The Welsh Government has offered to invest in the £1.3 billion Swansea Tidal Lagoon project.
The money is intended to kickstart plans for the clean project nearly a year after the Hendry Review backed it as a cost-effective pilot to test the technology – the local council has set up a clock to track the delay.
Reports suggest the sum offered is up to £100 million.
Initial plans to deliver the project as a precursor to several other large-scale, similar schemes stalled after the government raised concerns about its value for money.
First Minister Carwyn Jones said: “I want to make clear that I am prepared to consider a substantial equity and/or loan investment by the Welsh Government if that would enable the project to move forward.
“This investment could help to reduce the cost of capital for the project and hence reduce the subsidy requirement over the lifetime of any contract for difference.”