"To trade renewable and low-carbon hydrogen reliably across borders, we will need proper rules," Kadri Simson said, pointing to the two countries as a first step for establishing them.

The EU will also put hydrogen on the agenda in energy talks with the United States, Japan and South Korea, Simson said in a webcast.

In its hydrogen strategy published in July, the Commission, the EU executive, laid out targets to scale up renewable hydrogen projects to meet the EU's net-zero emissions goal by 2050.

By 2024, it wants to have 6 gigawatts (GW) of green hydrogen capacity produced from wind and solar power and 40 GW by the end of the decade for use in sectors that are hard to decarbonise, or where electrification is difficult, including chemicals and steel.

Both public and private investors must have confidence in the business model to get involved, the conference heard.

German Economy Minister Peter Altmaier cited Germany's provision of 2 billion euros (1.82 billion pounds) for the international sourcing of hydrogen announced in its national strategy passed in June.

"We are considering regions with high solar intensity and wind speeds," he said, naming parts of Asia and Africa, the Middle East and South America. He said two trade agreements were under discussion.

The chief executive of Siemens Energy supported import strategies while the head of Danish wind company Orsted said converted offshore wind could also fuel large-scale hydrogen flows.

(Reporting by Vera Eckert and Kate Abnett, editing by Riham Alkousaa and Barbara Lewis)

By Kate Abnett and Vera Eckert