sciam.com: By Matthew L. Wald

The need to tackle global climate change and energy security makes developing alternatives to fossil fuels crucial.

Renewable energy, such as from photovoltaic electricity and ethanol, today supplies less than 7 percent of U.S. consumption. If we leave aside hydroelectric power, it is under 4.5 percent. Globally, renewables provide only about 3.5 percent of electricity and even less of transportation fuels.

But increasing that fraction for the U.S.—as seems necessary for managing greenhouse gases, trade deficits and dependence on foreign suppliers—has at least three tricky components. The obvious one is how to capture the energy of wind, sun and crops economically. After that, the energy has to be moved from where it is easily gathered, such as the sunny American Southwest or the windy High Plains, to the places it can be used. And the third is to convert it into convenient forms. Most prominently in the last category, electricity for transportation has to be loaded into cars and trucks, either through batteries or perhaps as hydrogen. [ read more ]

sciam.com: By David Biello
Molten salts can store the sun’s heat during the day and provide power at night

Near Granada, Spain, more than 28,000 metric tons of salt is now coursing through pipes at the Andasol 1 power plant. That salt will be used to solve a pressing if obvious problem for solar power: What do you do when the sun is not shining and at night?

The answer: store sunlight as heat energy for such a rainy day.

Part of a so-called parabolic trough solar-thermal power plant, the salts will soon help the facility light up the night—literally. Because most salts only melt at high temperatures (table salt, for example, melts at around 1472 degrees Fahrenheit, or 800 degrees Celsius) and do not turn to vapor until they get considerably hotter—they can be used to store a lot of the sun’s energy as heat. Simply use the sunlight to heat up the salts and put those molten salts in proximity to water via a heat exchanger. Hot steam can then be made to turn turbines without losing too much of the original absorbed solar energy. [ read more ]

sciam.com: By Eitan Haddok and David Biello:

The enhanced system at Soultz in France is the first such artificial geothermal power plant. Since the 1920s The Geysers geothermal power plant 72 miles (115 kilometers) north of San Francisco has been pumping out electricity harvested from hot rocks deep within Earth’s crust. But there are only so many natural volcanic formations to be tapped. In locations that are not blessed by easy access to this natural resource, drilling into the hot rock bed and pumping fluid through it has the potential to unleash 2,000 times the total annual consumption of energy in the U.S., according to a 2007 report from the Massachusetts Institute of Technology. [ see more ]

discovermagazine.com: by Dava Sobel

One remarkable forest is busy purifying the planet. A legacy of the Argonne National Laboratory’s early foray into atomic energy lies buried here on its campus, about 25 miles southwest of Chicago. Although solid wastes from all sorts of experiments have been sealed in a landfill, certain liquids, mostly chlorinated solvents, still taint the water that runs under the site. The ongoing attempt to remove these contaminants occupies an enormous experimental facility that covers four acres and looks like a forest.

“I like to brag that I have the biggest lab at Argonne,” says agronomist Cristina Negri, indicating an expanse of 900 poplars and willows growing in rows. The trees stand about 30 feet high. More important, their roots extend 30 feet down, where they tap the contaminated aquifer and literally pull pollutants out of the ground. [ read more ]

newscenter.lbl.gov:

New window into nanoscale chemistry could help improve pollution control, fuel cell technologies

The first-ever glimpse of nanoscale catalysts in action could lead to improved pollution control and fuel cell technologies. Scientists from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory observed catalysts restructuring themselves in response to various gases swirling around them, like a chameleon changing its color to match its surroundings. [ read more ]

technologyreview.com: By Kevin Bullis

A novel photovoltaic technology moves into large-scale production.

In a significant milestone in the deployment of flexible, printed photovoltaics, Konarka, a solar-cell startup based in Lowell, MA, has opened a commercial-scale factory, with the capacity to produce enough organic solar cells every year to generate one gigawatt of electricity, the equivalent of a large nuclear reactor. [ read more ]

technologyreview.com: By Kevin Bullis

With catalysts created by an MIT chemist, sunlight can turn water into hydrogen. If the process can scale up, it could make solar power a dominant source of energy.

“I’m going to show you something I haven’t showed anybody yet,” said Daniel Nocera, a professor of chemistry at MIT, speaking this May to an auditorium filled with scientists and U.S. government energy officials. He asked the house manager to lower the lights. Then he started a video. “Can you see that?” he asked excitedly, pointing to the bubbles rising from a strip of material immersed in water. “Oxygen is pouring off of this electrode.” Then he added, somewhat cryptically, “This is the future. We’ve got the leaf.” [ read more ]

technologyreview.com: By Brittany Sauser

A large-scale tidal-power unit has started up in Northern Ireland.

The world’s first commercial tidal-power system has been connected to the National Grid in Northern Ireland. Built by the British tidal-energy company Marine Current Technologies (MCT), the 1.2-megawatt system consists of two submerged turbines that are harvesting energy from Strangford Lough’s tidal currents. The company expects that once the system, called SeaGen, is fully operational, it will be able to provide electricity to approximately one thousand homes.

The system is currently being tested and has briefly generated 150 kilowatts of power into the grid. But it has also damaged one of its rotors due to a failure in the control system when the rotor began turning too fast. Although the problem was a minor setback, the unit is not expected to start running continuously and at full capacity until November, says Peter Fraenkel, the technical director at MCT. [ read more ]

technologyreview.com: By Prachi Patel-Predd

Materials that change temperature in response to electric fields could keep computers–and kitchen fridges–cool.

Thin films of a new polymer developed at Penn State change temperature in response to changing electric fields. The Penn State researchers, who reported the new material in Science last week, say that it could lead to new technologies for cooling computer chips and to environmentally friendly refrigerators.

Changing the electric field rearranges the polymer’s atoms, changing its temperature; this is called the electrocaloric effect. In a cooling device, a voltage would be applied to the material, which would then be brought in contact with whatever it’s intended to cool. The material would heat up, passing its energy to a heat sink or releasing it into the atmosphere. Reducing the electric field would bring the polymer back to a low temperature so that it could be reused. [ read more ]

technologyreview.com: By Alexandra M. Goho

Frances Arnold is designing better enzymes for making biofuels from cellulose.

In December, President Bush signed the Energy Independence and Security Act of 2007, which calls for U.S. production of renewable fuels to reach 36 billion gallons a year–nearly five times current levels–by 2022. Of that total, cellulosic biofuels derived from sources such as agricultural waste, wood chips, and prairie grasses are supposed to account for 16 billion gallons. If the mandates are met, gasoline consumption should decline significantly, reducing both greenhouse-gas emissions and imports of foreign oil. [ read more ]