Flexible solar panel uses thin-film cells (photos)

Using a proprietary manufacturing process that layers copper, indium, gallium, and selenium on a flexible metal substrate, SoloPower can create thin-film solar panels in flexible rolls, which, the company says, are not only easy to manufacture but also to transport and install. For example, the panels can be applied directly to rooftops without the need for framing systems.

San Jose, Calif.-based SoloPower claims that just these few microns of semiconductor material--layers vary from a few nanometers to tens of micrometers thick--can generate returns that rival traditional silicon photovoltaic systems. In short: equal energy, fewer materials.

The production process begins with long rolls of thin stainless steel, which are layered with copper, indium, gallium, and selenium (CIGS). The completed panels can be rolled and shipped compactly. SoloPower has a production line in San Jose, Calif., but has been looking to manufacture on a larger scale.

SoloPower holds more than a dozen patents for its thin-film solar designs, with more than 30 percent of the patents relating to the specific chemical-plating processes used to apply various layers of metals and form the solar cell absorber layer. Here, we see SoloPower's proprietary plating-process machine.

Technicians at the SoloPower factory in San Jose, Calif., work at the Transparent Conductive Overcoat station, where a weather protecting layer is added to the panels, which also helps to complete the conductive circuit.

The SoloPower manufacturing process is designed to be flexible to allow integration of new methods. The pace of innovation within the solar industry is so rapid, says CEO Tim Harris, that in order to remain competitive, companies must remain adaptable.

Because SoloPower's thin-film design is so easily transported and can be rolled up into a compact cylinder after every step of manufacturing, it allows for a different approach to the factory process. Instead of a start-to-finish assembly line, where the process begins at one end and wraps up with a completed product on the other, the SoloPower factory is broken up into individual manufacturing stations. If need be, newer or better manufacturing steps can be easily integrated into the whole system.

Standing next to a rack of materials used to test variations in the thin-film manufacturing process, SoloPower CEO Tim Harris gets ready to take CNET on a tour of the company's 109,000 square foot production line.

A roll of the thin-film solar material--now fully layered with the electroplated copper, indium, gallium, and selenium (or CIGS)--prepares to move onto the next step of manufacturing. It will be cut into smaller, 5-by-3-inch squares before being strung together into the final 1-by-3-meter panels.

Conducting reliability tests on partially completed panels at the factory in San Jose.

Stacks of the 5-by-3-inch cut cells are ready for assembly.

The cut, 5-by-3-inch cells are now being sorted and prepared for assembly into the final completed panels.

Workers assemble rows of cells into panels in the final step of the SoloPower thin-film manufacturing process.

A technician analyzes solar cells before they're assembled into the finished thin-film solar panels at the SoloPower factory in San Jose.

SoloPower says its electrochemistry-based CIGS technology enables production of highly efficient solar cells at a fraction of the cost of traditional silicon-based solar technologies and alternative CIGS solar cell manufacturing techniques.

SoloPower flexible solar modules are lightweight and designed for commercial rooftops, where they can be easily and quickly rolled out and attached directly to rooftops without the need for more traditional racking systems that can increase the cost and complexity of installation.

Though thin-film solar cells are generally less efficient than traditional polycrystalline silicon panels, SoloPower says that the thin-film installation costs are lower.

With a $20 million Business Energy Tax Credit from the state of Oregon, and a $197 million loan guarantee from the U.S. government, SoloPower is soon breaking ground on a $340 million facility in Portland. A deal with nearby Wilsonville, Ore., recently fell through after opposition from some members of the community.

SoloPower still stands to get the same loan and tax credit deals from Portland, plus an enterprise-zone tax abatement of up to $17.9 million. The new facility is expected to produce a 75-megawatt manufacturing line within the first year, and eventually 300 megawatts of thin-film modules annually, when it's completed.