What I heard is done in some places like PNW is that we would buy hydropower during the day instead of using our own peaking plants. Then sell excess fossil generated power back at night. Maybe it's more efficient to throttle hydroelectric plants than combustion plants. They might have a limited amount of water so it makes sense to sell the power for the highest price possible. https://www.eia.gov/todayinenergy/detail.php?id=63684
What I heard is done in some places like PNW is that we would buy hydropower during the day instead of using our own peaking plants. Then sell excess fossil generated power back at night. Maybe it's more efficient to throttle hydroelectric plants than combustion plants. They might have a limited amount of water so it makes sense to sell the power for the highest price possible. https://www.eia.gov/todayinenergy/detail.php?id=63684