On the potential contribution of rooftop PV to a sustainable electricity mix: the case of Spain

TL;DR

This study assesses how rooftop photovoltaic systems can contribute to Spain's sustainable electricity future, considering different scenarios with renewables and storage, and finds that modest storage can enable low-cost, near-emissions-free electricity.

Contribution

It provides a detailed, granular analysis of rooftop PV's potential in Spain, incorporating storage and flexible generation, which is a novel approach for this context.

Findings

Modest storage capacities suffice for a sustainable system.

A near-emissions-free electricity system is achievable at low cost.

Rooftop PV can significantly contribute to Spain's energy mix.

Abstract

This work evaluates the potential contribution of rooftop PV to the future electricity mix. Several sustainable scenarios are considered, each comprising different shares of centralized renewables, rooftop PV and storage. For each generation scenario, the storage capacity that balances the net hourly demand is determined, and the portfolio combination that minimizes the cost of supplying electricity is obtained. The analysis is applied to mainland Spain, using public information and detailed granular models, both in time (hourly resolution) and space (municipal level). For the Spanish case, when the flexibility of hydro and biomass generation is taken into account, the least-cost portfolio involves rather modest storage capacities, in the order of daily rather than seasonal values. This shows that a sustainable, almost emissions-free electricity system for Spain is possible, at a cost that can be even lower than current wholesale market prices.