The old power-station retention concept does require a lot of maintenance work to keep them open.
Long start up times are also an issue particularly if the turbine and the whole of the steam system is cold.
In comparison the engine based local CHP option can operate happily with minimal maintenance and with remote unmanned start up and operation.
The benefits from wind are clear they replace fossil fuel but are not effective as replacement capacity unless linked to a sufficiently large area of the world to ensure some wind all the time.
Their capital cost and CO2 footprint can not be considered zero when one considers the embedded CO2 in their construction and the infrastructure of cables to support them.
Whilst a world wide DC Link concept is excellent it is vulnerable technically and politically.
How do other options compare to the CHP at every local transformer option as back up?
The CHP at every local transformer has the benefit of backing up wind as well as working with wind to reduce gas consumption in the UK. Once a city wide heat network is developed then biomass, nuclear or coal fired plants can act as a back up for wind. They do this be operating in pass out mode to supply heat when thier electrical efficiency drops to act as heat pumps when the wind is blowing and when it stops blowing they stop producing heat and produce more electricity. The heat can be readily stored and to provide back up for heat from a boiler is cheap compared to back up for electricity.
Trusts this assists in Claverton moving gently towards a consensus possibly coming out in of a piped heat supply concept and city wide CHP as the way ahead with wind.
Way back I remembering suggesting that Arthur Scargill was a blue under the bed as he managed to assist Mrs Thatcher (a blue) and managed to destroy the coal industry and encourage the Nuclear industry in the days when we were giving evidence to the Sizewell enquiry to explain that Coal fired CHP for London was the cleanest way to use coal and was more economic than Nuclear because we used the waste heat! Using the waste heat cleaned up the heat sector.
I sometimes wonder whether Greenpeace are Nuclear enthusiasts under the bed, by opposing the use of Coal in the way that they are doing without considering the CHP option to clean up coal to make it no more polluting overall than the current use of gas.
W R H Orchard MA(Oxon) MBA CEng FIMechE MCIBSE MIET FEI
Orchard Partners London Ltd
2 Dunmore Road
London SW20 8TN.
Tel +44(0) 020-8296-8745 Fax +44(0) 020-8947-5496
From: Chris Hodrien
Sent: 14 November 2008 13:22
Dave, I’m glad that you’ve been listening to the various discussions and now state that: “The value of wind is that it displaces fossil fuels, not that it displaces capacity.”(-my highlight). The basic problem is that the majority of the “pro-wind” lobby out there do not share your honesty and admit this basic fact – i.e. they simply ignore the backup capacity cost factor when doing cost comparisons.
Of course the main value of wind is in the fuel (and CO2) saved at fossil stations. “The issue” is how much extra the capacity backup is going to cost. (Per one of my previous EM), Graham Sinden’s C Trust analysis for a 40 GW (rated) WT fleet presented at conf. implied (by my calc’s) a penalty of 18% relative to these savings. I’d say that was a pretty spectacular “adjustment”. This implies an 18% longer payback period (prob’ more like 25-30% with compounded interest)
To give you one concrete example of the efficiency penalty (wasted fuel) involved in “stop-start” operation of exactly the type that would be required for WT back-up: – this data is for the old 1954 Barking coal-steam turbine power station (which was replaced by the present gas CCGT in the 1990s). For both the dates below it had been converted to oil firing, which reduces the stop-start losses, i.e. a coal station would have performed relatively worse. This is the average annual consumption figure, i.e. averaging all the stop-starts’ wasted fuel into the number of kWh actually sent to grid. It’s not a pretty sight.1965 (11 years old) – average efficiency 27.8% – by 1980 (26 years old) as the annual running hours decreased, efficiency dropped to 17.9% (i.e a 36% drop). Closed and replaced by CCGT c.1990 (36 years old).
Subject: RE: Turkey cogen presentaion – more info on UK CHP
Can I pontificate, that this discussion on the fact that sometimes there is no wind, is largely missing the point. As Graham Sinden emphasised many times, the value of wind, is five times the value of any calculated capacity credit.
The value of wind is that it displaces fossil fuels, not that it displaces capacity
And, as I have repeatedly pointed out, when there is no wind, for which there will be ample warning, you simply start up the already existing power stations, that have been maintained in a state of readiness.
This state of readiness is already the case for the majority of the stations used to come on line over winter compared to summer so nothing new there.
From: Fred Starr
Sent: 07 November 2008 05:13
To: Chris Hodrien; denis stephens; dave.andrews
Cc: Paul-Frederik Bach
You need to get your mind set away from the present situation and consider how much money might be made supplying power when wind and solar renewables are having a bad day.
This is the trouble about the energy situation.Everyone talks about the future, but the way they see things is as the power system operates now.
Back in 2005 the National Grid were paying Fawley the equivalent of ten thousand pounds per MWh to put some diesels on line. The average power price for a few days was £700 per MWh, when the average price was in the 20-30 range.