Assessing the need for flexibility technologies in decarbonized power systems: A new model applied to Central Europe

The increasing use of renewable energy leads to a higher share of intermittent and volatile electricity generation. In this paper, we develop FLEXIES, a new open-source power system optimization model to determine the cost-efficient deployment of renewable electricity generation technologies and flexibility technologies. We apply FLEXIES in a case study of power systems in Central Europe (Switzerland, Austria, France, Germany, and Italy) in 2030, 2040, and 2050. The case study indicates that low-carbon electricity generation, batteries, and power-to-gas, consisting of multiple gas storages, are cost-efficient in 2050 - rather than burning natural gas in gas turbines. Such decarbonized power systems could be cost-efficient earlier assuming sufficiently high carbon prices. Furthermore, we find that onshore wind is prioritized over highly volatile solar generation due to a lower need for electricity storage. Interconnections enable higher shares of uniform generation technologies (on- and offshore wind, nuclear, biomass-waste) and reduce the need for solar and storage. Hence, compared to a case in which countries are isolated, interconnections reduce total electricity generation by up to 8.2%, system costs by up to 16.3%, and carbon equivalent emissions by up to 9.0%. Finally, we observe that decarbonized power systems entail a cost shift from the operational to the investment phase and total normalized costs could be higher than power market prices. Thus, new mechanisms may be needed to incentivize decarbonized power systems.

Automated summary

The study introduces a new power system optimization model named FLEXIES to determine the cost-efficient deployment of renewable electricity generation technologies and flexibility technologies. Through a case study of power systems in Central Europe, it is found that low-carbon electricity generation, batteries, and power-to-gas are cost-efficient in 2050, while interconnections reduce total electricity generation, system costs, and carbon equivalent emissions.