Emisisons & Cost
Ah another 'Analysis' from Lewis. Some crude back of the envelope calculations:
Greenhouse gas emissions from desalination are by no means trivial. Assuming that the 7kWh per tonne figure is correct then this equates to greenhouse gas emissions of 3.4kgCO2 per tonne (based on 0.48644kgCO2e/kWh). Current ghg intensity of water supply in the UK is 0.34kgCO2e per tonne so we're talking about supplying water with 10 times the GHG emissions as is done currently.
http://archive.defra.gov.uk/environment/business/reporting/pdf/110819-guidelines-ghg-conversion-factors.pdf for the factors
And people who hate on renewables (i.e. The Register) are always telling us how having backup plant is wasteful and expensive. But here Lewis is proposing constructing a load of desalination plants for the occasional drought. What is the cost of keeping this plant operating under capacity?
They're also telling us how renewables are putting intolerable burdens on our energy bills but here Lewis is suggesting adding £22 of OPEX (being kind and ignoring the suggestions in comments above that this is an underestimate) and £25 of CAPEX (assuming it's paid off over 20 years and I can't be bothered to calculate the NPV) per *person*.
That's an increase in water bills of over £100 per household per year which represents an increase of nearly 30% in the average water and sewage bill (£350). But that's the cost of water AND sewage so the cost of the water component of your bill would likely increase by well over 50%.
What a great suggestion this is!
