fivemack | (no subject)

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A Greenpeace article

http://www.greenpeace.org.uk/blog/climate/greenpeace-shuts-down-coal-fired-power-station-20071008

includes the line 'And it will only be 45 per cent efficient, in an age when power stations can reach 95 per cent efficiency'.

This is a coal-fired power station, so 45% efficiency in converting thermal to electrical energy is I think extremely good.

95% thermal efficiency implies, by the Carnot equation, that the heater is twenty times hotter in Kelvin than the heatsink and that there are no other thermal losses in the system. With a heatsink laid on an infinite icefield at zero centigrade, the heater has only to be hot enough to boil tungsten. I was unaware that gas-cored fission reactors were either in production, or this enthusiastically endorsed by Greenpeace.

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They are arguing for what they call combined heat and power; re-using the waste heat of power stations. This is indeed very efficient, though perhaps not the best solution. Their objections to coal-fired plants are valid. And, you know, they're doing something. Perhaps not the best thing. But the people who could do the best thing aren't doing any damn thing. So why the objection?

My main objection is that trying to get a power station to drop off the grid is a very fundamental assault against the public good - if the people doing this were Muslim students from Birmingham rather than professional demonstrators from Greenpeace, they might well have been shot by now - and not something that should be done to make a minor and unrealistic point. There's a line somewhere between trying to stop whaling and nuclear-bomb tests, which are activities mostly without obvious positive consequences, and attacking the infrastructure that keeps us from starving, shivering in the dark.

Another annoyance is that the article fails to mention the trade-offs: the comments point out that they haven't found an application in Gillingham for two gigawatts of heat, and suggest that the power-station be scaled down to something that generates only the amount of heat usable in Gillingham. But the electricity demand is fairly fixed, so if you're building tiny power stations you do need to build lots of them, and you therefore need either to transport huge amounts of coal densely within the country, or to run everything on conveniently-piped natural gas and trust to the enlightened benevolence of Vladimir Putin and Dimitri Medvedev. The consequences of their arguments are either 'build a large oil refinery in Gillingham' or 'we ought to be building twenty times as many power stations as we do', and I feel they ought to mention those consequences.

I'm pleased to see that somebody has got planning permission for a square kilometre of CHP-heated greenhouses in Thanet (google 'thanet earth') - they're what I think of when I hear food-miles arguments. Though I can't find the electrical power output of the CHP mentioned anywhere; if you're going to build a facility to convert natural gas into cucumbers, you might as well generate electricity as well, but I'd like to know what proportion of the cash flow comes from kilowatt-hours and what proportion from cucumbers.

There is an interesting advertising exercise in promoting the pineapples from a potential giant greenhouse built at Hunterston to use the heat from the waste water of Hunterston B; to convert plutonium to xenon and strontium and thereby to grow pineapples in Ayrshire in the depths of winter is a great and useful miracle, but to convince people to buy the pineapples might require a greater one.

But it's not a minor point; Greenpeace is quite right that the construction of new coal-fired plants is a very wrong-headed thing. I, too question their solution to energy problems, but surely the sensible thing to do is to work on better solutions, rather than protesting the protests; if you side with Gordon Brown, you will get nowhere. As for shooting protesters, be glad that your government at least is still somewhat responsive and in check; in the USA, these people might have already been killed.

There is an interesting advertising exercise in promoting the pineapples from a potential giant greenhouse built at Hunterston to use the heat from the waste water of Hunterston B

Did you choose that station purely at random from among the nukes or did you deliberately pick one whose two reactors tripped (http://www.bmreports.com/servlet/com.logica.neta.bwp_PanBmData) on Wednesday (this is public data; search for BM units T_HUNB-7 and T_HUNB-8 for settlement days 2007-10-04 to 2007-10-08, period *) and have not yet returned to generation? (Also... (http://news.independent.co.uk/business/news/article2091904.ece))

I also note RWE's planned coal-fired station at Blyth (http://www.rwe.com/generator.aspx/presse/language=en/id=76864?pmid=4001632), with coal coming into the Tyne and up a disused-but-repairable railway track. I don't think that quite makes Northumberland the equivalent of Siberia, but it's still fun to compare. Some people reckon that EU emissions allowances need to be floating around the €30-40 mark before serious investment into clean coal becomes profitable, and Phase 2 has been more or less rangebound (to within +/- 5% or so) over the last month, as previously discussed. At least one major European financial player has suggested there's a lot of upside potential on the contract, though.

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