I think roughly yes. There may be a little bit more idk. It’s probably most if not all of it.

Will does it as part of his work on the Damus app, he relies on people saying thank you via zaps to keep it going. Others run them for fun or for small groups like churches, friends, family etc. Some relay providers charge money to connect. The more people that connect to the relay, the more compute and electricity it’ll take. People who run open ones I think usually use AWS or similar so the compute capacity is flexible.