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Waste Management

Coal Ash Management

Coal-fueled power plants produce a number of coal combustion byproducts commonly referred to as coal ash. Xcel Energy plants consumed about 29.3 million tons of coal in 2013, which is supplied from mines in Colorado and the Powder River Basin in Wyoming. Throughout our system, we try to recycle coal ash whenever possible for beneficial use, such as in concrete products, roadbed material, soil stabilization, engineered-fill material and more. Ash that is not reused is properly disposed.

Coal Ash Summary (estimated in tons)
  2011 2012 2013
  Produced Reused Produced Reused Produced Reused
Upper Midwest 885,455 94,033 586,293 87,677 658,392 123,697
Colorado 932,219 448,768 767,389 424,780 931,002 394,522
Texas/New Mexico 340,264 340,264 333,753 333,753 324,244 324,244
Total 2,157,938 883,065 1,687,435 846,210 1,913,638 842,463

Learn more about Xcel Energy’s coal ash management.

Waste Management

Waste Disposition Summary (in tons)
  2010 2011 2012 2013
Hazardous 50 47 98 42
Universal1 37 37 30 35
PCB related2 512 365 449 438
Asbestos 306 1,308 2,221 553
Special3 9,230 18,806 6,345 14,242
Scrap metal 11,500 15,805 10,633 8,924
Used oil 2,098 2,239 1,547 1,719
1 Universal waste includes regulated waste such as fluorescent light bulbs, rechargeable batteries and mercury switches.
2 PCBs (polychlorinated biphenyls) are chemicals controlled under the Toxic Substances Control Act. PCBs were historically used in transformer oil.
3 Special waste includes oily materials recovered from our operations, such as rags, filters, soil and water.

PCB Phase-out Effort

We have been phasing out equipment that contains PCBs from our transmission and distribution system for many years. The Toxic Substances Control Act of 1979 defines PCB equipment as equipment having a PCB concentration of 500 parts per million (ppm) or more, while PCB-contaminated equipment has a PCB concentration of 50 to 499 ppm.

Xcel Energy has made dedicated efforts to remove all known PCB equipment from its system, including transformers, capacitors and other regulated categories of equipment. This equipment was targeted, removed and replaced with non-PCB equipment. In many cases, we retrofitted systems to accommodate the removal and replacement of regulated equipment with non-PCB equipment.

In Wisconsin, we are in the final year of a multi-year project to retrofill (remove contaminated oil and replace with clean oil) or replace all known PCB-contaminated electrical equipment within our substations.

Other phase-out efforts include the replacement of regulated equipment with non-PCB equipment as systems are upgraded. Any regulated equipment removed from the field is immediately disposed of and replaced with non-PCB equipment unless there are extenuating circumstances associated with the design or procurement of the equipment. Xcel Energy personnel are trained on PCB regulations and the proper identification, handling, removal and disposal of this equipment to facilitate phase-out efforts.

Aside from PCBs that are occasionally discovered during facility upgrade projects in small sealed or previously untested specialized equipment, most of the PCB and PCB-contaminated equipment left on our system is the result of cross-contamination occurring during manufacturing or maintenance activities prior to or shortly after the adoption of the Toxic Substances Control Act.

PCB Contaminated Equipment and Oil Removed from the Xcel Energy System
  2010 2011 2012 2013
PCB and PCB-contaminated oil (gallons disposed) 100,010 30,597 53,470 23,075
PCB and PCB-contaminated equipment (units removed from service) 330 454 721 714

Legacy Manufactured Gas Plant Projects

In the 1800s up until the mid-1900s, gas was manufactured using coal, oil and petroleum. It was used as natural gas is today, primarily for heating, cooking and street lighting. The U.S. Environmental Protection Agency (EPA) estimates that more than 50,000 manufactured gas plant (MGP) facilities operated in the United States between 1815 and 1960. They were owned by municipalities and corporations, including predecessor companies to today’s electric utilities. MGPs produced a variety of wastes and byproducts, including coal tar. Some of the waste and byproducts were sold for reuse or disposed off-site, and some were left at plant sites.

Given the extensive history of our operating companies—going back more than 100 years—Xcel Energy has inherited legacy MGP sites. All the plant facilities were closed and dismantled years ago, and some of the properties where the MGP once operated have been sold. Over the years, Xcel Energy has worked cooperatively with environmental agencies and communities to successfully investigate and/or remediate former MGP sites. We currently have investigation and/or remediation activities underway at seven MGP sites across our service territory.

One of Xcel Energy’s operating companies, Northern States Power Company-Wisconsin, is part of an extensive remediation project underway in Ashland, Wis. During the late 1800s and early 1900s, the lakefront in Ashland was one of the busiest industrial ports in the country. It was the site not only of a legacy MGP, but also the site of lumber and wood treatment facilities, as well as a loading area for railroads. The MGP was operated at the site from 1885 to 1947 and provided gas for street lighting and businesses. Later the site was used for a city-owned landfill and waste water treatment plant. NSPW has owned a portion of the Ashland site since 1986.

The site is being cleaned under the supervision of the EPA and the Wisconsin Department of Natural Resources (WDNR). The EPA has identified several parties responsible for the cleanup. Under an agreement with the U.S. Department of Justice, the EPA and WDNR, we are conducting phase 1 of the project, which includes remediation of the impacted soils and groundwater at the site. In addition, we have initiated litigation against other potentially responsible parties (PRPs) for cost recovery of their fair share of the cleanup costs. Negotiations among the PRPs, EPA and WDNR are ongoing for the second phase of the remediation, which will address impacted sediments at the site in an area of Lake Superior’s Chequamegon Bay.

Learn more about the Ashland, Wis., project.