A new record in solar cells

A new record in solar cells
Posted by Michael Kanellos

The University of Delaware has inched up the record for solar cell efficiency with a new device that can convert 42.8 percent of the light that strikes it into electricity.

That beats the old record of 40.7 percent hit in December. The Defense Advanced Research Projects Agency, or DARPA, has been funding research to get efficiency up to 50 percent.

The cell, created by Christina Honsberg and Allan Barnett of UD, splits incoming light into three buckets: high energy, low energy, and medium energy light. The light is then directed to different materials, which then extract electrons out of the photons that make up sunlight.

The device also has an optical concentrator, sort of like a lens that directs more sunlight to the solar cell than would occur naturally and thereby increasing efficiency.

Various materials (silicon, germanium, etc.) react differently to different parts of the solar spectrum. Crystalline solar cells, for instance, can currently convert 22 percent of light into electricity (without concentrators). The theoretical maximum is 29 percent sans concentration. Combining different materials into multi-junction cells or adding concentrators helps get around the limitations of the materials.

Multi-junction solar cells and concentrators, however, are expensive. The initial customers for devices like this will be the military. Possible applications include portable charging packs for soldiers.

Concentrators can often add girth to solar cells, but the UD device is a little less than a centimeter thick.

How To Shop Green

How To Shop Green
Lauren Sherman, 07.31.07, 1:30 PM ET

Considering "going green"? You're probably not the only one.

Enter almost any grocery store and you're bound to find so-called green cleaning products next to traditional ones. Take Tide Cold Water detergent. Procter & Gamble claims it deep cleans clothes in cold water, cutting down on your energy use, not to mention your energy bill. Car buyers have plenty of environmentally friendly models from which to choose, and energy-efficient appliances get prominent placement on showroom floors.
Even retailers are getting in on the act. Sweden-based fashion emporium H&M introduced a green line in spring 2007, offering frocks and tops made with organic cotton. And Nike recently announced plans to make its footwear sustainable, vowing to adopt environmentally friendly production methods where possible.
But while an ever-growing range of "green" consumer products are finding their way into our homes, there is very little in the way of industry standard. One manufacturer's green product may have been produced in an entirely different manner than another's. As a result, experts say it's good to maintain a healthy dose of skepticism when choosing environmentally friendly products, and to rely on a select group of organizations monitoring the practices of certain industries.
Do Your Homework
Dig a bit and you'll likely come across the word "greenwashing." This, according to Julia Cosgrove, deputy editor of ReadyMade, a San Francisco-based magazine that focuses on do-it-yourself, sustainable projects, entails marketing a product as environmentally conscious without enough evidence that it really is.
"Much of what we're seeing now is just spin," she says. "When you look further, many of these companies are still making a big environmental footprint."
Translation: Even if a retailer offers clothes made with organic cotton, chances are they are being shipped via huge, gas-sucking airplanes.
Another example is vinyl. It is used in a great deal of vegan shoes, but the production of the material can create dioxin, a known carcinogen.
Clothing company Edun has experienced a case of greenwashing. Although some of its products are made of organic cotton, the company's main objective is to produce ethical (fairly traded, socially responsible)--not green--clothing. Although both concepts are positive, they certainly don't mean the same thing. Edun is an ethical clothing company, and although they take measures to protect the environment, they should not be categorized as green.
How to tell one from the other? Look to several watchdog organizations for a real education.
Digging Deeper
Netherlands-based Made-By tracks a garment's environmental footprint from the first thread on, and the International Forest Stewardship Alliance certifies wood-made products by ensuring that manufacturers collecting lumber are making the best use of forest resources, reducing damage and waste, and avoiding overconsumption and overharvesting. You can find a complete listing of their findings on www.fscus.org.
The Environmental Protection Agency's (EPA) labeling system, Design For The Environment (DfE), ensures that the chemicals in DfE-certified products--like Earth Choice's new range of household cleaners--are environmentally preferable, which means such products are created with lower volatile organic compounds. High levels of these materials can damage soil and groundwater, and emit greenhouse gasses, contributing to global warming.
Kitchen appliances now possess one of the most widely recognized labels, EnergyStar, another EPA-run unit. These labels ensure an appliance meets energy-efficient guidelines set by the EPA and the Department of Energy. Criteria for each appliance differs and can be found on www.energystar.gov under the Products tab.
"It's a fairly well-known metric that will reduce your energy use and save you money," says Ron Jones, founder of Greenbuilder, a development, media and consulting firm dedicated to sustainable development and green building, of EnergyStar. Often, buying a new, energy-saving air conditioner will save you in the end since older models not only cost more to run but often don't work as well.
Whether you're buying one piece of green clothing or remodeling your entire home with energy-efficient appliances, Jones says it's important to note how your everyday activities affect the environment.
"If you start to look at a person in terms of their individual footprint, which includes their transportation habits, eating habits, clothing and housing, it starts to get very complex," he says. "Think through everything. Determine how it will affect your everyday living conditions, and your quality of life going forward."

Clothing

Government regulations: Items must be made of organic cotton, which is free of chemicals and pesticides. These are noted with a "Made With 100% Organic Cotton" label.

Industry regulations: There is no industry standard.

Environmentalist regulations: Several not-for-profit organizations have set their own standards. Made-by, a Netherlands-based group, tracks the environmental footprint of a garment from the first thread on. Find their research at www.made-by.nl.

Cleaning Products

Government regulations: The EPA's labeling system, Design For The Environment, ensures that the chemicals in DfE-certified products--like Earth Choice's new range of household cleaners--are environmentally preferable, which means the products are created with safer formulas, with lower volatile organic compounds. High levels of these materials can damage soil and groundwater, and emit greenhouse gasses, contributing to global warming.

Industry regulations: There is no industry standard.

Environmentalist regulations: Ecologo, an organization that regulates the sustainability of consumer products throughout North America, lists specific criteria for each type and approved products on www.environmentalchoice.com.

Appliances

Government regulations: The Energy Star initiative, an Environmental Protection Agency-run unit, provides manufacturers with energy-efficient guidelines set in conjunction with the Department of Energy. Criteria for each appliance differs and can be found on www.energystar.gov under the Products tab.

Industry regulations: No industry regulations.

Environmentalist regulations: Most environmentalists recommend using the Energy Star label as a guide. Web sites like Treehugger.com also provide insight and tips on purchasing energy-efficient appliances.

Automobiles

Government regulations: The U.S. Department of Energy lists on its Web site the fuel efficiency of every model car made since 2000. Automobile makers must also adhere to the Corporate Average Fuel Economy, a fuel efficiency measure regulated by the National Highway Traffic Safety Administration.

Industry regulations: Automobile owners/repairmen/dealerships must not only comply with Corporate Average Fuel Economy, listed on www.nhtsa.dot.gov, they must follow state and local laws as well.

Environmentalist regulations: The not-for-profit National Automotive Environmental Compliance Assistance Center lists information on its Web site to help you to determine whether or not your car complies with current regulations.

Beauty/Personal Hygiene Products

Government regulations: The FDA requires that these products list all ingredients on their packaging.

Industry regulations: There is no industry standard.

Environmentalist regulations: ECOCERT, a France-based control and certification organization, approves organic products across the world, adhering to local laws. Cosmetics certified by ECOCERT include Stella McCartney's CARE. line. You can find a list of criteria and an in-depth explanation of certification on www.ecocert.com.

Furniture

Government regulations: There are no government regulations.
Industry regulations: There is no industry standard, but the nonprofit HauteGREEN, a group that recognizes contemporary sustainable design, provides criteria for green furniture makers. This includes the use of recyclable/reusable/renewable materials, as well as raw materials from fairly traded or low impact sources. Find more information at www.hautegreen.com.
Environmentalist regulations: The International Forest Stewardship Alliance certifies products made from wood by ensuring that those collecting the lumber are making the best use of forest resources, reducing damage and waste, and avoiding overconsumption and overharvesting.

Houses

Government regulations: There is not one federal body regulating green building. However, several local and state municipalities are setting up individual regulations, and most rely on the Department of Energy's Web site for guidance.

Industry regulations: In 2005, The National Association of Home Builders published a list of green building guidelines that include: lot preparation and design, resource efficiency, as well as occupancy comfort and indoor environmental quality. In conjunction with the former, the Sustainable Buildings Industry Council also publishes a set of criteria for home builders.

Environmentalist regulations: Experts suggest using a combination of certifications to build a proper green home--starting with Energy Star and ensuring your wood has been certified by the International Forest Stewardship Alliance.

Top 10 Emerging Environmental Technologies

Top 10 Emerging Environmental Technologies
livescience.com

Make Paper Obsolete

Imagine curling up on the couch with the morning paper and then using the same sheet of paper to read the latest novel by your favorite author. That's one possibility of electronic paper, a flexible display that looks very much like real paper but can be reused over and over. The display contains many tiny microcapsules filled with particles that carry electric charges bonded to a steel foil. Each microcapsule has white and black particles that are associated with either a positive or negative charge. Depending on which charge is applied; the black or white particles surface displaying different patterns. In the United States alone, more than 55 million newspapers are sold each weekday.

Bury The Bad Stuff

Carbon dioxide is the most prominent greenhouse gas contributing to global warming. According to the Energy Information Administration, by the year 2030 we will be emitting close to 8,000 million metric tons of CO2. Some experts say it's impossible to curb the emission of CO2 into the atmosphere and that we just have to find ways to dispose of the gas. One suggested method is to inject it into the ground before it gets a chance to reach the atmosphere. After the CO2 is separated from other emission gases, it can be buried in abandoned oil wells, saline reservoirs, and rocks. While this sounds great, scientists are not sure whether the injected gas will stay underground and what the long-term effects are, and the costs of separation and burying are still far too high to consider this technology as a practical short-term solution.

Let Plants and Microbes Clean Up After Us

Bioremediation uses microbes and plants to clean up contamination. Examples include the cleanup of nitrates in contaminated water with the help of microbes, and using plants to uptake arsenic from contaminated soil, in a process known as phytoremediation. The U.S. Environmental Protection Agency has used it to clean up several sites. Often, native plant species can be used for site cleanup, which are advantageous because in most cases they don't require pesticides or watering. In other cases scientists are trying to genetically modify the plants to take up contaminants in their roots and transport it all the way to the leaves for easy harvesting.

Plant Your Roof

It's a wonder that this concept attributed to the Hanging Gardens of Babylon, one of Seven Wonders of the World, didn't catch on sooner in the modern world. Legend has it that the roofs, balconies, and terraces of the royal palace of Babylon were turned into gardens by the king's order to cheer up one of his wives. Roof gardens help absorb heat, reduce the carbon dioxide impact by taking up Co2 and giving off oxygen, absorb storm water, and reduce summer air conditioning usage. Ultimately, the technique could lessen the "heat island" effect that occurs in urban centers. Butterflies and songbirds could also start frequenting urban garden roofs, and like the king's wife, could even cheer up the inhabitants of the building. Here, a green roof is tested at Penn State.

Harness Waves and Tides

The oceans cover more than 70 percent of the Earth's surface. Waves contain an abundance of energy that could be directed to turbines, which can then turn this mechanical power into electrical. The obstacle to using this energy source has been the difficulty in harnessing it. Sometimes the waves are too small to generate sufficient power. The trick is to be able to store the energy when enough mechanical power is generated. New York City's East River is now in the process of becoming the test bed for six tide-powered turbines, and Portugal's reliance on waves in a new project is expected to produce enough power for more than 1,500 homes. Here, a buoy system capable of capturing the ocean�s power in the form of offshore swells is illustrated by researchers at Oregon State University.

Ocean Thermal Energy Conversion

The biggest solar collector on Earth is our ocean mass. According to the U.S. Department of Energy, the oceans absorb enough heat from the sun to equal the thermal energy contained in 250 billion barrels of oil each day. The U.S. consumes about 7.5 billion barrels a year. OTEC technologies convert the thermal energy contained in the oceans and turn it into electricity by using the temperature difference between the water's surface, which is heated, and the cold of the ocean's bottom. This difference in temperature can operate turbines that can drive generators. The major shortcoming of this technology is that it's still not efficient enough to be used as a major mechanism for generating power.

Sunny New Ideas

The sun's energy, which hits Earth in the form of photons, can be converted into electricity or heat. Solar collectorscome in many different forms and are already used successfully by energy companies and individual homeowners. The two widely known types of solar collectors are solar cells and solar thermal collectors. But researchers are pushing the limits to more efficiently convert this energy by concentrating solar power by using mirrors and parabolic dishes. Part of the challenge for employing solar power involves motivation and incentives from governments. In January, the state of California approved a comprehensive program that provides incentives toward solar development. Arizona, on the other hand, has ample sunshine but has not made solar energy a priority. In fact in some planned communities it is downright discouraged by strict rules of aesthetics.

The 'H' Power

Hydrogen fuel cell usage has been touted as a pollution-free alternative to using fossil fuels. They make water by combining hydrogen and oxygen. In the process, they generate electricity. The problem with fuel cells is obtaining the hydrogen. Molecules such as water and alcohol have to be processed to extract hydrogen to feed into a fuel cell. Some of these processes require the using other energy sources, which then defeat the advantages of this "clean" fuel. Most recently, scientists have come up with ways to power laptops and small devices with fuel cells, and some car companies are promising that soon we'll be seeing cars that emit nothing but clean water. The promise of a "hydrogen economy," however, is not one that all experts agree will ever be realized.

Remove the Salt

According to the United Nations, water supply shortages will affect billions of people by the middle of this century. Desalination, basically removing the salt and minerals out of seawater, is one way to provide potable water in parts of the world where supplies are limited. The problem with this technology is that it is expensive and uses a lot of energy. Scientists are working toward better processes where inexpensive fuels can heat and evaporate the water before running it through membranes with microscopic pores to increase efficiency.

Make Oil from Just about Anything

Any carbon-based waste, from turkey guts to used tires, can, by adding sufficient heat and pressure, be turned into oil through a process called thermo-depolymerization, This is very similar to how nature produces oil, but with this technology, the process is expedited by millions of years to achieve the same byproduct. Proponents of this technology claim that a ton of turkey waste can cough up about 600 pounds of petroleum.

Fuel cell technology to help clean up shipping

The world's largest, longest, and tallest, transatlantic liner 'Queen Mary 2' leaves its dock at the Alstom shipyards in St Nazaire, western France, September 25, 2003. A group of north European companies aims to show how fuel cells can clean up ship engines, which now use filthy fuels such as oil refinery residues and can spew out hundreds of times more pollutants than automobiles. (Daniel Joubert/Reuters)


Fuel cell technology to help clean up shipping

By Wojciech MoskwaFri Aug 3, 9:29 AM ET

A group of north European companies aims to show how fuel cells can clean up ship engines, which now use filthy fuels such as oil refinery residues and can spew out hundreds of times more pollutants than automobiles.
The companies plan to install a clean fuel-cell engine aboard a supply ship in 2008 and believe that a large share of the marine world will follow suit within 25 years.
"Green" engines for ships will gain footing in the fiercely competitive global shipping industry, they say, as technology advances and relatively lax environmental norms toughen.
"Stricter regulations coupled with policies favoring green solutions will in future years more than compensate for the higher initial investment costs of fuel cells," Tomas Tronstad, who heads the cross-industry fuel cell project for Norwegian ship classifier Det Norske Veritas (DNV), told Reuters.
"We hope that in a decade there will be many similar projects around the world and in a quarter century a large part of the marine world could be on fuel cells," Tronstad said.
Iceland already plans to convert its entire fishing fleet to hydrogen fuel cell engines as part of its environmental drive.
The shipping industry says it is more green than other modes of transport considering the huge amount of trade that ships carry, although the heavy fuel used in shipping emits 700 times more sulphur dioxide than diesel exhausts from road vehicles.
DNV estimates that fuel cells -- which generate electric power from a chemical process instead of combustion like regular engines -- now cost about six times more than diesel generators.
But the technology can be up to 50 percent more efficient and much cleaner, helping to curb high costs of fuel and, as many expect in the future, the high costs of polluting.
When powered by liquefied natural gas (LNG), as the first full-scale test model will be, carbon dioxide emissions are cut in half compared to diesel engines running on marine bunker fuel and sulphur and nitrogen oxide exhausts are nearly eliminated.
Fuel cells have no moving parts, slashing maintenance needs and making them inherently silent and vibration-free.
LIMITATIONS
Norwegian shipping group Eidesvik Offshofre ASA plans to install a 330 kW fuel cell system on an oilfield supply vessel next year. It will be one of several engines on the ship, all powered by LNG stored in refrigerated tanks on board.
LNG tanks take up precious onboard space and need to be filled relatively often -- about once per week according to Eidesvik -- limiting the ships' range to coastal waters of regions with developed LNG infrastructure.
"These engines will be best suited for short-route shipping and vessels with predictable operational patterns...such as oilfield supply vessels or ferries," said Kjell Sandaker, fuel cell project developer at Eidesvik.
The fuel cell will be built by MTU CFC Solutions, a unit of German engine maker Tognum. Finnish ship and industrial engine builder Wartsila and Norway-based consultant Vik-Sandvik are also taking part in the project.
LNG is preferred to hydrogen-fed fuel cells, whose only exhaust is heat and water, because of the problems in storing large amounts of hydrogen and high costs of producing it, the project says.
But Iceland's idea is to use its cheap thermal energy and hydropower to the produce hydrogen that would drive its fishing fleet, one of the world's biggest, and cut emissions.
Other options for ship-based fuel cells, said DNV, could be methanol or biofuels, which are liquids in normal temperatures and more readily available throughout the world than LNG.