Tuesday, January 30, 2007

How to Replace One Cubic Mile of Oil

From IEEE Spectrum:

The fact that energy sources and uses are stated in so many different kinds of terms is increasingly seen as not merely an annoyance but as a serious impediment to public understanding of critical choices. In an effort to get matters onto a more intuitive, citizen-friendly basis, a number of experts have hit on the convenient fact that the world at present consumes about 1 cubic mile of oil (CMO) per year. Among these experts are Ed Kinderman and Hewitt Crane at SRI International, in Menlo Park, Calif., who are preparing a book for Oxford University Press that will be built around the idea of normalizing all energy units to 1 CMO (4.17 cubic kilometers).

One dramatic way of portraying their results is to ask how many alternative energy sources—say coal-fired plants or solar panels— it would take to produce the equivalent of one CMO.
And here's what they came up with:

Thanks to Colby Cosh for the pointer.

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KenG said...

Interesting, but I think it contains a basic error. The solar panel quantity seems adjusted for capacity factor but the wind turbine number is not. The 32,850 wind turbines is about 54 gigawatts capacity, the same as the coal or nuclear plants but the solar is about 191 GW capacity, indicating about a 25% capacity factor for the solar panels (reasonable). Similarly adjusted, the wind turbine quantity should be about 100,000.

David Bradish said...

Instead of saying power plants, they should be showing how much fuel from each. A nuclear plant only needs about 30-40 tons of uranium that last 18-24 months in the plant. A 1000 MW coal plant needs about 3-4 million tons of coal each year. Multiply that with 100 coal plants at 50 years and we're talking billions of tons of coal versus thousands of tons of uranium. Check out the middle of the page of this link.

Joffan said...

I saw the same error as keng, although I'd put the number of 1.65MW turbines at about 130,000. The other curiosity is that the coal plants have no capacity factor (ie. 100%) but the nukes do (90%). What's the reality on this one?

Also the basic logic of the comparison is odd... how can you replace one year's worth of oil with energy spread over 50 years?

These points aside though, I'm glad someone is trying to make a simple comparison between energy sources.

KenG said...


I think the 50 year factor was meant to reflect that if you built the various technology installations, they would operate for 50 years while the "CMO" just lasts one year. However, it does seem to confuse the issue. A wind turbine, PV cell, or dam (if it would last 50 years) would require no additional fuel, whereas the nuclear plant needs a small amount of fuel each year and the coal plant needs huge amounts of fuel. In fact this raises a whole different question: How many cubic miles of coal does it take to equal a cubic mile of oil?

Initially, this looks like a simplification but the more I look at it, the less value it seems to have.

Ira said...

I think the 50 years aspect of this concept is slightly confusing, however I think it is trying to capture the idea that the time to develop the project is limited. According to the CMO article on wiki, we have ~43 proven Cubic miles of oil. If you started working on the replacement you'd have ~50 years to complete it assuming that some of its capacity would come online before 50 years was up. For example, if you wanted to only solve the problem with solar cells you'd have to install 1.8million household rooftop solar installations per year for 50 years to end up with enough power to replace 1 CMO per year at the end of 50 years.

It seems likely to me that you could more easily try and complete parts of each solution. Make some dams, and some solar cells, and some wind, etc. It seems like wind power has the closest cost to oil according to the wiki article.