Documents filed under Pollution from UK

A guide to calculating the carbon dioxide debt and payback time for wind farms

Hall-co2payback_thumb It is broadly accepted that wind turbines do not emit CO2 at the point of generation. However, in common with all types of power station, it is emitted during their construction and, through damage directly inflicted on the construction site, over a much longer period. The total debt will vary from site to site but will comprise some or all of the following; • Emissions arising from fabrication (steel smelting, forging of turbine columns, the manufacture of blades and the electrical and mechanical components); • Emissions arising from construction (transportation of components, quarrying, building foundations, access tracks and hard standings, commissioning); • The indirect loss of CO2 uptake (fixation) by plants originally on the surface of the site but obliterated by construction activity including the destruction of active bog plants on wet sites and deforestation; • Emissions due to the indirect, long-term liberation of CO2 from carbon stored in peat due to drying and oxidation processes caused by construction of the site. It is important to recognise that peat is a major store of carbon accumulated from dead plant remains over many millennia. It is held in perpetuity because the bog’s wetness and acid conditions prevent the access of oxygen and inhibit the growth of bacteria which would otherwise rot the vegetation. Draining peat for construction reverses both these long-term processes: the soil is exposed to the air, the carbon is converted to CO2 and released slowly to the atmosphere. Several papers from the wind industry in Denmark and the UK have addressed the first two points with estimates of payback time ranging from about six to 30 months. However, the industry rarely, if ever, considers the last two. This is a fundamental omission as their contribution to the overall CO2 debt, in particular the last, can be far greater than all the others put together. This paper outlines a procedure for quantifying it. The guide has been prepared to enable anyone with access to the Environmental Statement (ES) that forms part of a Planning Application (PA) for a wind farm to estimate its CO2 debt. (If some of the requisite information proves to be unavailable, this ought to provide grounds for postponing consideration of the application and the commissioning of further assessment.) The results of the calculations described should be submitted to planning authorities or Public Inquiries as part of the arguments used in assessing the merits and demerits of an application.
1 Aug 2006

Reduction in Carbon Dioxide Emissions: Estimating the Potential Contribution from Wind Power

Renewable_energy_foundation_thumb In the UK, the parallel objective is to generate 10% of the UK’s electricity from renewable sources by 2010. Renewable electricity has become synonymous with CO2 reduction. However, the relationship between renewables and CO2 reduction in the power generation sector does not appear to have been examined in detail, and the likelihood, scale, and cost of emissions abatement from renewables is very poorly understood. The purpose of this report is to analyse a wide range of technical literature that questions whether the renewables policy can achieve its goals of emissions reduction and power generation. To some, renewable energy has the simple and unanalysed virtue of being “green”. However, the reality of this quality is dependent on practical issues relating to electricity supply. ......In conclusion, it seems reasonable to ask why wind-power is the beneficiary of such extensive support if it not only fails to achieve the CO2 reductions required, but also causes cost increases in back-up, maintenance and transmission, while at the same time discouraging investment in clean, firm generation.
1 Dec 2004
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