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Over the past 5 decades, investment by IEA member countries in energy RD&D has become progressively more diverse. Nuclear power, which accounted for 76% of the total in 1974, declined every year to 21% in 2021. RD&D budgets on fossil fuels, which were at their highest in the 1980s and early 1990s, have declined since 2013 (14%) to 8% in 2021.

Budgets for both energy efficiency and renewables expanded significantly faster during the 1990s and 2000s, from 7% each in 1990 to 22% and 21% respectively in 2010. Since then, the share of energy efficiency has increased to reach 26%, whilst the share of renewables has declined to 14%. Budgets for hydrogen and fuel cells maintained their share at 3% for the period 2012-2018 to increase to 5% in 2021.

Evolution of IEA total public energy RD&D by technology, 1974-2021


In 2021, the United States held on to first place followed by Japan in terms of RD&D budget for nuclear (USD 1738 million), while Japan remained the highest funder of hydrogen and fuel cell research (USD 233 million). In 2020, the European Union spent a fifth of its total RD&D budget on power and storage technologies (USD 514 million), making it the largest spender for this category. For all remaining technologies, the United States had the largest budgets.1

In 2021, the budget of IEA countries increased for all types of technology except for energy efficiency and cross-cutting technologies, which decreased by respectively 2% and 3%. The highest increase was 27% for hydrogen and fuel cells, which followed a 23% increase in 2020.

2002 and 2021 budgets by technology in selected IEA countries and in the European Union

Notes and references
  1. Data for the United States have been estimated by the IEA Secretariat for 2016-2021.