RE: RE: Baseload vs Intermittent Terry,
I have never heard of geothermal power being used for peaking. Maybe it has but it would be an unusual occurrence.
Yes it is technically possible to turn of a geothermal plant off for the night. Though there are likely some reliability issues with the thermal cycling of wells and equipment. Regardless PPAs for wind and geothermal are set up so that the utility takes what ever the plant generates. The utility usually can only curtail power generation in emergencies to maintain grid reliability not for commercial purposes. I know Bonniville Power was but that is an exception and new projects will not get financing without guarantees it does not happen again.
Part of the reason is the renewable energy credit, you don't get credit if the plant is turned off but it is just not economic to build a geothermal plant for as a peaker and it is the most expensive technology on a per MW basis. Technologies that are the cheapest on a per MW basis are used for peaking like simple cycle gas plants.
Also a utility that is primarily gas generation is going to be quite happy with a geothermal plant providing power at night so they don't have to burn gas.