Researchers in North Carolina have developed a way to more than double the performance of organic solar cells by adding a layer of upright optical fibers that act as sunlight traps.
David Carroll, a professor of physics at Wake Forest University, led the development of a prototype solar cell incorporating the fibers. He is the chief scientist at a spinoff company called FiberCell that is developing a reel-to-reel manufacturing process to produce the cells. “We’re on the cusp of having working demonstrators that would convince someone to go into production with this,” said Carroll.
The best organic solar cells today are nearly 8 percent efficient, although efforts are ongoing to develop organic chemistries that would push the efficiency of such cells above 10 percent. But Carroll says improved chemistries alone won’t be enough to catch up to the performance of silicon cells. “The answer doesn’t lie in chemistry–it lies in the architecture of the cell itself,” he says. Carroll adds that the dollar-per-watt cost of manufacturing fiber-based organic cells should be about the same cost as for flat organic cells. “But they can be produced in a factory costing one-tenth that of a silicon foundry,” he says. This would make them much cheaper to produce than silicon cells.
The problem with standard flat cells, whether they’re made of an organic or inorganic material, is that some sunlight is lost through reflection. To reduce this effect, cell makers apply antireflective coatings or etch the cell’s surface to increase photon absorption. Carroll’s team has taken a more dramatic approach by stamping optical fibers onto a polymer substrate that forms the foundation of the cell.
The fibers, which Carroll refers to as “light pipes,” protrude from the surface like coarse stubble. They are surrounded by thin organic solar cells applied using a dip-coating process, and a light-absorbing dye or polymer is also sprayed onto the cell. Light can enter the tip of a fiber at any angle. Photons then bounce around inside the fiber until they are absorbed by the surrounding organic cell.
The researchers tested a glass fiber cell in the lab and found that the fiber enhanced light absorption by about half. Carroll says that the cells can also produce twice as many watt-hours over the course of a day compared to flat panels because they can receive light from different angles. “It’s the same thing as taking a flat device and pointing it directly at the sun all day long,” he says.
Nearly a quarter of global electricity production could be drawn from solar power by 2050, according to analyses released today by the International Energy Agency.
Solar photovoltaic (PV) power, which is already commercially available, could provide about 11 percent of global electricity within 40 years, and concentrating solar power could produce 11.3 percent of electricity in that period, the Paris-based agency said.
But IEA warned that significant hurdles remain before those levels can be achieved.
“This decade is crucial for effective policies to enable the development of solar electricity,” IEA Executive Director Nobuo Tanaka said today in Valencia, Spain. “Long-term-oriented, predictable solar-specific incentives are needed to sustain early deployment and bring both technologies to competitiveness in the most suitable locations and times.”
Governments must institute policies that ensure long-term funding for additional research, development and demonstration projects to support cost reductions and longer-term breakthroughs, IEA said. They must also provide long-term targets and supporting policies to build investment confidence in PV-system manufacturing capacity and deployment. And they should focus on developing dedicated transport lines to bring electricity from concentrating solar power stations to cities.
In the still-tentative clean energy relationships between American and Chinese firms, Ming Sung sees himself as something of a marriage broker.
A chemical engineer and former Shell executive, Sung has spent the past two years with the Clean Air Task Force nonprofit connecting companies rich in technology know-how with those rich in dollars and influence. His passion is decarbonizing coal — particularly in China, the world’s largest greenhouse gas emitter — a goal he sees as a central element in mitigating the threats of climate change.
“If you really want to clean up the air, you have to start with China,” Sung said, noting that coal use there is expected to double in the next 20 years. While China has made serious strides in clean energy production, Sung argued that it’s not yet enough to meet much of China’s energy needs. Wind power, for example, doubles each year, but only about 30 percent of the energy is connected to the grid.
“So coal is still going to be the king,” Sung said. “There’s no other way. That’s why instead of ignoring it, we have to deal head-on with the emissions from coal.”
His ambitions are starting to pay off. In Washington, D.C., this week from Beijing, where he heads CATF’s Asia Clean Coal Initiative, Sung is touting a number of key joint ventures, including one between Duke Energy and China Huaneng Group. The two power producers signed an agreement last year, now coming to fruition, to cooperate on the development of so-called integrated gasification combined cycle (IGCC) systems — which convert coal into a synthesis gas — as well as the development of carbon capture and storage (CCS) technology.
Duke is building a $2 billion, 630-megawatt IGCC plant in Indiana that recently won U.S. EPA approval. Huaneng, meanwhile, is leading GreenGen, China’s first commercial-scale IGCC power plant, north of Beijing.
Samsung will invest 23.3 trillion won ($20.6 billion) in solar cells and other new technology over the next decade, in an attempt to boost sales and increase the company’s work force by tens of thousands of employees.
Samsung, which already covers dozens of companies making electronics to fashion, will broaden its work in five new areas: solar cells, rechargeable batteries for hybrid electric vehicles, LED technology, biopharmaceuticals and medical devices. That will create an estimated 45,000 jobs and bring in about $44 billion in new revenue by 2020. Top executives in the Samsung Group agreed to the new plan yesterday.
The company employs about 276,000 people worldwide, including 173,000 in South Korea. The country’s jobless rate reached a nine-year high of 5 percent earlier this year, though it now sits at 4.1 percent.
Of the $20.6 billion, Samsung will spend $5.28 billion on solar cells and $4.75 billion on rechargeable cells.
As crews continue to try to stop the massive BP oil spill in the Gulf of Mexico, proponents of alternative energy sources see the possibility that their causes may get more attention in Congress in the much-anticipated climate bill.
“I think folks are motivated. You’re seeing a lot of additional advertising from different groups, saying that we need a climate bill this year,” said Lisa Camooso Miller, spokeswoman for American Coalition for Clean Coal Electricity.
Miller acknowledged, however, that it may be too early to tell how this will play out in Congress, but there is no doubt the disaster has captured public attention. The Pew Research Center for the People and the Press found it at the top of the list of “stories most closely followed” in its latest survey.
Yet, Frank Newport of Gallup reported this week that his polling is showing “no sign of any major uptick in concern about the environment, energy or gas prices as a result of the Gulf oil spill “” yet. Our May update on most important problems facing the country, in the field last week, shows no change in the small number of people mentioning any of these issues.”
“There are too many pieces to put into play to see what is coming,” Miller said. “So much of it is sort of a guessing game. It may be impossible to really know right now what impact it’s going to have.”
But she added that one of the biggest factors may be the price of gas at the pump, if it surges again to more than $4 a gallon this summer, which experts have said is a possibility, given the immeasurable amount of oil that has spilled into the Gulf Coast.
Other groups think Congress will have no choice but to respond to the oil spill and make changes to the nation’s energy plan.
“I don’t think it’s appropriate to grandstand about this or to be opportunistic, but I think it’s naive if Congress won’t respond [to the oil spill],” said Brian Jennings, executive vice president of the American Coalition for Ethanol. “What we hope policymakers take away from this is that our status quo energy policy is broken because we’re relying on unconventional sources of fossil fuels. There’s a great chance to pivot to renewable fuels.”
The industrial Lublin and Podlasie basins of southeastern Poland are becoming major attractions for global energy giants hoping to tap into new sources for Europe.
Companies like Exxon Mobil, ConocoPhillips and Chevron have signed deals or are in negotiations for concessions from the Polish government to explore the region for shale gas, one of the most promising but elusive sources of energy on the planet.
And while the exact size of the gas deposits and the cost of extracting them are for the most part still the subject of conjecture, experts agree that the immediate attraction of shale gas in Europe is political: a desire to diversify energy sources away from a dependence on Russia.
“Shale can be a way to increase the region’s energy security, depending on what the results are of all these projects,” said Richard Morningstar, U.S special envoy for Eurasian energy, during a recent visit to Poland. “It is not a question of being independent from Russia. It is a question of having overall energy security.”
The attraction of shale gas is already well known in the United States, where diversification is an advanced theme in energy policy. With the discovery of big shale deposits several years ago, shale gas now accounts for nearly a fifth of the U.S. natural gas supply, compared with just 1 percent in 2000, according to a recent study by IHS CERA, an independent energy research center in Cambridge, Massachusetts.
Shale’s commercial potential is already bringing big money to the table. In November, Statoil, the Norwegian state oil company, agreed to pay $3.4 billion for 32.5 percent of assets held by Chesapeake Energy in the Marcellus Shale formation, one of the biggest in the continental United States.
Shale gas “ranks as the most significant energy innovation so far this century,” IHT CERA said in a recent report. “It has the potential at least to cause a paradigm shift in the fueling of North America’s energy future.”
In Europe, until recently, governments have shown little interest in shale gas “” a natural gas that is stored in organically rich rocks and interbedded with layers of shaley silt stone and sandstone.
But demand for natural gas is expected to rise worldwide over the next 20 years, with Europe needing to double its natural gas imports to about 476 billion cubic meters, or 16.8 trillion cubic feet, according to Cambridge Energy Research Associates.
The GeoForschungsZentrum or GFZ Institute, a German research center for geosciences in Potsdam, has estimated that Europe has 510 trillion cubic feet of shale gas, perhaps 5 percent of the world’s supply.
Political ideology helps determine whether homeowners respond to voluntary energy conservation programs, two University of California, Los Angeles, economists have found.
In a study published last month on the National Bureau of Economic Research website, Dora Costa and Matthew Kahn concluded that providing feedback on energy use can actually backfire with some conservatives.
Costa and Kahn merged utility data from 80,000 homes with corresponding voter registration and donation records. The economists found that a Democratic household with green bona fides — paying for electricity from renewable sources, donating to environmental groups and living in a neighborhood of fellow liberals — will reduce its consumption by 3 percent in response to feedback.
Meanwhile, a Republican household that doesn’t adhere to environmental behaviors will actually increase its consumption by 1 percent. The households that received home energy reports reduced their consumption by about 2 percent overall, but the Republican subset of this group reduced their energy use by 0.4 percent.
About half of the homeowners in the study received home energy reports from OPOWER, a company that contracts with utilities to compare homeowners’ energy use with that of neighboring homes of comparable size. Homeowners earn smiley faces if they use less energy than their neighbors. The reports also suggest efficiency improvements, such as installing solar panels or cleaning air conditioner filters.
More Republicans get ‘room to improve’
Some California homeowners received bar charts showing the kilowatt-hours they used, comparing it to their most efficient neighbors and then to their average neighbors. Those who scored high received two smiley faces. Those in the medium range got one. And low-ranking energy consumers got this message in bold black letters: ROOM TO IMPROVE. But they also received some money-saving tips.
Based on their usage, a more efficient air conditioning system could cut their energy use in half. If they installed solar panels on their rooftops, the annual return could be 11 percent, probably better than the return on many conservatives’ stock portfolios.
The economists speculate that some conservatives may react angrily at being told to save energy, while others may realize their energy use is lower than average and increase it to match perceived norms. Other tactics may be needed to get conservatives to conserve.