Long-Term Solar Photovoltaics Penetration in Single- and Two-Family Houses in Switzerland

Abstract

The Swiss energy strategy aims at increasing electricity generation from solar power by 2050, to fulfil Switzerland’s commitments in the Paris Agreement. However, the market of single- and two-family houses is characterized by low return rates for excess power injected to the grid, and the installation of rooftop solar photovoltaic (PV) is sensitive to financial incentives. We assess the drivers influencing the diffusion of rooftop solar PV systems until 2050, by employing an agent-based model. An agent is a single- or two-family house, and its decision to invest depends on the economic profitability of the investment, the agent’s income, environmental benefits (injunctive social norm), awareness and knowledge about the solar PV technology, and the impact of the social network (descriptive social norm). The model includes a synthetic population of agents, statistically equivalent to the true population. We also investigate the impact of different support policies, technology learning rates, electricity prices, and discount rates on the investment decision. We find that the concept of prosumer emerges, mainly via self-consumption strategies. The diffusion process of rooftop solar PV systems in single- and two-family houses gains momentum in the future. In the near-term, PV deployment is sensitive to the profitability of the investment, while after the year 2030, peer effects play an increasing role in the agents’ investment decisions.