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Although China may be a cheaper place than Europe for producing solar panels, the savings come at a higher cost to the environment, a new study says.

Weaker environmental standards and the more highly polluting sources of energy used by Chinese manufacturers are the reasons for the discrepancy, according to research by Northwestern University and the United States Department of Energy’s Argonne National Laboratory.

Researchers from the Illinois-based institutions looked at the carbon footprint and energy usage of making solar panels.

Their analysis tallied the costs at every step of production, including the mining of raw materials, transportation and the factory’s power supply.



The environmental cost of Chinese- made solar panels is about twice that of those made in Europe, said Fengqi You, a corresponding author of the paper, which will be published in next month’s issue of the journal Solar Energy.

‘‘While it might be an economically attractive option to move solar panel manufacturing from Europe to China, it is actually less sustainable from the life cycle energy and environmental perspective — especially under the motivation of using solar panels for a more sustainable future,’’ Dr. You, an assistant professor of chemical and biological engineering at Northwestern, said in a news release last week from the Argonne National Laboratory.

The authors proposed a tax on the energy consumption and carbon emissions caused by the manufacturing of solar panels to help encourage more sustainable production.

Sometimes the environmental costs of solar panel production can be lost among the drive to encourage the development of clean energy, said Huang Xianjin, a professor at Nanjing University who studies land use.

‘‘In China, we have a lot of photovoltaic makers, and it’s something that’s been encouraged by the government,’’ he said. ‘‘But there’s also a lot of pollution that comes from that.’’

Mr. Huang was one of three scholars who wrote a letter published last week in the journal Nature arguing that China had to do more to alleviate the damage done by the domestic solar industry. ‘‘Improved waste treatment, environmental monitoring and education are essential to avoid the undesirable impacts of these otherwise valuable technological advances,’’ they wrote.

In 2011 the Chinese authorities suspended production at a solar panel plant in Zhejiang Province after days of protests by residents who said emissions from the factory polluted the air and nearby bodies of water.

Thanks to lower production costs and government incentives, China has gone from being a relatively small player in photovoltaic production at the turn of the last century to the world’s leader today, manufacturing nearly 60 percent of the global total in 2012, according to the Earth Policy Institute. The next biggest manufacturers are Taiwan, Japan, Malaysia, Germany, South Korea and the United States.

The latest study found that a solar panel made in China would have to be in service for about 20 percent to 30 percent longer than a European model to compensate for the energy used in its production.

The researchers said that the gap between the environmental standards in China and Europe should lessen as China begins to take better account of the damage done by industry, including the manufacturing of solar panels.

‘‘It takes a lot of energy to extract and process solar-grade silicon, and in China, that energy tends to come from dirtier and less efficient energy sources than it does in Europe,’’ Seth Darling, a scientist at the Argonne National Laboratory and a co-author of the paper, said in the laboratory’s statement. ‘‘This gap will likely close over time as China strengthens environmental regulations.’’