MD DC DE VA Solar Energy Industries Association

Hybrid Solar Systems

22

Apr 14

0

Hybrid solar systems introduce the opportunity of 24/7 renewable energy supply, tackling the issue of intermittency surrounding solar energy today which threatens to limit solar energy to providing just 5 percent of energy in the U.S. [1] Solar power requires the sun in order to produce electricity; depending on geographic location this may present problems during certain weather conditions or times of year where there isn’t a sufficient amount of solar radiation or stored energy to meet electricity demand. The addition of wind or thermal to solar production through hybrid solar systems help to create a steady flow of energy, greatly increasing the capabilities of each technology. There are several types of hybrid solar systems such as photovoltaic-thermal, photovoltaic-wind and photovoltaic-diesel.

Photovoltaic-Thermal

There are a few different ways these two types of solar power can be combined. Storing electricity from solar panels is currently unfeasible or too expensive; where as solar thermal can store energy as heat which can then be used to create electricity through the process of a steam turbine. Concentrated photovoltaic systems generate a huge amount of excess heat which is currently dissipated into the atmosphere as waste. [1] The basic water system uses conductive metal piping or plates running along the back of the photovoltaic module, excess heat is then conducted through the metal and absorbed by a working fluid. Heat is easier and cheaper to store than electricity and can also be used to generate electricity through steam. [2]

Another type is by utilizing the whole solar spectrum. Photovoltaic cells are very good at converting certain wavelengths of light into electricity, however others are wasted. By combining photovoltaic and thermal the unabsorbed spectrums can be directed to heat a working fluid. Researchers at the University of Tulsa have developed a system which uses nanoparticles suspended in a translucent fluid. These nanoparticles absorb certain wavelengths while allowing others to pass through to the photovoltaic cell, utilizing the whole spectrum of light to generate energy from heat through the nanoparticles, as well as electricity through the photovoltaic cell. [1]

Photovoltaic-Wind

Another hybrid system is the combination of photovoltaic and wind. These two technologies were found to complement each other much better than previously thought. Solar produces a lot more electricity during the summer, while wind produces a lot more in the winter months. As the peak operating time for solar and wind occur at different times of the year/day , the hybrid system  can generate twice the amount of electricity than each system on its own and provide a steady supply of energy year round. [3] [4]

With the growth of these hybrid systems there is the potential for completely green energy production. In order to produce a more optimum and stable energy supply the type of hybrid system used depends on geographic location and resource availability. However, the capture of both electricity and heat in photovoltaic-thermal systems, and the combined electricity production of photovoltaic-wind allow these systems to be much more energy efficient than any of these technologies alone.

Sources

[1] “http://www.technologyreview.com/news/517511/hybrid-solar-power-works-even-when-its-not-sunny/”.
[2] “https://www.ecn.nl/fileadmin/ecn/units/egon/pvt/pdf/ises03_lca.pdf”.
[3] “http://cleantechnica.com/2013/05/01/solar-wind-hybrid-power-plants-approximately-twice-as-efficient/”.
[4] “http://energy.gov/energysaver/articles/hybrid-wind-and-solar-electric-systems”.

 

 

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