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Emissions Reporting

Today our emissions are lower thanks to a combination of renewable energy, energy efficiency and plant improvement projects. Since 2005, we have reduced by half emissions of nitrogen oxides and sulfur dioxide from the generating plants we own. We also are on track to surpass our goal to reduce carbon dioxide emissions by 20 percent by 2020 from 2005 levels, with current projections indicating a 31 percent reduction. Our clean energy strategy allows us to focus on those initiatives that produce the greatest benefits at the best price and positions us to meet future environmental regulations. Through this approach, we are meeting the many diverse—if not competing—interests of the people we serve by offering customers choice, keeping energy prices competitive, modernizing our infrastructure, investing in local economies and improving the environment.

CO2 Emissions Reporting and Third-Party Assurance

The CO2 emissions charts in this report show CO2 emissions from electricity produced at Xcel Energy generating plants and purchased from other suppliers. A system emission rate is included for each year. It provides the pounds of CO2 emissions produced for each megawatt-hour of electricity generated or supplied. Xcel Energy’s projected emission reductions are based on our most current energy forecasts.

We have provided only CO2, not other greenhouse gases, such as methane and nitrous oxide. These latter two emissions comprise less than 0.5 percent of total greenhouse gas emissions (CO2 equivalent) from electricity generation. Emissions reported here include biogenic CO2 from biomass power generation, as well as fossil CO2 emissions. However, biogenic CO2 is effectively carbon neutral, since compared to fossil fuels, the carbon released from biomass combustion is part of a relatively short-term cycling of carbon between ecosystems and the atmosphere.

Electricity production is Xcel Energy’s most significant source of emissions. We consistently report emissions associated with electricity production in short tons and in pounds per megawatt-hour in our annual form 10-K and Corporate Responsibility Report. This allows users of these reports to follow our company’s emissions trend.

More comprehensive reporting of our greenhouse gas emissions is provided in the GRI Index for this report. See indicators G4-EN15, G4-EN16 and G4-EN17 for Xcel Energy’s Scope 1, 2 and 3 greenhouse gas emissions.

Xcel Energy publicly reports annual CO2 emissions, as well as other greenhouse gases, through a number of different reporting programs, including The Climate Registry, The Carbon Disclosure Project and the U.S. Environmental Protection Agency’s mandatory greenhouse gas reporting rule. These programs each use a unique reporting protocol and may represent emissions differently. While reporting protocols and formats vary, the information we report comes from the same data sources.


Xcel Energy uses methodology that the U.S. Environmental Protection Agency established for reporting greenhouse gas emissions. We follow The Climate Registry’s protocol for greenhouse gas reporting and use The Climate Registry’s comprehensive and electric utility specific protocols. The Climate Registry bases its protocols on both the World Resources Institute (WRI) standards and the ISO 14000 standards on environmental management.

Third-party assurance and verification

The Climate Registry (TCR) is a nonprofit organization established to provide consistent and transparent standards for calculating, verifying and reporting greenhouse gas emissions into a single registry for North America. Xcel Energy recognizes the value and importance of using a formal emissions protocol and completing third-party verification for emissions reporting. We joined The Climate Registry as a founding member in 2007, and have since worked to third-party verify and register all of our CO2 emissions going back to 2005. Verification for 2008 and 2011 is complete, and verification for all remaining years through 2012 is anticipated to be done in 2014.

To learn more about greenhouse gas reporting methodology and third-party assurance for our emissions, go online to The Climate Registry, the U.S. EPA greenhouse gas mandatory greenhouse gas reporting, the WRI protocol and ISO 14000.

Carbon Dioxide (CO2 Emissions)

Xcel Energy
Upper Midwest

Texas-New Mexico

Air Emissions

Nitrogen-Oxide Emissions (owned generation)
  2005 2006 2007 2008 2009 2010 2011 2012 2013
Tons 122,949 114,783 105,151 89,244 66,068 66,439 61,862 55,228 54,115
Lbs/MWh 3.1 2.9 2.7 2.3 1.8 1.7 1.6 1.5 1.5
Sulfur-Dioxide Emissions (owned generation)
  2005 2006 2007 2008 2009 2010 2011 2012 2013
Tons 148,706 137,384 124,698 114,700 95,443 97,773 83,749 74,335 69,436
Lbs/MWh 3.7 3.4 3.2 3.0 2.7 2.5 2.2 2.0 2.0
Particulate Matter Emissions (owned generation)
  2005 2006 2007 2008 2009 2010 2011 2012 2013
Tons 7,125 9,154 8,844 8,625 7,594 7,113 7,637 4,856 3,803
Mercury Emissions (owned generation)
  2005 2006 2007 2008 2009 2010 2011 2012 2013
Pounds 2,654 2,579 2,118 2,007 1,915 1,557 1,333 1,344 1,333
Lbs/MWh 0.000033 0.000032 0.000027 0.000026 0.000027 0.000020 0.000018 0.000018 0.000019

Find Xcel Energy’s current Toxic Release Inventory information filed with the U.S. Environmental Protection Agency.

Efficiency, Control and Retirement Projects for 2013

We have a number of retirement, efficiency and emission control projects that are underway or were completed in 2013 that will reduce emissions and modernize our facilities.

Location Project Description Completion Date
Upper Midwest
Sherco Units 1 and 2 Emission control upgrades: Sparger project for additional SO2 reductions, as well as tuning and installation of combustion controls and coal mill improvements for additional NOx reductions. 2014
Sherco Units 1 and 2 Installation of activated carbon injection (ACI) systems for mercury emission controls with a goal of 90 percent reduction. 2014
Bayfront 1 and 2 Installation of fabric filters for particulate control and activated carbon injection for mercury control. 2014
St. Anthony Falls Hydro – Units 5 and 6 Turbine upgrades to improve efficiency 82 percent and increase power 6 percent. 2013
Big Falls Hydro - Unit 2 Turbine upgrade to improve efficiency 92 percent and increase power 16 percent. 2013
Wissota Hydro – Unit 2 Turbine upgrade to improve efficiency 90 percent and increase power 26 percent. 2013
Pawnee Clean Air-Clean Jobs emission control project: Installation of a lime spray dryer and selective catalytic reduction to reduce SO2 and NOx. 2014
Arapahoe Clean Air-Clean Jobs emission control project: Retirement of Arapahoe 3 and 4 in 2013. Emission reductions from Arapahoe 3 and 4 retirement include average reductions over the last three years of 1,020,900 tons of CO2, 2,115 tons of NOx and 2,380 tons of SO2. 2013
Hayden Clean Air-Clean Jobs emission control project: Installation of selective catalytic reduction on Units 1 and 2 to reduce NOx. 2015 (Unit 1)
2016 (Unit 2)
Texas/New Mexico
Harrington 1-3 and Tolk 1-2 Installation of activated carbon injection systems for mercury emission controls with a goal of 90 percent reduction. 2014
Tolk Unit 2 Low-NOx burner and separated over-fire air equipment for reducing NOx emissions about 30 percent. 2014


Xcel Energy has cost-effectively reduced methane emissions from the natural gas distribution system since joining the EPA’s Natural GasStar program in 2008. We estimate fugitive methane emissions from our natural gas distribution system to be about 590 million cubic feet per year, based on factors provided by the EPA to calculate these emissions. In general, emissions from the natural gas system are a minor contributor to our environmental impact, comprising less than 1 percent of our overall greenhouse gas emissions.

Our proactive approach to improving the natural gas system reduces methane emissions. Under the Natural GasStar program, Xcel Energy has reported reducing methane emissions by 28,106 million cubic feet per year through a number of efforts:

  • Replacing 117.6 miles of cast iron pipe since 2008—the oldest type of pipe on our system; we expect to completely replace cast iron pipe by 2015.
  • Using pressure reductions and other methods to reduce fugitive emissions while making pipeline repairs.
  • Increasing efforts to prevent dig-ins and other damage to our systems.
  • Replacing high-bleed valves on our distribution and high-pressure pipelines; we are currently looking at new programs to add instrument air at storage fields and processing plants that still use high-bleed devices to improve operations at these facilities.

Read more about environmental considerations with natural gas and find information on our natural gas system improvement efforts.