Tuesday, May 15, 2007

CO2 pollution from nuclear construction is irrelevant

Nuclear power is often cited as part of the solution of a low-carbon future, but detractors sometimes cite the CO2 pollution that would result from the concrete and steel needed for construction as a reason to hold back. While there may be other reasons for holding back, this particular one is spurious.

A way to measure the pollution performance of different energy sources is to divide the amount of CO2 pollution by the energy produced. For fossil fuels, looking at the fuel and not the plant cost (which we assume to be irrelevant), this number is between 300 and 900 g CO2/kWh, depending on whether you use gas, oil or coal, and how efficient your plant is. The CO2 involved with constructing (not operating or decommissioning, mind) is only 1 g CO2/kWh.

The calculation

How much concrete and steel in a nuclear power station? The Nuclear Energy Institute claim (http://www.nei.org/index.asp?catnum=3&catid=1525) 400,000 cubic yards (306,000 cubic meters) of concrete and 60,000 tons (67,000 tonnes) of steel in a 1 GW rated nuclear power station. Let's work out how much CO2 this means, then divide by the energy generated over the productive life of the plant.

Notice our input figures are rough, so we're really only looking at one significant figure accuracy.

CO2 from concrete

How much CO2 is produced when making 520,000 cubic meters of concrete? That depends on the kind of concrete. There are different types and different figures. One way - take the density of concrete (2,300 kg/m^3 from the Physics Factbook), the CO2 to make cement (0.8 kg CO2/kg cement), the cement in concrete (10% from cement.org). This makes a figure of around 100 million kg of CO2 in our nuclear plant.

However, the Danish Technology Institute report (http://www.danishtechnology.dk/) is probably more authoritative. They claim that a cubic meter of concrete requires the production of 100 kg CO2, giving us 50 million kg of CO2 in our nuclear power station.

Comparing the figures, the order of magnitude matches. To be harsh, though, let's take the bigger figure - 100 million kg of CO2 for the concrete in a 1 GW power station.

CO2 from steel

How much CO2 is produced when 67,000 tonnes of steel is made?

Blue Scope Steel (http://csereport2005.bluescopesteel.com/) claim they put out 14.5 million tonnes of CO2 equivalent gasses in 2004/2005 to produce 5.72 million tonnes of steel product, which suggests around 2.5 kg CO2 per kg of steel.

Azom.com materials suggests around 2 tonnes of CO2 per tonne of steel, and Tata Steel claim (http://www.tatasteel.com/webzine/tatatech39/page14.htm) between 1.2 and 1.9 tonnes of CO2 per tonne of steel, depending on the process.

Let's be harsh again and pick 3 tonnes of CO2 for a tonne of steel. So we have another 200,000 tonnes of CO2 from the steel, or 200 million kg of CO2 from the steel to make a 1 GW nuclear power station.

Sum the steel and concrete CO2 figures: 300 million kg of CO2. If we had been conservative, that would have been 100 million kg CO2.

Energy from a 1 GW nuclear power station

If the power station produces power for a conservative 40 years, and runs for a pathetic 60% of the time (thus we're allowing for maintenance periods), the plant will deliver 210,000 million kWh of electricity.

The ratio is nearly zero

The simple ratio is 300,000,000 kg CO2 / 210,000,000,000 kWh - nearly 0.001 kg CO2 / kWh. Irrelevant.

This ignores the pollution from getting the fuel and running the plant. Also remember the CO2 is largely produced up front, which is bad news for quick CO2 reduction, but even building 10 GW of capacity to replace the UK's ageing plants will only produce 3 million tonnes of CO2 during construction - less than 1% of UK CO2 pollution in one year.


David Bradish said...

Nice post. If you want to look at quite a few studies which look at nuclear's entire life cycle emissions check out this link.

It's amazing how the anti nuke folks have come up with a way to say that nuclear power contributes to climate change. Even being overly conservative in your assumptions gives you numbers that are like you said 'irrelevant.'

moliver said...

Greens heve infinite audacity. Compare material of nuke plants verswus solar plants per kwh f electric ENERGY, WHICH IS WHAT COUNTS, NOT JUST POWER WHICH IS MERELY THE RATE OF USING OR CONSUMING ENERGY, over a 60 year -0-0 thelifetime of both plants: about 200 times more concrete, steel, copper and other material is needed for solar than for nukes.
- the longest time of even the best solar units. Most,like Solar 1 and2 are already gone with the wind. . Ther capacity factors is 4 to 5 times less for solar than for nuke plants, even in the sunniest desert places. Which means that for each installed watt of nuke plant you need to install 4 to 5 watts of soalr to get the same amoujnt of electric ENERGY out of if even if the solar unit were installed in the Sahara desert. This is a proven fact that vcanjnot be denmied with all the hoopla dished out by green fascists. The seldom complain agaisnt the nuke plants being buit in China from US and FRench technology, or the nuke plant in the Republic of South AFrica, but surely hate it for the West!

Even Israel, with all its sunshine is using solar to provide 80% of its hot water, but to less than 1% fo electricity. Its own greens hate nuke plants for electricity whicvh is why it only now is planning to build a nuke power
plant.Try to discredit this , you phnoy creeps!
Try to prove that even oneperson was harmed by the TMI accident,and don't compare the YMI plant with Chernobyl. The Soviet oplants was build by Laurel and Hardy!

moliver said...

I was angry as hell, so I fired off my previous message without checking for spelling errors. So I repeat it:

Greens have infinite audacity. Compare material used for nuke plants versus solar plants per kwh of electric ENERGY, which is what counts, not just power, which is the RATE of using and consuming energy. Consider this over a lifetime of 40 years of both nuke plants and solar plants. You need at least 200 times more concrete, steel, copper and other material for the solar units than for nukes.

Most solar untis do not even last that long, while nuke plants do. Solar 1 and 2 are already gone with the wind. The Solar Electric Generating Systems (SEGS) in California's sunny desert use gas to supplement their solar parts, and like Solar 1 and 2, their solar parts have capacity factors of less than 20%, while their gas parts are available to produce electricity about 70 to 80% of the time. Meanwhile, nuke plants have capacity factors of 90%.

This means that to get the same amount of electric ENERGY,

Despite the pressure of its own greens, even Israel, with all its sunshine, is using solar to heat water to an extent of 80%, but to less than 1% to produce electricity. Not that its own greens are giving up! Israel continues to do the same thing over and over again, and is trying once more to go for solar electricity to some extent. Yet while its greens have blocked construction of nuke power plants in the past, it is now planning to build one of them -- at last.

Greens complain when the West builds nuke plants, but seldom do it if this is done in China, or the Republic of South Africa and will soon be done in Vietnam and oil rich Namibia.

Environmentalism was launched with good intention but, as happened to other initally good movementsm, has been captured by green fascists who hate freedom for everyone but themselves. They use environmentalism to destroy freedom for the masses. Look at the Holywood moguls , at Kennedy, at Kerry at Gore and at John Travolta (or is it John Revolting?) for proof of this. They are a bunch of phony creeps who consume 10 to 20 times more energy per person than do the rest of us and get it from oil, gas, and nuke units, and hardly from solar plants, or chicken droppings, or even windmills, to any significant extent!

Anonymous said...

Hi Tim:

Enjoyed your analysis. Here is some more supporting informatio which may be of interest.


andrew said...

400,000 cubic yards (520,000 cubic meters)

...not sure if it's worth leaving a comment on a blog post that's over a year old, but you got the metric/imperial conversion the wrong way around. 400,000 yd^3 is more like 306,000 m^3 (1 yard = 0.9144m)

Jason Ribeiro said...

Hi Tim,
This is an interesting analysis! I came across your site while searching for data about steel wind towers somehow.

According to this site:

80 Metric Tonnes of steel are used for a tower to supply a 2MW turbine. If you could build 500 of those that ran @ 100% capacity, using the 2.5 kg per kg of steel figure, would be 100 million tonnes of CO2 just for the towers, but since these run at an avg. 25% capacity, 4x the amount would be required for 1GW so 400 million tonnes of CO2--just for the towers!

The service roads, underground cabling and so on leave an environmental footprint as well.

Byggestyring said...

WOW, what a very interesting article. Thank you for sharing this very informative article.

Luigi said...

It's amazing how the anti nuke folks have come up with a way to say that nuclear power contributes to climate change.

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viagra online said...

In my opinion, anything related with pollution can be irrelevant, because the lives of too many people are in danger, including you and I.

Kevin "The Dark Ranger" Poe said...

Nuclear power is not as dangerous as coal/oil/gas industry and a few loud mouth and not-seeing-the-big-picture enviromentalist would like others to believe. BUT nuclear power will only last about 1000 years based on the planet's supply of obtainable uranium. So unless generation 4 reactor research gets funded again (again thank you fossil fuel and enviros)the only long term strategy 100 million plus years until sun becomes so hot planet is unlivable is wind, hydro, and solar. And though nuke accidents are rare wind & solar are completely unheard of.

What is pollution said...

Thanks for the post. Nuclear waste is of the deadliest matters on earth, and it's hightime we realised that nature will not withstand our waste much longer.

Concrete Cutting Equipment said...

It's amazing how the anti nuke folks have come up with a way to say that nuclear power contributes to climate change..

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