Thursday, January 26, 2012

A Greener Alternative To Conventional Solar Backsheets

As the solar market continues its dramatic growth, the future outlook for manufacturers is changing. While US photovoltaic module manufacturers were working on technology development and manufacturing strategies, their competition, mainly in Asia, was able to line up financing and build new factories more rapidly. The Chinese government also has been developing a set of subsidies to boost solar energy production in-country.

As a result, a great deal of industry buzz has been generated by the precipitous slide in solar module prices, which dropped approximately 40 percent from 2007 to 2010 and by another 40 percent in 2011. Most industry experts predict that solar module price will eventually bounce back from its lowest level of 2011 once demand catches up with supply as evidenced by steadily growing solar energy demand in the future.

As prices of solar modules continue to drop, however, manufacturers are searching for alternative PV components that cost less while matching or exceeding the durability of incumbent components. The pressure to cut costs continues to be intense this year as supply outstrips demand.

An Economical Green Backsheet

The solar industry is still in its relative infancy, and the question of how solar modules will ultimately be disposed of when they have exhausted their lifespans after 25 years or more is only beginning to be addressed. For an example, PV backsheets, the bottom most layer of crystalline silicon solar cells, have traditionally been made of petroleum-based plastics. Unfortunately, the widespread use of petroleum-based plastic backsheets raises the prospect that their disposal will result in the release of toxic chemicals, including harmful hydrogen fluoride, into the environment.

By contrast, BioSolar's BioBacksheet, a bio-based alternative to conventional petroleum based backsheets, does not pose such environmental issues when disposed. It does not require toxic and energy intensive manufacturing processes used in the manufacture of conventional petroleum based backsheets. BioBacksheet is produced by single-step film extrusion, whereas conventional multi-layer backsheets require extrusion extrusion processes followed by lamination of multiple film layers using industrial adhesives. It is not difficult to understand that BioBacksheet's simple manufacturing process means lower manufacturing cost.

Durable BioBacksheet Increases Solar Panel Efficiency

BioSolar's bio-based materials are engineered for extreme duty use. In addition, BioBacksheet is constructed as a single layer film that is more durable than backsheets with multi-layer construction. The adhesives used to hold the layers together in conventional multi-layer backsheets usually experience degradation over time, increasing the risk of inter-layer delamination that can lead to the loss of a solar module's hermetic seal against moisture. Should the seal fail, solar PV module manufacturers could be faced with the time, expense and inconvenience of replacing modules under warranty.

One important characteristic of the BioBacksheet is its higher thermal conductivity. BioBacksheet has approximately 80 percent higher thermal conductivity compared to those of conventional backsheets. Higher thermal conductivity allows the heat that builds up from solar exposure to be dissipated faster. Because the energy efficiency of crystalline silicon solar cells drops as the temperature rises, solar panels incorporating BioBacksheet can yield higher efficiency.

The development of BioBacksheet has been a five-year process that is now coming to a successful conclusion, for which the company expects full scale commercial production and volume delivery in 2012. As the first and only bio-based backsheet in the solar industry, BioBacksheet received material certification from the Underwriters Laboratory in February 2011 and a USDA BioPreferred product certification, which mandates preferential consideration by government agencies, in June 2011.

BioBacksheet made its debut at the recent GovGreen Conference in Washington, D.C., the market for government decision-makers looking for green solutions, and is now being considered by multiple PV manufacturers in full integration trials. While the company is now focusing on the full commercialization of its BioBacksheet, it is also developing other bio-based PV module components that will make solar energy even greener in the future.

As demonstrated by the BioSolar BioBacksheet, new opportunities can still be found to bring down the cost of solar and in doing so, contribute to the widespread implementation of solar, and thus to a cleaner environment, enhanced energy security and the mitigation of global warming.

But, much as has been the case with electronic waste, solar modules hold the prospect of leaving a toxic legacy if they end up in landfills where the harmful chemicals they contain can leach into our groundwater, or in incinerators, where those chemicals can be released into the air we breathe. Care must be taken that solar is green across its entire lifecycle, including the ultimate disposition of the modules. The development of the BioBacksheet is a major step in that direction.

Finally, green technology solutions must provide superior performance and attractive pricing compared to those of incumbent non-green counterparts in order for them to achieve commercial success. Being green alone is just not a guarantee for commercial success even in the presence of abundant government subsidies or policies favoring green technology.


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