The £700M (960M USD) spent on fish protection measures at Hinkley Point C would be a topical example [1]. It's expected to save an average of a few hundred twaite shad, six river lamprey, and eighteen allis shad per year, plus one salmon every twelve years, and a trout every thirty-six years.
https://www.salmonbusiness.com/nuclear-plants-new-700-millio...
The article you linked says "According to a government-commissioned review, Hinkley Point C’s suite of “fish protection measures” will cost more than £700 million".
I spent 10 minutes and have not been able to find said "government-commissioned review". Is this even true?