A good piece from Mike Giberson on the federal Production Tax Credit’s distortion of Texas’ electricity market. Giberson highlights the fact that West Texas wind-farm operators can bid into the electricity grid at negative prices and churn out excess electricity in order to capture more of the tax credit.
Infrequently, a power plant might choose to bid below the short term marginal price in order to stay in the market and avoid shutting down. It can be economically rational for operators of less responsive generation units to offer negative prices in order for it to avoid the costs of shutting down for just a few hours and then start up again when load increases – think coal-fueled or natural gas steam turbine. When energy load is very low, near zero or negative prices can result.
This isn’t the cast in West Texas. Instead, the negative prices appear to be the result of the large installed capacity of wind generation. Wind generators face very small costs of shutting down and starting back up, but they do face another cost when shutting down: loss of the Production Tax Credit and state Renewable Energy Credit revenue which depend upon generator output. It is economically rational for wind power producers to operate as long as the subsidy exceeds their operating costs plus the negative price they have to pay the market. Even if the market value of the power is zero or negative, the subsidies encourage wind power producers to keep churning the megawatts out.
Evidence from market data suggests that wind power producers will accept prices down to about negative $35 MWh before they shut down, since marginal operating costs are very low for wind power we can conclude that the subsidies are worth about $35 – $40 for each MWh of wind output.
Subsidies do this sort of thing – distort the market and lead to waste – and of course to some degree distorting the market is just what is intended when policymakers offer a subsidy. Only usually it isn’t so easy to see the evidence of the waste created by the subsidies. Wind turbines that operate more hours require more maintenance, so these hours spent producing negative-value electric power do consume real resources. At the same time, the conventionally-fueled generation that is forced offline temporarily will also face additional “wear-and-tear” and require additional maintenance because of the effects of shutting down and then restarting the machines. This extra wear-and-tear and extra maintenance also represents wasteful use of resources due to PTC- and REC-subsidized power production.
As I wrote in my recent wind study, many Texas wind-energy producers “will offer wind power at no cost or even pay to have their electricity moved on the grid, a response commonly referred to as ‘negative pricing.’ Wind providers have an incentive to sell power even at negative prices because they still receive the federal production tax (PTC) credit and renewable energy credits.”
So much for market pricing and a level playing field for energy resources.