The 2030 power sector transition in Spain: Too little storage for so many planned solar photovoltaics?

This work deals with the 2030 power transition in Spain following the pledges with the European Union targets of reaching climate neutrality, or net zero emissions, by 2050. Within this context, we analyze in this work the plan established by the Spanish government under the umbrella of the National Integrated Energy and Climate Plan which fixes very specific objectives for the evolution of the electricity power mix for the period 2020–2050. In the case of photovoltaics, it would imply to multiply by almost a factor of four its 2020 value, reaching near 40 GW in 2030. Being photovoltaics a variable, non-dispatchable renewable energy, to take full advantage of it, it would be needed a large amount of storage capacity and backup power with very fast ramping responses. Otherwise, we would have to curtail part of the incoming solar photovoltaic energy. Based on historical data and making use of duck curves, we have also shown that the large growth of PV (2020–2030) will require needs of storage capacity and/or backup reaching values of 5 GW per hour during 4 h during the afternoon–evening. According to the National Integrated Energy and Climate Plan, our results show that this plan has not yet properly foreseen these requirements and some curtailment may be needed.