.0 MJ. A comparison of the energetic efficiencies of the production of different e-fuels and evaluation of future potential sets OME in an overall context.
... Due to low capture costs, low CO 2 penalties, biogenic origins, and short distances to wind power plants, biogas upgrading facilities and a bioethanol plant were determined to be the CO 2 sources best suited for utilization in novel power-to-gas plants. Tsupari et al. 106 have carried out a study on the economic feasibility of power-to-gas integrated with a biomass red CHP plant. Country feasibility studies for long term power-to-gas projects have been carried out for Italy, 107 South and Central America, 108 Alpine region 109 and Germany. ...
Article
Full-text available
Offshore renewable energy resources have a great potential to contribute to the global energy supply chain however LCOE of offshore power is still higher as compared to the conventional power generation. With a growing interest in offshore resources and considering the capacity of offshore renewable resources, they are anticipated to contribute a larger share of electric power in the next decade. The existing dispatch of offshore wind electricity through offshore substation and sub-sea cables increases the cost of offshore electricity manifold. The offshore wind electricity can be dispatched by conversion into hydrogen and transportation through existing offshore gas pipeline infrastructure. The study presents a novel idea of performing the methanation process entirely offshore by utilizing the CCS in conjunction with electrolysis. A proposal of an artificial island that hosts the complete offshore power-to-gas is also presented. It has been found that the proposed arrangement can handle the offshore generated energy seamlessly and can be transported to onshore demand centers through the traditional natural gas pipeline infrastructure.
... In Figure 1 the general approach and the techno-economic feasibility platform used in the studies is presented. The details of the model, including operation strategy, is presented in Tsupari et al. (2016). ...
Conference Paper
Full-text available
High share of solar and wind energy challenges current energy systems as their production is intermittent and seasonal. Power-to-gas (P2G), or more widely, power-to-product (P2X) technologies producing synthetic fuels or other products have the potential to address the issue on intermittency and simultaneously contribute to the reduction of CO2 concentration in the atmosphere. Even though P2G technologies are available only a few commercial business cases have been implemented. The main focus in this paper has been on initial screening of several industry-integrated P2X concepts in order to identify the best business candidates for near term deployment in sectors that would also have high global impact. The work includes techno-economic feasibility analyses of specific system operations from operator’s / investor’s point of view in several market scenarios. As main results operational costs and incomes as well as profitability indicators (profit, EBIT, EBIT DA, payback time, pre-tax IRR, LCOF) are presented for selected business cases. As the paying capability seems to be the best in transportation sector, the most potential applications are determined by the utilisation possibilities of the side-streams from PtX processes and possibility to avoid electricity transmission costs as well as costs of CO2 or CO utilisation. In general, utilisation of at least 1-2 side products (heat, oxygen, steam) for additional revenue is typically required to enable profitability. Power-to-gas (P2G), or more widely, power-to-product (P2X) technologies producing synthetic gaseous fuels or other products have the potential to address the issue on intermittency and simultaneously contribute to the reduction of CO2 concentration in the atmosphere. It seems that in current business conditions P2X technologies are on the brink of profitable commercial project appearance.
... Wood biomass which includes bark, leaves, live and dead wood phones located above and below the ground can be accumulated into the mass. Production uses the process of fermentation of biomass to produce lignin and carbohydrates [45], [46]. Wood biomass can be used as electricity, solvents, lubricants, inks, plastics, and adhesives. ...
Article
Full-text available
Biomass is the world's most commonly used source of renewable electricity today. It is used primarily in strong form and, to a smaller degree, oil fuels or petrol. In contemporary times, the use of biomass for energy generation has risen at only a small pace. Biomass is the primary source of energy in Indonesia. Biomass is used to fulfil a range of energy requirements, including producing electricity, heating households, fueling cars and supplying industrial equipment with a heat process. Biomass potential includes waste from timber, animals and plants. Among biomass power sources, fuelwood might be the most important since it accounts for a large 17% share of Indonesia total power manufacturing. The complete biomass energy potential in Indonesia is about 38 million tons of oil equivalents (Mtoe). The quantity of biomass that can be used in Indonesia is roughly 32 Mtoe. The potential for electrical manufacturing from usable bioenergy sources in 2012 is 83 MW and corporate revenue, representing more than 350,000 jobs. This research shows that the potential for climate change mitigation and power sustainability in Indonesia is significant for biomass energy.
... Electric efficiency of power grid [40] h grid 92 % High heating value of cow manure [41] HHV feed 15.0 MJ/kg Low heating value of cow manure [41] LHV feed 13.75 MJ/kg Efficiency of heat transfer [40] h ht 80 % Thermal efficiency of biogas stove [42] h bs 55.67 % Thermal efficiency of biomass boiler [40,43] h b 90 % Conventional system Generating efficiency of coal-fired power plant [40] h CS e 45 % Electric efficiency of power grid [40] h grid 92 % Thermal efficiency of coal stove [44,45] h CS cs 35 % Thermal efficiency of straw stove [46] h CS st 15.77 % energy-saving than the CHPB system. ...
... In recent years, PtG potential is analyzed in several literature studies. Technical and economic analyses investigated different PtG solutions integrating renewable energy for the European context and in particular for Germany, where major efforts have been spent to develop this technology [12,[59][60][61][62][63][64][65]. Pilot and demonstration plants have been realized and a complete overview is available in literature [13]. ...
Article
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The power to gas process chain could play a significant role in the future energy system. Renewable electric energy can be transformed into storable methane via electrolysis and methanation. In the process, three water electrolysis technologies can be considered: alkaline, PEM and solid oxide. Alkaline electrolysis is currently the cheapest technology; however, in the future PEM electrolysis could be better suited for process chain. Solid oxide electrolysis could also be an option in the future, especially if heat sources are available. The methanation reaction can be catalytic, biological or bio-electrochemical, with respective advantages and disadvantages. Different sources of carbon dioxide can be used as biogas and syngas. Different process schemes are present in the literature about the integration of biogas and syngas plants with power to gas systems, also with the aim to improve the overall energy efficiency. Graphic Abstract Open image in new window
... A series eight node medium voltage network feeder is also analysed. Table 1 provides the analysis in terms of P2G assets, CHP plant, PV plant and Uncontrollable loads in connection with the electric grids [11]. ...
Article
In the recent days, energy mix performed by using the Renewable Energy Sources (RES) is gaining wide popularity. The control of predictability and generation takes a progressive loss as RES is penetrating increasingly in the energy mixes due to the non dispatchable nature of the energy produced from these sources. For ensuring and maintaining stable operation, the power system flexibility is increased when higher penetration levels are attained by RES. A Decision Support System (DSS) is used for energy conversion and storage systems which can be managed by an Information and Communication Technology (ICT) tool. The H2020 PLAnning and operational tools are used for optimizing energy flows and synergies between energy NETworks (PLANET) along with DSS for controlling the technology wherein power is converted into either heat or gas (P2X) by evaluation, management and dispatch. Further analysis is done in terms of energy evaluation and economic benefits with respect to P2X technology and its flexibility.
... As in the studies of Hannula [43] and Tsupari et al. [17], it is assumed that the conversion of the input gases is perfect in the methanation reactor and methane production is calculated from the Sabatier reaction (2) with stoichiometric feed of CO 2 and H 2 gases. Based on lower heating values of the hydrogen and methane, the efficiency of the reaction is 83%. ...
Article
Power-to-gas (PtG) is one option to integrate more renewable electricity production to the energy system, by offering flexible load, seasonal energy storage and low-GWP (Global Warming Potential) methane. The first step of the PtG process, hydrogen production by water electrolysis, requires electricity with low specific CO2 emissions. Therefore, the operation of electrolyser is most likely variating according to the intermittency of renewable electricity production. The downstream processes of PtG should be capable to follow the dynamics and utilize the produced hydrogen, avoiding curtailment. This could be done with a very dynamic reactor system, or with aid of buffer storages for feed gases. This paper studies the effect of dynamic properties of methanation reactor, hydrogen buffer storage and electrolyser full load hours on PtG system efficiency. The operation of electrolyser is following intermittent renewable electricity production and electricity markets, leading to varying full load hours (FLH) with different characteristics. Enhancement of single parameters related to thermal dynamics of the reactor could improve the system efficiency more than parameters related to the loading of the reactor. Coupled threshold were found for FLH and H2 storage size, after which average efficiencies became nearly similar as in steady-state operation.
... In order to validate the profitability of the PtG process technoeconomic analysis [21] and feasibility studies [22,23] of the plant are done. One approach for validating the gas production costs is to calculate the present value of the total costs for the construction and operation of a plant over its economic life, divided into equal annual payments. ...
Article
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The publication gives an overview of the production costs of synthetic methane in a Power-toGas process. The production costs depend in particularly on the electricity price and the full load hours of the plant subsystems electrolysis and methanation. The full-load hours of electrolysis are given by the electricity supply concept. In order to increase the full-load hours of methanation, the size of the intermediate hydrogen storage tank and the size of the methanation are optimised on the basis of the availability of hydrogen. The calculation of the production costs for synthetic methane are done with economics for 2030 and 2050 and the expenditures are calculated for one year of operation. The sources of volume of purchased electricity are the short-term market, long-term contracts, direct-coupled renewable energy sources or seasonal use of surpluses. Gas sales are either traded on the short-term market or guaranteed by long-term contracts. The calculations show, that an intermediate storage tank for hydrogen, adjustment of the methanation size and operating electrolysis and metha-nation separately, increase the workload of the subsystem methanation. The gas production costs can be significantly reduced. With the future expected development of capital expenditures, operational expenditure, electricity prices, gas costs and efficiencies, an economic production of synthetic natural gas for the years 2030, especially for 2050, is feasible. The results show that Power-toGas is an option for long-term, large-scale seasonal storage of renewable energy. Especially the cases with high operating hours for the subsystem metha-nation and low electricity prices show gas production costs below the expected market prices for synthetic gas and biogas.
... Hydrogen production by water electrolysis and the subsequent conversion of hydrogen and carbon dioxide to methane is considered a promising option to utilize low-cost power supply during peak production periods of fluctuating VRE generation [57,58]. As the electricity price is considered an important factor in the economic feasibility of electrolysis and methanation processes [59,60], the low-cost power supply during peak production periods of VRE in the Åland Islands is expected to increase the profitability of these processes. Therefore, an alkaline electrolyzer (2.6 MW e ) with 67% efficiency [60] was combined with the biogas plant. ...
Article
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Energy plays an essential role in circular economy because circular activities such as material processing require power and heat. In parallel, the rate of the transition to renewable energy is not adequate to meet the increasing energy demands. The objective of the study is to evaluate whether circular economy could increase the value of variable renewable energy investments and hence accelerate the transition towards renewable energy. The study involves a combined energy system and material flow analysis. The study is performed on a selected case region as the processes in circular economy and the availability of renewable energies are always local and depend on regional conditions. The Åland Islands was used as a case platform in the study as the electricity generation capacity from wind power in the region is expected to increase significantly in the near future resulting in high variability in the local power supply. Four alternative scenarios are analyzed in which the variable regional renewable energy supply exceeding the local demand is integrated for different purposes: power exports, circular economy, partly electrified transportation sector and district heating. With the highest annual system net profit (0.72 M€), integrating the power production peaks of variable renewable energy into circular economy was found to outweigh the annual economic benefits of power exports (−0.43 M€), the partly electrified transportation sector (−0.50 M€) and district heating (−0.27 M€). Therefore, the value obtained from the products derived from circular processes increased the value of the renewable energy system and would hence promote investments in renewable energy in the region.
Article
The suitability of existing sources of CO2 in a region (Ireland) for use in power to gas systems was determined using multi criteria decision analysis. The main sources of CO2 were from the combustion of fossil fuels, cement production, alcohol production, and wastewater treatment plants. The criteria used to assess the suitability of CO2 sources were: annual quantity of CO2 emitted; concentration of CO2 in the gas; CO2 source; distance to the electricity network; and distance to the gas network. The most suitable sources of CO2 were found to be distilleries, and wastewater treatment plants with anaerobic digesters. The most suitable source of CO2, a large distillery, could be used to convert 461GWh/a of electricity into 258GWh/a of methane. The total electricity requirement of this system is larger than the 348GWh of renewable electricity dispatched down in Ireland in 2015. This could allow for the conversion of electricity that would be curtailed into a valuable energy vector. The resulting methane could fuel 729 compressed natural gas fuelled buses per annum. Synergies in integrating power to gas at a wastewater treatment plant include use of oxygen in the wastewater treatment process.
Article
The objective of this paper is Modeling and simulation of electrolyzer model type proton exchange membrane (PEM) that it is connected with solar cells, for to define and identify the factors that influence the production of hydrogen and oxygen. To generate these types of gas, we have used water and a source of electricity generated by solar cells. To perform the simulations results by using MATLAB software. We have used different physical equations defining these types of problems (Nernst-Planck, Nernst −Einstein and Fick's law). The different results shown in this work, that these types of PEM are best suited for desert areas (Adrar) with high temperatures and solar flux. This study shows the influence of temperature on the various parameters (α,i0, D and Q), and it also shows an electrolyzer equipped with a membrane produces a relatively large amount of hydrogen, volume up to 2.25 L compared with an electrolyzer cell without membrane, volume of 0.0001 L.
Article
Producing Synthetic Natural Gas (SNG) via Power-to-Gas (PtG) is favourable for two reasons; it can be substituted for natural gas in the gas network, and it enables CO2 recycling as energy systems transition towards a low-carbon future. However, the expensive SNG production process is a barrier to being cost-competitive with other market gases. Several diverse factors influence SNG production cost, which results in several possible process configurations with varying performance which influence it. The hydrogen (H2) and carbon dioxide (CO2) required to produce SNG are available from multiple sources, while the SNG production cost is also influenced by the capital investment required for PtG process units, interim storage facilities, and operating expenses. Hence, an in-depth analysis of the factors affecting SNG production is required to understand their effect on the cost and to provide information on cost savings, economic implications, and optimal SNG production setup for decision-makers. In this paper, an optimisation algorithm is developed to model the PtG process units. The main objective of this work is to determine optimal process configurations for SNG production by analysing its influencing cost factors. A factorial design approach is integrated into the optimisation process to minimise the production cost by choosing the cost-effective process configurations. This work also determines the factors with a significant influence on the production cost using an ANOVA. The algorithm identifies the cost-effective H2 and CO2 source to obtain the least expensive SNG production setup. Based on the values of the cost factors, strategies for lowering the production cost in an existing setup are identified. The factors with the most influence on the SNG production cost are the capacity and capex of the methanator unit
Article
Full-text available
Global warming and climate change urge the deployment of close carbon-neutral technologies via the synthesis of low-carbon emission fuels and materials. An efficient intermediate product of such technologies is the biomethanol produced from biomass. Microalgae based technologies offer scalable solutions for the biofixation of CO2, where the produced biomass can be transformed into value-added fuel gas mixtures by applying thermochemical processes. In this study, the environmental and economic performances of biomethanol production are examined using artificial neural networks (ANNs) for the modelling of catalytic and noncatalytic hydrothermal gasification (HTG). Levenberg-Marquardt and Bayesian Regularisation algorithms are applied to describe the thermocatalytic transformation involving various types of feedstocks (biomass and wastes) in the training process. The relationship between the elemental composition of the feedstock, HTG reaction conditions (380 °C–717 °C, 22.5 MPa–34.4 MPa, 1–30 wt% biomass-to-water ratio, 0.3 min–60.0 min residence time, up to 5.5 wt% NaOH catalyst load) and fuel gas yield & composition are determined for Chlorella vulgaris strain. The ideal ANN topology is characterised by high training performance (MSE = 5.680E-01) and accuracies (R² ≥ 0.965) using 2 hidden layers with 17-17 neurons. The process flowsheeting of biomass-to-methanol valorisation is performed using ASPEN Plus software involving the ANN-based HTG fuel gas profiles. Cradle-to-gate life cycle assessment (LCA) is carried out to evaluate the climate change potential of biomethanol production alternatives. It is obtained that high greenhouse gas (GHG) emission reduction (−725 kg CO2,eq (t CH3OH)⁻¹) can be achieved by enriching the HTG syngas composition with H2 using variable renewable electricity sources. The utilisation of hydrothermal gasification for the synthesis of biomethanol is found to be a favourable process alternative due to the (i) variable synthesis gas composition, (ii) heat integration-, and (iii) GHG emission mitigation possibilities.
Chapter
Due to the environmental problems about climate change and global warming, carbon dioxide is transformed and valorized from an emission to a raw material of many chemical production processes. This contributes transforming the linear economy into a circular one, considering the principles of reduction, reuse, recovery, recycle. However, the potential carbon dioxide uptake is lower compared to the worldwide CO2 emissions, estimated of 37 Gt actually. In the literature, many utilization options are suggested and are evaluated according to the 3E performance criteria (engineering–economic–environmental), including nine key indicators. An economic estimation and an analysis about the market size of the main carbon dioxide-based products are here suggested. Moreover, with particular attention, in this work, different routes for carbon dioxide utilization are reviewed: chemicals, fuels, concrete building materials, horticulture and microalgae production as well as mineral carbonation, oil and methane recovery and some direct uses. Cycling, closed and open pathways can be realized. Carbon dioxide utilization pathways ensuring a promising development in the next years are suggested.
Article
Full-text available
Carbon Capture Utilization and Storage (CCUS) technologies are receiving increasing interest and its implementation at world scale appears to be crucial to reduce CO2 emissions. In this context, Power-to-Gas technologies (PtG) are very promising, allowing to store renewable electricity and valorize captured CO2 to produce Synthetic Natural Gas (SNG), among other. The present work simulates an integrated CO2 capture and conversion process to SNG, and investigates its techno-economic and environmental performances. Different scenarios are defined considering the application to a cement plant flue gas and the production of renewable hydrogen. An advanced CO2 capture unit is implemented, considering a configuration (Rich Vapor Compression and Inter Cooling) and a solvent (MDEA + PZ) allowing to minimize its specific energy consumption (35 % regeneration energy savings in comparison with a conventional amine-based CO2 capture system). The excess heat released by the catalytic conversion is recovered for the solvent regeneration maximizing the amount of captured CO2. From the scenarios analyses, it is shown that integrating the CO2 capture and conversion steps is beneficial for reducing both the net CO2 emission to the atmosphere, by 45 %, and the contribution to fossil depletion, by 81 %, in comparison with the non-integrated one, as the production of fossil-based natural gas is replaced by renewable SNG. The proposed process leads to a cost of 2.39 € per kg Raw-SNG, with expected revenues of 0.87 € per kg Raw-SNG. Significant subsidies and incentives would thus be needed to compete with conventional energy prices for natural gas (0.55 € per kg).
Article
The combined cooling, heating and power (CCHP) microgrid has the advantages of promoting cleaner production and improving energy utilization efficiency. With the development of renewable energy sources (RES), it is more and more significant to study the optimal operation of CCHP based on the uncertainties of RES outputs. This paper proposes a CCHP-P2G microgrid system, which combined the power-to-gas (P2G) device with traditional CCHP microgrid. And a Data-driven Set based robust optimization (DSRO) model considering the uncertainties of wind power and multiple demand response programs (DRPs) have been presented, which consists of two stages: Day-ahead dispatching stage and Real-time adjusting stage. Simulations are delivered to show the following outcomes: (1) the P2G device can improve the electricity-gas coupling in the CCHP-P2G system, enhancing the system’s stability and economy of the system operation; (2) the multiple DRPs in the DSRO model can play the role of peak shaving and valley filling of electrical load, heating load and cooling load, so as to further reduce the operating cost of the system; (3) the DSRO model can resist the interferences of uncertain wind power outputs and keep both the conservativeness and computational complexity in relatively low levels.
Article
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The low efficiency of renewable electricity storage has been considered as a bottleneck of the scalable and low-carbon Power-to-Gas energy transformation concept. This paper investigates the combination of CO biofixation using Spirulina platensis microalgae and catalytic hydrothermal gasification of wet organic feedstock for the storage of fluctuating electricity and direct utilisation of waste CO. The presented method enables wet microalgae biomass conversion into H and C1-C2 rich fuel gas stream using hydrothermal conversion that is valorised further to methane. For bridging the gap between theoretical investigations and the application of this approach, experiments were carried out at elevated temperatures (632.9-717.0 °C) based on a central composite design of the experiment. Biogas upgrading was evaluated by ASPEN Plus flowsheeting software. The results show that the proposed storage cycle outperforms the state-of-the-art biological and chemical-based Sabatier methanations with an overall round-trip efficiency of 42.3%. The optimised thermo-chemical process enables to achieve simultaneously high H (9.05 mol kg−1) and CH (7.91 mol kg−1) yields with an enhanced 71.23% carbon conversion ratio. Moreover, the environmental and cost evaluations of the currently proposed bio-synthetic process indicate low associated CO equivalent emission (99.4 ± 12.6 g CO2eq kWh−1) with 144.9 €MWh-1 normalised total annual natural gas production cost. Ideally the proposed storage cycle requires less H from external sources, effective CO utilisation becomes available through the biofixation and hydrothermal conversion of the wet organic feedstock and closed carbon emission cycle can be accomplished.
Article
Solid sorbent based air capture facilities (DAC) of carbon dioxide can come along with high water co-adsorption. Integrating the latter in power-to-gas (PtG) concepts might reverse this disadvantage by using water separated from air as a feedstock for electrolysis based hydrogen production. Investigation of the overall integrated system by detailed simulation reveals the possibility of realizing high degrees of synergies within the strongly coupled DAC-PtG process. Efficient water recovery can reduce the process water demand by a factor of 4. Focusing on the overall energy demand, detailed pinch analysis of the integrated DAC-PtG concept is performed. High temperature water condensation allows for heat recovery in the order of 1.5 times the heat of reaction released in methanation process. Electrolysis operation point was found to be of high importance. Operation at 1.5 equilibrium cell voltage results in excess heat production of 475 kJ per mole CO2 captured, whereas at equilibrium cell voltage process heat demand of 16 kJ mol⁻¹ is observed. Overall, the possibility of designing an autothermally operated process for the production of methane based on carbon dioxide and water from ambient air is confirmed, where the synergies between the process sections revealed are of interest for general power-to-X (PtX) applications.
Article
In this paper, a typical mCHP system was integrated by gamma type Stirling engine to meet electric, heating and hot water demands. The combustion test results, which is a key technology for small and micro scale mCHP systems have been presented and the combustion parameters for the Gamma type Stirling engine power system are discussed. Finally, the effect of SiO2 and Al2O3 nanoparticles, dispersed in Polyalkylene glycol (PAG) of mCHP system on the viscosity and thermal conductivity, were investigated. Also, the effect of sawdust biomass fuel on mCHP system emissions (such as CO, NOx, HC) have investigated. The test results confirm the fact that Stirling engines that are driven by the temperature of biomass gases are able to achieve a valuable output power. Also, Analysis of pollutants showed that by increasing of sawdust mass flow rate from 0 to 0.14 (g/s), CO emissions increased 164 vol%, also HC and NOx emissions increased 295–24 ppm respectively. Finally, the comparison between Al2O3/PAG and SiO2/PAG nano-lubricant demonstrate that Al2O3/PAG have better performance, therefore, the findings suggest Al2O3/PAG with a volume concentration of 0.010% as an optimum and best performance nano-lubricant for mCHP system. On the basis of the experimental results, we conclude that using the SiO2 and Al2O3 nanofluids in mCHP system can be introduced as new way to improve the performance of mCHP.
Article
Power-to-gas (P2G) has been proposed as an innovative energy storage system for a long period of time to manage unbalanced electricity generated from renewable energy. Here we report economic feasibility studies and uncertainty analysis of P2G technology for synthetic natural gas (SNG) production in Korea. Economic analysis in terms of itemized cost estimation was carried out based on capital cost and operating cost, and then a unit SNG production cost of 0.094 USD kWh⁻¹ was obtained for a SNG production capacity of 700 m³ h⁻¹, which is still higher than a conventional natural gas price in Korea (0.038˜0.069 $ kWh⁻¹). With a Monte-Carlo simulation method, uncertainty analysis was performed to predict the possible changes in a unit SNG production cost and a net present value due to fluctuating the renewable H2 cost (1.84˜2.76 USD kgH2⁻¹), CO2 capture cost (48˜111 USD tonCO2⁻¹), and CO2 tax credit (16˜24 USD tonCO2⁻¹) as a tool of quantifying risks associated with a premature P2G technology. The analysis confirmed the economical infeasibility of P2G technology in Korea requiring significant advancement in P2G technology and stability in CO2 tax credit and also suggesting a future drive for the detailed analysis of environmental impacts considering the life cycle of produced SNG.
Article
Full-text available
This paper describes implications of applying carbon capture and storage in combined heat and power (CHP) production and in steel industry through three case study approaches conducted in Finland. Utilisation of low temperature process heat from capture plant, air separation unit or CO2 compression in district heating system and/or industrial solutions offers significant potential to increase overall efficiency and feasibility of CCS processes. The effects of CCS on the local CHP systems were included within the studied system boundaries in order to evaluate the economics and emissions from investor's (local energy company) point of view. Effect of CCS on greenhouse gas (GHG) emissions and operation economics of the CCS cases are compared to the reference system with varying parameters of operation. Regarding the GHG emissions, besides the site emissions, the main effects on global GHG emissions are also taken into account by using system modeling and streamlined LCA.
Article
Full-text available
Since the very first European research project initiated in 1993, much progress has been made in Europe on the development of CO2 geological storage as a key tool for combating climate change. A review of the main achievements and remaining obstacles in Europe is proposed, with a glance at what is going on at global level. Scientific, technical, economic, regulatory and policy aspects are considered. The increasing role of the growing CO2GeoNet Association, a reference pan-European scientific body on CO2 geological storage, is emphasized, with actions both on the EU and global scene for enabling efficient and safe storage.
Article
Full-text available
In future energy systems with high shares of fluctuating renewable energy generation, electricity storage will become increasingly important for the utilization of surplus energy. The Power-to-Gas (PtG) technology is one promising option for solving the challenge of long-term electricity storage and is theoretically able to ease situations of grid congestion at the same time. This article presents the perspectives of PtG in an 85% renewable energy scenario for Germany, quantifying an economic optimum for the PtG capacity as well as an optimized spatial PtG deployment.
Article
Power-to-gas (PtG) technology has received considerable attention in recent years. However, it has been rather difficult to find profitable business models and niche markets so far. PtG systems can be applied in a broad variety of input and output conditions, mainly determined by prices for electricity, hydrogen, oxygen, heat, natural gas, bio-methane, fossil CO2 emissions, bio-CO2 and grid services, but also full load hours and industrial scaling. Optimized business models are based on an integrated value chain approach for a most beneficial combination of input and output parameters. The financial success is evaluated by a standard annualized profit and loss calculation and a subsequent return on equity consideration. Two cases of PtG integration into an existing pulp mill as well as a nearby bio-diesel plant are taken into account. Commercially available PtG technology is found to be profitable in case of a flexible operation mode offering electricity grid services. Next generation technology, available at the end of the 2010s, in combination with renewables certificates for the transportation sector could generate a return on equity of up to 100% for optimized conditions in an integrated value chain approach. This outstanding high profitability clearly indicates the potential for major PtG markets to be developed rather in the transportation sector and chemical industry than in the electricity sector as seasonal storage option as often proposed.
Conference Paper
Power-to-gas (PtG) technology has received considerable attention in recent years. However, it has been rather difficult to find profitable business models and niche markets so far. PtG systems can be applied in a broad variety of input and output conditions, mainly determined by prices for electricity, hydrogen, oxygen, heat, natural gas, bio-methane, fossil CO2 emissions, bio-CO2 and grid services, but also full load hours and industrial scaling. Optimized business models are based on an integrated value chain approach for a most beneficial combination of input and output parameters. The financial success is evaluated by a standard annualized profit and loss calculation and a subsequent return on equity consideration. Two cases of PtG integration into an existing pulp mill as well as a nearby bio-diesel plant are taken into account. Commercially available PtG technology is found to be profitable in case of a flexible operation mode offering electricity grid services. Next generation technology, available at the end of the 2010s, in combination with renewables certificates for the transportation sector could generate a return on equity of up to 100% for optimized conditions in an integrated value chain approach. This outstanding high profitability clearly indicates the potential for major PtG markets to be developed rather in the transportation sector and chemical industry than in the electricity sector as seasonal storage option as often proposed.
Book
Increased production of energy from renewable sources leads to a need for both new and enhanced capacities for energy transmission and intermediate storage. The book first compares different available storage options and then introduces the power-to-gas concept in a comprehensive overview of the technology. The state of the art, advancements, and future requirements for both water electrolysis and methanation are described. The integration of renewable hydrogen and methane into the gas grid is discussed in terms of the necessary technological measures to be taken. Because the power-to-gas system is very flexible, providing numerous specific applications for different targets within the energy sector, possible business models are presented on the basis of various process chains taking into account different plant scales and operating scenarios. The influence of the scale and the type of the integration of the technology into the existing energy network is highlighted with an emphasis on economic consequences. Finally, legal aspects of the operation and integration of the power-to-gas system are discussed
Article
Large-scale systems suitable for the production of synthetic natural gas (SNG), methanol or gasoline (MTG) are examined using a self-consistent design, simulation and cost analysis framework. Three basic production routes are considered: (1) production from biomass via gasification; (2) from carbon dioxide and electricity via water electrolysis; (3) from biomass and electricity via hybrid process combining elements from routes (1) and (2). Process designs are developed based on technologies that are either commercially available or successfully demonstrated at precommercial scale. The prospective economics of future facilities coproducing fuels and district heat are evaluated from the perspective of a synthetic fuel producer. The levelised production costs range from 18–37 €/GJ for natural gas, 21–40 €/GJ for methanol and 23–48 €/GJ for gasoline, depending on the production route. For a given end-product, the lowest costs are associated with thermochemical plant configurations, followed by hybrid and electrochemical plants.
Article
Mitigation of the variability in output power of renewable generators such as solar photovoltaic (PV) systems is a growing concern as these generators reach higher penetrations on electric grids. Furthermore, increased penetration of electric vehicle (EV) loads presents a challenge for distribution feeders. This paper presents a system where a bidirectional, highly efficient, dc-dc EV charger is placed between the high-voltage dc bus of a PV inverter and the EV battery. The system partially alleviates feeder overloading by providing fast charging for the EV battery from the PV system. In addition, the charger is capable of diverting fast changes in PV power output to the battery, thereby reducing the rate of change of inverter output power to a level below the ramp rate of existing grid resources. The paper addresses sizing of the charger and energy storage based on the PV system rating, the desired maximum ramp rate, and site solar irradiation characteristics, including geographic dispersion of PV arrays. Analysis suggests that small amounts of energy storage can accomplish large reductions in output power ramp rate. Experimental results are shown for a 10 kW, 98% efficient dc-dc charger based on bidirectional four-phase zero-voltage-switching converter.
Article
Since large-scale and cheap energy storage is an unsolved problem, the main difficulty of using wind and solar electricity is caused by their intermittent nature. It is a widespread belief that the combination of the two renewable technologies generally improves the reliability and supply quality of electricity generation. Indeed, there are some locations where wind speeds are definitely larger during the nights because of the increased stability of the atmospheric boundary layer. However, a proper decision making requires to study the supposed benefits at the very location of designed installations. Here, we report on a model study, where the whole area of Hungary is evenly covered by wind generators and solar photovoltaic units of various composition and total rated power. The combined model output is compared to the recorded electricity consumption in Hungary. Our results indicate that the integrated output of combined renewable production can be definitely lower than the output of “pure” (either solar or wind) resource network of the same rated power. The main reasons are the lack of daily cycle of wind strength and the strong annual seasonality of insolation in the Carpathian basin. Benefits of combined production show up at unrealistically high rated power values which is a consequence of limited capacity factors of both renewable sources around Hungary.
Article
The paper is focused on the idea of large-scale CFB boiler operation with oxygen/CO2-modified atmosphere inside combustion chamber. The following main advantages can be found for this technology: reduction of pollutant emissions, possibility of high efficiency separation of CO2 from the exhaust gases that results from increased CO2 concentration, lower chimney loss due to the reduction of flue gases in a volume, limitation of the combustion chamber dimensions etc. The paper presents a model of coal combustion in oxygen-enriched CFB environment, where air staging, desulfurization process, NOx formation and reduction as well as a stationary dense phase of coarse particles in the bottom part of combustion chamber and a circulating dilute phase in the upper part are included.
Article
In this work, we examine some of the limits to large-scale deployment of solar photovoltaics (PV) in traditional electric power systems. Specifically, we evaluate the ability of PV to provide a large fraction (up to 50%) of a utility system's energy by comparing hourly output of a simulated large PV system to the amount of electricity actually usable. The simulations use hourly recorded solar insolation and load data for Texas in the year 2000 and consider the constraints of traditional electricity generation plants to reduce output and accommodate intermittent PV generation. We find that under high penetration levels and existing grid-operation procedures and rules, the system will have excess PV generation during certain periods of the year. Several metrics are developed to examine this excess PV generation and resulting costs as a function of PV penetration at different levels of system flexibility. The limited flexibility of base load generators produces increasingly large amounts of unusable PV generation when PV provides perhaps 10–20% of a system's energy. Measures to increase PV penetration beyond this range will be discussed and quantified in a follow-up analysis.
Article
Oxygen enrichment of the combustion air in pulverised coal combustion for power plant is seen as a possible retrofit measure to improve CO2 scrubbing and capture. This technique produces a reduced volume of flue gas with higher CO2 concentration than normal air combustion that will contributes to the enhancement of amine scrubbing plant efficiencies. We report in this article the results of a study at the small pilot scale into the effect of these combustion modifications on the formation of NOx and associated carbon burnout changes. Experiments were performed using a Russian coal, typical of that used in some UK power stations with shea meal and Pakistani cotton stalk as biomass fuels co-fired at a fraction of 15%th. The down-fired pulverised coal combustor was operated at 20 kWth under air-staged conditions for NOx control and the secondary and over-fire air flows were both enriched by up to 79% (100% O2) for a range of splits giving a 35% overall O2 concentration for full enrichment. When the same enrichment process was applied to biomass/coal combustion different behaviour was observed with respect to NOx formation. We have shown that oxygen enrichment can achieve benefits of improved carbon burnout with a positive impact on NOx emissions over and above the primary aim of increasing CO2 concentration in the flue gas for enhanced capture efficiencies. With all other conditions of overall stoichiometry, OFA levels and O2 enrichment levels remaining the same, NOx levels at 22% OFA initially increased over the range of secondary air enrichment, particularly for shea meal/coal co-firing. At 31% OFA the trends were to lower NOx at high enrichment levels. However, co-firing with shea meal initially showed an increase in NOx emission at lower levels of enrichment (up to 40% O2) followed by overall lower NOx emissions at 100% O2 in the secondary air. The results show that NOx emissions can either increase or decrease depending on the operating conditions. The differences in behaviour are attributed, not only to the effects of enrichment on the stoichiometry of the near-burner zone, but also on the flame dynamics and intensity of combustion related to the associated reductions in gas velocity and swirl intensity by the transition from air to pure O2 in the secondary oxidant stream.
Fuel classification for national GHG inventories
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The role of power-to-gas in achieving Germany's climate policy targets with a special focus on concepts for road based mobility
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Concept description and safety considerations for the application of oxygen enriched air (OEA) technology in recovery boilers
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Oxygen-enriched biomass combustion studies and an analysis of the development of the carbon capture and storage industry in the UK. Integrated PhD and Master thesis
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