The feed-in tariffs for renewable energy recently introduced by the government heightened interest at the sixth Photovoltaic Science Application and Technology Conference (PVSAT-6), hosted by the University of Southampton’s School of Electronics and Computer Science in late March. Event organizer professor Darren M. Bagnall, a member of the school’s Nano Research Group, said: “With householders alone, the feed-in tariffs provide an exciting opportunity for PV that we believe will have a big and lasting impact in the UK.” Under the scheme, a subsidy will be paid to anyone generating electricity from a renewable source, ranging from solar rooftop panel systems to wind turbines. Feed-in tariff regulations already exist in more than 40 countries. Event organizer Darren M. Bagnall, a member of the University of Southampton’s Nano Research Group, discussed the hottest topics up for debate at the sixth Photovoltaic Science Application and Technology Conference. Inset photo courtesy of the University of Southampton. According to Bagnall, the conference provides an ideal opportunity for the PV community to come together to share ideas and keep current with developments including materials characterization, manufacturing processes, system modeling, system design and system components, performance measurement and field experience, economics, market development and the environment. “Photovoltaics has rapidly evolved into a multibillion dollar industry. It continues to grow, and as it grows, new technologies and challenges arise,” he said. “The PVSAT conference looks at a wide range of issues surrounding PV and invites speakers from around the world in order to gain a comprehensive and up-to-date overview on a range of aspects of PV systems.” Among the invited speakers was Christian N. Jardine, senior researcher at the University of Oxford’s Environmental Change Institute and the technical director of Joju Ltd., a solar PV installation company. Jardine provided careful analysis of the government’s intended subsidy scheme and suggested that the new tariffs represent a marked improvement on prior policy that should, however, be treated with caution. “Rates of return are modest, between 3 and 5 percent per annum, depending on interest rates and electricity gas prices,” he said. “Returns will not be as high as might be hoped, and although householders will be attracted, it is less obvious that business, local government and communities will be attracted, since the return on investment is not sufficient to justify a bank loan.” Although it is hoped that the government has or will allocate further resources to make low-interest bank loans available to make up for this shortfall, the news is still being met with enthusiasm. “The subsidy could help to build an infrastructure while we await grid parity,” Bagnall said. Innovations in PV technology The economics of PV systems was not the only thing on the agenda at PVSAT, however, as guest speakers from around the globe discussed their latest research. For example, Christopher R. Wronski, professor emeritus of electrical engineering at the University Park campus of Pennsylvania State University in the US, highlighted the current massive scale of thin-film silicon manufacture. He also described ways in which new technologies and designs are improving the efficiency and stability of these devices, in particular noting that double- and triple-junction formations (two or three different solar cells on top of each other) can achieve laboratory cell efficiency values of up to 14 percent. Some of the most promising avenues of research involve looking for ways in which nanotechnology can be used to make better solar cells, especially how nanostructured metal nanoparticles might be used to scatter – and thereby trap – light in thin-film solar cells. The hope is that these plasmonic particles will boost the efficiency of a solar cell or greatly reduce the cost. Perhaps the most important question in terms of PV technology is: When might grid parity be reached? According to Bagnall, there is a feeling that, over the next two or three years, module and system costs will be sufficiently low to ensure a big rise in PV uptake that is no longer driven by subsidy but by straightforward economics.