National hydrogen strategies:Policy impacts and adoption drivers

The global transition to low-carbon energy has led many countries to adopt national hydrogen strategies, yet their policy impacts and adoption drivers remain poorly understood. This paper investigates these issues using panel data for 49 countries from 2010 to 2023. Policy impacts are assessed via a staggered difference-in-differences framework, while the determinants of adoption are analysed using a fixed-effects linear probability model. We find that adoption is associated with a sustained and economically significant increase in public hydrogen R&D spending, signalling credible government commitment, and a smaller rise in carbon capture, utilisation, and storage (CCUS) R&D, reflecting continued support for fossil-fuel-linked technologies. No short-run reduction in industrial process emissions is observed, suggesting that decarbonisation effects materialise gradually. Turning to the determinants of adoption, within-country growth in renewable electricity generation emerges as the strongest predictor of adoption, highlighting the interdependence between renewable expansion and hydrogen policy formation, while macroeconomic and political factors appear largely insignificant. These results shed light on the effectiveness and determinants of national hydrogen strategies in the global energy transition.