Yes its nice of them to put to use that heat, but that ROI can suddenly go from 3 to 6 or 7 years after May. BUT, after 4 years (with 3 remaining) halving hits again and now the ROI adds 7 or 8 more years... Kinda like cloud mining.
I have to admit that I was checking the news from several sources, and that what I wrote about ROI may be wrong/inaccurate. The facility was renovated and the total cost was about $65 million, so investment in mining rigs is included in this price. Considering that at the current price, the power plant mines 5.5 BTC per day ($43000) it gives them around $15,7 million per year which will change with halving/by changing the price.
When you say ROI is 3 years it sounds (dangerously) like the average American miner. In my country you could achieve ROI in 3 months. I think those large miners will move to where the electricity/fuel is cheaper. New York State doesn't appear to be that cheap.
You didn't understand the essence of the story, they are not big miners, and they only use surplus energy produced from their plant. They will not move anywhere, because mining is not their primary activity.
“We are in a favorable market position regardless of how the halving materializes,” said Tim Rainey, chief financial officer at Greenidge. “Due to our unique position as a co-generation facility, we are able to make money in down markets so that we’re available to catch the upside of volatile price swings.”