Exogenous influences on deployment and profitability of photovoltaics for self-consumption in multi-apartment buildings in Australia and Austria

Although the amount of solar photovoltaic systems installed in residential buildings is increasing globally, it is largely limited to single-occupancy dwellings and is extremely uneven across jurisdictions. Deployment on apartment buildings remains low, even in Australia with its world-leading residential photovoltaic penetration, or in countries subject to specific enabling legislation, such as Austria. We present a comparative study of photovoltaic system deployment on multi-occupancy residential buildings in these two countries, examining the impact of their distinct climates, financial settings, heating and cooling technologies and regulatory environments. A mixed-integer linear optimisation model is used to compare cost-optimal photovoltaic system size and achievable cost savings for a nine-apartment building. We find that Australia’s higher insolation and lower investment costs drive higher optimal system size and bill savings, but lower electricity tariffs and regulatory barriers constrain deployment. By contrast, European enabling legislation has not yet achieved success in overcoming Austria’s higher investment costs and lower solar exposure, partly due to significant administrative hurdles. Our findings point to possible country-specific policy approaches to increase deployment in this important sector.