Over 1.7 Australian households have taken the opportunity to generate some of their own power and reduce both their electricity bills and carbon emissions by installing rooftop photovoltaic (PV) systems on their homes. However, regulatory, technical, financial and organisational challenges have largely prevented Australia's growing number of urban apartment dwellers from accessing these benefits.
Although a number of apartment buildings have installed PV systems to meet common property (CP) loads, over 60% of Australian apartments are in buildings of less than four storeys, where potential rooftop PV generation is likely to exceed CP demand. Shared PV systems in such buildings might be configured to supply local generation to apartments either 'behind the metre' (BTM) or via an embedded network (EN). There are, of course, different implications for these approaches in terms of the risks, costs and benefits for different stakeholders.
Aggregation of diverse apartment energy demands through an embedded network can flatten overall load profiles and increase PV self-consumption, as well as affording access to more beneficial retail arrangements. However, the complexities of the regulatory environment and costs of EN installation can create barriers to this approach. BTM solutions may allow residents to avoid engagement with the regulatory requirements placed on retailers and EN operators, but typically result in lower levels of self-consumption and higher household tariffs. This study seeks to compare the costs and benefits of these two possible arrangements.
There is a dearth of published interval load data for Australian apartment buildings. However, the Smart Grid Smart Cities (SGSC) dataset includes 30-minute annual load for 2080 apartments across New South Wales. Firstly, using this data, this study examines the effect of aggregating apartment loads on the variability of total load profiles and on PV self-consumption. Then, SGSC apartment load profiles are combined with CP load profiles collected for building energy audits at 10 sites in the Sydney metropolitan area to create multiple 'virtual apartment buildings' for each site. Rooftop solar generation is modelled for these buildings using historic weather data and visual assessment of rooftop potential, and energy flows are calculated throughout the buildings for both EN and BTM arrangements. Some initial financial settings are applied to assess the relative total benefits of each scenario.