This already happens in at least two ways. First way is called demand response, and entails the operator asking some users “how much is the next MW worth to yo

This already happens in at least two ways. First way is called demand response, and entails the operator asking some users “how much is the next MW worth to you?” If no one can supply that MW at that price or less, the customer can agree to not consume that MW. It is significant for some operators, but by design of the market, is only an option for industrial customers, really. Some utilities also offer a limited form of this, where you can allow them to shut off your AC, receiving a discount on your bill, generally. Both work, in their way. Would have a much larger effect if they were more universal, and of the price signal were felt more strongly by consumers. Which I think was your point.