JJ's TechnoBlog: December 2010

Thursday 2 December 2010

Boeing to mass-produce record-breaking 39.2 percent efficiency solar cell

When it comes to solar cells, everyone is chasing the highest conversion efficiency. Although we’ve seen conversion efficiencies of over 40 percent achieved with multi-junction solar cells in lab environments, Boeing subsidiary Spectrolab is bringing this kind of efficiency to mass production with the announcement of its C3MJ+ solar cells which boast an average conversion efficiency of 39.2 percent.

As far back as 2006 Spectrolab was achieving conversion efficiencies of over 40 percent in the lab with its high-efficiency multi-junction concentrator solar cells and it reached a peak of 41.6 percent with a test cell last year, setting a new world record. The company’s newest terrestrial concentrator photovoltaic (CPV) cell, called the C3MJ+, uses essentially the same technology as its record breaking test cell and follows on from its C3MJ solar cell in production since mid-2009 which boasts a conversion efficiency of 38.5 percent. The C3MJ+ solar cells

"Given the new cells' close similarity to our existing production cells, we believe that our current C3MJ customers will be able to easily upgrade for more efficiency," said Russ Jones, Spectrolab director of CPV Business Development.

Spectrolab claims the title of the world’s leading supplier of solar cells for satellites with its cells supplying power to around 60 percent of satellites currently in orbit, as well as the International Space Station. Boeing hopes to transfer that success to the terrestrial solar cell market with the new high-efficiency solar cells that are expected to be available from January. And it won’t be resting on its laurels. It expects Spectrolab will achieve a 40 percent average production efficiency for terrestrial solar cells in 2011.

'Plastisoil' could mean cleaner rivers and less plastic waste

A new cement-like material that could be used to form sidewalks, bike and jogging paths, driveways and parking lots, may be able to lessen two environmental problems, namely plastic waste and polluted rainwater runoff. The substance is called Plastisoil, and it was developed by Naji Khoury, an assistant professor of civil and environmental engineering at Temple University in Philadelphia. In order to make Plastisoil, discarded polyethylene terephthalate (PET) plastic bottles are pulverized and mixed with soil, and then that mixture is blended with a coarse aggregate and heated. The result is a hard yet non-watertight substance, similar to pervious concrete or porous asphalt.

With traditional concrete and asphalt paving, rainwater stays on the surface and runs into the storm sewers, accumulating oil and other road filth along the way. With pervious surfaces such as Plastisoil, that water is able to go down through them, and into the soil below. This certainly reduces the amount of pollutants entering the rivers, although Khoury and his team at Temple are currently trying to determine if Plastisoil could even serve as a filter, that removed pollutants as the water filtered through.

Khoury said that it uses less energy to produce one ton of Plastisoil than one ton of cement or asphalt, and that it’s less expensive to manufacture than similar products. It takes 30,000 PET bottles to make one ton of the material, although he is hoping to be able to use other types of plastic in the future.