I NOTE with interest Iain Macwhirter's article on energy ("The rise and rise of the energy production racket", The Herald, February 21).
As a chartered electrical engineer with around 35 years' experience in the energy industry I feel compelled to take issue with the emergence of a new energy unit called, apparently, the "home".
I refer to the often-heard statistic that a new wind farm or renewable energy device will power or provide enough energy for many hundreds or thousands of homes.
The data, promulgated by power companies and repeated by bodies such as the Scottish Parliament, local councils, equipment manufacturers, and countless quangos without challenge are, at best, misleading and, conveniently, support the impression that the energy being generated from renewables is considerably more than the reality.
Most power-generating companies adopt the RenewableUK assessment of average household usage of 4266 kilowatt hours per year when calculating the average number of homes that can be supplied from the output of a new renewables project.
This annual total is equivalent to less than 12 kilowatt hours per day per average home – that is, a one-bar 1kW electric fire operating for less than 12 hours each day, so includes next to nothing for electrical heating.
However, half of the energy consumed in Scotland is in the form of heat, with approximately half of that being consumed in our homes. Ofgem's detailed statistical 2011 assessment for the (median) dual fuel needs of an average UK home is 4000 kilowatt hours per year of electricity plus 16,900 kilowatt hours of gas for heating/cooking . It also calculated typical high usage figures of 5100 kilowatt hours of electricity and 23,000 kilowatt hours of gas depending on the size and location of your home and the calorific value of your supplied gas (the equivalent amount of energy you get from burning the gas).
Scotland is of course at the high end of these figures given our cooler climate.
Domestic gas energy consumption for the typical home is therefore in addition to and between four and six times higher than the household electrical energy usage and much cheaper, at a cost of around one third per kilowatt hour of electricity at standard tariffs.
So the actual total average energy requirements for a UK home is approximately 20000 kilowatt hours per year whether you are all-electric or have both gas and electricity and not 4266 kilowatt hours. So wind farms provide around one-fifth of the actual energy requirements of the number of homes they claim to provide for.
The fallacy of the home claim is further apparent when you consider that in Scotland around one-third of domestic properties are not connected to the national gas network, compared to only one in 10 in the rest of the UK and this means there are more than 800,000 homes in Scotland that have to use electricity (the vast majority) and/or solid fuel or bottled gas for heating and cooking. Ironically, this includes all the island communities and much of the Highlands, where several of the wind farms are located.
It is of little surprise therefore that more than 120,000 Scottish families are officially in fuel poverty.
Almost every major wind farm generates into the nationwide electrical network and is distributed throughout the country, so the power companies' claims that 4266kW hours per year provides enough electricity for a certain number of homes does not apply to at least 800,000 homes in Scotland.
Similarly, all claims that 4266kW hours powers a home are wrong as they do not include the heat energy we require and this applies equally to the rest of the UK.
This is important because the renewable industry also claims it is the future with gas supplies due to run out, by which argument it will then have to supply all the energy presently provided by gas. Then its current misleading claims will be shown to be wrong.
The renewables industry's marketing people can't have it both ways.
All in the industry and the politicians and the quangos need to start playing it straight with the public.
D B Watson,