Owner/operator: Sempra Generation

The current largest photovoltaic plant in the U.S., the 48-MW Copper Mountain Solar 1, utilizes approximately 775,000 solar panels to generate emission-free electricity for about 14,000 homes without the use of water. The facility was constructed in less than a year—an unprecedented achievement for a project of this size.

Courtesy: Sempra Generation

Nevada is a sparsely populated state that contains large expanses of desert dotted with sagebrush and tumbleweeds. Because the southern Nevada desert offers intense year-round sunshine, there are few places in the world better suited for solar energy development.

The ample solar resource in southern Nevada was a main reason that Sempra Generation chose to build the Copper Mountain Solar 1 plant on a 380-acre tract in Boulder City, which is about 20 miles southeast of Las Vegas (Figure 1). Additional factors that made this location optimal for solar development were expansive available land and close proximity to major transmission lines that provide access to major markets, Scott Crider, director of external affairs, Sempra Generation, told POWER in October. (Boulder City sits between the Hoover Dam Powerplant and Las Vegas.)

1. Hitting the jackpot. The 48-MW Copper Mountain Solar 1 is located in Boulder City, approximately 20 miles southeast of Las Vegas. The facility is currently the largest photovoltaic (PV) solar plant in the U.S. Its PV modules do not require the use of water to produce emissions-free electricity. Courtesy: Sempra Generation

When the facility entered service in December 2010, it was the largest photovoltaic (PV) plant in the U.S. The 48-MW installation produces an estimated 100 GWh of emission-free electricity on an annual basis. The new plant is located adjacent to Sempra Generation’s 10-MW El Dorado Solar installation (a 2009 POWER Top Plant). Power generated from the project is sold to Pacific Gas & Electric under a 20-year contract.

On March 18, Nevada Governor Brian Sandoval, Boulder City Mayor Roger Tobler, Sempra Generation President and CEO Jeffrey W. Martin, and other dignitaries gathered to officially dedicate the new solar plant.

In his comments, Governor Sandoval praised Sempra Generation for its commitment to Nevada and for creating hundreds of local construction jobs during building of the solar facility: “This project exemplifies my goal of making Nevada into the renewable energy capital of the country. Projects of this magnitude provide hundreds of jobs and invest millions of dollars in our state.”

Copper Mountain Solar 1 was named “Solar Project of the Year” by Renewable Energy Magazine.

Operations Overview

“The landmark solar installation was built in less than a year, which required an innovative approach to development in order to achieve this scale and construction efficiency,” said Crider.

First Solar supplied the thin-film PV solar panels and served as the engineering, procurement, and construction contractor for Copper Mountain Solar 1.

First Solar’s PV modules have a number of key design features:

  • The front (superstrate) and back (cover) glass laminated sheets are heat-strengthened to withstand handling and thermally induced stresses, while avoiding breakage over the 25-plus-year module life.
  • The semiconductor stable cadmium telluride (CdTe) compound semiconductor material, applied in a very thin layer, forms the active photovoltaic cells, which convert sunlight into electricity.
  • Laminate material is used to bond the cover glass to the substrate and thereby seal the PV device from the environment.

The PV module specifications are as follows:

  • Length: 1,200 mm (47.24 inches)
  • Width: 600 mm
  • Weight: 12.0 kg (26.45 pounds)
  • Thickness: 6.8 mm

Crider pointed out that Copper Mountain Solar 1 is the first renewable power plant to operate under a unique California Independent System Operator (CAISO) “pseudo-tie” pilot program. The “pseudo-tie” transmission arrangement allows an out-of-state renewable resource generating plant to deliver electricity as if the generator were located in, or directly connected to, CAISO. He emphasized that “the pilot program is providing critical data to help CAISO test and validate its systems and procedures for the management of out-of-state variable resources.”

In support of CAISO’s new interconnection initiatives for renewable power generators, Copper Mountain Solar 1 was also among the first solar power plants to implement a customized plant control system that allows active power management, Crider explained. This functionality allows the plant operations team to quickly respond to system requirements—such as limiting power output—from a consolidated control center, rather than manually shutting down individual units distributed throughout the facility.

Boosting the Nevada Economy

Sempra Generation received federal and state tax incentives for the development of Copper Mountain Solar 1. These incentives play a critical role in the ongoing development of utility-scale solar projects in the U.S., according to Crider. However, this project is a net revenue generator for taxpayers. Crider noted that “for every $1 in tax incentives received, Copper Mountain Solar 1 will generate $2 in new land lease and tax incentives for federal, state, and local governments.” Additionally, the project created hundreds of new construction jobs and is helping move Nevada’s clean energy economy forward. Eight full-time maintenance and operations employees currently operate the plant.

“Over the life of the project, the facility will generate about $135 million in new revenue for state, local, and federal governments,” Crider said. “For example, Boulder City, Nev., is using the land lease revenue from the project to fund essential city services like police, fire, and park maintenance.”

Looking Ahead: Copper Mountain Solar 2

“Copper Mountain Solar 1 represents Sempra Generation’s commitment to developing world-class alternative energy projects that generate a new source of clean power and create jobs,” said Sempra’s Martin. “But the success of Copper Mountain Solar 1 can be directly attributed to the vision and support of Boulder City, Pacific Gas & Electric, and many state and federal officials in Nevada. Their leadership is accelerating our country’s transition to a more sustainable energy future.”

In keeping with its goal of promoting solar energy, Sempra Generation is now planning a major expansion of its landmark solar installation in Boulder City. “The new facility will be called Copper Mountain Solar 2, and it will further solidify Sempra Generation and Boulder City as sustainable energy leaders,” Crider said.

Construction on the 1,100-acre site is expected to begin in early 2012. Power generated at the new 150-MW solar plant will be sold to Pacific Gas & Electric under a 25-year contract.

The first 92 MW of solar panels at Copper Mountain Solar 2 will be installed by 2013; the remaining 58 MW are expected to be completed by 2015. The new facility will deliver the following benefits:

  • Create about 175 construction jobs, plus five positions to operate the facility.
  • Generate approximately $150 million in new revenue for state and local governments over the life of the project.
  • Require no water to generate electricity.
  • Produce a new source of clean, emissions-free electricity.
  • Be located near existing power plants and transmission lines.

In addition to Copper Mountain Solar 2, Sempra Generation is expanding its renewable energy portfolio throughout other parts of the U.S. Southwest. It recently broke ground on a massive new solar facility in Arizona called Mesquite Solar, which could produce up to 700 MW of electricity at full build-out. The company also is pursuing additional solar installations in California. Sempra Generation has a solar development pipeline that could ultimately exceed 1,300 MW.

Angela Neville, JD, is POWER’s senior editor.