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Xcel Energy recently completed construction of a 1-megawatt community solar garden near Cashton that is the second of three planned for western Wisconsin.

The election of Tony Evers as Wisconsin’s new governor heralded a clear shift in state politics. And Gov. Evers’ subsequent push to make utilities 100 percent “carbon-free” by 2050 would make Wisconsin a key state for renewable energy. But is his “clean energy” plan truly feasible?

Right now, Wisconsin generates roughly 55 percent of its electricity from coal, with another 20 percent from natural gas. Nuclear power produces an additional 15 percent. And renewables contribute about 9 percent — with half of that coming from hydroelectric stations.

All of this electricity matters, since Wisconsin is a key manufacturing state. In fact, Wisconsin’s industrial sector is the state’s single-largest energy consumer, accounting for roughly one-third of end-use energy consumption.

Gov. Evers envisions Wisconsin shifting its entire electricity portfolio over the next 30 years to a system completely dependent on wind, solar and nuclear power. Essentially, Wisconsin would have to scrap 70 percent of its existing electricity-generating infrastructure. But how would that affect electricity prices? And could Wisconsin keep meeting its large energy needs?

Germany offers a helpful comparison since it has been incorporating a similar clean energy effort for more than a decade. Despite massive subsidies to ramp up its renewable energy platform, Germany’s wind turbines and solar panels still provide only 29 percent of total electricity generation. And getting there has already driven Germany’s electricity costs to roughly 30 cents per kilowatt-hour, the highest in Europe. By comparison, Wisconsin residents currently pay an average of 14 cents per kilowatt-hour.

It’s not just pricing issues, however, that arise from such a fundamental transformation of energy production. The addition of wind and solar systems necessitate both an overall reconstruction of the electricity grid and the installation of back-up systems — for when the weather doesn’t cooperate. The Department of Energy estimates that even the most advanced wind turbines reach their full capacity only 42.5 percent of the time. And the highest-performing solar panels — ones in the Southwestern U.S. that feature sun-tracking motors — reach their full capacity an even lower 30 percent of the time. To fill in the gaps that come with weather interruptions, renewables require on-demand energy from “spinning reserves” — typically provided by fast-responding natural gas and coal power plants.

Nuclear power plants simply aren’t designed for this balancing role. They run at full capacity all the time. And while they help to provide fuel security and low-emissions baseload power for the grid, they are of little help when integrating wind and solar generation.

Many wind and solar advocates are now looking to battery storage as the solution for wind and solar’s intermittency. But the best available grid-scale battery technologies provide only hours of backup. And that’s simply not enough to compensate during days — and even weeks — of low wind and solar output.

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The recent “Polar Vortex" demonstrated exactly this sort of unpredictability, since bitter cold can freeze gearboxes and shatter turbine blades. During the recent cold snap, many utilities were forced to shut down their wind systems entirely. Wisconsin is certainly familiar with such conditions, since winter temperatures in the northern part of the state can fall to -30 degrees Fahrenheit.

Gov. Evers shouldn’t overlook the intermittency challenges posed by wind and solar power. Nor should he take for granted the reliability and affordability provided by the state’s current mix of fuel sources. Wind and solar undoubtedly have a growing place. But advanced technologies are also making natural gas and coal power plants more efficient — and reducing emissions at the same time. All of these options should be used in combination to help Wisconsin responsibly meet its considerable energy needs.

Terry M. Jarrett of Jefferson City, Missouri, is an energy attorney and consultant who has served on both the National Association of Regulatory Utility Commissioners and the Missouri Public Service Commission. He contributes regularly to LeadingLightEnergy.com.

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