Bishop Hill The BBC and the great levelised costs lie
Apr 8, 2013 BBC Energy: wind When watching Matt Briggs' lecture on the use and misuse of statistics by climatologists and social scientists, I was struck by his summary of the problems with the use of p-values, namely the view within the field that since everybody uses them, it doesn't matter that doing so is silly.
The reason I noticed Briggs' point was that it reminded me of an exchange I'd had with a BBC journalist about the use of levelised costs by advocates for windfarms. I had explained how misleading levelised costs are, a point that elicited the following response:
...this is the current standard measure - used by governments, industry, academics and international bodies. Any such measure, by its nature, will have limitations.
It doesn't matter that it's misleading. Everybody is being misleading.
Reader Comments (54)
BB - what are your long and short lists of sites along with prospective capacities?
Capell, wouldn't you find some already-built lakes rather than digging them? Scotland is peppered with lochs and I imagine there must be some suitable spots, at least augmenting existing hydro plants. There's an interesting, perhaps crazy, recent proposal to use Loch Morar to provide 1800GWhr of storage.
Loch Morar scheme: this was the subject of a D.Phil thesis
http://theenergycollective.com/julian-hunt/199896/energy-storage-solution-uk-large-scale-pumped-storage-site
Here's a resume:
"It turns out that the lower reservoir of a pumped-storage site can be a drained lake and the drained water can be used to increase the height of a new upper reservoir. [Nothing new there, all of the UK's pumped storage schemes are exactly that type]. This is the case of Loch Morar, the deepest loch in the UK with a depth of 310 metres. If a 280 metres high and 1.8 km long dam is built on the surrounding highlands, an upper reservoir with a water level of 300 metres above sea level can be created. As the water is drained from Loch Morar its altitude could reach as low as -300 metres. This results in a height difference of 600 metres between the two reservoirs".
His numbers are slightly wrong. Loch Morar has a surface area of 26.7 sq km ), an average depth of 87 metres and a stored volume of 2.3 km^3 (26 times the area, 230 times the volume of Dinorwig). Building a dam 280 m high thus gives a mean operating head of 180 m, one third that of Dinorwig. (That's not the highest dam in the world, but has anyone ever built a dam of that height and length?). The upper lake area would have to be 10 sq km. Potentially 75 Dinorwigs. Another couple of those and you're there. But I don't think there's a cat-in-hell's chance of building that for anywhere near £12b. And you've just trashed about 40 sq km of Scotland's landscape, and there'll be a requirement for a new, long transmission line to the site.
If you want more of this idiocy, MacKay does it rather well:
http://www.withouthotair.com/c26/page_192.shtml
Of course, there's another huge snag to this. We start with our windmills having an effective capacity factor of 24 %. The storage efficiency of pumped storage is typically 75 %. (It might be lower for Loch Morar as the head's lower). So your windmills now have an effective capacity factor of 18 %. Throw in Gordon Hughes' analysis of the reliability of windmills which effectively halves their lifetime capacity factor and we'll be down to 9 %. Not exactly stunning are they?
Sorry for restarting this painful discussion, but as the author of the article about the solution for energy storage in the UK. I would like to point out 3 things.
1) Onshore wind power alone with large scale pumped storage is already cheaper than nuclear.
Considering we want to generate reliably 120 GW for the UK in 2050 (electrifying the heating and transport sectors) and one quarter of this energy (30 GW) would come from Nuclear or Wind Power.
As 1 GW of Nuclear costs £ 10 B (including decommission costs and radioactive waste storage), it would cost £ 300 B for 30 GW of Nuclear.
In order to provide reliable 30 GW from wind power, it will be required 25 GW of pumped storage for a cost of £ 25 B (Loch Morar project) and the other 5 GW left would be guaranteed from the 200 GW of wind installed. The capacity factor of wind power in the UK is around 18% (including Gordon Hughes factor) and assuming that 50% of the energy will have to be stored with an overall efficiency of 75%. If all the energy produced was consumed it would require 30/(0.18* (0.5+0.5*0.75)) = 190 GW, however at maximum generation around 45 GW will still have been wasted so this capacity (190 GW) should be multiplied by 5%, which results on 200 GW of wind power. As Wind turbine costs £ 1 B per GW, 200 GW will cost £ 200 B. The final cost assuming £ 25 B for transmission would result in £ 250 B.
2) Regarding the Loch Morar Project, The reservoirs at full capacity will have the upper reservoir at 300 meters and the lower at -300 meters (600 meters difference). With no energy stored in the site the upper reservoir will have 170 meters and the lower reservoir (Loch Morar) will have 9 meters (161 meters difference). The average height difference of the site is 310 meters and not 180 meters.
3) The Loch Morar site is a feasible site that can store the most energy in the UK, but it is the one with the highest capital cost and environmental impact out of the other sites that I have found. Scotland has enough sites to store 60 GW of energy for a week feasibly. But that would involve completely draining Loch Morar or partially draining other Lochs...
It might be idiotic to do this now. But it might not be so idiotic when the price of offshore wind and solar power become competitive, which will probably happen in the next 5 years, and ocean energy in the next 15 years.