Announcement of contract
Start of operation
Spring 2006 for Ronzone Reservoir
Las Vegas, USA
The Las Vegas Water District has issued financing bonds. Nevada Power will buy renewable credits, and sell surplus to the grid.
Water District of Las Vegas
Utilities Commission of Nevada
Eleven ground-mounted Power Trackers
Three 225kW Xantrex inverters
Data Acquisition System (DAS)
One of the world’s largest photovoltaic systems is now under construction near Las Vegas, USA. The 3.1MW solar electric array is being built by PowerLight Corporation, and has eleven solar electric systems. Six are at the Water District’s Las Vegas Springs Preserve, with five more at three reservoir sites within the water distribution system.
Over their 30-year operating life, the systems will generate clean electricity and save the equivalent of 5.8 million barrels of oil. The project uses no water, and is emission free. A key solar benefit is that maximum power is developed during summer, when electricity use is at its highest and state transmission lines are the most constrained. By avoiding hundreds of tons of carbon dioxide emissions, it is equivalent to planting 1,320 acres of trees or saving on 350 million miles worth of car journeys.
The Public Utilities Commission approved the $22.6m Las Vegas project as part of Nevada’s 2001 Renewable Energy Law. It is part of Nevada Power’s plan to meet its 7% renewables target (with 5% coming from solar). Besides renewable power, the Springs Preserve arrays provide shaded parking for up to 200 cars. That makes the solar panels very visible to visitors, increasing awareness of the installation and the technology.
DISTRIBUTED GENERATION IS THE FUTURE OF THE ELECTRIC GRID
The Las Vegas Springs Preserve is a 180 acre site of artesian springs. This is probably the only site that will use all the electricity generated by the PV systems. The other sites have only reservoirs, and any surplus will be put into the network.
Construction at the Ronzone Reservoir was completed in Spring 2006, and the system generated nearly 200,000kWh in the first month. It uses ground-mounted Power Trackers, with 4,005 Sharp solar panels over five acres (two hectares).
The panels are arranged in multiple rows, rotating on a single axis to track the sun’s motion. This tracking system allows the solar array to produce up to 25% more energy than a stationary solar array. The steel frame is galvanised and corrosion resistant and withstands high winds. The system uses a robust active tracking motor, with a ‘linked’ design requiring only one drive motor per 200kW.
The panels convert sunlight to DC output, which is converted to AC by three 225kW Xantrex inverters. A Data Acquisition System (DAS) provides daily system performance monitoring.
STEWARD TO THE SPRINGS PRESERVE
The Las Vegas Water District began providing water to the Las Vegas Valley in 1954 and now supplies more than a million people in Southern Nevada. The Water District is also steward to the Springs Preserve, the location of the City of Las Vegas’ first source of water. The District is a partner in developing the preserve into a cultural resource centre, featuring exhibits, trails, gardens and more. It started developing the solar project in October 2004. Other systems are under construction at Fort Apache and Grand Canyon.
Nevada Power will buy renewable credits, and put any surplus generation on the grid. The Las Vegas Water District issued bonds to finance the project. More funding is coming from fees from developers to connect to the distribution system. Nevada Power’s incentives have led to other solar projects, with customers receiving a $5/W rebate for installing new systems. LVVWD does not expect to or plan to raise water rates to pay for the project.
SUBSIDIARY OF SIERRA PACIFIC RESOURCES
The project was selected by Nevada Power Company as part of its 2003 Renewable Energy Request for Proposals. Nevada Power is a wholly owned subsidiary of Sierra Pacific Resources. It is a regulated public utility that generates, distributes, buys and sells electric energy in southern Nevada. The company provides electricity to about 725,000 residential and business customers over 4,500 square miles.
PowerLight Corporation has built more than 300 large scale solar projects since it was founded in 1991. The company has been ranked among the top 500 fastest growing privately held companies for five consecutive years. The company has built and operates many of the largest solar electric systems in North America and Europe.