PLEA Network

2 February 2016, Climate News Network, Useful waste offers win-win benefits. An unsung success story in the switch to renewable energy is the use of waste to produce gas – and a valuable by-product. The future is increasingly bright for renewable energy, with the US aiming to cut the price of solar photovoltaics by 75%between 2010 and 2020. Denmark plans to obtain 50% of its energy from windjust five years from now. But one form of renewable energy – and one which attracts few headlines – manages to create two useful products at the same time, and is making a growing contribution to combatting climate change. The medieval alchemists who sought to turn base metal into gold would have thrilled at   chemistry that let them turn waste into both fuel and fertiliser. Their twenty-first century successors have discovered the secret of doing exactly that. Unwanted food, animal waste, municipal rubbish, crop and forestry residues, sewage and dozens of other left-overs of civilisation can and are now being turned into methane to generate electricity, provide district heating and to fuel road vehicles. Big contribution This largely unheralded revolution takes different forms across the world, mostly because governments set their own rules to encourage the technology, and also because local circumstances provide contrasting piles of waste. But in every case the waste can be converted into gas for use as fuel. Although the technology is only part of the solution to climate change, theEuropean Biogas  Association estimates that over time it should be able to replace 30% of current natural gas consumption in Europe. The technology is roughly the same whatever the size of the plant or its location. Biogas plants use microbes to eat waste in an oxygen-free environment to produce methane, and leave fertiliser or soil conditioner as a useful by-product. The plants vary from small household types, very popular in China and India, to farm plants and larger-scale municipal installations in Europe.  Read More here