The anti-renewable policies would cost the UK a roughly similar amount to Brexit.

Some random numbers:

Renewables reduced UK energy costs by 100 Billion over the 2010-2023 period (despite just getting started and costs continuing to decline)

The conservative "cut the green crap" changes around 2013 that are milder versions of what Farage would do, add a cost of about 5-15 billion a year (ongoing) in higher bills.

EVs will be 30 to 70 Billion a year savings once you get to 33 million.

He's also against grid batteries that will save about 5 to 15 billions per year once scaled.

Brexit is about 100 billion a year according to Bloomberg.