2004 R&D 100 Award Winner
Lightweight, Flexible, Thin-Film CIGS PV Modules
Principal Developers: Dr. Harin Ullal, Ken Zweibel, and Dr. Bolko von Roedern, National Renewable Energy Laboratory; Dr. Jeffrey Britt, Dr. Scott Wiederman, Dr. Markus Beck, and Robert Wendt, Global Solar Energy, Inc.; Dr. Ingrid Repins, ITN Energy Systems, Inc.
Portable electricity from the sun. Thanks to Global Solar and its partners at ITN Energy Systems and NREL, the world now has its first portable, flexible PV systems made from copper indium gallium selenide (CIGS) — for use in mobile applications. These are PV systems that can provide from 12 W to 56 W of power, can be folded into sizes as small as a 9 x 12 envelope, can be easily stowed in a small backpack, are light enough to be carried over long distances, and can be connected together, when needed, to provide as much as 2.8 kW of power.
The U.S. Army is already using these new systems in applications where both weight and space are at a premium - such as by scouts, forward field officers, special operations units, or forward communication units. But the features that make this technology so attractive to the military also make it appealing to a wide range of other applications, providing reliable power for:
- Hikers, campers, and boaters;
- Portable electronics, such as cell phones, satellite phones, GPS units, MP3 players, and more;
- Survival kits; and
- Mobile agricultural uses.
The CIGS systems are not the first portable PV systems available. Others, based on amorphous silicon technology, have been on the market for a few years. But the new CIGS portable PV technology has many advantages over these other systems. Compared to them, for example, the CIGS systems:
- Are lighter, more flexible and portable;
- Are more efficient and reliable;
- Have two to three times the power-to-weight ratio;
- Have more than 5 times the power-to-volume ratio;
- Cost less; and
- Are inherently self-repairing due to the natural tendency of copper atoms in the CIGS material to spread into damaged areas, thereby repairing the crystal structure. In fact, CIGS modules can even take a bullet hole and continue to operate.
Another advantage of the CIGS technology is that it is extremely versatile in that the modules may be fabricated on a variety of substrates — flexible, rigid, or substrates that can conform to many surfaces. As such, the CIGS systems can be included on all kinds of structures, such as signs, bus shelters, sun roofs, or awnings; or they can be integrated into building applications and be used on metal roofs, as roof shingles, or in architectural fabrics or facades.