Fact sheet - Big Stone II generation: Needed to meet the clear and urgent regional need for more baseload energy

Big Stone II Generation

Big Stone II is a two-part project — increased power generation and transmission.

Big Stone II is a two-part project proposed by a unique alliance of five power companies representing two types of company structures, investor-owned utilities and municipals. The project includes:

Building a 500- to 580-megawatt coal-fired generating plant using advanced proven emission-control technology on the site of the existing Big Stone Plant near Milbank, S.D.
Upgrading and adding to the transmission system to deliver the power generated by the proposed plant.

More generation is needed to meet growing energy demand and consumption.

More people are using energy than ever before, and regional energy consumption continues to rise.

Conservative estimates by the Mid-Continent Area Power Pool (MAPP) forecast usage to increase as much as 15% over the next decade.
Increasing demand has caused the regional electric generation capacity reserve to steadily decline. MAPP projects that, without Big Stone II, reserves will fall below the minimum level by 2011.

Yet the last significant baseload power plant built in this region was constructed in the mid-1980s.

The need for more generation can’t wait.

For many years MAPP has been one of the nation’s most reliable power systems. But according to Resource Data International, as of mid-2001 MAPP had less than 2,700 megawatts of new generation scheduled to come online in the next several years — 6,600 megawatts less than the region may require. Ensuring a continued reliable power supply requires investing now and planning ahead. Because planning, siting, and building a baseload generating plant takes four to six years, we must act now.

Building on the Big Stone site has economic advantages.

Otter Tail Power Company has operated Big Stone Plant, which it owns jointly with Montana-Dakota Utilities Co. and Northwestern Energy, for more than a quarter century. There are significant advantages in adding a second plant to an existing site.

The site contains much of the expensive infrastructure needed to support a second unit.
A well-trained staff is in place, as are a railroad line, coal-handling facilities, and a water supply.
In addition to having some existing transmission corridors, it’s close to load centers where demand is high. This reduces by tens of millions of dollars the expense of building additional transmission lines further away from load centers.

Big Stone II technology will deliver more energy with fewer emissions.

Participants have chosen commercially proven technology (including a supercritical pulverized coal-fired boiler and highly advanced wet scrubber) that will minimize coal consumption and achieve greater efficiency with fewer emissions — without compromising their ability to provide customers with reliable, affordable energy.

Emissions of sulfur dioxide, nitrogen oxides and mercury from the two plants will be less than or equal to historical emissions from the existing plant.
The existing Big Stone Plant emits 189 pounds of mercury each year. By committing to a 90% removal goal, which mirrors the 2006 Minnesota Mercury Reduction Act, emissions from the combined plants will be reduced to about 70 to 90 pounds — cutting mercury emissions to less than half.
Carbon dioxide emissions from Big Stone II will be 20% lower than existing regional power plants. Project participants will also offset 100% of Big Stone II’s carbon emissions attributable to Minnesota consumers.
The fly ash and gypsum that would be collected with the wet scrubber are saleable products. Every ton of fly ash used in place of cement in concrete production reduces by one ton the carbon dioxide that otherwise would be emitted.
Big Stone II is designed to be carbon capture retrofit-ready, with the capacity to incorporate carbon capture technology when it be comes available and cost effective.

Coal-fired plants provide reliable, affordable power around the clock.

Coal is abundant and available. The nation’s coal reserves are sufficient to meet its electricity needs for more than 200 years and will help reduce our dependence on imported fuels.
Coal is reliable. Renewable fuels, such as water, wind and biomass are important components of any energy mix. But hydro sites no longer are available, the wind doesn’t always blow, and alternate fuel is limited.
Coal is less subject to price volatility. Natural gas prices are much more subject to dramatic fluctuations than are coal prices. The decision to use coal in concert with energy conservation and renewable energy is in the best economic interest of the region.

Wind is not an alternative for baseload generation.

Wind energy proponents have suggested Big Stone II is not needed because wind energy units could meet future energy requirements. But wind does not meet the reliability test and is not a viable option for generating baseload energy.

Because the wind doesn’t blow around the clock or at optimum speeds, it has a low capacity factor. A typical wind energy unit located in the upper Great Plains operates at a capacity factor of about 30% to 40%, which is unacceptable for customer baseload needs.
Because of its erratic availability, wind cannot be counted on during times of peak use. That’s why the Big Stone II participants – who include wind in their energy mix – also include coal.

Big Stone II is part of an energy-balanced future.

Big Stone II will provide baseload generation and transmission capacity and support the use of intermittent renewable resources. For each of the participants, Big Stone II represents just one part of a diverse and balanced power supply portfolio. In addition, one of the Big Stone Transmission lines will be “super-sized” so that – when added to other planned transmission projects – it can help to carry 800 to 1,000 megawatts of additional generation, most likely wind energy. Participants also continue to be involved as individual companies in renewable energy projects, clean coal research, and emission control technology research.