Theoretical numbers
Bob Spanswick’s letter “Interesting numbers” does raise some interesting theoretical numbers, in particular his fifth point. “11,200: The litres of fuel sustainably saved on average every day of the year by one 3.6MW turbine operating at 50 per cent.”
Interesting because this is very close to what Burradale produces – 3.68MW plated capacity operating at 52 per cent.
With that in mind I would like to point him back to my letter in The Shetland News (“How much CO2 has really been saved?”, 31st July) and again invite Shetland Aerogenerators, Scottish & Southern Energy and now Mr Spanswick to demonstrate these offsets are genuinely being made.
Looking at Shetland Aerogenerators’ figures for 2009 the firm claims to have displaced 7,052 tonnes of carbon dioxide or 9,955 tonnes if you use a fossil fuel mix, which it could do in the isolated context of the Shetland grid.
By Mr Spanswick’s reckoning Scottish & Southern Energy should have saved c.4,088,000 litres fuel equivalent between the Lerwick power station and Sullom Voe power station in 2009. These figures should be quantifiable.
Billy Fox
Chairman,
Sustainable Shetland
Brennek,
Quarff.
Colin Hunter
It’s really quite a simple sum to do if you can be bothered. The specific fuel consumption of an engine is measured in Grammes per Kilowatt per hour (Or lb/shp/hr in imperial) and, seeing as a Kilowatt hour is one “unit” of electricity, if you know the amount of units produced in the last year to the grid by Burradale, the power station and the SVT power station and the amount of fuel burnt by each to achieve these outputs. Simply divide the power stations KWh by the fuel consumed and multiply the result by the KWh produced by Burradale. It is defintely quantifiable if you can source the relevant information.