IBM's breakthrough in solar farm technology

USA: According to Solarbuzz, IBM has announced a research breakthrough in photovoltaics technology that the company says could significantly reduce the cost of harnessing the Sun's power for electricity. If it can overcome additional challenges to move this project from the lab to the fab, IBM believes it can significantly reduce the cost of a typical CPV based system.

By using a much lower number of photovoltaic cells in a solar farm and concentrating more light onto each cell using larger lenses, IBM’s system enables a significant cost advantage in terms of a lesser number of total components.

For instance, by moving from a 200 sun system ("one sun" is a measurement equal to the solar power incident at noon on a clear summer day), where about 20 watts per square centimeter of power is concentrated onto the cell, to the IBM Lab results of a 2300 sun system, where approximately 230W per square centimeter are concentrated onto the cell system, the IBM system cuts the number of photovoltaic cells and other components by a factor of 10.

“We believe IBM can bring unique skills from our vast experience in semiconductors and nanotechnology to the important field of alternative energy research,” said Dr. Supratik Guha, the scientist leading photovoltaics activities at IBM Research. “This is one of many exploratory research projects incubating in our labs where we can drive big change for an entire industry while advancing the basic underlying science of solar cell technology."

The trick lies in IBM’s ability to cool the tiny solar cell. Concentrating the equivalent of 2000 suns on such a small area generates enough heat to melt stainless steel, something the researchers experienced first hand in their experiments. But by borrowing innovations from its own R&D in cooling computer chips, the team was able to cool the solar cell from greater than 1600 degrees Celsius to just 85degrees C.

The IBM research team developed a system that achieved breakthrough results by coupling a commercial solar cell to an advanced IBM liquid metal thermal cooling system using methods developed for the microprocessor industry.

Specifically, the IBM team used a very thin layer of a liquid metal made of a gallium and indium compound that they applied between the chip and a cooling block. Such layers, called thermal interface layers, transfer the heat from the chip to the cooling block so that the chip temperature can be kept low. The IBM liquid metal solution offers the best thermal performance available today, at low costs, and the technology was successfully developed by IBM to cool high power computer chips earlier. While concentrator-based photovoltaics technologies have been around since the 1970s, they have received renewed interest in recent times.