In The Solar Energy World, This Process Delivers More Energy Per Acre And It’s Priced Comparable To Coal Derived Energy.
A small solar company Amonix, based out of Seal Beach, California, and the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL), combined talents to developed a solar power concentrator that generates electricity at prices competitive with natural gas. The Amonix 7700 Concentrated Photovoltaic (CPV) Solar Power Generator, is the size of an IMAX screen but costs much less than comparable generators, partly because of the efficiency of its small solar cells. It delivers more “energy per acre” than anything yet available in the solar energy world.
NREL’s partnerships with industry, such as this one with Amonix, are key to reaching aggressive White House goals including lowering solar energy’s installed cost to $1 a watt. That would be a great step towards reducing our dependence on foreign oil and releasing Big Oil’s strangle hold on the whole wide world.
The 7700 uses acrylic Fresnel lenses to concentrate sunlight up to 500 times its usual intensity and direct it onto 7,560 tiny, highly efficient multi-junction PV cells. The cells, originally developed by NREL scientists, can convert 41.6% of the sunlight that shines on them into usable electricity in a laboratory setting, a world record. Production cells never work quite as well as cells produced in the lab. But the multi-junction cells on the Amonix 7700 are achieving 31% efficiency at the module level and 27% at the system level in the field, the highest ever achieved for an operating CPV concentrator.
That unprecedented efficiency opened the door to reducing costs and reducing land use, both key for solar electricity to reach cost-parity with fossil fuels. And causing this public-private partnership to win a 2010 R&D 100 award (called “The Oscars of Invention”), at the annual event honoring the greatest breakthroughs in technology.
The key breakthrough that lifted the 7700 to a 50% greater power output than previous generations of Amonix generators was the substitution of the multi-junction cells made of gallium indium arsenide and gallium phosphide for the more common silicon cells, more expensive to produce today, but also can be more efficient at converting the sun’s photons into usable electrons for electricity.
Amonix, with technical support from NREL’s High-Performance PV Project and financial support through the Department of Energy (DOE), and its Solar Energy Technologies Program, redeveloped its flagship CPV system using the multi-junction cells. A six-inch square silicon wafer in traditional photovoltaic (PV) panels produces about 2.5 watts of electricity. That same-sized wafer, cut into hundreds of square-centimeter cells in the Amonix 7700, each teamed with a Fresnel lens, produces more than 1,500 watts. It reduces the required area for cells 500 times. (Fresnel lens were originally developed by French physicist Augustin-Jean Fresnel for lighthouses, a design that captures more oblique light from a light source without the mass and volume of material required by conventional lens.)
Researchers teamed the inexpensive Fresnel lens — at less than $2 a pop — with each of the 7,560 high efficiency solar cells that make up one 53-kilowatt 7700 system. The 500-power amplification of the Fresnel lens allowed the solar cells to be tiny — thus a small fraction of the cost of bigger cells — while still packing record-setting efficiency. Setting the potential for game-changing cost cuts,
The 7700 also keeps down costs by integrating the lenses, the cells and the mounting structure into a single unit that eliminates most of the parts and costs associated with other concentrator designs. The seven MegaModules that make up the 53-kilowatt system can be hauled on two flatbed trucks, then assembled in the field in hours, rather than weeks. Twenty Amonix 7700s, erected on just five acres of desert, can generate more than a megawatt of rated capacity, enough to power 750 homes. That’s half the space typically needed to generate that much power.
The 7700 already has driven the price of electricity from solar down to the price of electricity from natural gas, according to the California Market Price Referent, which establishes a proxy price for electricity generated by a new state-of-the-art natural gas plant. Solar power is at or near price parity in six other states that share California’s sunny and dry climates — Arizona, Nevada, Utah, New Mexico, Colorado and Texas.
Amonix has 15 years of experience developing CPV systems, while NREL has a record of more than three decades of research and development in PV technologies such as PV cells used to power spacecraft. The fruitful partnership, had several problems to overcome. Researchers developed a new receiver package of cells and lenses to ensure that the cells would not short out. They solved the distortion problem that happens when a lens doesn’t focus all colors on the same convergence point. And they overcame the thermal issues that crop up when a cell has to handle the intensity of 500 suns.
Presently, as with most all solar collection systems, the 7700 is for the commercial generation of electricity. But once these system become more common place and therefore affordable, there should be no reason they can not be scaled down for rural individual and small community applications.
Solar energy needs to come in at or below the costs of electricity generated from coal, which is projected to cost from 6 cents to 15 cents per kilowatt-hour in four years. The 7700’s cost per kilowatt-hour is expected to be well within those price ranges as production and sales continue to grow.
Tags: amonix, concentrator, dependence on foreign oil, electricity, energy, energy world, Everything Solar, fresnel lenses, national renewable energy, national renewable energy laboratory, nrel scientists, production cells, public private partnership, renewable energy laboratory, seal beach california, solar cells, solar company, solar electricity, solar power generator, unprecedented efficiency, wind