Friday, 1 May 2015

An absorbing story

Experimental carbon capture panel
For the last few years we've put climate change on a back burner because of the financial crisis. But it is not going to go away. The Green Party wants us all to abandon the use of oil and gas to move to low carbon sources of energy generation like wind and solar (they conveniently forget that nuclear is low carbon). However, like most of the Green Party's manifesto, this is a desire based more on hope than an understanding of human beings.

Frankly, a much better way of getting people to do the right thing than forcing the hair shirt option on them is to make it easy. So, for instance, I would leap at having an electric car as a runaround if you could buy a Leaf or a Zoe for the price of an Aygo. But charge three times as much and I'm not going to be in the queue.

When it comes to power generation from oil and gas (and even, dare we mention it, coal), the Cinderella technology is carbon capture and storage (CCS). The developers of CCS recognise that we are not going to ignore out fossil fuel reserves, but that it should be possible to use them while at the same time taking carbon dioxide out of the atmosphere, so the net contribution is zero or even negative. At one time the British government was quite enthusiastic about CCS... but then withdrew most of the funding.

There are a number of mechanisms for storing carbon dioxide away when it has been captured, but we don't have very efficient means of doing the capture in the first place. So I was interested to see this piece in Physics World on a synthetic material for capturing CO2 from the atmosphere. Remarkably, this stuff is 1,000 times more efficient than trees at sucking in the carbon dioxide. And let's face it, trees are very slow absorbers (which is one of the problems with using trees in carbon offsetting programmes).

The substance used is a resin that collect between 10 and 50 per cent of the CO2 passing over a collection panel made from it. Of course this doesn't just remove the CO2 from a power station exhaust - but it doesn't matter. Carbon dioxide is carbon dioxide. As long as you can hoover it up fast enough, you can balance out the output.

Apparently you would need about 100 million large collectors to totally counter the world's carbon emissions - but that's a huge step forward, and even reducing emissions by a small percentage would help.

The biggest problem with this approach is dumping the CO2 once it is captured. The collectors would become saturated in about an hour, needing replacing in some kind of conveyor system that takes them to deposit their load, when they can be reused. The CO2  naturally emerges from the resin in a humid atmosphere (so the CCS devices would have to be sited in dry locations) - it could then be taken away in a number of ways.

The concept isn't perfect. Although releasing in a damp atmosphere is easy to do, it also limits their value in, say, the UK. And there would be no point using such an approach unless the energy used in swapping out the panels and dumping and storing the CO2 was a lot less than the energy produced in emitting the carbon dioxide in the first place.

Even so, there can be little doubt that this is a step in the right direction.

This has been a green heretic production.

No comments:

Post a Comment