My parents (who live in Texas) get a rebate like this from their electricity company, which surprised me by even having an option to do it manually without a Nest-style internet-connected thermostat. If it's a day that the company wants reduced peak usage, they text+email you that you can get a rebate if you reduce usage during a certain set of hours. They judge whether you did or not by measuring your usage during those hours against your historical usage on similar-temperature days, so you can get the credit just by turning up your thermostat manually for a few hours. (This does require a new-style meter that reports hourly usage.)