“Dear Aunty, is it true what Gail says – that we can meet all our needs with just renewables?”
It’s certainly true that more and renewable energy generating capacity is being added to the network every year, dears, but I’m afraid the notion that we can somehow power the UK just with renewables is somewhat fanciful right now.
Mrs Hodson, a Labour councillor in West Lancashire, along with her husband (also a councillor) has become an ardent opponent of shale gas fracking in the last few years and, recently, I’ve seen her take to Twitter to extol the virtues of “clean”, renewable energy.
Quite frankly, poppets, I think she is really just another NIMBY – opposed to fracking because there’s a chance it may happen near where she lives – and that her current fascination with renewable energy is just a green smokescreen used to mask her true motives.
During a Twitter exchange a few days ago, I pointed out to Mrs Hodson how it would take 80-90 years to reach a stage where renewables could meet all of our electricity needs. She argued that I was wrong.
As loyal readers will know, Aunty is rarely wrong, but I don’t mind admitting that on this occasion, I did make a mistake cherubs.
You see, it would actually take 135 years at the average rate of renewables deployment seen since 2010. Assuming, of course, that it is even possible.
Mind the (capacity) gap
According to statistics compiled by the Department of Energy and Climate Change (DECC), at the end of 2013, the UK had a total electricity generating plant capacity of 84,990 MW, of which 13,320 MW is sourced from renewables. The remainder – a gap to fill of 71,670 MW – is supplied by coal, gas, oil and nuclear.
Since 2010, renewables deployment has averaged 3,474 MW a year sweeties. If this were to continue at this rate, it would take just 20 years to add an additional 71,670 MW of generating capacity onto the network.
But that’s just capacity, not actual output.
You need to adjust for efficiencies and capacity factors to take account of the times when the sun isn’t shining or the wind isn’t blowing, for instance.
Assuming an average capacity factor of 30%, that means that to get the output we need dears, we’d need installed capacity of 235,567 MW. At the current annual average, that would take 68 years to achieve.
But that’s unlikely.
Some renewables will shrink whilst others grow
According to those same DECC statistics, a lot of our renewable energy capacity is provided by engines that burn gas from old landfill sites, but as recycling levels continue to grow and organic waste is diverted from landfill, that resource will gradually shrink. Right now, the organic wastes, like food and farm waste, are being converted into biogas using anaerobic digestion facilities, pumpkins, but according to National Grid, even if all such waste could be turned into biogas, it still wouldn’t be sufficient. And we’re unlikely to build any new large-scale hydroelectric dams because of the unacceptable environmental impacts they create during construction.
So, most renewables growth will have to come from solar and wind. But as I’ve pointed out already, my loves, these are by nature intermittent.
Demand isn’t static
Right now, over 80% of UK homes are heated with natural gas. That’s about 19 million properties.
With the exception of anaerobic digestion, most renewables only generate electricity and not gas, and so to do away with gas, we’d need to switch all those properties to all-electric space heating instead.
What effect would that have, poppets?
Well, it depends how you achieve it. You could use air source or ground source heat pumps, but these installations are very expensive, starting at £7,000 for air (£133 billion to retrofit in 19 million homes) and £11,000 for ground source systems (that’s £209 billion).
A more palatable installation cost would see electric night storage heaters used instead, which might cost under £5,000 per installation dears.
Either way, demand for electricity would soar, to potentially more than double the current levels and capacity would have to double to match it – growing to 471,135 MW.
At current rates of renewables growth, that would take 135 years to accomplish.
We’d run out of fields and rooftops first
Before we’d get anywhere close to deploying enough solar or wind power, cherubs, we’d run out of land and rooftops.
Gail suggested I was being silly to say this, but I suspect that’s because she hasn’t yet read David McKay’s excellent free book, Sustainable Energy Without the Hot Air.
Perhaps when she has a better grasp of the physics, the limiting factors and the costs of renewables, she’ll reach the same conclusion as the rest of us that actually understand this topic in detail:
A future powered entirely be renewables just isn’t feasible.
And, in actual fact, it’s not even a sensible aim. The UK needs, and will continue to need, a mixture of energy sources all working in concert together. Our most pressing priority is to limit coal-fired electricity generation and then phase this out in order to drastically cut CO2 and particulate emissions, improving both climate and local health outcomes. To eradicate coal, we will need nuclear, natural gas and renewables together. Anything else just isn’t workable.
Until next time, dears xxx