Last night the government announced that it looks set to take a direct stake in the Wylfa nuclear power station. The proposed new plant in North Wales is already estimated to cost an eye watering £20billion – a number which will almost certainly rise if recent nuclear history is anything to go by.

The public subsidy for this project is being justified by ministers as a way for them to keep the ‘strike price’ down. This figure, which essentially means the minimum that the plant owners will be paid for providing electricity, is set to be £77.50 per megawatt-hour. Keen nuclear watchers will note that this would be around £15 less than that provided by Hinkley Power Station, because of the the Government’s plan to take a stake – but it is still a whopping £20 above the cost of offshore wind.

The Government’s stake in the project means that the taxpayer will be liable for any delays or problems with the project – both of which seem almost inevitable if you look at the obstacles that have beset Hinkley. In many ways, that makes the deal much worse than Hinkley, because at least there project taxpayers haven’t provided a massive down payment before any electricity is produced. Indeed, given the failure of the technology in terms of cost as well as delivery to time, direct public investment in the nuclear industry seems utterly reckless.

The proposal is all the more galling given the total lack of detail and transparency in the statement released yesterday – instead, we are left to read reports in the Japanese and British media to learn how our money is being spent. It seems likely that a strike price has already been agreed, a Memorandum of Understanding signed, loans and loan guarantees offered, and an equity stake made available. Monday’s announcement was the time to give serious detail, but all we got was waffle. 

The context for this public payout for new nuclear is an energy market that’s making it blindingly obvious that renewables are the future. Solar and wind are now the cheapest forms of new electricity generation, and new technology means that power from the sun, sea and wind, balanced with batteries and interconnection, are able to be the backbone of British energy in the future. Onshore wind – which the Government has all but banned – could have a strike price a whopping £37.50 lower than Wylfa’s.

Despite this the government, behind its shiny green veneer, has overseen the funding stream for clean energy fall to its lowest levels since 2008, with further falls set to come. Weigh that against the government’s obsession with new nuclear, and you get a true sense of where their energy priorities lie.

The frequent retort to those of us who oppose nuclear is centred on the need for ‘baseload’ power – but such arguments are increasingly weak. We know that battery technology is coming on leaps and bounds – and even the ex-head of National Grid, Steve Holliday, has said that “the idea of large power stations for baseload is outdated”, and noted that “from a consumer’s point of view, the solar on the rooftop is going to be the baseload”.

But it’s not just the government’s skewed financial priorities that make Wylfa the wrong move at the wrong time. At the heart of the problems with nuclear energy is the stark fact that there is still no solution to the nuclear waste problem. It must be kept in incredibly secure conditions for thousands of years – and we know that the cost of cleaning up Sellafield alone – the crumbling reactor that sits on the edge of the Lake District National Park – currently stands at £70billion.

The reactor technology that will be used in the Wylfa Newydd plant has a poor record on reliability and cost, and the company set to run the plant, Hitachi, has had two serious safety breaches in its nuclear developments, one of which resulted in a $2.7million fine in the United States.

The Government’s bias in favour of nuclear power isn’t just plainly illogical in its own terms, it also contradicts their normally steadfast belief in privatising everything in sight. It is deeply curious that their commitment to the so-called free market runs deep enough that they will sell off the Ministry of Defence’s own fire service, but doesn’t extend to letting nuclear power stations run without huge handouts.

It’s now time for a proper debate about Britain’s energy future – with the full facts on the table and a vote in Parliament on new nuclear. That would give the chance for the Government to think again, and for Labour to provide some actual scrutiny on this issue after taking part in this cross-party stitch up for too long. I’ve no problem with the Government setting priorities and supporting certain energy industries, but they should be doing so with the support of MPs and after an informed public debate, not blindly handing over billions of pounds to a technology whose time has passed.

Caroline Lucas is the co-leader of the Green Party and MP for Brighton Pavilion