Depending on your context they read very slightly differently:
2 reads in a very slightly more general way than 1, suggesting also the costs to the environment and humanity as a whole, but that may only be to a British English speaker's ear.
3 suggests a narrowing, for example "For this project which is already over-budget, what can we do to reduce the costs for electric power generation". Otherwise the preposition "for" seems awkward.
Again all of them are fine, but 1 is simpler and reads better, but I'd expect to see 2 rather than 1 in a government communique, as it sounds more pompous.