Pipe dreams

Technology Review: Carbon Capture Remains Elusive

Technology Review usually seems a wildly optimistic magazine, so when it has an article expressing doubts about CO2 sequestration, we should take note. Here are some reasons why government plans to rely heavily on this technology should be taken with a bucket of salt:

One of the geological challenges faced by Duke Energy and others investigating in CCS is ensuring that the pressure inside reservoirs deep beneath the surface of the earth doesn't climb too high as carbon dioxide is injected. "There are only certain safe levels that you can raise the pressure to before you get into issues of seismicity," Herzog says....

As I suspected, finding the right places to pump it in is the biggest problem, even in geologically diverse North America:

...one of the biggest remaining questions is whether sufficient reservoirs exist to store all of the carbon dioxide that may be captured.

The best-studied storage deposits are former oil and gas reservoirs capped by layers of nonporous rock that kept the petrochemicals locked deep underground for millions of years. Yet of an estimated 3,947 gigatonnes of carbon dioxide storage capacity under the U.S., only 1 percent consists of depleted natural gas and oil reservoirs. The vast majority of capacity--3,630 gigatonnes--consists of deep saline formations that have received less scrutiny.

"We're at the place where there is no problem doing millions of tonnes a year, but to solve the climate problem we need to do billons of tonnes or gigatonnes a year, and at that scale, storage becomes a real issue," Herzog says.

The Greens Senator Christine Milne was on Radio National this morning complaining that the Rudd government's plan relies almost exclusively on CO2 sequestration coming on line in (I think) 2030, and it providing the actual reduction in greenhouse gases that Australia makes. Before that, it's all overseas permits.

Her criticism is very valid, but on the other hand the Green's solution (that Australia is capable of making a rapid changeover to run purely on renewable energy) seems wildly off the mark too. (Especially if you read Barry Brook's blog.)

Why is it impossible at the moment to find any political party in Australia that actually makes sense on CO2?