April 13, 2013, by Tim Radford
Not just portable power, but storable as well: A step forward for renewables?
FOR IMMEDIATE RELEASE The prospects for some forms of renewable energy look brighter after scientists said they had found ways to store excess power and to take carbon dioxide straight from the atmosphere to make fuel. LONDON, 13 April – Researchers in North America claim to have found two new ways to deliver power to the people – and reduce the global carbon footprint. One team hopes to produce a low-cost, efficient technique for storing the surplus energy from wind power, or the solar panels on the roof. The other team hopes to deliver biofuels from the carbon dioxide in the air without even troubling the photo-synthesising plants that have, for the last half a billion years, taken on the task. The first advance is from chemists at the University of Calgary in Canada, who report in the journal Science that they have found new catalysts that could convert electrical energy, which cannot be simply stored, into chemical energy, which can. This is a serious problem for renewable suppliers. On a sunny day, photo-voltaic cells deliver generous quantities of power, but on a sunny day, fewer people need to turn on the central heating or use the electric lights. Wind turbines can generate whenever there is wind, but on a still, frosty day, they deliver little or nothing to shivering households. If the turbines could pump water that could be used later for hydro-electric power, that would be a solution, but if the consumers already had generous hydro-electric sources, they wouldn’t need wind turbines anyway. But Curtis Berlinguette and Simon Trudel at Calgary have thought of another way of using water. Fuel cells use electric current and catalysis to drive a reaction that splits water into hydrogen and oxygen that can be stored separately as fuels and then reconverted back into water at any time, delivering generous quantities of energy that can be turned into electricity. There would be no exhaust, and no pollution, no carbon dioxide emissions and, in theory, no loss of water in the process. The catch so far has been that catalysis has depended on rare, expensive and toxic crystalline minerals. The Calgary team report that they have driven a successful reaction using a new family of electro-catalysts made out of cheap, safe, amorphous mixed metal oxides of iron, cobalt and nickel (an oxide of iron, of course, is also known as rust: never a rare commodity). These, they say, perform as well as any catalysts now on the market, but are a thousand times cheaper.
Still to be proved
“We are essentially showing, even with our first generation of catalysts, we are equal to or better than anything that’s sold commercially right now after 30 years of development”, says Trudel. The duo have patented the process and created a university spin-off company called FireWater Fuel Corporation. They foresee small household energy systems no bigger than a home freezer, running on a few litres of water. They hope to be testing a prototype before 2015. These are large claims, yet to be tested in the marketplace. An even bigger claim, and still a very long way from the marketplace, comes from the University of Georgia in Athens in the US, where Michael Adams and colleagues have developed a micro-organism that absorbs carbon dioxide and generates stored energy in the form of tissue. They report in the Proceedings of the National Academy of Sciences that they have genetically manipulated a new strain of Pyrococcus furiosus that lives on carbohydrates in superheated ocean waters near geothermal vents. They have adjusted its metabolism to make it capable of feeding on carbon dioxide at much lower temperatures. They believe that they could use it to generate other useful products, including fuel, from carbon dioxide. Anyone who burned biofuel would be putting back into the atmosphere only the carbon dioxide that had been recently removed from it and stored in the organism’s tissue: that is why ethanol fuel from sugar cane or maize husks is described as carbon-neutral. “What this discovery means is that we can remove plants as the middle man”, said Adams. “We can take carbon dioxide directly from the atmosphere and turn it into useful products like fuels and chemicals without having to go through the inefficient process of growing plants and extracting sugars from biomass.” – Climate News Network
Tim Radford, a founding editor of Climate News Network, worked for The Guardian for 32 years, for most of that time as science editor. He has been covering climate change since 1988.