Mining the Sky

Portable Metrology Energizes Solar Power Plant Design-to-Assembly

SolarReserve’s first-generation solar power plant is a welcome sign of green progress. Once the Crescent Dunes Solar Energy Project is completed in 2013, it will generate roughly 480,000 megawatt hours per year of clean, renewable electricity to power 75,000 homes during peak electricity periods.  The company’s unique concentrating solar power (CSP) technology and innovative energy storage was developed by the same Rocketdyne engineers and scientists who designed Apollo rockets, Space Shuttle engines, and the solar power system for the International Space Station.

Harnessing Sunlight with Concentrating Solar Power Technology

Tonopah Solar Energy, a subsidiary of SolarReserve, manages the project located on 1,600 acres northwest of Tonopah, a historical silver mining town near the Nevada desert. The site selection was based on key ingredients for optimum solar energy  - hours of direct sunlight, altitude (more intense sunlight), and DNI (Direct Normal Irradiance) strength. The power plant design includes a tall receiver tower and power block positioned centrally in a large circular field of mirrors known as heliostats. The 100 ft. receiver is mounted upon the 553 ft. concrete tower. Tower height is essential for plant efficiency and ensures the heliostat array can concentrate sunlight onto the receiver.

Comprised of thousands of tracking mirrors in a two-square mile area, the solar collection field operates whenever there is ample solar resource to collect energy. SolarReserve’s propriety motion control software lies on a central computer that sends angle location data to the heliostat field, and the mirrors move simultaneously as the sun travels across the sky.  The energy is stored and delivered to the grid anytime, even after sundown. The 110 MW plant will utilize an ordinary steam turbine generator to produce electricity, but integrates a sophisticated hybrid cooling system using less than 600 acre-feet/year of water, a scarce commodity in the Southwest.        

The power tower receiver glows as it soaks up the sun during the day, but remains dormant at night. Its high heat flux hardware is a unique blend of liquid rocket engine heat transfer technology and molten salt handling expertise. Inside the receiver, concentrated sunlight heats molten salt to more than 1,000 degrees Fahrenheit. The liquid then flows into an insulated storage tank maintaining 98% thermal efficiency. It is eventually pumped to the generator to produce electricity. This process is similar to a standard coal-fired power plant, but it is fueled by clean and free solar energy.

The solar power plant utilizes components primarily manufactured in the U.S.A., as opposed to competing technologies using mostly imported parts and assemblies. Bar a few one-of-a-kind components, the plant employs readily available materials (mirrors) and established technologies (steam generators and turbines). The inexpensive molten salt is made from an environmentally-friendly mixture of sodium and potassium nitrate, the same ingredients used in garden fertilizer. This configuration of materials and equipment will enable SolarReserve to provide electricity at or below prices from traditional sources such as coal or natural gas.