It still looks like a perverse incentive to me. If I were operating a gas plant and charging too much, and also building out renewables, it naively seems that I should be able to continue overcharging for gas, lining somebody's pocket to maintain the contract, and building out more renewables for ever more profit. I'm not in the UK so I'm only passingly familiar with the existence of this policy; I do hope that it's got an offramp.
Edit to answer my own concern: But, reading this article, it does seem like the auction is the offramp. The government takes bids for enough power to supply the country, and once the auction is settled the worst-case cost is paid to all winners. So there's a hope that gas will eventually subsidize its replacement with renewables.
I wonder, what’s to stop an energy company with a mixture of RE and gas from disabling X% of their RE infrastructure, forcing gas to come online and the higher rate? Only the biggest producers control enough of the market to do it, but it seems plausible for the company to find specific demand scenarios where they could tip the price in their favor.
So, what's auctioned here isn't power.
What they're auctioning are what's called "Contracts for Difference". The contract has a "Strike price" which is in essence the price the government (via a for-purpose company) agrees you will be paid regardless of what happens for electricity sold to the system.
Now as the word "difference" might suggest there will be a difference between the market price at any particular moment and this strike price. The CfD works by the government paying you the difference when the market price was lower, and you pay the government the difference when it's higher. You can definitely afford to pay them 'cos you just got to sell power for $$$$
Why do this? Well, the trick is that a government (even if politicians don't always act like it) is here for the long haul. So for them guaranteeing how much you'll be paid for energy you're not going to make for ten years is fine. Tax will still exist in ten years, houses with electric light will still exist in ten years, this is an easy bet. But for a wind farm company, a commercial undertaking, such guarantees are incredibly valuable and would be unaffordable from elsewhere. So this is (relatively) a very cheap subsidy.
When there was a gas price spike because Russia invaded Ukraine the contracted wind farms paid a whole lot of money because of that difference I talked about, if you'd gone freelance, no CfD subsidy well, you're printing cash, 'cos at those prices you probably made back your whole install costs in a year of trading.