More Light for Solar Cells

The slackness in sales in the photovoltaic industry does not only have a dark side: In the battle for customers, the manufacturers are focusing more intensively on innovations. The greatest advancements have been in the classic silicon cell style: New crystalline technology absorbs more of the sun’s rays and provides a higher performance.

For years, customers have been positively tearing solar modules from the hands of photovoltaic manufacturers: Generous buy-back prices for solar electricity in many European counties have driven the demand for panels from one record to the next. And this meant, the companies themselves could achieve top prices for the simplest technology which they manufactured in standard processes on depreciated production lines.

In the meantime, the market has turned. Many suppliers have been left holding their modules as important countries such as Germany and Spain have reduced their solar tariffs, thus putting the brakes on the solar boom. For the first time in the history of photovoltaics, the European Photovoltaic Industry Association (EPIA) has forecast a decline in the global market for 2011 and 2012.
As a result, the manufacturers are faced with a major challenge: They must rapidly improve the price-performance relationship of their products in order to be able to hold their own against the competition. This is forcing them to create far-reaching innovations.

The latest developments include cells, on which the electrical connections are fitted on the reverse so that the front side is not shaded by contacts and busbars. As a result, more sunlight can penetrate and the electricity yield is increased.

The protagonist of these “rear contact cells” is the US manufacturer, Sunpower. Their cells convert light into electricity with an efficiency of 22 percent, based on the module– which is currently being introduced on the market with the name of “Maxeon”– with no less than 20 percent. This is one percentage point more than Sunpower’s previously established modules of rear contact cells and a quarter more than the commercially available silicon modules, which currently achieve an average of 15 percent efficiency.