Project purpose

The TransWest Express Transmission Project will provide the transmission infrastructure and 3,000 MW of capacity necessary to reliably and cost-effectively deliver approximately 20,000 GWh/yr of clean and sustainable electric energy generated in Wyoming to the Desert Southwest region, which for the purposes of the project is Arizona, Nevada and southern California.

National, regional and state environmental policies have significantly increased the need for renewable resources in this area. At the same time, Wyoming has an abundance of high-quality, low-cost renewable resources in the form of wind energy. In fact, the vast majority of the best winds in the Continental U.S. are available in Wyoming.

Wind map of the United States
This wind resource map shows the mean annual wind speed measured at 80 meters.
Dark orange represents winds of 8 meters per second, and speeds increase
as the orange-red gets darker. (Map by AWS Truewind)

However, California and Desert Southwest utilities do not have a direct way to access the benefits of Wyoming’s rich renewable energy resources without new transmission lines such as the direct current TWE Project.

The TWE Project will make Wyoming's wind-generated electricity available to utilities to serve citizens in more densely populated regions. This electric power is roughly equivalent to three-fourths of the electric power used in Los Angeles alone. In addition, many experts recognize that providing more connectivity between geographically diverse and complementary renewable resources can help smooth grid operations as the grid grows “greener.” Using Wyoming wind to help fill in the times when California’s wind isn’t blowing or the sun isn’t shining, for example, helps utilities reduce their reliance on traditional peak-priced fuels and therefore helps contribute to California’s GHG emissions reduction goals as well as their renewable energy goals. The bidirectional TWE Project also could provide export capacity for Desert Southwest solar resources, particularly during overgeneration events.

Ultimately, the TWE Project will:

  • Broaden consumers' access to domestic, clean, renewable energy sources.
  • Contribute to meeting national, regional and state energy and environmental policies, including state-mandated renewable portfolio standards and greenhouse-gas reduction targets.
  • Help meet increasing customer demand with improved electrical system reliability.
  • Provide system flexibility and increased access to the grid for third-party transmission users.
  • Expand regional economic development through increased employment and enlargement of the property tax base. (TransWest will pay property taxes in every county the transmission line crosses.)
  • Maintain the standard of living associated with highly reliable electricity service

The need for the TWE Project is supported by numerous studies that have documented the increase in demand for renewable energy resources within the Desert Southwest. For purposes of electric supply reliability, the TWE Project will be built in accordance to standards developed and enforced by the North American Electrical Reliability Corporation and the Western Electricity Coordinating Council.

What else is driving the project's need?

  • Renewable Portfolio Standards. Like many other states, Arizona, Nevada and California have adopted renewable energy standards, commonly referred to as Renewable Portfolio Standards. Legislation in these states require utilities to meet a portion of their overall customer energy supply with renewable energy resources by specific dates. For example, 33 percent of California’s electricity supply must come from renewable resources by 2020. These standards combine to an overall regional renewable energy need of 55,000 more gigawatt-hours per year of renewable energy, according to forecasts from National Grid research. The TransWest Express transmission line alone will deliver about 20,000 gigawatt-hours per year, significantly helping address this demand.
  • Greenhouse-gas reduction mandates. Renewable energy like wind energy helps reduce greenhouse-gas emissions because it requires no fossil fuels and generates zero emissions or pollution. Since many states and the federal government are considering various GHG emission reduction policies, having an increased amount of wind energy available will be vital to achieving GHG goals. Several western governors, including the governors of California, Arizona and Utah, formed the Western Climate Initiative in 2007 to reduce regional GHG levels. The WCI members have established a regional goal, and details of the programs are being developed.
  • Large house with lights on, evening
  • More people, more electricity use. The demand for electricity in the Desert Southwest is expected to grow as the population grows. According to the U.S. Census Bureau, the western U.S. has experienced a population growth of approximately 10 percent from 2000 to 2006. Its latest projection of population growth between 2000 and 2030 for Arizona, California and Nevada is nearly 50 percent. Arizona and Nevada were identified as the fastest-growing states during this period.

In addition, the amount of electricity used per person is also expected to increase due to the continued electrification of day-to-day life: more air-conditioning, computers, high-definition televisions, gaming systems, industrial applications, and potentially electric-powered cars. Even with ongoing energy conservation efforts, the demand for electricity is expected to increase about 2 percent per year in the Desert Southwest.

Project-specific highlights

  • Provide for the efficient, cost-effective and economically feasible transmission of approximately 20,000 GWh/yr of clean and sustainable electric energy from Wyoming to markets in the Desert Southwest region.
  • Meet North American Electric Reliability Corporation Reliability Standards and Western Electricity Coordinating Council planning criteria and line separation requirements.
  • Maximize the use of existing and designated utility corridors and access roads in order to minimize environmental and social effects of the TWE Project to the extent practical.
  • Provide these benefits to the Desert Southwest region and the broader Western United States in a timely manner to meet the region's pressing environmental and energy needs. TransWest has identified a need for the TWE Project by the expected in-service date of 2015 or as soon as the regulatory reviews can be completed.
  • Provide for flexibility and maximize the use of transmission capacity that may become available by configuring the TWE Project to allow for future interconnection with the Intermountain Power Project transmission system near Delta, Utah.

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In the news

"A number of peer-reviewed studies have documented that the aggregate output of wind and solar plants spread over a large geographic area is much less variable than the output of plants clustered into a small area. Thus, a more robust grid can significantly reduce the cost of integrating wind and solar power with the grid by allowing larger power flows between regions as well as making it possible to access renewable resources from a greater diversity of areas."

- AWEA/SEIA Green Power Superhighways report, February 2009