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The value of co-operation: Opportunities for deployment of rooftop photovoltaics on Australian apartment buildings
Abstract and Figures
Photovoltaic (PV) generation is emerging as a significant technology in the global energy
transition. However, while rapid urbanisation is driving increasing housing density, PV uptake in multi-occupancy housing has been limited by comparison with stand-alone housing in many jurisdictions, including in Australia, despite its world-leading 22% residential PV penetration. This thesis presents a multidisciplinary analysis of the opportunities and challenges for, and costs and benefits of, rooftop PV deployment on Australian apartment buildings.
A novel geospatial analysis was used to assess the opportunity for solar on Australian apartment rooftops. Statistical and cluster-based analysis was used to characterise individual and aggregated apartment load profiles. Reviews of the academic literature and Australian regulatory arrangements, together with a series of stakeholder interviews, were undertaken to identify potential implementation arrangements for, and barriers to, deployment of apartment PV. Modelling of PV generation, energy and financial flows was used to compare outcomes for diverse buildings under different PV configurations. The size and diversity of the dataset and the variety of arrangements modelled represents a significant contribution to the literature.
The thesis identifies potential PV capacity of 2.9GW – 4.0GW on Australian apartment buildings and describes significant differences between load profiles of apartments and houses. Applying PV generation to aggregated building loads is shown to increase self-sufficiency and PV self-consumption, compared to separate systems supplying common property or individual apartments, and can sometimes generate financial benefits for customers. While embedded networks can enable access to beneficial retail arrangements, behind the meter solutions may reduce regulatory complexity and cost. Optimum solutions depend on building characteristics and financial settings. Adding battery energy storage systems (BESS) can further increase self-sufficiency
and decrease peak demand but the economic case is not compelling with current
capital costs.
Barriers including building stock diversity, demographic factors and knowledge issues, as well as specific Australian regulatory arrangements concerning governance of apartment buildings, regulation of the energy market, and electricity tariff policies, impact on the options available to apartment residents to act co-operatively in accessing renewable energy. This research identifies possible emerging business models and policy approaches to support increased apartment PV deployment.
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... There is generally a mismatch between the profile of solar PV generation and that of the building energy use [13]. The former typically peaks around midday, while the peak demand for residential buildings often occurs in the afternoon, at around 5 pm [14]. When a building has rooftop PV, any surplus PV generation is sold back to the electricity network. ...
Ever increasing numbers of air-conditioners and, in many places, more extreme weather and urban overheating are placing additional stresses on electricity networks globally, reflecting not only their high power draw but also highly correlated operation driven by weather conditions. The resulting peak demands can be considerably greater than average network flows requiring additional electricity generation and network capabilities for what might only be infrequent periods. Energy users must of course pay for this additional investment, including potentially via peak demand and time-of-use charges. Pre-cooling of buildings to spread air conditioning demand is one approach to reduce these peaks. Its potential contribution depends on the thermal performance of the building stock, particularly how long it can retain pre-cooled air, and patterns of weather on warm days. The use of solar energy, including particularly rooftop solar photovoltaics presents another possible option. Photovoltaics generates during daylight hours, which is well-matched with higher temperatures. However, photovoltaics generation may often be declining while heat loads in buildings and hence air conditioning are still climbing in the late afternoon. This suggests the potential of solar pre-cooling when solar photovoltaic electricity is used to run air conditioners in the pre-cooling phase. Literature reviews to date have tended to focus on only aspects of pre-cooling and solar pre-cooling, for example, the effect of thermal mass on the energy performance of buildings but not specifically on peak demand shifting and cost reduction. There is a particular gap with review papers that investigate pre-cooling and solar pre-cooling together with detailed characterization of their potential in different circumstances. The review presented here covers a wide range of state-of-the-art studies in the field of pre-cooling and solar pre-cooling covering the period 2014 to 2021. It also presents, for the first time, the necessary steps to design and implement pre-cooling and solar pre-cooling strategies. It is intended to support the growing research studies and practical implementations of pre-cooling and solar pre-cooling within the electricity sector.
This handbook provides a broad introduction to qualitative research to those with little to no background in the subject while simultaneously providing substantive contributions to the field that will be of interest to even the most experienced researchers. The first two sections explore the history of qualitative research, ethical perspectives, and philosophical/theoretical approaches. The next three sections focus on the major methods of qualitative practice, as well as on newer approaches (such as arts-based research and internet research); area studies often excluded (such as museum studies and disaster studies); and mixed methods and participatory methods (such as community-based research). The next section covers key issues including data analysis, interpretation, writing, and assessment. The final section offers a commentary about politics and research and the move toward public scholarship. The Oxford Handbook of Qualitative Research is intended for students of all levels, faculty, and researchers across the social sciences.
As subsidised feed-in-tariffs for distributed photovoltaic (PV) generation are reduced or abolished in many jurisdictions, there is growing interest in increasing self-consumption to realise greater value from rooftop PV generation. However, deployment of PV on apartment buildings lags behind other residential deployment despite the potential advantages of load aggregation. We present a study of electricity and financial flows in ten 'virtual' Australian apartment buildings under a range of technical implementations and financial arrangements, using real load profiles and simulated generation profiles. Aggregation of diverse household and shared loads, either through an embedded network or 'behind the meter' of individual dwellings, can increase self-sufficiency and self-consumption of on-site generation compared to separate systems supplying common property or individual apartments. While embedded networks can enable access to more beneficial retail arrangements, behind the meter solutions may allow residents to avoid regulatory complexities and additional costs. The relative benefits of each arrangement are dependent on building characteristics and financial settings.
Over the last two decades, grid-connected solar photovoltaic systems have increased from a niche market to one of the leading power generation capacity additions annually. In 2018 the total installed photovoltaic electricity generation capacity exceeded 500 GW. Another doubling is forecasted until the early 2020s. Therefore, the further development is coupled with the question at what prices solar photovoltaic electricity can be provided and delivered to the customers. The installation of PV systems for self-consumption is already now an interesting option for many people but in general limited to those who have access to a rooftop they own or can use. A new envelopment to enable residents of multi apartment buildings to commonly use electricity generated by a PV system (collective self-consumption) is a relatively new development and is still facing a lot of administrative and regulatory challenges.
Understanding of residential electricity demand has application in efficient building design, network planning and broader policy and regulation, as well as in planning the deployment of energy efficiency technologies and distributed energy resources with potential emissions reduction benefits and societal and household cost savings. Very few studies have explored the specific demand characteristics of apartments, which house a growing proportion of the global urban population.
We present a study of apartment electricity loads, using a dataset containing a year of half-hourly electricity data for 6,000 Australian households, to examine the relationship between dwelling type, demographic characteristics and load profile. The focus on apartments, combined with the size of the data set, and the representative seasonal load profiles obtained through clustering full annual profiles, is unique in the literature. We find that median per-occupant household electricity use is 21% lower for apartments than for houses and that, on average, apartments have lower load factor and higher daily load variability, and show greater diversity in their daily peak times, resulting in a lower coincidence factor for aggregations of apartment loads. Using cluster analysis and classification, we also show the impact of dwelling type on the shape of household electricity load profiles.
Distributed photovoltaics is playing a growing role in electricity industries around the world, while Battery Energy Storage Systems are falling in cost and starting to be deployed by energy consumers with photovoltaics. Apartment buildings offer an opportunity to apply central battery storage and shared solar generation to ag-gregated apartment and common loads through an embedded network or microgrid. We present a study of energy and financial flows in five Australian apartment buildings with photovoltaics and battery storage using real apartment interval-metered load profiles and simulated solar generation profiles, modelled using an open source tool developed for the purpose. Central batteries of 2-3 kWh per apartment can increase solar self-consumption by up to 19% and building self-sufficiency by up to 12%, and shave overall building peak demand by up to 30%. Although the economic case for battery storage applied to apartment building embedded networks is not compelling at current capital prices, with cost thresholds of AU750/kWh compared to AU1000/kWh for individual household systems, there are clear financial benefits to deployment of embedded networks with combined solar and battery storage systems for many sites.
Clustering is one of the important unsupervised learning in data mining to group the similar features. The growing point of the cluster is known as a seed. To select the appropriate seed of a cluster is an important criterion of any seed based clustering technique. The performance of seed based algorithms are dependent on initial cluster center selection and the optimal number of clusters in an unknown data set. Cluster quality and an optimal number of clusters are the important issues in cluster analysis. In this paper, the proposed seed point selection algorithm has been applied to 3 band image data and 2D discrete data. This algorithm selects the seed point using the concept of maximization of the joint probability of pixel intensities with the distance restriction criteria. The optimal number of clusters has been decided on the basis of the combination of seven different cluster validity indices. We have also compared the results of our proposed seed selection algorithm on an optimal number of clusters using K-Means clustering with other classical seed selection algorithms applied through K-Means Clustering in terms of seed generation time (SGT), cluster building Time (CBT), segmentation entropy and the number of iterations (NOTK−means ). We have also made the analysis of CPU time and no. of iterations of our proposed seed selection method with other clustering algorithms.
The decreasing cost of energy storage and increasing demand for local flexibility are opening up new possibilities for energy storage deployment at the local level. Community energy storage (CES) is expected to contribute positively towards energy transition while accommodating the needs and expectations of citizens and local communities. Yet, the technological and societal challenges of integrating CES in the largely centralized present energy system demand for socio-technical innovation. In this article, we develop and discuss several configurations of CES. Applying system innovation and socio-technical transition frameworks and conceptualizing CES as a complex socio-technical system, different dynamics of CES in the energy systems such as coordination and interaction among actors and components of CES and the larger energy system is explored. The responsible research and innovation (RRI) framework can provide a new discourse in design and implementation of CES, facilitating the transition to a sustainable, reliable, inclusive and affordable future energy system.
Cityscapes provide a complex environment, where solar radiation is unevenly distributed, especially since urban features started to propagate more and more vertically. Due to the dynamic overshadowing effects present on building surfaces, quantifying these phenomena is essential for predicting reductions in solar radiation availability that can significantly affect potential for solar energy use. Numerical radiation algorithms coupled with GIS tools are a pathway to evaluate those complex effects. Accurate representation of the terrain, vegetation canopy and building structures allows better estimation of shadow patterns. Higher spatial and temporal resolutions deliver more detailed results, but models must compromise between accuracy and computation time. In this paper, models ranging from simple 2D visualization and solar constant methods, to more sophisticated 3D representation and analysis, are reviewed. Web-based solar maps, which rely on the previous features to successfully communicate the benefits of the solar resource to the public and support in the policy-making process, are also addressed.
This paper reviews opportunities for, and barriers to, increasing photovoltaic (PV) deployment on apartment buildings, with a particular focus on the Australian experience.
As rapid urbanisation drives increasing housing density, PV penetration in multi-occupancy housing has been limited by comparison with stand-alone housing in many jurisdictions, including in Australia despite its worldleading residential PV penetration. Given the growing commercial attractiveness of residential PV, this also raises equity concerns for apartment households.
PV can potentially be installed to supply electricity to common property, to serve individual apartments, or as a resource shared between multiple apartments through embedded networks, local energy trading or ‘behind the meter’ deployment models.
Our study undertook a review of the academic literature in this space and of specific Australian regulatory arrangements, as well as conducting a series of semi-structured interviews with a range of relevant stakeholders.
Barriers identified include the huge variety amongst existing apartment building stock, demographic factors and knowledge issues. However, the Australian regulatory context - including governance of apartment buildings, regulation of the energy market, and electricity tariff policies - also impacts on the options available to apartment
residents.
New business models for deploying PV on apartments are emerging, including initiatives from retailers, developers and community energy organisations. While some issues are specific to the Australian context, or to buildings governed under strata-type arrangements, broader lessons can be taken from the Australian experience,
including to inform the design of the regulatory framework required to facilitate widespread PV deployment across all residential housing types.
Residential solar photovoltaics (PV), a once niche technology reliant on direct regulatory support to stimulate its adoption, has progressively become more competitive because of economies of learning and scale in production. Given its extraordinary market growth, a better understanding of the various market and social factors affecting residential consumers’ PV purchasing decisions is required for policy makers to create efficient support mechanisms, by industry participants to better target marketing activities, and for more informed planning of centralised electricity generation and network infrastructure development. This paper reports on an analysis of the behavioural drivers of households as decision-making units fulfilling an intention to adopt PV. Drawing upon Rogers’ diffusion of innovation theory and using a logistic regression choice model, the actual outcomes of the residential PV market are examined in the state of Queensland, Australia. A recent survey of more than 8000 households is used to investigate the difference in demographic and motivational factors among households with the stated intention to purchase PV with those that have already adopted the technology. Our findings suggest that PV is the technology of the middle class. This reasoning is made based on surveyees’ stated concerns over rising electricity bills and survey data which indicates that economic life events have a significant influence over perceptions of affordability. Households need to be concerned with rising electricity bills to be motivated to adopt PV, but must also have access to sufficient capital to afford its upfront cost. Familiarity with the technology appeared to reduce adoption motivations based on self-sufficiency and intentions to go off grid.