Self-consumption potential and surplus compensation policy impact on rooftop photovoltaic systems in Spain

This research examines the viability of rooftop photovoltaic systems for electricity self-consumption in Spain's residential sector, analyzing municipality-level data on electricity demand, rooftop availability, solar irradiance, and various electricity market and surplus policy scenarios. Differences are found between rural and urban contexts, with rural areas exhibiting greater potential for photovoltaic systems deployment due to more available rooftop space. The study highlights the crucial role of surplus electricity management, showing that an efficient use can significantly boost self-consumption potential, particularly in rural areas where surplus constitutes about two-thirds of the photovoltaic production. Economic analyses under different electricity market conditions and surplus compensation policies show that these factors critically affect the attractiveness and viability of these systems. Current high electricity prices in Spain have reduced their payback period, but the prevalent surplus compensation policy, a 1-month net billing feed-in tariff, reduces their cost-effectiveness by up to 60 % compared to a hypothetical 12-month net billing approach. The findings underscore the need for policy adjustments to maximize rooftop occupancy and ensure fair compensation of surpluses, highlighting the importance of tailored strategies for effective sustainable photovoltaic systems deployment in residential contexts.