Concentrating photovoltaic (CPV) solar system maker Soitec of Bernin, France? and Maxwell Technologies Inc, a developer and manufacturer of storage and power delivery solutions, are to collaborate on a California Energy Commission (CEC)-funded, two-phase program to demonstrate the cost and efficiency benefits of combining an energy storage system with Soitec's Concentrix concentrated photovoltaic (CPV) technology.
Maxwell has been awarded a $1.39m contract by the California Energy Commission's Research and Development program to fund the design and integration of an ultracapacitor-based energy storage system with Soitec's CPV system located on the campus of UC San Diego, and a second commercial scale system at Soitec's solar power plant in Southern California. The integrated systems will also take advantage of other technology advances, including solar forecasting and predictive energy control.
The project started in June 2013 and will run through November 2015. Independent evaluation of the performance of the integrated systems will be performed by BEW Engineering under a sub-contract with Maxwell.
"This innovative energy storage system combining ultracapacitators and Soitec's CPV technology, which is already installed on campus, is a welcome addition to UCSD's existing microgrid and provides a unique diversification of our existing energy storage capacity," said Byron Washom, director of Strategic Initiatives, UC San Diego.
"Investing in solar energy research is vital to California reaching its goal of 33 percent renewable generation by 2020," said California Energy Commission Chair Robert B. Weisenmiller. "This innovative project combining energy storage with concentrated photovoltaic technology has the potential to increase the state's renewable energy portfolio, decrease greenhouse gas emissions, and create a more reliable electricity grid."
Soitec's new fifth-generation Concentrix CPV systems incorporate modules with a 30% module efficiency. CPV technology converts sunlight directly into "clean" electricity via concentrator optics and high-efficiency solar cells, offering the best design for use in sunny regions as it delivers environmentally friendly, low-cost, reliable solar generated electricity. Additionally, the CPV system's 2-axis tracker allows a high and constant power production throughout daylight hours.
Ultracapacitors are energy storage devices that charge rapidly from any electrical energy source and discharge their stored energy on demand. In combination with a photovoltaic system, their function will be to act as a standby reservoir of electrical energy to mitigate the variability of solar energy generation.
This 'firming' of the output of a utility scale commercial CPV system is intended to reduce demand on the electric grid to fill in short-term solar 'valleys' to maintain a facility's electricity output. In addition to reducing the variability of a solar power plant, integrated ultracapacitor-CPV systems will benefit public utility customers by reducing investment in utility generation capacity to meet transient peak power demand.
Unlike batteries, which produce and store energy by means of a chemical reaction, Maxwell's ultracapacitor products store energy in an electric field. This electrostatic energy storage mechanism enables ultracapacitors to charge and discharge in as little as fractions of a second, perform consistently over a broad temperature range (-40C to +65C), and operate reliably for up to one million or more charge/discharge cycles.
"Soitec's durable CPV systems are specifically designed to deliver higher efficiency and lower cost of electricity. By working together, we are confident that we can improve the integration of solar power plants into the grid and ultimately increase the penetration of solar in the electricity grid helping California to meet its 33% RPS goals." said Clark Crawford, VP of US sales & business development, Soitec Solar division.
