This is a comparison of the Green Bond principles posted by the International Capital Markets Association (ICMA) and the European Union (EU) Green Bond Regulation. In general, the ICMA regulations are somewhat more restrictive, although the changes are relatively minor. Energy efficiency and renewable energy promotion are the main targets of the regulations, and the allowable mechanisms differ. With the U.S. Department of Energy subordinating the Energy Efficiency and Renewable Energy office into the Office of Critical Minerals and Energy Innovation (CMEI), in which these sorts of innovations would regularly have to compete for attention and analysis with nuclear energy innovations, which would be preferred by this Administration, the trend-setter of the actual implementation of these innovations could become Europe.
3 sources are useful for this. The first is by Carpenter Wellington PLLC - "A Guide for Companies Issuing Green Bonds" - https://www.lexology.com/library/detail.aspx?g=ae3fd405-b797-4afd-a9db-8fc0b70a2a86&utm_source=Lexology+Daily+Newsfeed&utm_medium=HTML+email+-+Body+-+General+section&utm_campaign=Lexology+subscriber+daily+feed&utm_content=Lexology+Daily+Newsfeed+2025-12-09&utm_term=
The second is by Clifford Chance - "ICMA GREEN BOND PRINCIPLES AND THE EU GREEN BOND REGULATION : A COMPARISON NOVEMBER 2023". Note that the one case where the EU standards are more strict than the ICMA standards is that the issuance proceeds MUST be allocated to the projects beforehand (subject to issuance costs), whereas the ICMA standard only insists that the issuance proceeds SHOULD be allocated to the projects beforehand. It is likely that any serious publicity for a project would minimize this difference, but there is a different legal standard. The ICMA standards are more severe regarding information provided per report, and also requiring external review of the information (which I like), but the EU regulations seem to require many more reports. See Icma’s green bond principles and the eu green bond regulation : A comparison
The third is by The Center for Sustainability and Excellence, a business consulting group based in Chicago, Illinois, in the U.S. This is "Green Bonds in Europe: Driving the EU’s Path to a Low-Carbon Future", and covers how the European countries have implemented the principles up to August 2025 (the data are up to 2024). The fraction of the bond market for green bonds in 2024 is reported as 6.9%, which seems high, but may reflect favorable tax and regulatory treatment. See Green Bonds in Europe