Over the first 30 months of the project, the research has mainly consisted in identifying and exploring, monographically, relevant case studies in the history of economics, when controversies emerged on the role of energy in economic development, or when economists participated to the design of energy policies, in different places around the world. To date, research has been carried out on almost 10 countries, including The Netherlands, Belgium, Spain, France, Great Britain, the United States of America, India, and Japan. Significant achievements have already been reached regarding for instance how economists and engineers differently considered energy efficiency as a lever of resource saving and climate mitigation, especially in Europe and North America. More specifically, results have been obtained on the reasons why state intervention remained quite low in the efficiency sector in the 1990s and 2000s, under the influence of economists. Another inquiry, into the reaction of Dutch economists to the discovery of gas reserves in the late 1950s, produced important insights with respect to today's attitudes in countries which have recently discovered energy reserves (e.g. Mozambique, Senegal). It appears that over-optimism is quite common when it comes to energy resource discoveries, whether fossil fuels (e.g. oil, gas) or new renewables (e.g. green hydrogen). The lessons of history are that optimism is often short-living and that energy diversification should remain a priority, even when new bonanzas seem to come true. Finally, in its early months, ETRANHET also enabled the start of a digitalisation process of relevant primary archival materials in the history of energy economics. Documents in Dutch, Portuguese, English, French, and Japanese have been collected during visits in The Hague (The Netherlands), Aberystwyth (Wales), Cambridge (England), Paris (France), Rio-de-Janeiro (Brazil), and Tokyo (Japan). These materials constitute new sources for future research in economics, history, and environmental humanities, to be consolidated in the next phases of the project.