From a distance, they almost look like a massive mosaic swimming-pool cover. They are photovoltaic panels, half-millimeter thick silicon wafers that are erected over reservoirs. Their function: Generate power while also conserving water.
For years, the technology was just a niche product. Now, with drought concerns growing in many places across the planet, it?s showing signs of taking off.
In parched parts of California and Australia, as well as in Japan, where cramped living conditions put land at a premium, the panels can increasingly be seen dotting the water. According to Infratech Industries Inc., a Sydney-based developer of the technology, they can produce almost 60 percent more electricity than land-based solar farms and they reduce evaporation by 90 percent.
While still representing less than 1 percent of the power generated by all solar installations today, up from about zero a few years ago, Infratech anticipates much more growth in demand for the floating panels — on reservoirs and even above hydro dams — as global temperatures rise.
?Water is a commodity that is only going to increase in value,? Felicia Whiting, an Infratech director, said in a telephone interview.
For the technology to keep gaining market share, though, producers will have to overcome what could be their biggest obstacle: The higher cost of installing and maintaining the panels relative to conventional units, which could limit their spread to drought-stricken or crowded areas.
?Making the system float has to be more expensive than putting a solar panel on a roof, or in a field,? Paul Meredith, a materials physicist at The University of Queensland who is investigating the efficient production of solar energy, said by phone. ?Operating and maintenance is difficult enough on land without having to get into a row boat.?
Kyocera Corp. and Century Tokyo Leasing Corp. have built three plants in Japan?s Hyogo Prefecture, with combined capacity of 5.2 megawatts, according to a May statement. One megawatt is enough to power 357 Japanese homes, Kyocera said.
The Japanese plants are being developed on water in regions that lack available land for utility-scale generation, Hina Morioka, a Kyoto-based spokeswoman for Kyocera, said May 28 in an e-mailed response to questions. There are projects planned on about 30 reservoirs in Japan to generate about 60 megawatts. There are at least 5 operating plants in Japan with a combined capacity of 7.4 megawatts, less than 1 percent of the country?s 23.3 gigawatts of installed solar.
Kyocera?s 2.3 megawatt rectangular plant at Kasai City has more than 9,000 solar modules sitting on floating platforms, which are anchored to the bottom of the reservoir. It covers about 40 percent of the water.
Solar Power Inc., backed by China?s LDK Solar Co., is planning projects in the U.S. and Mexico. The company has teamed with San Diego-based Aqua Clean Energy and identified more than 50 megawatts of potential plants for places including California, according to a statement in March.
Floating panels help conserve water, a shortage of which is threatening the production of coffee, almonds and other commodities. A record drought in California left millions of acres of farmland fallow.
The sun could become the largest source of electricity by 2050, provided solar costs can be lowered, the International Energy Agency said in September. Panel prices are about two-thirds lower since 2010 because of a global supply glut driven by production in China.
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