"The report implies from wholesale cost you can identify the total impact to retail customers, and that is not accurate," said Paul Suskie, SPP's executive vice president for regulatory policy.
The debate hints at the wider challenges facing a power sector in transition. SPP, with a service territory that covers the Great Plains, boasts one of the best wind resources in the country.
The grid operator has been adding wind capacity at a rapid clip and, on Feb. 12, set a record for wind generation, with more than half of the region's power coming from wind.
The influx of wind resources creates operational and economic challenges for SPP and other grid operators. They must be able to forecast sudden increases and decreases in wind generation, and ramp other power plants up and down to coordinate with fluctuations in the breeze.