Because the owner does not typically sell with a market price but with a power purchase agreement where the buyer agrees to buy all electricity produced at the agreed price.
(This is an educated guess, not knowledge, so take with a grain of salt.)
It is true that the plants have power purchase agreements, but:
The owner can still buy back the power in the spot market and turn off his plant. He can then deliver the power he bought on the spot market to the PPA. If prices are negative, this means the owner gets paid for turning off the plant buying back the power.
So the plant still gets curtailed.
All this is assuming no subsidies and that the PPAs don’t contain any weird origination provisions.
konschubert|2 years ago
The owner can still buy back the power in the spot market and turn off his plant. He can then deliver the power he bought on the spot market to the PPA. If prices are negative, this means the owner gets paid for turning off the plant buying back the power. So the plant still gets curtailed.
All this is assuming no subsidies and that the PPAs don’t contain any weird origination provisions.