Posts Tagged ‘Carbon Capture and Storage’

I am a carbon capture sceptic

May 15, 2012

The Mongstad demonstration CCS plant.

I sincerely hope that carbon capture and storage (CCS) technology will work. But a few calculations, and a little bit of reading leave me thoroughly sceptical. I can imagine that we can technically conquer the ‘CC’ part of the challenge, and perhaps even the ‘S’ part might be just possible. But it is another ‘S’ – one with two lines through it: ‘$’ – that makes it unfeasible.

The concept of CCS is simple: if power stations burn carbonaceous fuels such as methane or coal, they add a ‘capture unit’ which stops the carbon dioxide being emitted into the atmosphere. Instead the carbon dioxide is ‘captured’ and somehow ‘stored’.

A few calculations reveal the scale of the CC and S problems. A large coal-fired power station produces roughly 1 gigawatt (GW) of electricity. During every hour of operation it produces around one million kilograms – 1000 tonnes – of carbon dioxide .

  • According to the counter on the Zero Emissions Platform (ZEP) web page, the entire world is currently capturing less than 500 tonnes per hour.
  • Assuming we can capture this carbon, the storage requirements as a liquid at room temperature would  fill a container 50 metres in diameter and 16 metres high. Every day.
  • On this mild May day, the UK would need 13 such containers, just for the coal-fired plant. And as if you didn’t know, there are 365 days in every year and the power station would be expected to operate around 90% of the time.

Of course engineers have proposed solutions to the storage problems.

  • The one I like the most is to react the carbon dioxide with calcium oxide to create calcium carbonate – limestone – which could be used in the construction industry.
  • The scheme which seems closest to implementation involves keeping the carbon dioxide as a gas, and sending it on a pipeline to underground geological structures. Typically these would be structures from which we have previously extracted natural gas or oil. This would generally require building new power stations near to places where the carbon dioxide could be stored.

Both schemes are eye-wateringly expensive. Covering the opening of the world largest CCS plant at Mongstad in Norway, Richard Black recounts the superlatives for the BBC with the headline ‘Norway aims for Carbon Leadership‘. However Spiegel Online captures the essence of the project in its headline and byline':

Norway’s ‘Moon Landing': Massive Carbon-Capture Facility Spawns Skepticism and Hope.

This is the world’s largest plant, but it is still only at demonstrator scale, capable of capturing less than 1% of the output from a large coal-fired power station i.e. just 80,000 tonnes per year.

To implement this technology requires investment at ‘moon landing’ levels. It requires the construction of a new infrastructure on a scale and complexity equivalent to the entire existing gas delivery infrastructure and – IMHO – that just isn’t going to happen in the UK. As Richard Black mention in an earlier BBC article, and as the EU’s ZEP report concluded,

CCS requires a secure environment for long term investment.

Sadly, no government on Earth can currently provide that.

Slowly I am coming to appreciate the role of finance in re-building our energy infrastructure. I now understand that if the capital investment required to drive a project forward is beyond a certain threshold, then long-term projects will never be funded privately. The combination of political and technical risk will simply never make purely financial sense. In contrast, solar PV and wind-farm projects can proceed incrementally with investment  on the level of millions of dollars, which will then add up to billions. These projects don’t make as much strategic sense as other investments, but the risk is much lower and it is possible to start them now. As the old saying goes “A wind farm in the field is worth two nuclear power stations on the drawing board.”

I suspect the threshold investment level is around ten billion US dollars – which means that the Severn barrage will never be built without explicit government investment. Similarly I cannot imagine that CCS will ever take off if it requires ‘moon landing’ levels of investment, and even building a single new nuclear power station looks unlikely.


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