More info on this at

https://en.wikipedia.org/wiki/Pelamis_Wave_Energy_Converter .

The company was bought by E.ON and the project was killed. At that time, there were working 450 Kilowatt prototypes (see the video). 450 Kilowatt is a power volume that took wind power plants over three decades (about from 1970 to 2000) to achieve.

The technology was then apparently copied by a Chinese company.