Simona Benedettini and Carlo Stagnaro make the case for allowing negative prices in electric power markets in Europe. A few of the larger power markets in Europe allow prices to go negative, but others retain a zero price lower limit. Benedettini and Stagnaro explain both why it is reasonable, economically speaking, to allow electricity prices to go negative and the hazards of retaining a zero-price minimum in a market which is interconnected to markets allowing the more efficient negative prices.
It is all good, but I can’t resist quoting this part:
Negative prices are not just the result of some abstruse algorithm underlying the power exchange and the functioning of the power system. They are also, and more fundamentally, the way in which the market conveys the decentralized information that is distributed among all market participants, and that cannot be centralized in one single brain, as Nobel-prize winner Friederich Hayek would say. That information is translated into two major market signals, which are embodied in negative prices.
In the short run, negative prices show that there is a local condition of oversupply under which electricity is not an economic good which society is willing to pay for, but an economic bad for which consumers should be compensated. Therefore, negative prices create an economic incentive for consumers to shift their consumption patterns so as to capture the opportunity of being paid, instead of paying, to receive energy….
However, in the long run, negative prices talk to energy producers, not to energy consumers. The emergence of negative prices, although strongly conditioned by demand-side constraints, shows that the generating fleet encompasses too much “rigid” capacity (i.e. too much nuclear and coal-fuelled plants) and too little “flexible” capacity (for example CCGTs or turbo-gas power plants); or that grid interconnections are insufficient to properly exploit the spare, flexible capacity available within a market area.
So far as I know, all of the regional power markets in the United States now allow prices to go negative. The connections between wind power policy and negative prices have politicized the issue a bit in the United States. Benedettini and Stagnaro explain in a straightforward manner why, no matter what you think of renewable energy policies, you ought to favor allowing wholesale power market prices to go negative.