New Mexico company Focused Sun is partnering with Xiang Yang Institute (XYI) in Hubei, China to develop solar microgrids with thermal storage to help relieve China’s smog problems.
“Focused Sun has squeezed the cost out of solar concentrators, the key part of the microgrid system that focuses sunlight. Together with thermal storage and Chinese turbogenerators, we can produce small power plants for microgrids,” said XYI Dean Jihong Chen, in a news release.
The system uses mineral oil heated by the sun to 300C to operate a turbogenerator. Thermal storage holds the heat for a day or more, so that it can generate electricity day or night.
“The solar energy peak is at mid-day, but people need heat and electricity in the evening,” says MIT David Gordon Wilson, an expert on thermal storage and turbomachinery and a professor at the Massachusetts Institute of Technology.
Wilson says thermal storage can power generators until the next day.
“For microgrids in the 100 kW to 10 MW range, low cost solar concentrators and thermal storage combined with turbogenerators make more sense than photovoltaic collectors and battery storage. Thermal storage is the key missing ingredient,” he said.
Focused Sun says that four times more solar energy is captured by the concentrators than by conventional PV panels of the same size. During the day, solar energy is stored thermally. At night or during cloudy periods, the energy is pumped from storage to the turbogenerator where 20 percent of the energy is converted to electricity, according to the news release.
Another 50 percent of the sun’s energy is available as heat to warm homes, hotel rooms and greenhouses or other structures. The system produces both electricity and hot water and can pay for itself in as little as two years, according to the company.
The solar microgrid system is built in a modular fashion so that it can be customized to various power plant sizes.
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