Future electricity mix and the role of natural gas in Western Europe's carbon-free transition

Abstract

This thesis studies the optimal electricity mix to be implemented by 2050 in six Western European countries (Belgium, Luxembourg, France, the Netherlands, Germany, and Great Britain), interconnected by electricity and gas grids, enabling their electricity demand to be met under the climate constraint of net carbon neutrality across the entire system.

This system is modelled using the optimisation language GBOML (Graph-Based Optimisation Modelling Language), which allows writing mathematical problems. Several scenarios aim to best estimate the future of the electricity mix in 2050 by imposing realistic limits on the installation capacity of renewable technologies, as well as the future of nuclear power in Europe, while observing the fluctuating prices of natural gas. The main objective is to determine under which conditions gas-fired power plants can still contribute to a zero-carbon electricity system by analysing their economic competitiveness despite ecological constraints and exploring the use of alternative low-carbon fuels such as hydrogen.

The results obtained demonstrate the need to use gas-fired power stations, even in scenarios with a high penetration rate of renewable energies or scenarios with low restrictions on nuclear energy, as back-up sources of production during periods of high electricity demand or low renewable electricity production. Conversely, in the most limited scenarios with restrictive limits on renewable capacities or without nuclear power plants, gas-fired power plants therefore play a role as an essential component for the system's electricity production and no longer simply as a backup solution. However, their economic profitability depends heavily on the purchase price of natural gas. In a system constrained both by the renewal of the existing nuclear fleet in 2019 and by the imposition of limits on the installation of renewable capacities, the economic tipping point at which the system uses hydrogen to fuel gas-fired power plants instead of natural gas is reached from a natural gas price of 145 €/MWh. In another configuration in which the system is devoid of nuclear production capacities but accepts double the maximum installation of renewable power sources compared to the previous case, this threshold is pushed back to 155 €/MWh.