Solar panels linked to "powerful" greenhouse gas

Nitrogen trifluoride (NF3) is at least four times more prevalent in the atmosphere than scientists previously thought, according to recent research.

The compound, which is 17,000 times more effective at warming the atmosphere than an equal mass of CO2, is used in the production of solar panels, flat-screen TVs and computer displays.

Researchers from Scripps Institution of Oceanography at the University of California San Diego (UCSD), discovered that the amount of the gas in the atmosphere was about 4,200 metric tons, compared with previous estimates of 1,200 tons. The quantity of gas in the atmosphere is also increasing by 11 per cent per year.

Scripps geochemistry professor Ray Weiss was able to make more accurate atmospheric measurements of NF3 than has been previously possible. "Accurately measuring small amounts of NF3 in air has proven to be a very difficult experimental problem and we are very pleased to have succeeded in this effort," said Weiss.

Emissions of NF3 were thought to be so low that the gas was not considered to be a significant contributor to global warming. The compound is not covered by the 1997 Kyoto Protocol. Although the gas survives in the atmosphere about five times longer than C02, it only contributed about 0.04 per cent of the total global warming effect contributed by human-produced C02.

NF3 is one of several gases used in the production of thin-film photovoltaic cells. It has been used as an alternative to perfluorocarbons which are also significant greenhouse gases as it was believed than not more than two per cent of the NF3 used in industry escaped into the atmosphere.

Asked whether the Scripps research may lead to curbs on how NF3 is used in the solar industry, Andrew Cooper, head of onsite renewables for the Renewable Energy Association, said that all industries produced some greenhouse gases and the onus should be on how the amount of CO2 and other harmful compounds have been reduced by the use of solar energy.

"The thing about photovoltaics is that they mitigate greenhouse gases and they are a very long-lived product as well," he said. "Also, thin-film solar uses one per cent of the amount of silicon that is used in the current process so you would expect a huge reduction in emissions to occur as a result of that. "

NF3 is also used in the production of flat-screen TVs and computer displays, which some commentators believe is another reason why the information technology industry should also be scrutinised for its contribution to global warming.

"This result reinforces the critical importance of basic research in determining the overall impact of the information technology industry on global climate change, which has already been estimated to be equal to that of the aviation industry," added Larry Smarr, director of the California Institute for Telecommunications at UCSD.

Comment from representatives of the solar energy industry – including Sharp UK and Nanosolar – were sought but did not reply in time for this article.