July 15, 2008

Global Monitor (July 2008)

CPV cells get cooling chips from IBM

A new solar energy system invented by IBM researchers could render concentrator photovoltaic (CPV) technology cost-effective and more efficient. The computer technology company has combined innovations from its R&D in cooling computer chips with a large magnifying glass and a tiny solar cell—and it has so far generated power of a density five times that of CPV cells used in typical solar farms.

The scientists used a large magnifying glass to concentrate about 200 sun systems onto a 0.4-square-inch solar cell into 2,300 sun systems (“one sun” is a measurement equal to the solar power incident at noon on a clear summer day). The team then used a liquid metal cooling interface used in microprocessor technology to cool the intense heat of about 2,912F—enough to melt stainless steel, as researchers experienced firsthand in their experiments—to about 185F. The device ultimately captured a record 230 W on the solar cell and then converted it into 70 W of electric power, IBM said (Figure 2).

2. Big Blue goes green. IBM researchers have coupled a liquid metal cooling technology developed for the microprocessor industry with a large magnifying glass and a tiny solar cell to render concentrator photovoltaics more effective. Courtesy: IBM

IBM had earlier developed the liquid metal cooling technology to cool high-power computer chips. It consists of a very thin layer of a liquid metal made of a gallium and indium compound that is applied between the chip and a cooling block. Such layers, called thermal interface layers, transfer heat from the chip to the cooling block so that the chip temperature can be kept low.

IBM said that if it can overcome additional challenges to commercialize the project, the technology could lower the number of photovoltaic cells in a solar farm by concentrating more light onto each cell using larger lenses—and that this could ultimately make CPV technology more cost-efficient.

Though concentrator-based photovoltaics technologies have been around since the 1970s, they have received renewed interest recently.With very high concentrations, they have the potential to offer the lowest-cost solar electricity for large-scale power generation—provided the temperature of the cells can be kept low and that cheap and efficient optics can be developed for concentrating the light to high levels.

IBM is currently exploring four main areas of photovoltaic research: using current technologies to develop cheaper and more efficient silicon solar cells; developing new solution-processed thin-film photovoltaic devices; concentrator photovoltaics; and future generation photovoltaic architectures based upon nanostructures such as semiconductor quantum dots and nanowires.

StatoilHydro to pilot test first offshore floating wind turbine

If an $80 million plan by Norwegian oil company StatoilHydro to test a full-scale floating deepwater wind turbine off Norway’s coast next year is successful, the wind industry could see renewed installation frenzy.

StatoilHydro’s 2.3-MW wind turbine will be built by Siemens atop a “Spar-buoy,” which is based on the design of production platforms and offshore loading buoys. The rotor blades on the floating wind turbine will have a diameter of 262 feet, and the nacelle will tower 213 feet above the waves (Figure 3). The floatation element, built by Technip, will have a draft of 1,076 feet below the sea surface, and it will be moored to the seabed using three anchor points. From tests that StatoilHydro conducted with a 10-foot-high model in a wave simulator in Trondheim, Siemens and StatoilHydro have determined that the turbine can be located in waters with depths of 394 feet to 2,297 feet.

3. Come wind or high water. Norwegian company StatoilHydro will test the world’s first floating deepwater wind turbine in 2009 off Norway’s coast. The device’s rotor blades will have a diameter of 262 feet, and the nacelle will tower 213 feet above the waves. Courtesy: StatoilHydro

The pilot project will be assembled in Åmøyfjorden, near Stavanger, and is to be located some 6.2 miles offshore Karmøy in southeast Norway. Siemens, which has entered into a technology development agreement with StatoilHydro on the project, will ensure that the turbines function optimally during the two-year test, even in large waves.

The goal of the pilot is to qualify the technology and reduce costs to a level that will enable floating wind turbines to compete with other energy sources, said Alexandra Bech Gjørv, head of New Energy at StatoilHydro.

“Floating wind power is not mature technology yet, and the road to commercialisation and large scale development is long. An important aspect of the project is therefore research and development,” she said. “If we are to succeed, we will need to cooperate closely with the authorities. As with other technologies for renewable energy, floating wind power will be dependent on incentive schemes to be viable.”