Modelling reliability under deep decarbonisation of the European electricity grid

We introduce a new model able to characterise the relative costs of low-carbon generation mixes when subject to varying grid-reliability targets, which are evaluated using 43 years of historical weather data. The model can be used to develop cost-minimising strategies, and to assess the extent, duration, and frequency of outages under different technology mixes. For a 35-country subset of the European electricity grid, we show that reliably meeting the last 1% of demand accounts for about 36% of the entire system cost when only onshore wind, solar, and storage are used in the generation mix. We also show that by including small amounts of low-cost, dispatchable load-following generation (e.g., natural gas, hydro, or similar) the cost of a reliable, high-renewables grid can be drastically reduced. For example, the system cost can be reduced by 31% when just 1% of generation is allowed to come from natural gas.