Relative costs of generation

From Energy-Experts

Cost of Electricity in the UK in 2020 pence/kWh

On Land wind 1.5 - 2.5

Offshore wind 2 - 3

Energy crops 2.5- 4

Wave and tidal power 3 - 6

PV Solar 10 - 16

Gas CCGT 2 - 2.3

Large CHP/cogeneration under 2p

Micro CHP 2.3 - 3.5

Coal (IGCC) 3 – 3.5

Nuclear 3 - 4

Source: Performance and Innovation Unit,‘The Energy Review’ UK Cabinet Office,2002 I am very comfortable with Dave Eliott’s comments. If only the government believed those cost figures! I make two points:

1. It is not renewables, as such, that needs storage, but ambient generation. That is generation without inherent storage, such as wind, wave, tidal flow, run of river hydro, over which we have no control (except, I suppose, in the Gaian sense of anthropogenic climate change). Biomass generation, from (say) coppiced wood, is renewable, but the coppiced wood is storable, and we can control it conversion to electricity. Dammed hydro is renewable, but is itself storage. By building in storage (hot salts), CSP seems able to achieve larger load factors (and so greater capital efficiency).

2. Storage is transport through time, so by changing the timing of demand (and a lot of our demand can be made reasonably flexible), we achieve the precise equivalent of storage. Its only difference from conventional storage is that there are no losses. As soon as we have conversion, we have losses, into and out of the storage medium. I understand lithium ion batteries to achieve round trip losses of only about 5%, but all large scale electricity storage schemes (including pumped storage) lose around 20% plus in the round trip.

So long as we build no more coal plant, I would think it feasible to displace all high emitting plant with about 25 years – I would hope less. Some will be gas, I hope with Heat Distribution. It will take longer to get enough renewables to feed the transport fleet, but my car has average storage of perhaps 250kWh – many days of normal domestic consumption – so provides a huge storage buffer, potentially for free. So I would guess there is enough storage in the system without building more. Regards

David Hirst