Environment groups are pressing Xcel Energy to close base load power plants, such as the Sherco coal plant and Monticello nuclear. Wind and solar power are suggested as replacements. Variable, low-density solar and wind have not replaced a single fossil-fuel power plant anywhere on Earth. Imagine a muggy summer night when there isn’t a breath of air, no sun and all air conditioners are running. At least they would be running if Sherco and Monticello nuclear were sending their reliable power. In 2011, U.S. wind power had a capacity factor of 27 percent and solar at much less.

That means most of the time they weren’t producing anything. They are too variable and too low density to be more than an expensive energy supplement. Take away the direct subsidies and both sink into well-deserved oblivion. There is potential to improve solar with research in areas like nanotechnology, a focus here at the University of Minnesota. But $2 billion projects like Cape Wind off Cape Cod and Ivanpah Solar in Nevada are premature ratepayer-funded fiascos.

Current numbers from the Energy Information Administration report energy fuel subsidies on a barrel of oil equivalent energy produced basis. Subsidies are $0.28 cents for oil and gas; $1.79 for nuclear; $20.37 for biofuels; $32.59 for wind and $63 for solar. Xcel Energy does use the highest percent of wind of any U.S. utility. But its natural gas plants have to run in start-stop mode to back up intermittent wind farms. This wastes fuel, stresses machinery and increases greenhouse gas emissions.