US aims for top solar slot: Neil Eisberg reports from the largest ever annual Solar Energy conference and exhibition, when 17,000 delegates gathered this year in San Diego, California

Chemistry and Industry, Nov 10, 2008 by Neil Eisberg

It takes 20 years to make an overnight success, at least that was what the famous US comedian, singer and actor Eddie Cantor once said. For solar power, it has taken even longer--about 50 years--according to many industry experts gathered in San Diego. A surprising comment as solar energy has been an aspect of space exploration since the first satellites in the 1950s, and a familiar sight on parking ticket machines, roadside signals, and Norwegian mountain huts, in fact any location isolated from accessible electricity supplies. Solar energy produces no greenhouse gases or other pollution, and photovoltaic (PV) panels are extremely reliable, have no moving parts and last for at least 25 years, while all new homes in Spain, Israel and Hawaii are legally required to have solar hot water systems.

Commercial and residential buildings consume about one-third of the world's energy. In the US, buildings account for an even higher proportion, over 40%, of total energy consumption, including 72% of electricity generation. This compares with 32% for the industrial sector and 28% for the transportation sector. According to the US National Science Technology Council (NSTC), if current trends continue, by 2025 buildings will become the largest consumer of global energy, consuming as much energy as the transportation and industry sectors combined.

The NSTC's Buildings Technology Research Development Subcommittee, under the auspices of the US president's Office of Science & Technology Policy, has recently published a report: Federal R&D Agenda for net-zero energy, high performance green buildings, which describes US R&D activities that could decrease use of natural resources while reducing greenhouse gas emissions, as well as improving indoor environments and reducing harmful pollutants from the building sector. One of the goals detailed in the report is to enable designs of new buildings and retrofitting existing buildings so that over their life cycle they produce as much energy as they consume--net-zero energy--over a set time period, typically a year, and significantly reduce greenhouse gas emissions. Using net metering, such systems can supply energy to the grid during the day and draw power back from the grid during the night or at times of peak loads such as air conditioning in the late afternoon, only paying for the net amount of electricity drawn from the grid.

The energy consultancy, Energy Insights believes that building integrated photovoltaics(BIPV) could assist in solar energy gaining greater market penetration. BIPV represent a potential game-changing technology and deployment approach capable of achieving photo voltaic cost parity vis-a-vis conventional energy sources', says Roberta Bigliani, Energy Insights' research director for Europe, the Middle East and Africa. BIPV involves the integration of solar modules embedded into various facets of a building, functionally satisfying conventional building application as well as generating electricity.

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Energy Insights believes that, although currently hampered by prices higher than standard flat photovoltaic (PC) modules, BIPV systems are beginning to gain attention around the world. Flexible thin-film PV developments are finding applications in rooftop installations, for example, while more conventional tile systems, like that launched by California-based Open Energy at Solar Energy 08 in San Diego, are designed to blend with the existing roof in terms of colour and appearance of concrete tiles, especially when used in retrofitting existing buildings.

Before the current economic downturn, it had been predicted that the US would see an increase in solar energy capacity of more than 30-fold between 2009 and 2016. If achieved this would have represented more than 60bn kWhr of solar generation, as well as 440,000 jobs and over $230bn in investments and associated economic benefits. According to the US Solar Electric Power Association (SEPA), the new solar electricity capacity will come from a combination of large-scale power plants, including PV, concentrating solar thermal electric and distributed PV rooftop systems for both the residential and commercial sectors. Up until 2008, the predominant market in the US was distributed PV systems on homes and businesses.

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Following the eight-year extension in investment tax credits (ITCs) incorporated in the recent financial bail-out agreed by the US Congress (C&I 2008, 20, 9). In addition to the ITC extension, a prohibition on US utilities taking advantage of ITCs was lifted along with a $2000 cap for residential installation. Solar investment tax credits were introduced in 2005, and according to the US Solar Energy Industries Association (SEIA), the amount of solar electric capacity installed in 2007 was double that installed in 2006 as a result.

According to an economic study by Navigant Consulting, which did not factor in the removal of the residential credit cap, the ITC extension will create 440,000 permanent jobs and unleash $325bn of private investment in the solar industry. 'This is a big boost for the residential market in particular, allowing homeowners to contribute to our nation's energy independence. It also opens the floodgates for building large, utility scale power projects that need longer timeframes to complete,' said Roger Efird, SEIA chairman and president of Suntech America, a Chinese manufacturer of solar power systems. SEIA believes there are some 27 utility-scale solar power projects, totalling 5,400MW of power, in various stages of development in the US. However, most were put on hold due to the uncertainties over the possible termination of ITCs.