Product has been added to the basket

Carbon capture and storage

Bryan Lovell* gives a personal account of a recent GSL-hosted conference on CCS, and the events that gave rise to it

“Fellows must not presume to be experts in fields other than their own, or accept professional obligations that they are not competent to discharge.” Code of Conduct, Geological Society of London.

LovellPresidentresized.JPGIn other words, if you don’t know what you talking about, please hold back. I think we geologists knew that already, in relation to rocks at least. Red cards can be swiftly displayed for those giving bad advice about what lies beneath the surface.

Pic: Bryan Lovell

Against that unspoken shared background of understanding, John Lorenz and I met for the first time in Burlington House on 2 March 2010. We were to discuss storage of carbon dioxide in rocks. The American Association of Petroleum Geologists, of which John was then president, has many members interested in pumping carbon dioxide underground to recover more oil, but rather fewer bent on burying carbon to cope with human-induced climate change.

At the time of my meeting with John Lorenz, the Geological Society was preparing a statement on climate change. To those of us on Council, it was already clear that this GSL statement would contrast with the published AAPG view, which in effect said that unabated burning of fossil fuels was not much of a problem. In November 2010 GSL said publicly that we do indeed have a problem with anthropogenic climate change. That conclusion was based on the evidence of past climates recorded in rocks: it was reached by a group of Fellows who knew what they were talking about.

In March 2010, the significant difference in attitude between AAPG and GSL on climate change was for me quite pointed. I had in recent years been a public critic of the AAPG’s position, in their own Bulletin and Explorer. I was not confident of a productive outcome as I entered the office of the Executive Secretary to join the discussion with the AAPG representatives.

My fears were groundless. John Lorenz said that he was in favour of our proposal that we should hold a series of joint AAPG-GSL meetings on carbon capture and storage, provided that these conferences were not a mixture of science and policy. We should, at each joint meeting, first present the science, argue about the science, agree where we could, and plan more research where we could not. Then, and only then, should we invite those professionally concerned with more general policy to join us, at a separate meeting.

“That’s fine” we said, “we think that is sound practice. And even if we didn’t, we would be nudged by our Code of Conduct that bids us be adamant only when we have agreed on what the implacable rocks are telling us.” (Or words to that effect…)

Meeting

So it was that on 14-15 April 2014 we met in Burlington House for the third and last in that series of joint meetings. This time we concentrated not just on storage of carbon dioxide in the subsurface in conventional traps, but also considered the possibility of extending storage to a wider range of rocks. The practical advantages to society of such an extension of storage capacity are obvious enough. Honouring the Lorenz/GSL edict on separation of science and policy, we postponed consideration of these benefits to a separate session on 15 April.

The outcomes of these science and policy meetings will be reported by GSL elsewhere. For me, there is one main conclusion. Storage of carbon dioxide in conventional reservoirs is safe, given sound practice in selection of reservoirs and construction of wells. That safe storage requires a good understanding of current oil-industry technology, adapted to deal with carbon dioxide rather than with methane. Our ability to control pressures during injection of carbon dioxide promises to give us an advantage in safety over routine production of oil and gas.

So far so good: now can we safely extend the choice of storage site? Is it possible to store supercritical carbon dioxide safely in open rather than closed structures, by residual trapping in pore spaces, and in solution in brines? We don’t know yet, but we will find out, by a combination of theory, experiment and field trials. This combined approach has been successful over many years in oil exploration and production, notably in the North Sea basin.

Meanwhile, we can with confidence implement storage of carbon in conventional reservoirs. To do that, we need to move beyond the realm of rocks, with which we know we cannot argue. We must enter the world of economics and politics, where final judgements are made by humankind and not by the geological record. We geologists may become testy at this lack of our usual Earth Court of Appeal.

First we need to recognise the scale of the challenge presented by our dump of carbon into the atmosphere, by reference to existing industry. Each day we pump over 300 million barrels of fluid to the surface, of which a quarter is oil, the rest being brine. We could, in principle, set up a global industry devoted to injecting back into the ground a comparable volume of supercritical carbon dioxide, at a comparable rate. That would cope with a substantial proportion of the Princeton target of some 200 gigatonnes of carbon emissions not to be released to the atmosphere by mid-century. Achieving that target will keep atmospheric concentrations of carbon dioxide close to present- day levels.

Who might be responsible for storing such large amounts of carbon? Does responsibility rest with the fossil-fuel industries themselves? They are the ones who take all that fossil carbon out of the ground in the first place. Surely they can put the carbon back again, once we’ve had the use of it? We know the answer to that question is, yes, they can do that and they can do it safely. But at what price, and who pays?

There those who suggest that all responsibility and costs should fall on the fossil-fuel companies. Some groups have little faith in carbon capture and storage, and scorn the notion of clean coal. They believe that shareholders of companies producing coal, gas and oil should sell their stock now, because many carbon-based assets of those companies are potentially ‘stranded’ and worth little.

It is the customers of these companies who are responsible for the greater part of the emissions. Are fossil-fuel companies to be held responsible for the use of their products, as well as for emissions resulting from their own operations? Is that responsibility also retrospective, traced back to a particular point in our developing understanding of the science?

As for the ‘stranding’ of carbon, are we always to shudder at the sight of a petrol pump, a gas-fired industrial plant or a cargo of coal destined for an Asian power station? What if, in the background, CCS was in full compensatory play?

Tackling these questions requires expertise, balance, leadership and effective action. The panel on CCS policy at the 15 April meeting was certainly expert, and was balanced by contributions from both academic and industry experts. For leadership and action we can look to the fossil-fuel industries themselves, as they develop their expertise in carbon storage. That development will be in collaboration with the main industrial users of their products, not least the generators of electricity from coal and gas: we the customers will be the beneficiaries.

We have a problem that can be solved, but only if we use a range of low-carbon technologies that includes CCS. Geological storage of carbon dioxide is feasible: now all we need is a code of conduct.

*Lovell is at the University of Cambridge. He is adviser to BHP Billiton.