by Ed Gould
A breakthrough in battery technology, which combines waste carbon dioxide with tiny microbes, could help provide an answer to intermittent wind power.Scientists at Pennsylvania State University are pioneering a method whereby electrical energy is stored as methane, which can then be burned to release power when it’s needed. The system’s active ‘ingredients’ are a combination of tiny microbes and CO2. Placed under an electrical current – for example from an off-grid renewable power source such as wind or solar – the microbes convert the CO2 into methane. Professor Bruce Logan, head of the research team, explains that they work in a similar way to the natural process found in marshes. He suggests that the initial carbon dioxide needed for the chemical reaction could even come from industrial sources: “CO2 is soluble in water, so the gas stream could be bubbled or transferred” in pipes from factories, for example. The ‘battery’ is designed to work as a closed loop, capturing and reusing the CO2 that’s released when the methane is burned. The energy conversion is about 80%, Logan claims, but admits that “a lot more research into scaling up these systems is needed” before commercial viability could be assessed. Gaynor Hartnell, Director of Policy at the Renewable Energy Association, agrees that it’s early days, but adds that “if it were cost-effective and could be used on CO2 from power generation, then it would appear to be a dream come true”. The most advanced trial of renewable energy storage is under way at a Minnesota wind farm. The batteries use sodium sulphur chemistry and operate at temperatures of more than 430ºC. In May, General Electric announced the opening of a factory in New York to develop sodium-based batteries, which will help power the company’s hybrid rail locomotives, and could also be used as storage for intermittent types of renewable energy such as wind power.
This piece originally appeared on Green Futures. Green Futures is published by Forum for the Future, one of the leading magazines on environmental solutions and sustainable futures. Its aim is to demonstrate that a sustainable future is both practical and desirable – and can be profitable, too.
Image credit: Harry Gruyaert, Magnum Photos