WTF, page-27

Geothermal is commonly used in volcanic regions such as NZ (where locals can "tap" into hot water for home heating almost freely), Iceland and many other places. In Aus there wasn't much pumped in to research although there were some sites identified. but the hot rock on the East Coast was found to be over 1,000 m down and determined to be uneconomic.

"The projects we have funded uncovered significant barriers in Australia, which helped inform energy developers and policy makers. This included a 1MWe pilot plant that ran at Innamincka Deeps in South Australia from April to October 2013." https://arena.gov.au/renewable-energy/geothermal/

Wave/Tidal has been found to be pretty limited although some projects around the ROTW.

However hydrogen is quite different from these pi-in-the-sky ventures. and I agree with you, although we have already one co. producing hydrogen on a commercial scale, Hazer, from coal gas, green hydrogen does have along way to go for commercial production. the Sweden/Finland project estimates 10 years but china is (perhaps ) more ambitious with a prospective shorter timeframe.