We take our role as a responsible corporate citizen seriously, working to balance our business goals with the environmental, social and economic needs of our communities. An overview of how Great River Energy works to protect the environment and partner with our communities can be found in our 2007 Environmental Performance Report (pdf file).

Also available is our 2006 Environmental Performance Report.

Our Resource Mix

Great River Energy and many Midwest utilities have traditionally relied on coal-based power plants to generate the bulk of their electricity. Approximately 77 percent of Great River’s energy is generated from coal. On average, Minnesota consumers receive approximately 63 percent of their electricity from coal-based generation. Our mix includes a greater percentage of coal-based energy than neighboring utilities because we have no nuclear generation and less hydropower.

Coal Facility Emissions

Emission tracking is just one component of an environmental management system. At our baseload and peaking facilities, we have continuous emissions monitors that record stack emissions.

By continuously tracking our emissions and electric generation, we are able to calculate our emission intensity. Emission intensity (lb/MWh) is a metric that takes into account plant efficiency in megawatt-hours (MWh) and stack emission rates in pounds per hour (lb/hr). Lower emission intensity values are ultimately better for the environment because there are fewer emissions for each unit of electricity generated.

In order to gauge our emission intensity performance, we compare ourselves with other coal-based power generation in the region. For this report, 2003CLE data from the Energy Information Administration are used because they are the most current information available on region emissions sources.

Great River Energy’s sulfur dioxide (SO2) emission intensity has decreased significantly over the years. At just over 7 lb/MWh, our emission intensity has dropped by almost 50 percent since the 1990s. This success is attributed to the installation of acid gas scrubbers at both Coal Creek and Stanton stations. We are performing near the top of regional coal generation.

Since 1995, Great River Energy reduced our nitrous oxide (NOx) emissions from our coal facilities by almost 40 percent through the installation of low-NOx technologies. Almost a decade later, we continue to out-perform other coal generation by state in our region.

We include carbon dioxide (CO2) emissions as a non-regulated greenhouse gas. This comparison takes into account efficient combustion practices, because coal generation has no stack controls for CO2 emissions (unlike NOx and SO2 emissions controls).

Great River Energy’s facilities generally continue to out-perform other coal generation by state. We expect to have more measurable improvements in future years after we implement additional environmental programs.

The second component of our environmental policy seeks continuous improvement. Improvements are achieved through periodic audits, management review and corrections.

Overall Emissions

Despite our significant reliance on coal, Great River Energy’s overall air emissions are near the regional average.

Although we have some of the cleanest coal plants in the region, our total emissions are close to the average because we have less hydropower and no nuclear generation.

Mercury Research

Great River Energy has been a pioneer in mercury research. We have participated in more than $20 million of research focused on developing mercury emission controls and emission monitors for coal-based power plants. Our partners include the EPRI, DOE, the North Dakota Research and Development Work Group, and the North Dakota Energy and Environmental Research Center (EERC).

Stanton Station has been the test site for a long-term study of MerCAP™, a potential mercury control technology. Initially, this technology proved effective at mercury reduction. However, long-term tests have shown performance variations which have required design modifications.

Coal Creek Station hosted a mercury oxidation catalyst study, which included a pilot-scale scrubber to determine if the oxidized mercury could then be scrubbed from the flue gas. Two of the catalysts successfully oxidized mercury over a two-year period, even though there was some efficiency degradation over the test. Two other oxidation catalysts were not successful. Ash fouling is a consistent problem with these oxidation technologies.

Stanton and Coal Creek stations’ proactive participation in these research projects is another example of Great River Energy’s commitment to superior environmental performance.

Efficiency

Station Service. Power plant equipment uses electricity to generate electricity. This power is called “station service.” A decrease in station service means less fuel is burned to produce a megawatt-hour of electric energy and, thus, fewer emissions are produced. Coal Creek Station sets annual goals to reduce station service. We continue to meet or exceed those goals.

Coal Drying. Our coal drying project at Coal Creek Station is one of eight projects selected in the initial phase of the Clean Coal Power Initiative, a 10-year, $2 billion commitment to clean coal technology and a key component of the national energy policy. Great River Energy and our research partners will conduct the

$28 million project at Coal Creek Station. It began in 2003 with construction and operation of a pilot-scale 2-ton coal dryer, which was used to refine the prototype’s design.

The new technology uses waste heat to dry nearly a quarter of the moisture in the coal before it is fed into the boiler. By drying the lignite coal first, we expect to lower its moisture content by at least 10 percent, resulting in an estimated 2.8 to 5 percent improvement in the plant’s efficiency. This improvement could result in a 25 percent reduction of SO2 emissions and 7 percent fewer emissions of mercury, CO2, NOx and particulates per unit of electricity output.

The U.S. Department of Energy awarded Great River Energy $11 million through a cooperative agreement to help fund a large-scale coal-drying study at Coal Creek Station. We have constructed and are testing a 2-ton per hour pilot scale dryer to obtain data for the design and operation of a large-scale dryer. So far the testing has provided valuable information for that design.

Water and Wastewater

Great River Energy’s largest power plant, Coal Creek Station, utilizes cooling towers to reduce the amount of fresh water needed for cooling at the plant. The cooling towers allow the water to be reused at least 12 times before being discharged.

Wastewater discharges from Stanton Station were significantly reduced by installing a dry fly ash system in 1995 and by upgrading water-handling technologies.

Ash storage ponds at Stanton Station and Coal Creek Station are protected against any potential leaking that could occur into the surrounding natural water systems. The ponds at both sites are dually lined with clay and then a high-density plastic. Coal Creek Station also lines its water evaporation ponds with the same protection. Water samples are tested monthly from area water wells, sloughs and rivers at both facilities to ensure natural water systems are protected.

Solid Waste

Coal combustion produces ash. This ash is often disposed of in landfills. However, ash from Coal Creek Station is valuable as a feed stock to other processes and the ash marketing efforts at the plant have been underway for several years. The use of fly ash and bottom ash in products reduces the need for the ash to be stored in landfills on the site. Fly ash is mainly used as a cement replacement for making concrete, but has several unique uses including carpet and shingle backing and flowable fill for construction projects. Bottom ash is used as a gravel replacement, road de-icer and as a bed base for building roads.

Total production of fly ash from Coal Creek Station is about 440,000 tons. In 2003, an 85,000-ton fly ash storage dome was built at the plant to ensure that an adequate supply of fly ash is available throughout the year. This will allow Coal Creek Station to fulfill long-term ash contracts and expand into new markets.

Stanton Station’s by-products are currently being tested for similar usage.

In addition, Great River Energy is a partner in the U.S. Environmental Protection Agency’s new Coal Combustion Partnership Program (C²P²) which supports, encourages and promotes the utilization of coal combustion products, such as fly ash.