This month, the Star Tribune Editorial Board endorsed Gov. Tim Walz's vision of a 100 percent carbon-free electric grid ("Time to move ahead with clean energy," March 7), largely due to their belief that concerns about the intermittency of wind are overblown and that wind is now the most affordable source of electricity in Minnesota. Both of these perceptions are incorrect.
The fact that the wind does not blow 24/7 is not an oversimplification or a disservice to the debate. It is the debate, because the intermittency of wind and solar has profound implications for reliability and cost.
For example, each of Minnesota's three investor-owned utilities told the Minnesota Public Utilities Commission that production from their wind turbines plummeted during the polar vortex on Jan. 29. Wind turbines in North Dakota either were shut down because it was too cold to safely operate them, or their output was greatly diminished because of low wind speeds.
As a result, wind provided just 4 percent of electricity output during the polar vortex, while operating at only 24 percent of capacity. In contrast, 45 percent of the electricity generated in the regional power grid, the Midcontinent Independent Systems Operator (MISO), during the cold snap came from coal, 13 percent came from nuclear and 26 percent from natural gas.
The fact that the wind cannot be relied upon to generate electricity when we need it most means we must still pay to keep our coal, nuclear and natural gas plants online, in addition to paying for wind and solar power. In the end, Minnesotans must pay twice for electricity they use once.
The Editorial Board cited Steve Morse, who claimed it is cheaper to put in new wind than to operate old coal, but this is demonstrably false.
Form 1 data submitted to the Federal Energy Regulatory Commission (FERC) by Minnesota utilities show the cost of generating electricity at two of Minnesota's largest coal plants, Sherburne County and Clay Boswell, was $30.58 per megawatt hour (MWh) and $32.34 per MWh, respectively, in 2017, the most recent year for which data were available.
In contrast, Bloomberg New Energy Finance estimates the unsubsidized cost of generating electricity from new wind is $38 per megawatt hour, meaning it is 24 percent more expensive than electricity from Sherburne County.