100% of state's power can come from wind, solar

If you've ever driven past the wind farms in southern Minnesota or seen a house with solar panels, maybe you've wondered how much of the state's total electricity demand wind and solar power could support.

According to a study released Tuesday, March 13, the answer is 100 percent.

All of Minnesota's electricity generation could be met by a combination of wind and solar energy, as long as it's combined with big energy storage and grid improvements that dramatically reduce demand, the study by the Institute for Energy and Environmental Research says.

In the end, electricity would cost about 3 cents more per kilowatt hour than today's statewide average of about 10.6 cents for residential customers, the study by the Takoma Park, Md.-based think tank concluded.

That's a steep increase. But the researchers say that by the time these improvements take in place - in roughly 40 years - Minnesota will have to replace its aging coal and natural gas plants, so prices would be going up one way or another.

Reducing demand would offset the greater cost of creating new generation alone, the study argues.

Arjun Makhijani, president of the group, acknowledges the study's conclusions fly in the face of conventional wisdom about renewable energy.

That wisdom says wind and solar energy are intermittent and therefore need assistance. Only coal and nuclear plants can produce what utilities call baseload power - steady, uninterrupted electricity.

Makhijani called the baseload concept obsolete. "It's like living in the age of punch cards and IBM machines when we should be living in the age of the iPhone," he said.

Compressed-air energy storage - think pressurized underground caverns - could act like batteries and solve the intermittence problem, Makhijani said. Utilities could pressurize underground caverns at night when the wind blows hardest and tap the pressure to turn turbines when the wind tends to die, advocates have long said.

The paper also suggests that major reductions in electricity demand can be achieved.

According to Makhijani, 58 percent of the grid's capacity is idle during the year. Most of that occurs at natural gas plants that are turned on only when demand begins to peak, he said.

If the grid was more "intelligent," allowing machinery to be turned on and off to manage the load, about one-third of residential demand could be eliminated with no discernable notice, he argued.

The state is moving toward renewable energy but its goals are less lofty. It wants most utilities to produce 25 percent of their electricity from renewable sources by 2025, and Xcel Energy, the state's dominant utility, to hit a 30 percent target by 2020.

At present, Minnesota produces 10 percent of its energy from wind, according to American Wind Energy Association. Solar power, meanwhile, represents about one-tenth of 1 percent of the U.S. energy supply and about the same percentage in Minnesota, solar advocates say.

The Institute for Energy and Environmental Research wanted to show that a fully renewable system was technically and economically feasible, Makhijani said. Now he wants some entity to conduct a demonstration project to prove out the concept.

Minneapolis-based Xcel Energy, the nation's No. 1 wind power provider, would not comment directly on Makhijani's study. But it said it is on target to meet it own renewable energy goals.

The utility, which has the state's biggest coal plant in Becker and two nuclear power plants in Minnesota, said it tries to put together a balanced energy portfolio that includes energy conservation and efficiency programs.

"Because it is good for customers and the environment, we will continue to look to add renewable resources onto our system if it makes economical sense," the utility said in a statement.