Minnesota Nuclear Plant Upgrade Is $267 Million Over Budget

A nuclear plant's 20-year extension comes at a high cost

2 min read
Minnesota Nuclear Plant Upgrade Is $267 Million Over Budget

After being shut down for four months, Minnesota’s Monticello nuclear power plant will restart this week with an additional 71 megawatts of capacity, a 12 percent power uprate. The increased costs, however, will far outstrip the additional percentage of power production.

The project, which included maintenance, upgrades and the uprate, was budgeted at $320 million. But Monticello has cost overruns of about 83 percent, or $267 million, according to the Minneapolis Star Tribune.

The plant's owner, Xcel Energy, has not released the final cost to the public, claiming that the figures are trade secrets. But state regulators do know the costs, which will be passed on to Xcel’s customers. The company told the Star Tribune it would release details on the cost and why the project went so over budget in the future.

Monticello is hardly the first nuclear power plant to suffer a massive cost increase. In three southern U.S. states, Florida, Georgia, and South Carolina, customers are paying billions for reactors that aren’t yet producing power, according to Mark Cooper of the Vermont Law School Institute for Energy and the Environment. And elsewhere in Georgia, Southern Company reportedly spent at least $737 million more than it originally slated for two new nuclear reactors it is adding to a facility along the Savannah River.

Nuclear power comprises about 20 percent of electricity production in the U.S., and much of that fleet is aging. Existing reactors are an important base load of power for some utilities, especially as there is increasing regulatory pressure to close old, dirty coal-fired power plants. But the nuclear plant inventory is aging too, and of the country’s more than 100 reactors, 73 have received approval to operate until they are 60 years old.

Regulators and plant operators are wading into uncharted waters in measuring, monitoring and modeling key components of the aging reactors. Researchers at Pacific Northwest National Laboratory, for instance, are developing acoustic modeling tools that can identify cracks or corrosion. In Monticello, which is less than an hour from the twin cities of Minneapolis and St. Paul, part of the cost increase, according to the Star Tribune, was that additional engineering problems surfaced once the upgrades were underway. 

Besides high costs and uncertainty about the lifespan of reactors, other forces are at work too that could sideline upgrades for existing nuclear. Xcel Energy cancelled plans for a similar uprate to another nuclear power plant it operates in Minnesota because of a decline in power demand, according to Nuclear Street. Electricity use in the U.S. has more or less flat-lined in recent years, partially because of the recession but also due to a larger trend of energy efficiency measures. That's fortunate, because the public's appetite for nuclear power, never large, has only gotten smaller since Japan’s Fukushima Dai-ichi nuclear accident in March 2011.

Fortunate too, is the availability of cheap natural gas, which has also made gas-fired power plants an attractive option for utilities that need to build new capacity or replace older plants. The majority of new generation being installed in the U.S. is gas. Another benefit of gas, compared to coal or nuclear, is that it can ramp up or down quickly to balance out intermittent renewable energy sources such as wind or solar. Still, natural gas can't be the whole answer for Xcel Energy. A 2007 Minnesota law requires it to produce 31.5 percent of its energy from renewable sources by 2020.


Photo: John Doman/The St. Paul Pioneer Press/AP Photo

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