scinerd:

Artificial Leaf Moves Two Steps Closer to Reality

In the first, researchers led by Daniel Nocera, a chemist at the Massachusetts Institute of Technology in Cambridge, report that they’ve created an “artificial leaf” from cheap, abundant materials that splits water into molecular hydrogen (H2) and oxygen (O2), somewhat similar to the way plants carry out the first step in photosynthesis. The leaf consists of a thin, flat, three-layered silicon solar cell with catalysts bonded to both faces of the silicon. When placed in a beaker of water and exposed to sunlight, silicon absorbs photons of sunlight, generating electrons with enough energy to conduct through the silicon.

In the second study, a team led by chemists Richard Masel of Dioxide Materials in Champaign, Illinois, and Paul Kenis of the University of Illinois Urbana-Champaign, report that they’ve come up with a more energy-efficient approach to converting carbon dioxide (CO2) into carbon monoxide (CO), the first step to making a hydrocarbon fuel. Other researchers have worked for decades to devise catalysts and the right reaction conditions to carry out this conversion. But converting CO2 to CO has always required applying large electrical voltages to CO2 to make the change. That excess voltage is an energy loss, meaning it takes far more energy to make the CO than it can store in its chemical bonds.

“These papers are nice advances,” says Daniel DuBois, a chemist at Pacific Northwest National Laboratory in Richland, Washington, who works on catalysts for both splitting water and re-energizing CO2. But he cautions that neither solves all of their respective issues. The oxygen-forming catalyst in the artificial leaf, for example, remains slow, DuBois says. And the efficiency of the overall leaf is only 4.7% at most, and just 2.3% in its most simplest design. The catalyst in the CO2 system is even slower. But DuBois says that because other researchers in the field now have a good examples of systems that work, they can now focus on designing improved catalysts to speed them up.

(via ikenbot)

jayparkinsonmd:

“A human being at rest runs on 90 watts,” he says. “That’s how much power you need just to lie down. And if you’re a hunter-gatherer and you live in the Amazon, you’ll need about 250 watts. That’s how much energy it takes to run about and find food. So how much energy does our lifestyle [in America] require? Well, when you add up all our calories and then you add up the energy needed to run the computer and the air-conditioner, you get an incredibly large number, somewhere around 11,000 watts. Now you can ask yourself: What kind of animal requires 11,000 watts to live? And what you find is that we have created a lifestyle where we need more watts than a blue whale. We require more energy than the biggest animal that has ever existed. That is why our lifestyle is unsustainable. We can’t have seven billion blue whales on this planet. It’s not even clear that we can afford to have 300 million blue whales.”

kateoplis:

A graveyard for vehicles highly contaminated by radiation, near the Chernobyl nuclear power plant, seen on Nov. 10, 2000. Some 1,350 Soviet military helicopters, buses, bulldozers, tankers, transporters, fire engines and ambulances were used while fighting against the April 26, 1986 nuclear accident. All were irradiated during the clean-up. Photo: Efrem Lukatsky/AP

The Chernobyl Disaster: 25 Years Ago | In focus

theeconomist:

Daily chart: the windy world. In 2010 China overtook America as the world leader in wind power, and now accounts for 22% of the world’s total wind power capacity. Globally, however, the installation of new wind power facilities has started to slow.