Carbon footprint of solar panels made in China is double of those made in Europe due to lax standards and more coal fired plants in China-National Geographic

11/11/14, "How Green Are Those Solar Panels, Really?" National Geographic News, Christina Nunez

"As the world seeks cleaner power, solar energy capacity has increased sixfold in the past five years. Yet manufacturing all those solar panels, a Tuesday report shows, can have environmental downsides.

Fabricating the panels requires caustic chemicals such as sodium hydroxide and hydrofluoric acid, and the process uses water as well as electricity, the production of which emits greenhouse gases. It also creates waste. These problems could undercut solar's ability to fight climate change and reduce environmental toxics.

A new ranking of 37 solar manufacturers, the Solar Scorecard, shows that some companies are doing better than others. Chinese manufacturer Trina scored best, followed by California-based SunPower.

The annual scorecard was created by the Silicon Valley Toxics Coalition (SVTC), a San Francisco-based nonprofit that has tracked the environmental impact of the high-tech industry since 1982. It's the group's fifth scorecard, and it shows that the industry is becoming more—not less—opaque when it comes to the sustainability of its manufacturing practices.

The coalition hopes the scorecard will increase transparency in a burgeoning industry that tends to be more focused on survival and growth than on tackling the dirtier side of an otherwise clean energy source.

Patchy Data on Chemicals, Emissions

The SVTC relies on companies' self-reported data for its scorecard, which looks at such things as emissions, chemical toxicity, water use, and recycling. 

The coalition says the market share of companies willing or able to share details about their operations 

is declining. 

It praises the third- and fourth-ranked companies, Yingli and SolarWorld respectively, for responding to the survey every year and for showing a continued commitment to sustainability.

Name-brand companies on the scorecard represent about 75 percent of the solar panel industry, but more generic players that care less about their environmental impact have been entering the market, said Sheila Davis, the coalition's executive director. Her group is concerned that as these discount competitors gain market share, fewer companies will make sustainability a priority.

Varying regulations and manufacturing practices make it difficult to get standardized data about the environmental footprint of photovoltaic panels. A study released in May by Northwestern University and Argonne National Laboratory found that
 

the carbon footprint of a panel from China is twice that of one from Europe, because China has fewer environmental standards and more coal-fired power plants."...

[Ed. note: "The study did not include the energy cost of transporting a solar panel to its final destination. Transportation would magnify the difference even further."...]

(continuing): "China has already seen a backlash. Panel manufacturer Jinko Solar, for example, has faced protests and legal action since one of its plants, in the eastern province of Zhejiang, was accused of dumping toxic waste into a nearby river.

Solar manufacturers in the United States are subject to both federal and state rules that dictate, for example, how and where they can dispose of toxic wastewater. In Europe recent regulations mandate the reduction and proper disposal of hazardous electronic waste.

Still, researchers say it's difficult to get quality data across solar panel markets. 

The numbers available on the environmental impact of solar panel manufacturing in China are "quite different from those in the U.S. or in Europe," said Fengqi You, 

assistant professor of engineering at Northwestern University and a co-author of the May study. "It is a very complicated problem."

The SVTC hopes that pushing for more transparency now will lead to better practices later. "It's a new industry," said Davis. If companies adopt sustainable practices early on, she said, "then maybe over the next 10 or 15 years-as these panels begin to come down, the first wave of them, and we're beginning to recycle them-the new panels that are on the market are zero waste."

Not Enough to Recycle Yet

Right now, solar panel recycling suffers from a chicken-or-egg problem: There aren't enough places to recycle old solar panels, and there aren't enough defunct solar panels to make recycling them economically attractive.

Ben Santarris, strategic affairs director for SolarWorld, said his company has made efforts to recycle panels, but the volume isn't there yet. "We have product that's still performing to standard from 1978, so we don't have a big stream," he said. "It is a problem, because on one hand there is an interest in getting ahead of a swelling stream of returning panels. On the other hand, there's not a big market for it right now."

Recycling is particularly important because of the materials used to make panels, said Dustin Mulvaney, an assistant professor of environmental studies at San José State University who serves as a scientific adviser to SVTC. "It would be difficult to find a PV module that does not use at least one rare or precious metal," he said, "because 

they all have at least silver, tellurium, or indium."

Because recycling is limited, Mulvaney said, those recoverable metals could go to waste: 

"Companies that are reporting on a quarterly basis, surviving on razor-thin margins—they're not thinking 20, 30 years down the road, where the scarcity issue might actually enter the conversation."

The silicon used to make the vast majority of today's photovoltaic cells is abundant, but a "silicon-based solar cell requires a lot of energy input in its manufacturing process," said Northwestern's You.  

The source of that energy, which is often coal, he added, determines how large the cell's carbon footprint is.

The SVTC said it's leading an effort to develop a first ever sustainability standard for solar panels, similar to the U.S. Green Building Council's Leadership in Energy and Environmental Design or LEED, within the next two years. That effort will get under way as new solar panel factories come online in the U.S. and elsewhere: Mission Solar just opened a plant in San Antonio, Texas, and SolarCity plans to open a five-billion-dollar factory in western New York.

It remains to be seen whether solar companies will face enough external pressure to drive significant change in a business that, from a power-generation standpoint, already has plenty of environmental credibility.

"Despite the efforts of the SVTC," said Santarris, "there still is not nearly the awareness there should be that solar panels are not all created equal from an environmental standpoint."

But there is optimism that as the industry matures, solar companies will adopt stronger sustainability measures. In just the five years since the SVTC began its scorecard survey, Mulvaney said, it has seen a change.

"When we started this, there was no information on environmental performance, aside from the fact that it saves us from the dirtier fuels," he said. "Now these companies are producing sustainability reports."

On Twitter: Follow Christina Nunez and get more environment and energy coverage at NatGeoGreen.

The story is part of a special series that explores energy issues. For more, visit The Great Energy Challenge."

Image above: from 1/27/14, "China’s Growing Coal Use Is World’s Growing Problem," ClimateCentral.org, Eric Larson

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Linked in above article: CO2 footprint is twice as high for solar panels made in China not including additional footprint of transporting panels to Europe:

5/29/14, "Solar panel manufacturing is greener in Europe than China, study says," Argonne National Lab, by Lois Lerner

"Solar panels made in China have a higher overall carbon footprint and are likely to use substantially more energy during manufacturing than those made in Europe, said a new study from Northwestern University and the U.S. Department of Energy’s Argonne National Laboratory. The report compared energy and greenhouse gas emissions that go into the manufacturing process of solar panels in Europe and China.

“We estimated that a solar panel’s carbon footprint is about twice as high when made in China and used in Europe, compared to those locally made and used in Europe,” said Fengqi You, assistant professor of chemical and biological engineering at Northwestern and corresponding author on the paper.

“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,” he said.

The team performed a type of systematic evaluation called life cycle analysis to come up with these hard data. Life cycle analysis tallies up all the energy used to make a product—energy to mine raw materials, fuel to transport the materials and products, electricity to power the processing factory, and so forth. This provides a more accurate picture of the overall energy consumed and produced and the environmental impact of making and using a solar panel.

Assuming that a solar panel is made of silicon—by far the most common solar panel material—and is installed in sunny southern Europe, a solar panel made in China would take about 20 to 30 percent longer to produce enough energy to cancel out the energy used to make it. 

The carbon footprint is about twice as high.

The biggest reason is that China has fewer environmental and efficiency standards for its factories and plants and generates more electricity from coal and other non-renewable sources, the authors said.

“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,” said Argonne scientist and co-author Seth Darling. “This gap will likely close over time as China strengthens environmental regulations.”

The study did not include the energy cost of transporting a solar panel to its final destination. Transportation would magnify the difference even further if it—like 60 percent of all solar installations in 2012—went up in Germany or Italy, Darling said.

The team also compared the numbers for different types of silicon solar panels. Single-crystal solar panels are better at harvesting energy than other types, but take the longest to “pay back” the energy used to manufacture them because the process is more energy-intensive. Multicrystalline panels came next, followed by ribbon silicon panels, which are easiest to manufacture but least efficient—however, their payback time was fastest.

To encourage more sustainable production of solar cells, the authors suggest a break-even carbon tariff.  “This would be based on the carbon footprint and energy efficiency difference between manufacturing regions, and would be a better market- and science-based solution than a solar panel tariff,” said Dajun Yue, a Northwestern graduate student in You’s research group and lead author on the paper.

“The break-even carbon tariff we calculated, which is at the range of €105-129 per ton of carbon dioxide, depending on the possible carbon tax to be imposed by these two regions in the near term, is close to the reported CO₂ capture and sequestration cost,” You said."

"Funding for this research was provided by the Institute for Sustainability and Energy at Northwestern University. The research was performed in part at the Center for Nanoscale Materials, a U.S. Department of Energy user facility.

The paper, “Domestic and overseas manufacturing scenarios of silicon-based photovoltaics: Life cycle energy and environmental comparative analysis,” is available online and will be printed in the July issue of the journal Solar Energy."

"Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy's Office of Science.

The Center for Nanoscale Materials at Argonne National Laboratory is one of the five DOE Nanoscale Science Research Centers (NSRCs), premier national user facilities for interdisciplinary research at the nanoscale, supported by the DOE Office of Science. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE’s Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos National Laboratories.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov."






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