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The US Department of Energy’s National Renewable Energy Laboratory advised that it recently validated Semprius’ triple-junction cells at greater than 41% efficiency at a concentration of 1,000 suns – said to be one of the highest efficiencies recorded at this concentration. The North Carolina company makes its cells from gallium arsenide with the lenses laying claim to concentrating the sunlight onto the small cells 1,100 times.
Most notable about the small size of the cell, is that they occupy 1/1000 of the entire solar module area, which is said to lead to an overall reduction of the module cost. Furthermore, Semprius acknowledges that by putting such large numbers of small cells together, the heat is better distributed across the cell’s structure, which can eliminate the need for thermal management equipment.
Semprius states that it grows a temporary layer on the original gallium-arsenide substrate and then grows the multi-junction solar cell structure on top of that layer.
Once the wafer is processed, the transfer printing process removes the cells from the gallium-arsenide substrate and transfers them to an interpose wafer. Semprius used its micro-transfer printing process to allow the micro-cells to be transferred from the growth substrate to a wafer. A large parallel process allows thousands of cells to be transferred at the same time, which additionally allows for the original substrate to be used repeatedly.
"We're using a completely different approach to what has been practiced," said Kanchan Ghosal, CPV applications engineering manager and the principal investigator for Semprius' PV Incubator Award. "This approach uses micro-cells and transfer printing to significantly reduce the use of materials in highly concentrated PV modules. And it provides a highly parallel method to manufacture the module, based on established microelectronics processes and equipment."
Semprius told the NREL that its low-cost approach can cut manufacturing expenses by 50%, a figure that the NREL noted Siemens acknowledged by taking a 16% stake in the company.
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I may have misread your question, sorry if I did.There is no energy savings by using an alternative source. Most of the alternative sources are in fact MORE expensive. People choose to pay more for solar, wind, and other alternative sources a lot more in some cases. As alternative energies become more efficient and cost effective they replace fossil fuels more and more, but there is still a cost to the production of the PV cells and wind turbines lots of metal, and lots of composites including plastics, in relation to the power they produce. Energy savings comes from conservation and increasing efficiency. Right now, renewable energy accounts for about 7% of US energy consumption. Most of the 7% is hydro-electric and wood burning.
Actually it is wonderful and efficient! The city of Sevilie in Spain runs entirely on electric solar power. The reson for everyone not using solar power in the US was because of the Bush administration. Bush was big on oil and gas and didn’t favor alternative fuel. As a result, solar power was not granted its potential. Although its available now, people don’t understand its effectivness and benefits it provides.
That is all nice but there are other multi-junction cell manufacturers that can claim the same or better efficiency. They claim lower cost for cells, but in the end, the cell costs are not the major costs associated with HCPV in the field. The real question is what will the module efficiency be once it is mounted on a 2 axis tracker taking into account the shadows cast and resultant poor land use efficiency? How many watts per acre will they achieve? Not much better than others like Solfocus but substantially worse than other technologies coming in the near future.