Clean Power BioSolar introduces biobased solar cell backsheet

Published on March 14th, 2013 | by Tina Casey


Tired Of Your Solar Panel? Eat It!

March 14th, 2013 by  

Well, to be honest we’re not quite there yet when it comes to edible solar panels, but a company called BioSolar has been working on a bio-based solar panel component for several years now, and they’ve just introduced it to the commercial market. Called a backsheet, it’s the same kind of protective covering that you’ll find on practically any photovoltaic cell today, but instead of being made with petroleum film it’s made from a proprietary material based on cotton and castor beans. Come to think of it, you would not want to eat cotton or raw castor beans anyways (they’re poisonous), but using bio-based materials to generate renewable energy is a step in the right direction.

BioSolar introduces biobased solar cell backsheet

Castor Beans courtesy of USDA

Bio-Based Materials For Solar Cell Backsheets

We first noticed BioSolar back in May 2010, when it was ready to go public with the proprietary secret behind its bio-based backsheet. The castor beans contribute a resin, which is processed to form a polyamide resin similar to nylon. The cotton contributes tough cellulosic fiber.

The result is a highly durable material, as BioSolar describes it:

“This new tough bio-based material will be able to offer the durability and environmental characteristics of conventional petroleum-based plastics, such as electromagnetic properties, mechanical strength, dimensional stability, and weatherability required by PV solar applications.”

For an extra pop of sustainability, the cotton is apparently derived from cotton rags, not raw cotton (the use of bio-based materials won USDA BioPreferred Certification status for BioBacksheet, btw).

Aside from the sustainability benefit, BioSolar lists a couple of straight bottom-line advantages for the backsheet, which it calls the BioBacksheet. It costs less to produce than petroleum-based backsheets, which are typically made with polyester film, partly because the base materials are cheaper than petroleum and partly because it consists of a single composite layer rather than laminated layers.

BioBacksheet also avoids the use of toxic industrial solvents that are needed to produce Tedlar film, another conventional backsheet component.

Another benefit that comes into play is the high thermal conductivity of the BioBacksheet. That helps draw excess heat out of the solar cell, helping to increase its useful life.

Who Is Buying BioSolar Backsheets?

BioSolar announced its first commercial customer just yesterday without disclosing the name, but the company did reveal that the first shipment of BioBacksheets will be used to make photovoltaic panels for electric utility vehicles.

That’s a little vague, though electric solar powered golf carts and other small EVs with flat roofs come to mind (and oddly…Justin Timberlake, too).

Partly due to the advantage of its USDA certification, BioSolar is anticipating additional customers in the government sector, particularly the U.S. military.

About Those Castor Beans…Let’s Fix This!

One thing that could be a little problematic in terms of costs is the use of imported castor oil. Though castor can thrive in the U.S., it is rarely grown here due to the toxic characteristics of the raw beans, which can provoke severe allergic reactions during processing.

On the other hand, that might not be so much of a problem in the future. Castor oil is a valuable commodity with numerous industrial uses, and partly for that reason USDA researchers have been working on developing strains that are less toxic and allergenic, with an eye to developing domestic production of castor oil.

Follow me on Google+ and Twitter


Check out our new 93-page EV report, based on over 2,000 surveys collected from EV drivers in 49 of 50 US states, 26 European countries, and 9 Canadian provinces.

Tags: , , , , , , ,

About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.

  • This is an interesting concept. This is just another reason to add more solar energy into the energy mix. Solar will solve our energy problems if we can adapt and adopt.

  • UKGary

    You missed mentioning the fact that using bio-backsheet will allow delivery of more kWh per kW peak as solar cells running at lower temperatures are more efficient. (heat is shed faster through the back of the panel so cells run cooler)

  • The beans are NOT produced in the US, so there’s the same problem of IMPORTING key features.

    • Ronald Brakels

      If you like I can avoid buying US products to cut down on the amount the US imports.

    • Tina Casey

      tx for pointing that out, that’s covered in the section about why castor is rarely grown in the U.S.

    • Tina Casey

      thanks for pointing that out, it’s covered in the section about why castor isn’t a popular crop in the U.S. (at least not for now)

      • Vinay Patel

        It is now possible to grow efficiently and safely in the US.
        Moreover, safe handling and processing will never create any issue to process castor to produce its unique oil.

    • Bob_Wallace

      Castor beans grow well in parts of the US. If they turn out to be a good source of raw materials for resin then we can farm ourselves a load.

      I suspect we don’t grow them in quantity because we just don’t use a lot of castor oil any longer.

      • Vinay Patel

        The US importing over 100,000 Tons of castor oil annually and increasing consumption. The consumption will increase substantially if produced domestically.

  • First paragraph needs editing. A ‘not’ should be included.

    • Tina Casey

      fixed, tx!

Back to Top ↑