Answer Lies in Solar

BM Solar Energy Tech Claims to Harness Power of 2,000 Suns

IBM is working on an affordable photo voltaic system capable of concentrating solar radiation 2,000 times and converting 80% of the incoming radiation into useful energy.

IBM, working with other researchers, has announced an "affordable photo voltaic system that can concentrate solar radiation 2,000 times."

A byproduct of the system is that it also produces a massive amount of heat. That heat can be harvested to perform other functions, such as desalinating water and creating cool air in sunny, remote locations where they are often in short supply, the IBM researchers said.

The High Concentration Photo Voltaic Thermal (HCPVT) system can convert 80% of the incoming solar radiation into useful energy.

Bruno Michel, a research scientist with IBM Research, Zurich, points to the HCPVT solar conversion system.

If IBM's claims prove true, its solar concentrator would surpass a recently achieved world record for solar conversion efficiency, which is 44.7%. That system, created by a team of scientists from the Fraunhofer Institute for Solar Energy Systems along with others, was able to concentrate power that is the equivalent of 297 suns.

The HCPVT system uses a big mirror that looks like a satellite dish to concentrate sunlight onto a small semiconductor chip, which then converts that light into energy. Because of the high concentration, along with energy, heat is also concentrated and must be dissipated so it doesn't melt the system. That heat can be used for other processes, such as desalination (evaporating saltwater to make potable water), according to Bruno Michel, a lead scientist with IBM Research, Zurich.

"The Sun is the [source of the] most abundant energy we have. We get 85,000 terawatts of energy [from the Sun] on the face of the globe, and we only need 15 terawatts," Michel said. "So we only need a fraction of .3 or .4% of the surface of the earth in order to provide all our energy.

"So we could build a solar power station in unused land in the Sahara, for example, to provide enough energy in the long term to replace all of the fossil and nuclear energy," he added in a video describing the technology.

The prototype HCPVT system includes a Sun tracking system that positions the dish at the best angle to capture the sun's rays. The mirror reflects onto several micro channel-liquid cooled receivers with triple junction photo voltaic chips -- each .39-in. x .39-in. chip can convert 50 watts, on average, over a typical eight-hour day in a sunny region.

The entire receiver combines hundreds of the chips and provides 25 kilowatts of electrical power. The photo voltaic chips are mounted on micro-structured layers that pipe liquid coolants within a few tens of micrometers off the chip to absorb the heat and draw it away. The system is 10 times more effective than passive air cooling.

"The coolant maintains the chips almost at the same temperature for a solar concentration of 2,000 times and can keep them at safe temperatures up to a solar concentration of 5,000 times," IBM said in a statement.

The HCPVT was created as part of a three-year, $2.4 million grant from the Swiss Commission for Technology and Innovation awarded to scientists at IBM Research; Airlight Energy, a supplier of solar power technology; ETH Zurich (Professorship of Renewable Energy Carriers); and Interstate University of Applied Sciences Buchs NTB (Institute for Micro- and Nanotechnology MNT).

The researchers believe they can achieve a cost-per-aperture area below $250 per square meter, which is three times lower than comparable systems. The cost of energy will be less than 10 cents per kilowatt hour (KWh). For comparison, feed in tariffs for electrical energy in Germany are currently still larger than 25 cents per KWh and production costs at coal power stations are around 5-10 cents per KWh.

"The design of the system is elegantly simple," Andrea Pedretti, chief technology officer at Airlight Energy, said in a statement. "We replace expensive steel and glass with low cost concrete and simple pressurized metalized foils. The small high-tech components, in particular the microchannel coolers and the molds, can be manufactured in Switzerland with the remaining construction and assembly done in the region of the installation. This leads to a win-win situation where the system is cost competitive and jobs are created in both regions."

Bruno Michel, a research scientist with IBM Research, Zurich, explains how the solar concentrator works.