It's not a subsidy it's a fixed price contract that was intended to provide stability to investors to finance projects.
The problem is the auctions were so long ago that the fixed price contract with the national utility is way below the market price and the price of construction.
It's actually a negative subsidy. If the market price for wind energy goes over the fixed price contract, then the wind farm has to pay the govt the difference. If the price for wind dropped below the market rate then the govt would subsidize the wind farm.
If this had worked as intended, then taxpayers would have been protected and wind project investors would have the assurances to proceed. Nobody makes a lot of money, but nobody loses a lot of money. But the massive, unexpected spike in global inflation because of a pandemic threw labor costs completely out of whack and so the best economical choice for wind projects is to simply cancel them than rather than pay hugely inflated labor costs to build the farm and then end up paying taxpayers on top of that for the inflated energy market rates for the theoretical insurance that taxpayers were going to provide. There's no reason to buy insurance for something you KNOW you're going to lose money on.
Think of it like a crop. The government says "We'll buy your entire crop for $1/kg of grain". The farmer says "great" and starts planting. But then the price of labor skyrockets and the cost to actually harvest the grain goes up to $2/kg of grain. Now the farmer is in a predicament. Every kg of grain they harvest will lose them $1. So there's no reason to bother harvesting the grain. The govt contract which was designed to ensure the farmer had a sufficient incentive to plant the crop--has backfired and the farmer is trapped in a horrible deal that incentivizes them to just let the crop rot rather than sell the crop to the govt (or sell it on the market and pay the govt the difference).