Across the great divide

Over the past week I heard most of a radio discussion where the participants thought sustainability was a good idea and a blog post suggesting that most of the UK’s electricity could come from wind and solar resources.  Against this we have two political parties who are actively hostile to wind farms.  I would suggest that for many people don’t perceive that there are benefits to sustainable energy sources and more to the point, see them as increasing energy bills.  This should not be lightly dismissed, the wind and sun are free to all, so why is this stuff expensive.

Some caveats before going further.  First, fossil/nuclear sources will play a role in the energy economy of developed countries for the foreseeable future, most likely supplying the base load of urban infrastructure e.g. transport, schools, hospitals etc.  However, by the use of storage and renewables it may be possible to reduce the amount of capacity and to operate it more efficiently.

Secondly, in my opinion, a triage approach should be adopted to the energy economy.  Some older buildings might require so many resources to raise them to a modern standard, those resources might better be applied to new-builds (my house might come in that category).  Some buildings might respond to moderate expenditure such as loft insulation, heating controls and things which recover their expenditure.  Prioritise “quick wins” (a.k.a. low hanging fruit).   Four LED lamps have worked for us and taken £60 of the electricity bill.  Is it better to have 100 homes with a few LEDs saving 5,000 kwh/year than one home producing 2,500 kwh/year from rooftop PV?  This could be expanded to provide a framework for a debate.

Thirdly, its easier to get a result when starting from scratch.  I have not worked this scheme through in detail, but there may be some balance in the numbers.  Project economics can always  be performed in a way that gives the required outcome, so that might not be convincing or a good use of time.

Lastly, whilst micro generation can work in some situations, the economics of wind and solar are more attractive at the utility scale.  I am fortunate in having a small section of south facing roof, my neighbour’s is orientated towards the north and we are both in the wind shadow as the result of living on the western side of an urban valley.

The average annual household electricity bill is approximately £500.  Using a 5% discount rate and the typical mortgage term of 25 years, this represents a Net Present Value of roughly £10,000.

A few minutes scanning Wikipedia suggests that onshore wind generating capacity is in the range £1m – £2m per MW or nameplate capacity and that 1 MW of generating capacity can supply 500 homes.  This suggests the cost of utility scale wind generating capacity is in the range £2,000 – £4,000 per home.

Skipping over some more boring calculations, within the £10,000 there is room to accommodate the purchase of some capacity at a solar park and some storage.  It is an interesting concept to bundle up £5,000 – £10,000 in the purchase price of a new-build house to fund the construction of wind and solar capacity.  The grid provides a transport mechanism from utility scale projects to individual households.  During the life of the house electricity bill consist of depreciation (cost of replacement) and operating cost (repairs and insurance etc.) which hopefully are a lot less than £500/year.

More thought and sums needed.

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About SolarBucket

I trained as a mechanical engineer in the 1970's and then spent most of the following 25 years doing sums and software for Oil and Gas Exploration. Current interests are the study of wind and solar resources.
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