For some sceptics the results of the study reported in The Guardian on November 30 on the benfits of domestic wind turbines will come as no surprise. It all depends on where you are. Building Research Establishment(BRE), which advises the government and private sector, has found that in built-up towns and cities weak winds and turbulence mean that turbines are likely to add to, not subtract from, a home's carbon footprint. BRE took data from sites across the UK and analysed the likely performance of three models of turbine. In Manchester two-thirds of the 96 different options studied for siting turbines produced a carbon dioxide impact that could never be paid back. Manufacturing, installing and maintaining the units would, on balance, exacerbate global warming. The same was true in a third of cases in the coastal city of Portsmouth. After the energy used in the manufacture of the turbine from aluminium, steel, copper and fibreglass, the carbon footprint of the turbine is exacerbated by transportation to the site and the need for regular maintenance to moving parts which bear the strain of rapidly changing loads during heavy winds, the report found. The likely output of a micro-wind turbine on a pitched roof house in a large city such as Manchester would be less than 150kWh a year; about 3-5% of the electricity consumption of an average house. But in a windy location such as Wick in northern Scotland, the output is likely to be around 3,000kWh a year - about +80% of electricity use. The carbon payback in this coastal town would come in less than a year in most cases, and after no more than seven years in the most difficult conditions. The CO2 embodied in the manufacture of the turbines ranged widely, at best 180kg - equivalent to the amount emitted in a 45-mile car journey and at worst 1,444 kg, close to the impact of one person taking a return flight to New York. Delivery, installation and maintenance over a 20-year lifespan could add from 18kg to 147kg of CO2. To make them work efficiently, keep them big seems to be the answer. Have you been passed Avonmouth recently? take a look next time and see what you think.
Yes