Growing Crops While Generating Electricity

As the global use of greenhouses for food production has increased six-fold over the past 20 years to more than 9 million acres, reducing the energy consumed by greenhouses has become a priority. Imagine being able to generate electricity and grow crops at the same time? It can be done, according to a recent study by the University of California Santa Cruz---their paper appears in the current issue of the American Geophysical Union's journal Earth's Future.

"Smart" greenhouses serve multiple purposes

These electricity-generating solar greenhouses have recently been tapped for what is called "dual-use farming" and the first crops of tomatoes and cucumbers have just been harvested. It turns out, they are as healthy as those raised in conventional greenhouses. That means they hold substantial possibilities for the future---including the production of renewable electricity---without sacrificing plant growth.

Special solar technology

Utilizing more efficient Wavelength-Selective Photovoltaic Systems (WSPVs), electricity-generating solar greenhouses actually cost less than traditional photovoltaic systems. While transparent magenta WSPVs absorb some of the blue and green wavelengths of the solar spectrum, they transmit the remaining wavelengths that can be used for photosynthesis in the plants growing below. But here's the most fantastic news: The cost per panel of WSPV technology is only 65 cents per watt---about 40 percent less than the per-watt cost of traditional silicon-based photovoltaic cells.

Magenta panes have beneficial effects

These transparent roof panels are embedded with a bright magenta luminescent dye; the panels absorb light and transfer energy to narrow photovoltaic strips, where electricity is produced. Moreover, the magenta panels seem to help tomato plants save water---5 percent less water to grow the same amount than more conventional glasshouses. Interestingly, while 80 percent of the plants were not affected at all, 20 percent actually grew better.

What this development means for the future

Expect to see this technology applied worldwide. Additionally, in 2012 two of the co-authors, Sue Carter and Glenn Alers, both professors of physics at UC Santa Cruz, founded the company Soliculture to bring the WSPV technology to market. This technology appears to be a real winner!

Special thanks to our friend and futurist Dr. Oliver Markley for bringing this important development to our attention.