The resilience of a decarbonized power system to climate variability: Portuguese case study

Climate influences renewable energy resources and energy demand, and therefore its interannual variability ought to be considered when designing future renewable-based power systems. This work models a 100% renewable power system considering 473 climate projections based on IPCC RCP4.5 and 8.5, using Portugal in 2050 as a case study. Five demand-flexibility scenarios are explored, combining different levels of electricity demand and system flexibility. It is found that demand and climate variability are crucial to the planning of power systems. When planning for a median climate, the required capacity varies 3-fold for the range of demand scenarios considered. For the system to be resilient under unfavorable climates, cross-border interconnection power capacity should be doubled while storage should increase up to 200-fold, compared to the system designed for the median climate. Modeling for unfavorable climates leads to +54% renewable power capacity and a 6-fold increase in curtailment of renewable energy generation, thus increasing electricity cost. It is therefore shown that the design of a fully decarbonized power system ought not to be based only on median future climates but should take into account its interannual variability. •The resilience of a fully decarbonized power system is explored.•Climate variability and electricity demand scenarios are considered simultaneously.•A 3-fold increase on renewable capacity is required from low to high demand scenarios.•Twice as much cross-border interconnection capacity required for unfavorable climate than for median climate.•Unfavorable climate requires +54% renewable capacity than the median climate.