Stories tagged environment

This page lists stories about the environment, energy, climate change, and global warming from Science Buzz, a website devoted to science in the news, emerging research, and seasonal phenomena.

A company in California is harvesting the power of cow patties, using manure to produce natural gas for home heating.

Apr
27
2008

What is the best way to store solar energy?

Solar Two: Heat from the sun is stored in a tower containing molten salt.
Solar Two: Heat from the sun is stored in a tower containing molten salt.Courtesy United States Department of Energy
What is a good way to store solar energy for when the sun doesn't shine? Batteries are expensive and wear out. Instead of storing electricity, solar thermal systems store heat. A coffee thermos and a laptop computer’s battery store about the same amount of energy. The thermos costs about $5 and the laptop battery $150.

Molten salt at 1000+ degrees

By reflecting sunlight at a tall "power tower", tens of thousands of gallons of molten salt can be heated to very high temperatures (1000 degrees F). The heated salt is used to boil water into steam, spin a turbine and make electric power. By regulating the release of heat, generators can continue to run on rainy days and during the night.

"This technology has been successfully demonstrated and is ready for commercialization. From 1994 to 1999, the Solar Two project demonstrated the ability of solar molten salt technology to provide long-term, cost effective thermal energy storage for electricity generation."

SolarReserve will build solar thermal electric plants

SolarReserve, a company backed in part by United Technologies, is using funding from a U.S. Department of Energy grant to develop utility-scale solar thermal electric generating plants between 100-600 megawatts of electricity. One megawatt is enough power to supply approximately 1,000 US households. Read more at SolarReserves FAQ webpage.

Sources:
New York Times
SolarReserve website (includes a video)

Apr
19
2008

Popcorn shaped dye particles double cheaper solar cell efficiency

Popcorn-ball design doubles efficiency of dye-sensitized solar cells: A close-up of a single ball, taken with a scanning electron microscope. The 300-nanometer sphere is large enough to scatter light. But its insides are made of tiny grains just 15 nanometers across.
Popcorn-ball design doubles efficiency of dye-sensitized solar cells: A close-up of a single ball, taken with a scanning electron microscope. The 300-nanometer sphere is large enough to scatter light. But its insides are made of tiny grains just 15 nanometers across.Courtesy University of Washington
Dye-sensitized solar cells, which are more flexible, easier to manufacture, and cheaper than existing solar technologies just got even better.

By using particles shaped like popcorn, University of Washington researchers were able to increase solar cell efficiencies from 2.4 up to 6.2 per cent. The porosity of the large balls (300nm) allowed light to penetrate into the layers and bounce around between balls increasing absorption. Each balls surface was made of smaller spheres (15nm) increasing the effective surface area. One gram of this material has a surface area of 1000 square feet.

The research used the pigment zinc oxide, which is of lower efficiency than the commercially used titanium oxide, but easier to work with during experiments. Titanium oxide layers are expected to show similar gains. While titanium oxide cells currently have a record efficiency of 11 percent, the researchers hope that by using the new method they can by far surpass this old record, possibly even surpassing silicon cell efficiencies. Such progress could make silicon cells, used for decades, obsolete, replaced by cheaper, more efficient, flexible cells.

Source; University of Washington News

Apr
08
2008

With the price of gasoline going up, the price of ethanol may be coming down: A new process may lead to low-cost ethanol in the near future.
With the price of gasoline going up, the price of ethanol may be coming down: A new process may lead to low-cost ethanol in the near future.Courtesy swankslot

Right now, ethanol is expensive to make; the only reason it is priced competitively with gasoline is because the government subsidizes it with tax dollars. General Motors is partnering with Coskata, a biofuel company, to create low-cost ethanol. The new process uses micro-organisms to turn just about any carbon-based material into ethanol, including switchgrass and agricultural waste. Not only will this make ethanol cheaper, but it will also reduce the use of grains to make ethanol when they could be used to make food.

Mar
01
2008

Renewed hope for nuclear fusion

Magnetized Target Fusion
Magnetized Target FusionCourtesy Los Alamos fusion energy sciences
Nuclear fusion has been "just around the corner" for more than 50 years. Fusion reactions occur in the sun and in hydrogen bombs. Tremendous quantities of energy can result from the fusion of hydrogen atoms into helium.

VCs bet big money on fusion power futures

Wealthy investors in California are betting hundreds of millions of dollars that the difficulties of producing power with fusion may soon be solved. The CEO of Chrysalix Energy Venture Capital thinks that "Within five years, large companies will start to think about building fusion reactors." Chrysalix invested in General Fusion, a Canadian company that says it has found a way to hurdle many of the technical problems surrounding fusion.

The company's ultimate plan is to build small fusion reactors that can produce around 100 megawatts of power. The plants would cost around $50 million. That could allow the company to generate electricity at about 4 cents per kilowatt hour, making it competitive with conventional electricity.c/net News.com

Magnetized Target Fusion

Using a technique called Magnetized Target Fusion (MTF), a current within a plasma containing lithium creates a magnetic field which allows it to be squeezed . The resulting temperature spike breaks down

the lithium into helium and tritium. Tritium, an unstable form of hydrogen, is separated and then mixed with deuterium, another form of hydrogen. The two fuse and make helium, a reaction that releases energy that can be harvested.

For updates check this General Fusion Inc. wiki.

Jan
08
2008

Large scale study shows 540% net energy gain when ethanol is produced from switchgrass

Panicum Vergatum: Switchgrass
Panicum Vergatum: SwitchgrassCourtesy U S Govt

Kenneth Vogel, a geneticist with the U.S. Department of Agriculture in Lincoln, Nebraska, and his colleagues, found that ethanol produced from switchgrass yields 540% of the energy used to grow, harvest, and process it into ethanol.

Their results, published online in Proceedings of the National Academy of Sciences, shows that switchgrass, farmed using conventional agricultural practices on less-than-prime cropland yields only slightly less ethanol per hectare on average than corn.

Farmers planted switchgrass on 10 farms, each of which was between 3 and 9 hectares. They then tracked the inputs they used--diesel for farm equipment and transporting the harvested grasses, for example--as well as the amount of grass they raised over a 5-year period. ScienceNOW Daily News

Switchgrass monoculture or mixed prairie grasses?

Anyone remember our Buzz post "Chalk one up for diversity"? David Tilman in that post is quoted saying, "diverse prairie grasslands are 240 percent more productive than grasslands with a single prairie species"
Now I read:

... Vogel says, is that yields on farms using fertilizer and other inputs, such as herbicides and diesel fuel for farm machinery, were as much as six times higher than yields on farms that used little or no fertilizer, herbicides, or other inputs to grow a mixture of native prairie grasses. ScienceNOW Daily News

Who is right? Can anyone explain why two reputable researchers are getting such different results?

According to recent studies, shopping on-line and having stuff sent to you uses less energy than going to the store yourself.

Dec
18
2007

Silicon solar obsolete soon?
Silicon solar obsolete soon?Courtesy D. O. E.

NanoSolar, cheaper than coal

Renewable energy becoming cheaper than fossil fuels may happen soon. Today, Nanosolar CEO Martin Roscheisen says his startup took a step in that direction by shipping its first thin-film solar panel (via TechCrunch). In a blog post, Roscheisen claims his company has produced

“the world’s lowest-cost solar panel – which we believe will make us the first solar manufacturer capable of profitably selling solar panels at as little as $.99/Watt.”

Electricity from a new coal burning plant costs about $2.10/watt.

Nanosolar can change the world

Popular Science gave Nanosolar's Powersheets the top technical innovation of the year award. The NanoSolar website provides this list of news and events:

You can watch a video showing how NanoSolar photocells are manufactured (via KQED).

Dec
18
2007

Burning methane hydrate
Burning methane hydrateCourtesy United States Geological Survey

What is Methane ice?

Huge amounts of methane are being found on the ocean floor, trapped within cages of water molecules.

Methane clathrate, also called methane hydrate or methane ice, is a solid form of water that contains a large amount of methane within its crystal structure (a clathrate hydrate). wikipedia

Geologists estimate that significantly more hydrocarbons are bound in the form of methane hydrate than in all known reserves of coal, natural gas and oil combined. India and China plan to spend hundreds of millions of dollars learning how to tap into this huge reservoir of energy (Spiegel online).

Carbon curse or cure

Relying on this carbon based energy instead of renewable energy sources could worsen global warming by releasing more greenhouse gases. To be carbon neutral the carbon dioxide from burning carbon fuels needs to be captured and sequestered (locked up). Harvesting methane ice offers just this opportunity.

When a certain amount of pressure is applied to the cage-like crystal structure, carbon dioxide can penetrate the layer of ice, at which point it displaces the methane. Then a new cage of frozen water molecules forms around the carbon dioxide. Klaus Wallmann, Uni Kiel

Wallman is also impressed by the ratio at which the gases are exchanged. For each dissolved molecule of methane released, up to five molecules of carbon dioxide disappear into the ice cage. Wallmann hopes to see, in the not-too-distant future, tankers filled with CO2 heading out to sea to pump their climate-damaging cargo into the depths.

You might also read about research being done at Columbia University, "Carbon Neutral Methane Production Via Hydrates".