Photovoltaic cells may be good for energy consumption, but the materials they are built from are not good for the environment. Unless they are built using castor beans, by Californian company BioSolar, that is. By Mallika Naguran.
Los Angeles, 20 Feb 2011. Most people think solar panels are green. They are definitely a green source of energy, but some of the components are definitely not. According to BioSolar CEO, David Lee, many are made from the same compounds used in computers and mobile phones – many of them toxic.
The problem is that solar panels have to be toughened up to last a long time in the environment, says Lee. For example, the backsheets, the bottom-most layers of solar panels, need to withstand 20 to 30 years in the environment, sometimes in the desert, sometimes in the rain.
BioSolar's Dr. David Lee is convinced bio-plastics will help solve the problem of toxins in PV cell manufacture
“This means manufacturers use very toxic processes to toughen them up. For example one common kind of backsheet, Tedlar, is solvent-cast in DMAC, a cancer-causing material,” he says. Worse still, when the life of the product is over, you cannot burn it, because it can release hydrogen fluoride into the environment so it has to be buried in the ground.
Lee’s company has taken a more environmentally friendly route. His company is looking at renewable materials that would last as long or longer than their petroleum counterpart. His alternative is called Nylon 11, and is a polymer derived from the castor bean, and extremely durable.
“We add certain ingredients to make it tougher,” says Lee, “and help it retain electrical properties that are superior to anything else out there.”
BioSolar’s approach — replacing petroleum-based plastic components with those made from renewable plant resources — doesn’t just make environmental sense, but it will save manufacturers money, too, he claims.
Originally trained as an electrical engineer, Lee earned his Ph.D. in electrical engineering from Purdue University. He worked on vehicle safety systems and then went on to help several startup companies until in 2006, he decided he wanted to be his own boss and go after a life’s dream – working on things that could change the Earth and the way people behave.
The big problem in PV cell construction has traditionally been in the way the layers are bonded. BioSolar aims to solve this - and cut costs
“Now is the time for green technology to actually be beneficial, and not just a name tag,” he says. So he started BioSolar to go green, reduce cost and to simplify designs. Conventional solar panel backsheets consist of three layers — Tedlar on the top, polyester in the middle, and Tedlar or EVA on the bottom. Not only do these layers tend to split apart with time, they are potentially toxic.
“So making a single (bean-based) layer avoids all these issues,” he points out.
His company has been selling the idea to solar panel makers – but its biggest appeal (not surprisingly) has been cost, not green credentials. None were concerned about (sustainability) as much as cost. Cost was the number one concern.
It might not sound glamorous, but the castor bean could just bring a revolution in cell construction
“But they love to use it as propaganda, to be 'green'. Right now, it’s just a value-add. But the decision comes from the fact that it is more durable and costs less,” he says. Even with the use of contract manufacturers in the United States, they are still competitive when compared to the Chinese. Once the volume matures, it might be easier, says Lee. The company is also considering licensing and acquisitions later.
“This is a new industry that’s been invigorated. So far, all bioplastics have been focused on making compostable, throw-away products. Now bioplastics are focusing on more durable products. We chose a material that’s inherently strong,” he points out. “There are so many plastic parts used by heavy industries that are made from petroleum, then toughened up by adding fluoride to it. And that’s always toxic.”
Lee notes that in today’s market there is a strong drive to make more plastics with bio-based materials, so there are fewer ongoing and disposal pollution problems and their costs will be lower.
Nylon 11 has been used a long time in underwater cabling and some deep-sea drilling, and the material itself is already recognized as being durable.
“What we do is make it more durable still. We change the properties of the polymer to make it tougher,” Lee explains. “There’s more money to be made from tough bioplastics.”
We all know that the petroleum supply is dwindling. Maybe beans will give us some of the answer to our energy needs.
Photos courtesy BioSolar