Hybrid solar power works at night and on cloudy days
By combing the strengths of two different solar technologies -- photovoltaics with solar thermal -- researchers hope to develop cheap solar power that can be even when it’s not sunny.
And the U.S. government’s Advanced Research Projects Agency-Energy (ARPA-E) is devoting $30 million to demonstrate that this hybrid solar power could actually work. Technology Review reports.
Solar electricity’s intermittency limits it to providing just 5 percent of total energy in the U.S. Sometimes a lot of solar ends up going to waste.
Currently, storing electricity from solar panels is either prohibitively expensive or, in some areas, unfeasible. Solar thermal power, which concentrates sunlight to heat water and make steam for turbines, can store energy by keeping heat in insulated containers. But overall, solar thermal power is twice as expensive as power from solar panels.
According to ARPA-E, there are several ways to combine heat with electricity:
- There are existing systems that concentrate sunlight on tiny, super-efficient solar cells; the heat is extracted and allowed to dissipate in the air. But if it’s collected and stored, it could be used to generate electricity later. However, this requires operating solar cells at temperatures much higher than normal, which could be damaging. So, researchers are working on solar cells that are more resistant to higher temps.
- Solar cells convert only certain wavelengths of light into electricity. If wavelengths that can’t be used efficiently could be redirected, they could be used to heat up water and produce steam.
- Engineers at the University of Tulsa are using nanoparticles suspended in a translucent fluid to absorb certain wavelengths -- while allowing others to pass through to a solar cell. As the nanoparticles absorb sunlight, they heat up, and the fluid can be used to generate steam.
The idea of using both heat and electricity from solar panels isn’t new, but these systems haven’t been very efficient. Additionally, ARPA-E is looking to fund novel energy storage technologies that use both heat and electricity.
Image: Candie_N via Flickr
This post was originally published on Smartplanet.com