Plaid MEP Jill Evans has slammed a deal on the EU budget which will give over a billion pounds to the controversial ITER nuclear fusion research project.
MEPs meeting in Strasbourg voted to approve the deal which will take €1.3 billion from the EU budget over the next two years to fund the project's substantial budget over-run.
The Plaid MEP criticised the huge waste of public money when taxpayers in Wales and across Europe are facing hardship due to cuts in public spending.
Speaking after the vote in Strasbourg, Ms Evans said:
"With public spending and public services in Wales being slashed, people will rightly be angry that the European Union is wasting more than a billion pounds to bail out unproven and untested nuclear technology.
"The ITER nuclear fusion project, based in France, has been hugely controversial. It will not be commercially viable until 2050, if at all, and is proving enormously expensive.
"In this age of austerity, it is totally unacceptable for such huge sums of taxpayers' money to be spent on a nuclear research project that may never actually work.
"This money would be better spent investing in tidal, solar, wind and hydroelectric power and in promoting energy efficiency. Wales has huge potential for developing renewable energy and creating green jobs."