The U.S. Department of Energy last week announced $2.7M USD in American Recovery and Reinvestment Act Funding (ARRA) for three ANL solar projects.  An additional $5M USD in ARRA Funding was awarded jointly to ANL, Commonwealth Edison Co., GridPoint and the University of Illinois Sustainable Technology Center (ISTC).

The first project will invest $945,000 in developing transparent thin films for solar cells.  Project leader Dr. Jeffrey W. Elam, a chemist with ANL's Energy Systems Division, writes that this project will look into both "transparent conducting oxides using indium (ITO)" and "TCO films with little or no indium".  The TCO films seem particularly promising, as they reduce the reliance on indium, a scarce metal.  The indium free films are deposited on zinc oxide or tin oxide, and many of them are being custom-developed for the project.

While there's typically a gap before such materials hit the market, improving efficiencies of commercial designs, Dr. Elam sees that gap as relatively short for these films.  He states, "In two of our current solar cell projects, we have fabricated prototype devices and we are engaged in 3-year projects to scale these up and demonstrate manufacturability. These solar cells should be ready for commercialization in 3 years."

A second project, led by chemist Alex Martinson, has received $750,000 in funding to develop high-efficiency thin films via unconventional materials and woven films.  We inquired about the significance of weaving the films.  Martinson replied, "The 'weaving' may allow the incorporation of affordable materials with modest electrical properties into photovoltaics with good light harvesting efficiency. The advantage is that the requirement for active layers with both superior optical and superior electrical properties is relaxed."

As to what unconventional materials will be explored, he states, "Some of the atypical active layers being considered include copper sulfide (Cu2S), iron oxide (Fe2O3) and pyrite (FeS2)."

A third project led by ANL materials scientist Dileep Singh has received $1M USD to explore fluids to store thermal solar power and to more efficiently transfer solar thermal energy during the day at concentrated-thermal solar power plants.  Improving storage will help reduce the inconsistency of solar power availability, while improving energy transfer will significant lower the cost of solar power, bringing it closer to power from fossil fuel sources.

Describes Singh, "There is a disparity in the levelized cost of energy (LCOE) between solar and fossil fuel, etc., which prohibits the widespread use of solar energy. To reduce this disparity, in concentrated solar plants, we are considering two approaches: storage of solar energy so that power plant can be operational during night time or cloudy days and more efficient transfer of thermal energy from heat transfer fluids (that are heated by mirrors) to steam in the heat exchanger. For instance, if thermal properties of the heat transfer fluids are enhanced then the inlet temperature into the turbine can be increased. For every 10°C increase in the inlet temperature of turbine, the LCOE for solar will be reduced by $9 per MWh. With current difference between solar and combined cycle natural gas power plant being $44 per MWh, it will make a significant impact. This does not include the cost reductions from energy storage aspects. DOE’s goal is to increase storage capability up to 6 hours by 2015 and 16 h by 2020."

Finally, the bulk of the money will go to a joint experimental deployment of solar power by ComEd, GridPoint, and ISTC to approximately 200 customers' homes.  These homes will receive smart meters, as will other homes without solar power.  Some of the solar households will also receive a battery backup system, which will provide 10 kWh energy storage at 4.9 kW of power.

The study will run 12 months and will look at how the smart meters affect customer's usage, and additionally how much energy saving the solar and solar+battery backup installations yield, respectively.

We would like to thank Argonne National Laboratory's employees for their help with this article.