Solar Research Hits the Sunshine State

California and other western states get lots of ink for mega solar power projects and technology research, but the Sunshine State is eager to build a legacy in the history of solar energy.

Florida now claims to be home to the country's largest solar-panel installation. One of its cities, Gainesville, was the first in the United States to adopt a solar incentive policy that resembles the kind that has made Europe the center of solar energy generation.

A recent webinar hosted by Greentech Media highlighted solar and other renewable energy research being undertaken by the Florida Energy Systems Consortium, a state-funded effort to bring together researchers from 11 universities to work on renewable energy technology development.

Tim Anderson, director of the consortium and a professor at the University of Florida, noted that although solar is an even more intermittent resource in Florida than it is in the western deserts because of its cloud cover and other issues. 

The state gets a good share of hurricanes, which also pose a technical challenge for operating and maintaining a field of solar panels or mirrors for harnessing the sun's heat. In fact, Ausra ditched a solar thermal power project in Florida after realizing its equipment could be toppled by hurricanes.

Here are some projects under developing by the consortium:

Sunlight to Hydrogen Fuel: The process begins with mirrors to concentrate and direct the sunlight to a tower for heating zinc oxide and then reducing it to metal. When combined with water, the zinc metal oxidizes and produces hydrogen. Combine the hydrogen with an organic material to produce transportation fuel. When the engine runs, a catalyst releases the hydrogen, which is burned as fuel. The organic material is then recycled to pick up more hydrogen. "It's a recycled closed system to solve our transportation problem with solar thermal," Anderson said.

There is a complementary research project on developing a fluidized bed reactor to create a more efficient conversion of metal oxide to hydrogen.

Solar-Powered Desalination: This research focuses on using the sun to create drinking water from seawater. The process involves using solar energy collectors to heat the seawater at above the boiling point to collect evaporated water, which then contains no salt. The vapor is condensed after going through a heat exchanger that uses cold seawater. The fresh water is then position to fall 10 meters or more to run a vacuum, which increases the evaporation rate. The brine, with concentrated salt, is sent back to the ocean.

Germ Killer From the Sky: Early research is in place to use solar energy to disinfect water. The idea is to create a catalyst using materials such as titanium dioxide that can absorb sunlight and create free radicals. The free radicals then seek out and kill microbes in the water.

A Cooler Way to Generate Solar Thermal Power: Solar thermal power needs to be cheaper in order for it to be competitive with conventional power, Anderson said. Cutting the equipment cost by about 50 percent is the way to do it. But how? Researchers are exploring the use of ammonia to generate solar thermal power at a much lower temperature. The lead researcher of the project, Yogi Goswami, has gotten funding from venture-backed and India-based SunBorne Energy, where he serves as its technology advisor, to commercialize his research. He's planning a pilot plant at the University of South Florida. 

Solar Cell/LED/Battery Module: A solar cell produces direct current. A light-emitting diode runs on a direct current. A battery can store direct current. So why not combine them together to create a lighting system with energy storage? That's idea behind the research to build a solar cell with transparent organic material on top of an organic LED. The LED emits light downward and sits on top of a transparent platform that's embedded with lithium-ion batteries. The solar cell charges the battery during the day, and the batteries can power the LED light at night.

This design would make solar energy more efficiently because there will be no need for an inverter, Anderson said. Packing all these functions into the same module also would save material costs, he said. "It might be a perfect application for a parking lot."

Other research being undertaken by the consortium includes improving the rate of producing solar cells with copper, indium, gallium and selenium; the use of magnetic coupling to transmit solar power wirelessly from the outdoors to inside a building; and a microinverter with built-in controllers and software to communicate with the grid.

By the way, South Plainfield, N.J.-based Petra Solar has licensed the microinverter-with-grid-communications technology.