Severn Trent Wind Turbine Application
Wind Turbine Planning Application Year 2 Wind Data/ Generation Estimates
Although the planning application by Severn Trent Water to erect a 3.3MW wind turbine at their Newthorpe Sewage Works was approved in June 2012, there has been no further progress with this project. However, due to the poor calculated capacity factor for 2011 (24.93%), it seemed a good idea to continue monitoring the wind data in 2012 and identify whether the calculations were based on a particularly poor year in respect of average wind speed. Therefore, similar monthly data has been collected for 2012.
Although the highest average wind speed was recorded in December 2011 and continued into January 2012, the last 12 months, with the exception of December 2012 have illustrated lower average wind speed than in 2011, with a reduced calculated average capacity factor of 21.69% or 6833MWh/annum for a Siemens SWT-3.6mW-107m (MG) wind turbine. Therefore, it is likely the proposed 3.3MW turbine would deliver 6286MWh/annum, which would provide power to 1337 homes.
Table 1 shows the monthly wind data, calculated energy and capacity factor that a Siemens 3.6MW wind turbine would have delivered in 2012 at the location being considered.
|Month||Height Adjusted Ave Wind Speed m/s||Height Adjusted Steady Wind Speed kW||Height Adjusted Variable Wind Speed mean power kW per month||Height Adjusted Steady Wind estimated monthly kWh||Height Adjusted Steady Wind Estimated annual kWh||Height Adjusted Variable Wind estimated monthly kWh||Height Adjusted Variable Wind Estimated annual kWh||Turbine Capacity kW||Height Adjusted Variable Wind Capacity Factor %|
Chart 1 created from the table above highlights the relationship between wind speed, output and efficiency if the turbine had been operational in 2012. The table and chart can be compared with similar data and calculated output for 2011 at the following link. https://woodmeadenergyservices.com/renewable-energy/wind-turbine-planning-application/
Annual Hours of Operation Summary Table 2012
Table 2 provides an approximate indication of the hours/ efficiency of the turbine if it had been operational during 2012. Again there is clear evidence that the intermittency of wind would have meant that the turbine operated approximately 50% of the year below 20% efficiency.
|Jan-12||Feb-12||Mar-12||Apr-12||May-12||Jun-12||Jul-12||Aug-12||Sep-12||Oct-12||Nov-12||Dec-12||Annual Total Hours||% Year|
|Hours zero% CF||95||77||142||52||124||82||107||106||43||95||68||51||1042||12%|
|Hours less than 8% CF||206||282||361||210||322||226||321||322||193||270||257||169||3139||36%|
|Hours less than 20% CF||285||375||490||340||471||341||479||477||318||406||382||286||4650||53%|
|Hours greater than 20% CF||437||319||253||362||270||362||264||266||377||336||336||455||4037||46%|
|Hours 100% CF||30||4||1.33||7||0||82||0||0||0||4||4||16||148.33||2%|
Comparing the data for 2012 with the 2011 data (see hyperlink), it highlights the findings of the Stuart Young consulting report using metered data which identified that wind turbine capacity factors over three years were substantially below 30% and less than 20% for approximately 50% of the year.