Solar cells are facing a new challenge. Five years ago they were simply too expensive, a common problem for any emerging technology. Now, however, there is an additional problem on the horizon: availability of raw materials.
Nearly 90 percent of photovoltaic modules are based on silicon, a material that has been extensively studied for decades because of the key role that it plays in the microelectronics industry. Such a legacy means that solar-cell manufacturers could quite happily give 25-year guarantees on the quality of their products. But it also means that the photovoltaics industry has grown up piggy-backing on the microelectronics industry; photovoltaics cells tend to be built from off-spec silicon materials and feedstock from the microelectronics industry. Such reuse sounds impressive. But the photovoltaics industry, growing as it is at a rate of 25-30 percent per year, has now outgrown the quantity of silicon available from the microelectronics industry's castoffs.
CAPDS research tool
For Siva Sivoththaman of the University of Waterloo (Waterloo, Ontario, Canada), this is a blessing in disguise. His reasoning is that the persistent cost challenge for solar cells is partly due to the use of microelectronics-grade silicon. "Nearly 50 percent of the cost of photovoltaic modules comes from the semiconductor material and the associated purification steps that are expensive," he explains. Integrated circuits have very stringent requirements in terms of crystal quality and density of defects in the silicon.
Photovoltaics, on the other hand, if smartly processed, according to Sivoththaman, can work well with relatively lower-quality silicon but are much more constrained on cost. Indeed, being low-cost is crucial for the uptake of solar cells: customers will only opt for energy from the sun if it gives a comparable price per Watt to that from their current fossil fuel energy supplier.
This is one of the reasons why Sivoththaman, who heads Waterloo's new Centre for Advanced Photovoltaic Devices and Systems (CAPDS), is excited about university involvement in a new international research network. His is one of six universities and research institutes currently involved in the Masdar Research Network (MRN), part of the Al Masdar Initiative, which was launched last year by the Abu Dhabi Authority.
Al Masdar, which comes from the Arabic for "source," is Abu Dhabi's answer to the long-term challenge of what a country built on oil wealth will do when that oil supply runs low or if public opinion turns against oil. The multibillion-dollar initiative aims to "create a new framework for the development and promotion of world-class, and global scale, renewable energy and resource sustainability industries in Abu Dhabi," according to the Abu Dhabi Authority. Its plans include a postgraduate research institute, being established with help from MIT, that is expected to begin admitting students in 2009. The Masdar Clean Tech Fund has $250 million, from the Abu Dhabi government and elsewhere, to invest in companies with promising clean energy technologies and sustainability-related technologies.
The Masdar Research Network will play a key role in all these activities from education to commercialization. Researchers from the United Arab Emirates will work on projects at the partners' facilities. And once Masdar's research institute has been built, scientists and engineers from around the world will go to Abu Dhabi to carry out research and to feed into the institute's postgraduate education program.
Meanwhile, Masdar envisages that industry involvement in MRN projects will accelerate the progress of new technologies to commercialization. The projects chosen will receive half their funding from Masdar and half from industrial partners. The institutions involved have strong relationships with industry, and the Al Masdar Initiative itself has partnerships with global energy companies such as Shell, BP, Occidental Petroleum, Total, Mitsui, GE and Rolls Royce.
"Masdar's insistence on the presence of industry is a big strength. For any research to have meaningful results, industry presence is very important," said Waterloo's Sivoththaman. "The research initiatives put together by the network partners will be applied research and will involve working with industry. This gives a wonderful opportunity for sustainable energy businesses across Europe, North America and elsewhere."
The actual research is still at an early stage. The six MRN partners -- the UK's Imperial College London, RWTH Aachen University in Germany, Canada's University of Waterloo, Columbia University in the US, the German Aerospace Centre and the Tokyo Institute of Technology in Japan - are currently working on their project proposals. These are in Masdar's initial core research areas of solar thermal energy, solar photovoltaics, carbon management and water management.
CAPDS silicon spheres
For Sivoththaman and colleagues at Waterloo's CAPDS, the challenge of lower-cost silicon raw materials for photovoltaics was an obvious choice for one of the first MRN projects, which is expected to start later this year and go on for three years. The main aims of this project, which already has at least one Canadian industrial partner, will be to develop low-cost, flexible, silicon-based photovoltaic modules. The partners aim to reduce the costs of electricity from solar cells to below 1 US$ per Watt by developing silicon raw materials for photovoltaics rather than the high-purity silicon castoffs from the microelectronics industry.
This cost-reducing approach sounds straightforward at the base material level, but there are the inevitable challenges, which is where the project with MRN comes in. The technology used to make the modules needs to be compatible with these low-cost, lower-quality materials. For this reason, new technology development is an important part of project, for both large-scale electricity production and smaller-scale applications. Sivoththaman also sees industry involvement as a strong part of getting this right. "We have to take care that the technology can be scaleable to large-scale production and we are very mindful to make it industry compatible," he explained. Efficiency of the modules is also important in order to produce smaller cells and better price per Watt.
CAPDS Solar cell
In addition to the MRN project, Waterloo's CAPDS is also working on much longer-term photovoltaic technologies. In the future, more solar cells could be based on thin films, advanced semiconductors, and nanotechnology. Such developments could reduce costs and boost efficiencies of the cells enormously, but there is still a need for fundamental research on issues such as stability, reliability and toxicity, not to mention the challenges of scaling up to mass production.
CAPDS's research into other areas outside of the MRN project is typical of the partners in the network. All were selected as partners because of their established infrastructure, expertise, reputation and industrial partnerships.
The University of Waterloo also has expertise in wind and hydrogen energy through its Green Energy Research Institute. RWTH Aachen University has several research institutes involved in energy and water research. Columbia University is a leader in sustainable energy through the Earth Institute the School of Engineering and Applied Science, while the Tokyo Institute of Technology carries out advanced research on innovative solar thermal systems.
Another of the partners, the German Aerospace Centre, has a particular research focus in concentrating solar power, conducting research in this area with numerous organization. For example, a joint venture with New Energy Algeria (NEAL) will work on research projects in solar power. They are also interested in producing hydrogen using solar power, fuel cell technology, thermal process technology, system analysis and technological assessments.
Similarly, Imperial College's Energy Futures Lab was formed in 2005 to enable the college to take on big multidisciplinary projects in the field of sustainable energy. It particularly brings expertise in systems design and carbon management to MRN, as well as having been involved in the early stages of defining the scope of the network. "Our interest is in partnering in interesting projects," explained Peter Evans, who works for the Energy Futures Lab. And, for Imperial, the Al Masdar Initiative definitely fits this description. "UAE is a very successful country but realizes that its wealth is based on finite resources. The Masdar project takes a long-term view for a sustainable economy," he explained.
Such a long-term view, with vast reserves of oil money behind it, should help Abu Dhabi's bid to become a leading for renewable energy. And it will certainly help the latest research in photovoltaics and other renewable technologies move toward commercialization.