Researchers at Tel Aviv University are developing a new technology to combine conventional fuel with solar power, which could provide a cost-effective and realistic way to integrate solar technology.
In solar thermal power plants sunlight produces high-temperature (400 to 500 °C ) and high-pressure steam to turn turbines that generate electricity. However, these plants can be expensive to build because they often require expensive metals to handle the high pressures and high-accuracy concentrator technology to harvest solar energy.
Avi Kribus, Tel Aviv UniversityNew technology developed by Avi Kribus of Tel Aviv University’s School of Mechanical Engineering and its new Renewable Energy Center combines conventional fuel with steam produced by solar power but at a lower pressure and temperature. This technology could be used in hybrid power plants, where 25 to 50 percent of fuel is green energy.
With graduate student Maya Livshits, Kribus is developing a steam-injection gas turbine. The gas turbine uses a mixture of hot air and steam. “We still need to burn fuel to heat the air, but we add steam from low-temperature solar energy, approximately 200 °C,” Kribus said. This hybrid cycle is highly efficient in producing energy and the lower pressure and heat requirements allow the solar part of the technology to use more cost-effective materials, such as common metals and low-cost solar collectors.
They have performed a thermodynamic analysis of this hybrid cycle, finding that this approach has the potential to have an overall conversion efficiency (with fuel and solar contributions) from heat to electricity in the range of 40–55%. The system has the potential to use very little water because the injected water can be recovered and recycled with the use of a very low cost condenser.
The researchers hope that a hybrid plant will have a comparable cost to a fuel-based power plant, making the option of replacing a large fraction of fuel with solar energy competitive and viable. They are starting to collaborate with a university in India to further develop the technology and are looking for corporate partnerships willing to put the hybrid technology into use. It’s a stepping-stone that will help introduce solar energy into the industry in an accessible and affordable way, Kribus says.