May 13, 2014, by Tim Radford
Reach for the sky: Grand Fir trees are being used to make high-octane rocket fuel
Image: Crusier via Wikimedia Commons
FOR IMMEDIATE RELEASE From making electricity available without wires to using fir trees to produce high-octane rocket fuel, science is making ingenious breakthroughs in energy alternatives LONDON, 13 May − New scientific discoveries have been made to beef up a biofuel, re-use waste heat, get more power from solar panels – and even deliver electricity across a room without using wires. Scientists in the US have crossed a fir tree with a gut bacterium, fed it beef soup, and watched it deliver the chemistry of the highest-octane rocket fuel. They combined genetic manipulation and microbiology to open the way for a new kind of biofuel manufacture for military aviation and space technology. Pamela Peralta-Yahya and research collaborators at the Georgia Institute of Technology report in the journal Synthetic Biology that their new technique has some way to go before it delivers a high-energy spirit to match the missile fuel JP-10, which has the chemical formula C10H16, costs $25 a gallon, and only tiny amounts of which can be extracted from each barrel of crude oil. But the scientists say their approach has produced six times the pinene of earlier biofuel efforts. Pinene, an aromatic chemical produced by conifers, is a precursor to JP-10 and it too has the chemical formula C10H16. The researchers engineered the microbe Escherichia coli with enzymes from two North American pines and the Grand Fir tree (Abies grandis), then set the bugs to work on flasks of beef broth. Their best result was 32mg of pinene per litre. To be competitive with JP-10, the scientists need to do 26 times better. Dr Peralta-Yahya says the problems ahead are “difficult, but not insurmountable”.
In another instance of laboratory ingenuity and scholarly resource, Mercouri Kanatzidis and colleagues at Northwestern University, Illinois, began experimenting with crystal forms of the compound tin selenide, and found it to be a marvel of thermoelectric potential. Thermoelectric materials are very poor conductors of heat, but good conductors of electricity. Most energy is wasted as heat, which is conducted away from a combustion engine or coal-fired power generator. The discovery therefore raises the possibility that this waste heat could contained and be converted to electricity. The evaluation of thermoelectric devices involves highly-specialised calculations, such as the “dimensionless figure of merit ZT”, but the researchers report in Nature journal that, at around 650°C, their tin selenide crystal has the highest reported ZT to date. Because it is such a poor conductor of heat, one side of the sample can heat up and stay hot, while the other stays cool. And because the heat is not dissipated, it remains concentrated and can be used again to generate more electricity. “A good thermoelectric material is a business proposition – as much commercial as it is scientific,” said Vinayak Dravid, one of the study’s authors. “You don’t have to convert much of the world’s wasted energy into useful energy to make a material very exciting.”
While US scientists were looking for more powerful biofuels, and finding unexpected thermoelectric properties in relatively common minerals, British scientists found a way to take the shine out of solar panels. Solar energy farms can generate a problematic glare, and a team from Loughborough University, UK, has devised a multi-layer, anti-reflection coating that could reduce reflection from photovoltaic panels, while at the same time improving their efficiency. A glass surface reflects 4% of the light that smacks into it, so the scratch-resistant, durable coating – of zirconium oxide and silicon dioxide – would actually improve power output by 4%. Other researchers are engaged in finding innovative ways to get the power to the consumer. At the Korea Advanced Institute of Science and Technology (KAIST), researchers report that they have a developed a dipole coil resonant system that can transmit electricity across a range of five metres, and power, for instance, a large LED TV system and three 40 watt fans. This is an advance on a 2007 experiment at the Massachusetts Institute of Technology (MIT) in the US, when electric current was transmitted wirelessly across a two-metre space. The technology remains – for the time being at least − costly to implement, and still in its early stages. But its begetters have high hopes. “Just like we see Wi-Fi zones everywhere today, we will eventually have many Wi-power zones at such places as restaurants and streets that provide electric power wirelessly to electronic devices,” predicts Chun T Rim, a nuclear and quantum engineer. “We will all use the devices anywhere without tangled wires attached, and anytime without worrying about charging their batteries.” – 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.