UniSource Energy

From Global Energy Monitor
UniSource Energy Corporation
TypePublic (NYSEUNS)
Headquarters1 South Church, Ste. 100
Tucson, AZ 85701
Area servedAZ
Key peopleJames S. Pignatelli, CEO
IndustryElectric Producer, Distributor & Utility
Natural Gas Utility
ProductsElectricity, Natural Gas
Revenue$1.32 billion (2007)[1]
Net income $58.4 million (2007)[1]
Employees1,951 (2007)
SubsidiariesTucson Electric Power
UniSource Energy Services
UNS Electric

UniSource Energy Corporation is a holding company that has no significant operations of its own. Operations are conducted by UniSource Energy’s subsidiaries, each of which is a separate legal entity with its own assets and liabilities. UniSource Energy owns 100% of Tucson Electric Power Company (TEP), UniSource Energy Services, Inc. (UES), Millennium Energy Holdings, Inc. (Millennium) and UniSource Energy Development Company (UED).[2]

TEP, a regulated public utility, is UniSource Energy’s largest operating subsidiary and represented approximately 81% of UniSource Energy’s assets as of December 31, 2008. TEP generates, transmits and distributes electricity to approximately 400,000 retail electric customers in a 1,155 square mile area in Southern Arizona. TEP also sells electricity to other utilities and power marketing entities primarily located in the Western U.S. In addition, TEP operates Springerville Unit 3 on behalf of Tri-State Generation and Transmission Association, Inc. (Tri-State).[2]

UES holds the common stock of UNS Gas, Inc. (UNS Gas) and UNS Electric, Inc. (UNS Electric). UNS Gas is a gas distribution company with 146,000 retail customers in Mohave, Yavapai, Coconino, and Navajo counties in Northern Arizona, as well as Santa Cruz County in South Central Arizona. UNS Electric is an electric transmission and distribution company with approximately 90,000 retail customers in Mohave and Santa Cruz counties.[2]

The company was founded in 1902 and is based in Tucson, Arizona.[1]

Power portfolio

Out of its total 1,656 MW of electric generating capacity in 2005 (0.16% of the U.S. total), UniSource produced 61.8% from coal, 37.9% from natural gas, and 0.3% from solar. All of UniSource's power plants are in Arizona.[3]

Existing coal-fired power plants

UniSource owned 3 coal-fired generating stations in 2005, with 1,023 MW of capacity. Here is a list of UniSource's coal power plants:[3][4][5]

Plant Name State County Year(s) Built Capacity 2007 CO2 Emissions 2006 SO2 Emissions
Springerville AZ Apache 1985, 1990 850 MW 9,733,000 tons 4,889 tons
H. Wilson Sundt AZ Pima 1967 173 MW 1,067,000 tons 2,230 tons

In 2006, UniSource's 2 coal-fired power plants emitted 10.8 million tons of CO2 and 7,100 tons of SO2.

Articles and Resources


  1. 1.0 1.1 1.2 UniSource Energy Corp., BusinessWeek Company Insight Center, accessed Aug. 2008.
  2. 2.0 2.1 2.2 "UniSource 2008 10K report" Edgar Online, Filed August 6, 2009
  3. 3.0 3.1 Existing Electric Generating Units in the United States, 2005, Energy Information Administration, accessed April 2008.
  4. Environmental Integrity Project, Dirty Kilowatts: America’s Most Polluting Power Plants, July 2007.
  5. Dig Deeper, Carbon Monitoring for Action database, accessed Aug. 2008.

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