IEA (2022), Variations in public low-carbon energy RD&D budgets for selected IEA countries and the European Union, 2021, IEA, Paris https://www.iea.org/data-and-statistics/charts/variations-in-public-low-carbon-energy-rd-and-d-budgets-for-selected-iea-countries-and-the-european-union-2021, Licence: CC BY 4.0