MPUC Continues to Address Utility System Reliability: Gas System Shortcomings Addressed, Electric Generation Issues Receive Scant Attention
The Minnesota Municipal Utilities Association (MMUA) represents electric utilities that are owned and operated by municipal governments throughout the state of Minnesota. The association publishes a monthly newsletter, and one article highlighting the serious reliability issues presented by last winter’s polar vortex was very interesting. I have reproduced the article below and added additional commentary to supplement some of the points made.
Minnesota’s electric and natural gas utility systems were stressed last winter, failures occurred, and the Minnesota Public Utilities Commission (MPUC) has addressed the issue several times since then, including Oct. 10.
The latest meeting revolved around the Xcel Energy gas outages in the rural Princeton and Hugo areas, natural gas customer curtailment penalty levels and other lessons learned.
Minnesota “experienced an extreme weather event” Jan. 28-Feb. 1, noted MPUC staff briefing papers, with some of the coldest weather since 1996. Utilities generally performed well, but along with the isolated service issues, a large number of interruptible natural gas customers failed to fully comply with curtailment requests.
Fully 25 percent of the state’s electric generating resource was unavailable during the event, noted the briefing papers, mainly because wind generation shut down due to extreme cold.
This admission is stunning. I covered this story in real time as the situation was unfolding thanks to the app Electricity Map, which I encourage you to download, but for utilities to admit to the Public Utilities Commission that a quarter of the generation capacity online was unavailable during the power vortex, when they were needed most, should sound the alarm that relying on wind and solar power is a dangerous game.
It isn’t just extreme weather events that render wind and solar useless, either. The graphic above shows that wind and solar generated almost no electricity on February 5, 2019, as well. This is possible because wind and solar are weather-dependent resources. The wind wasn’t blowing, and solar panels were covered in snow.
Interestingly to the municipal utilities that were called upon to generate electricity during the event, electric generation issues were addressed in just three pages of the 45-page document, and the issue was not discussed. Dakota Electric stated that Great River Energy (GRE) wind generation went off-line due to excessive cold temperatures late Jan. 29 and returned on the morning of Jan. 31. Coal, gas and solar saw no issues.
Xcel Energy stated that wind generation dropped from 1,500 MW on Jan. 28 to 150 MW on Jan. 30, picking back up to 580 MW on Jan. 31. Some of that variation was due to plants going offline due to cold, and some was due to reduced wind velocities producing “suboptimal generation conditions.” All Xcel Electric wind farms have cold weather cut-offs at -22, except Mower County, which cuts off at -13.
“Sub-optimal generation conditions.” Can you imagine a more patronizing way for Xcel to admit that their wind turbines were worthless when it mattered most? Imagine telling senior citizens that their power went out, causing their furnace to shut down, when temperatures were -24 F because it was too cold for wind turbines to generate electricity. I sincerely doubt they would agree that the situation was only “sub-optimal.”
Several of Xcel’s gas-based peaking units had difficulties at start-up due to frozen fuel valves. Xcel also reported that its Black Dog, High Bridge and Riverside natural gas plants were reduced to “economic minimum generation levels” for three hours Jan. 30 due to a compressor station failure at the Northern Natural Gas (NNG) facility in Farmington. The shutoff was taken by Xcel to maintain natural gas pressure for retail customers in the Metro area.
The Department of Commerce, Division of Energy Resources, noted that the NNG issues resulted in over 1,000 MW of capacity reduction over a 10-hour time period. Xcel said it had adequate alternative resources online during the event to cover load, even with reduction in power at those plants and at its wind facilities.
In other words, thank goodness for Xcel’s coal-fired power plants and nuclear plants. Without these sources of power, they fact that there was no wind or solar production and three natural gas power plants operating at “economic minimum generation levels” would have been absolutely devastating. There’s no question that coal saved lives during polar vortex.
Xcel Energy residential customers have seen their electricity rates skyrocket as more renewable energy resources have been added to the grid. In fact, the average Xcel energy bill was $21 higher in 2018 than it was in 2004 (in 2018 inflation adjusted dollars), the year before Xcel was required to start purchasing renewables. If Xcel customers are going to be forced to pay more for their electricity, this power should be available on demand. This simply isn’t the case with wind and solar.
Minnesota Power (MP) had its Taconite Ridge Wind Farm stop generating due to cold temperatures, but there was “no material effect” on overall generation due to low wind. MP’s Bison wind facility did not shut down due to cold, but went from 450 MW to 0 MW production during the afternoon and evening of Jan. 29, due to lack of wind.
MP said a biomass generating facility was offline due to gas supply issues and one natural gas-fired unit was taken offline due to a cold related mechanical issue. MP reported no weather-related issues at coal and hydroelectric plants. Solar plants operated as normal, though limited by clouds and snow.
This paragraph is exactly why I have strongly advocated for keeping the Clay Boswell coal-fired power plants open for as long as possible.
MP wind turbines generally shut off at -22, though one installation goes offline at -4. Solar generators are not guaranteed below -22, said MP, but did not report issues. Otter Tail reported several wind farms were offline due to cold on Jan. 30-Jan. 31. Its wind turbines all have shut off temperatures of -22.
Overall, 25 percent of generation was unavailable during part of the event. Wind forecasting was “erratic” with large over-forecasts for all utilities.
It was a review of electric utility load management use, during the emergency event, that lifted the veil on the dire state of electric generation.
Minnesota’s only state regulated electric cooperative—Dakota Electric—stated that it responded to calls for load management from GRE, which reportedly managed about 359 MW in overall load reduction that day. GRE called for full load control on Jan. 30 from 3 p.m. to 9 p.m.
GRE and its member co-ops reportedly saw a total demand response of 459 MW. The Midcontinent Independent System Operator (MISO) declared an emergency on Jan. 30, at 3 a.m., and it ended at 11 a.m. on Jan. 31.
In addition to the usual emergency processes, large ‘firm load’ customers implemented voluntary curtailments until 9 p.m. on Jan. 30. Minnesota Power reported 235 MW of demand response, including 200 MW of load reduction from industrial customers.
Xcel and Otter Tail tariffs, noted regulatory documents, contemplate summer interruptions rather than winter. Xcel Gas and CenterPoint are to file information with the MPUC on their system reinforcement projects. The state-regulated natural gas utilities received approval of a number of tariff changes.
Not only are calls to shut down Minnesota’s coal plants and replace them with wind, solar, and natural gas incredibly expensive, they are also indefensibly dangerous. There should be zero irony lost when considering that Xcel Energy wants to shut down Sherco units 1, 2, and 3, but it was the electricity generated by these turbines that powered the electric space heaters used to keep pipes from freezing in the Princeton area because Xcel shut off their natural gas for home heating.
The article in the MMUA magazine was written by Steve Downer.