 |
The idea of thin films is relatively simple: we can produce truly low-cost PV devices by using pennies worth of active semiconductor materials rather than the larger quantities required for crystalline-silicon cells.
The Thin Film Partnership Program works within focused research areas: amorphous silicon (a-Si), copper indium diselenide (CuInSe2 or CIS) and related materials, cadmium telluride (CdTe), environment, safety, and health (ES&H), and module reliability. Each of these research areas has an active National Research Team associated with it. The teams of manufacturers, academia, and NREL experts focus their efforts on materials, processes, devices, and manufacturing scale-up, coming together to discuss issues common to a each technology.
For example, if a CdTe manufacturer is having trouble with encapsulation, a researcher on the CdTe or the Module Reliability team can diagnose the problem and offer solutions. This give-and-take of information can produce better and faster solutions.
The Partnership funds research in two categories:
- Technology Partners are leading U. S. companies that are in transition to manufacturing thin films in large volume. Contracts are for up to one million dollars per year for three years; companies match federal funding with their own funding to indicate their level of commitment.
- R&D Partners are universities and small businesses that support Technology Partners while developing key innovations to help further progress.
Thin-Film Research
The Thin Film Partnership Program Web site provides up-to-date resources that address the following areas of thin-film R&D:
- Amorphous and Thin-Film Silicon
- Amorphous silicon (a-Si) was heralded as the "only" thin-film PV material in the 1980s; a decade later, many people wrote it off for its instability and low efficiencies. Multijunction cell configurations have helped solve these problems. In the near term, look for modules with 6% to 8% efficiencies, as well as the construction of multi-megawatt a-Si facilities.
- Copper Indium Diselenide (CuInSe2-alloys, or "CIS')
- With 19.5% efficiency under standard test conditions, the best CIS cell is about as efficient as the best polycrystalline-silicon cell. The potential for high module efficiencies and low cost has led to a large increase in private investment. The technology is making the transition to first-time manufacturing.
- Cadmium Telluride (CdTe)
- CdTe thin-film technology is being actively commercialized. CdTe cell efficiencies are over 16% in the laboratory; commercial module efficiencies are in the 7%-10% range in the first manufacturing plants. Companies have an array of inexpensive options to choose from in CdTe fabrication—there are more than a dozen ways to make 10%-efficient cells.
- Environment, Safety, and Health (ES&H)
- ES&H addresses the impact of thin-film technologies on the environment and on the health and safety of the plant workers. The use and disposal of cadmium and selenium are particularly important. It also clarifies why thin films are safe to make and use.
- Thin-Film Module Reliability
- Studying and testing the reliability of thin-film modules are important steps in understanding how various module designs work and which areas need improvement to assure 30-year outdoor reliability. Understanding reliability is crucial when researchers develop or change modules.
- General Interest
- Thin films have an important place in the overall role of PV in meeting key issues like climate change, oil depletion, and energy diversity and security. In fact, many believe that thin films are the most crucial PV options for addressing these important societal goals. The nature of the problems and the role of thin films in addressing them are given in this General Interest section, along with other information of interest for policy and perspective.
Thin Films and the Future
The performance and potential of thin-film materials are excellent, reaching cell efficiencies of 12%-20%; prototype module efficiencies of 7%-13%; and production modules in the range of 9%. Annual manufacturing volume in the United States has grown from about 12 megawatts (MW) per year in 2003 to more than 20 MW/yr in 2004; 40-50 MW/yr production levels are expected in 2005 with continued rapid growth in the years after that.
Future module efficiencies are expected to climb close to the state-of-the-art of today's best cells, or to about 10%-16%. Costs are expected to drop to below $100/m2 in volume production, and could reach even lower levels—well under $50/m2, the DOE/NREL goal for thin films—when fully optimized. At these levels, thin-film modules will cost less than fifty cents per watt to manufacture, opening new markets such as cost-effective distributed power and utility production to thin-film electricity generation.
Related Links
|
|
