Thursday, July 23, 2009

Renewables supporters twisting the facts

Die Zeit has published an article critical of the nuclear power sector in France, and it contained the following contention:

"Dass beim Abbau und der Aufbereitung des Kernbrennstoffs Uran mehr Kohlendioxid pro Kilowattstunde Strom anfallen kann als etwa in einem modernen Gas-Blockheizkraftwerk, wird in den CO₂-Bilanzen der Atomlobby verschwiegen."

(The nuclear lobby fails to mention that more carbon dioxide can be emitted per kilowatt-hour of nuclear power than in a modern combined cycle gas turbine once the emissions from the mining and processing of uranium are calculated in.)

Because that figure is much different than what I am used to seeing, I contacted the author to see if she would provide me with her source. She responded by saying that the figures are not new, and she has them from Mycle Scheider, among others.

I looked up Schneider online, and immediately found something more in line with what I am used to seeing:
"The Darmstadt-based ├ľko- Institut, a think tank, has calculated that a typical nuclear plant in Germany, with enriched uranium from a mix of supplier countries, emits 32 grams of carbon dioxide per kilowatt hour"
You can view a chart at that website that is in line with what I am used to seeing; clearly, once the provisioning of uranium is calculated in, carbon emissions from nuclear power are a fraction of emissions from cogeneration gas turbines (meaning that the waste heat from the gas turbine is piped to consumers nearby rather than sent up the chimney) and are more in line with emissions from renewables (while wind turbines and solar power also do not entail any direct emissions, the manufacture of such systems does).

I kept looking, and then discovered where the figures come from:
"the report concludes that unit CO2 emissions from nuclear power plants are approximately the same as those from natural gas cogeneration systems... The comparison, however, is made between a natural gas cogeneration system and a system which supplies electricity through nuclear generation and heat by oil."
In other words, since nuclear power generally does not provide heat (though it certainly does in France, where electric heating systems in many homes switch on at night to create demand so that nuclear power plants can keep running at high capacity), Schneider then added in the emissions from oil heating.

This is quite a pernicious argument, and proponents of renewables must be careful not to use it lest it be turned against them. After all, like nuclear, wind and photovoltaics also mainly produce electricity, not heat, so anyone could then make the same calculation and discover that renewables have the same emissions as a modern cogen gas turbine.

I reported this to the author, but she merely responded by saying that "I sent the figures by Schneider, and he approved the wording before publication" -- as though nonsense became legitimate if you get the source's approval.

I support renewables, but I don't support nonsense. If we want to have renewables, we have to have good reasons, and we cannot twist the facts to serve our ideology.

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