CO2 payback time for a wind farm on afforested peatland in the UK

The siting of wind farms on natural and afforested upland peatlands presents an interesting public policy dilemma. Such locations may offer developers attractive wind characteristics amidst sparse human settlement, but the associated disturbance of carbon from soils and vegetation may reduce the carbon benefits that can be derived from wind farm operation. To examine the relative impacts, an estimate was made of the CO2 payback time for a wind farm hypothetically sited on an afforested peatland in north-east England known as Harwood Forest. The location is representative of many potential wind farm sites, and was chosen for this study because its carbon fluxes and stores have been extensively characterised. We adjusted a published LCA for a wind farm in another location to take account of CO2 that would be emitted or not sequestered as a result of site disturbance if it were constructed and operated in Harwood Forest. The results show that the wind farm would compensate for its life cycle CO2 emissions in less than three years of operation in Harwood Forest, whereas the CO2 payback time would be reduced to less than five months if it were placed at an alternative site where CO2 emissions from disturbed soil and vegetation were not an issue.