On flexible hydropower and security of supply: Spain beyond 2020

Generation adequacy is a key ingredient to security of electricity supply (SoS). Some national plans envisage a future decrease in the number of coal-fired stations and an increase in renewable installed capacity. This forecast, along with the future reduction of nuclear capacity, will lead to a combination of less baseload plants and sizeable intermittent generation. Hence there is a risk that supply will be unable to meet demand and generation adequacy will suffer. We assess how the flexible management of hydro resources can alleviate this risk by adjusting power generation to peak demand. Indeed there is empirical evidence that they are positively correlated. We compute this correlation in the case of Spain (an ‘electric island’). Besides, hydro plants operate in combination with other non-dispatchable technologies within the system. Therefore, we also take their hourly seasonality into account. Next we run a Monte Carlo simulation to derive the risk profile of several adequacy metrics in the coming decades. Our results show that flexible hydro generation certainly mitigates the risk but is insufficient to bring an adecuate level of SoS when the enhanced renewable capacity goes hand in hand with a decreased baseload capacity. The risk further decreases after accounting for seasonal non-dispatchable generation, yet it still looms large. These results can be important for policy makers, system operators, and power companies when analizing investments in renewable energy with a long lifespan. •Generation adequacy is a key ingredient to security of electricity supply.•We check the feasibility of meeting stochastic demand with a given generation park.•We consider Spain (an ‘electric island’) up to 2050 and several adequacy metrics.•Flexible hydro generation significantly alleviates the risk of power shortages.•It is unable to keep risk subdued despite other non-dispatchable seasonal generation.