Category: Carbon capture & storage

During my second year at University I worked for two months in a cement plant as part of the “practical experience” element of my chemical engineering studies. This was about 30 years ago and in those days nobody talked about CO2 – I don’t recall any mention of the CO2 footprint of cement or the overall impact of the industry on the environment (nor, for that matter, when I worked for the local electricity generator – mainly coal – a year later).

Today, CO2 emissions have a very high profile in the cement industry. The CO2 intensity of cement manufacture is one of the main issues being addressed by the Cement Sustainability Initiative (CSI) formed under the auspices of the WBCSD. Of course there are good reasons why this is necessary – the manufacture of a tonne of cement can deliver up to three quarters of a tonne of CO2 released into the atmosphere. This comes from two sources;

1. The chemical reaction that converts limestone into cement, which results in ~0.42 tonnes of CO2 per tonne of cement produced;
2. The energy required in the cement plant to drive the conversion, which varies significantly depending on efficiency and fuel types, but for a modern cement plant 0.3 tonnes of CO2 per tonne of cement is probably a fair number. Some are better but equally some are worse, although the CSI is doing much in this area.

I think that the issue with cement is not so much the impact it is having today (although with global production of some 2.7 billion tonnes total emissions are about 4%) but the impact this industry will have over the rest of this century. A simple analysis shows that the industry must also deliver on some very substantial reductions in the relatively near future.

Cement (and the concrete it is used to make) is quite literally the backbone of our civilization. It is hard to imagine the cities we have built existing without cement. But with production growing rapidly as new cities spring up across the developing world, a very substantial emissions impact is in store for us.

Current estimates show cement production reaching over 5 billion tonnes per annum by 2030. Let’s also assume that after that it continues to grow, but plateaus between 7 and 8 billion tonnes per annum in the second half of the century. That will mean a total cumulative cement production between now and the end of the century of more than half a trillion tonnes.

In a previous posting I discussed the issue of cumulative CO2 emissions as the better measure of what must be managed, rather than emissions in any given year. The researchers who presented this concept made the point that to stay under 2⁰ C we should limit total carbon emissions to 1 trillion tonnes, or 3.7 trillion tonnes of CO2 – of which we have now used half. So we have 1.8 trillion tonnes of CO2 emissions left at the very maximum (there were various confidence level reasons why they thought we should actually aim for less than this, but I will work with the upper limit).

Society has now recognised that the oil, gas and coal industries must develop technologies such as carbon dioxide capture and storage (CCS) in response to this. But the fossil fuel industry won’t be on its own. Industries like cement are going to have to respond as well, and energy efficiency is not going to get them there.

The half trillion tonnes of cement could lead to total CO2 emissions this century of some 400 billion tonnes, or about 22% of the available emissions space. Even the chemical process emissions on their own would use up some 13% of the total (assuming a zero emission alternative fuel is used – e.g. bio derived).

So it seems to me that the cement industry and probably some other industries as well are also going to have to develop CCS solutions. One of the issues faced by this industry could be cost. Whilst sequestering all the CO2 emissions associated with a barrel of oil might amount to a third or less of the cost of that barrel (assuming $60 per tonne for CCS in the long term and 0.3 tonnes of CO2 per barrel and oil at current prices), in the case of cement which costs something like $60 per tonne, the implication is an 80% price rise.

This presents the industry with quite a challenge.

There has been quite some discussion in the press this week about the ability of the UK to meet its 2020 renewable energy targets, with a particular focus on the lack of progress in offshore wind. This highlights again the recent announcement by Shell that our main  “low carbon” focus will be in the areas of biofuel and carbon capture and storage (CCS) and not in areas such as wind and solar.

That announcement (and our pullout from the London Array offshore wind project last year) resulted in quite a bit of criticism – and a subject I almost always get questioned on when I speak at an event. As you have read in my posts, there is no question that wind and solar will be important in our global energy future, as will nuclear, biofuels and carbon capture and storage. We will need all the energy we can get to meet growing demand. In the energy space, there are in fact only four things the world can do to manage CO2:

1. Use nuclear for electricity.
2. Use renewable energy (winds, solar, bio, hydro, geotherrmal, wave, tidal).
3. Use CCS in conjunction with fossil fuels.
4. Use less energy for a given GDP output.

The flip side of this is that society has to do all of them, in very large doses, starting now,  not just to manage CO2 but also to deliver sufficient energy at reasonable cost to meet the needs of a growing global economy.

Oil companies are already big players in the global energy market, but they don’t typically sell electricity. They do supply gas and oil to the electricity sector, but their focus is much more on transport and chemical feedstock. Yet there is an expectation by many that oil companies such as Shell should rapidly transition to technologies like wind and solar. But both are outside their core competencies in terms of technology, which means the companies may struggle to add value and compete against others that can bring significant expertise to the table (e.g. Japanese electronics companies in solar).

Yet Shell and others must move forward as the new low CO2 emission economies are created. This then brings us back to areas where the oil industry may be more successful at adding value. Collectively, we are good at geology, drilling, gas handling, gas separation and compression, gas treatment, large scale chemistry and the distribution of flammable liquid and gas products. These are all technologies that sit behind CCS and bio as an energy source – important components in the short list of options we actually have.

In particular, CCS needs gasification (i.e. large scale chemistry that turns the energy feedstock into synthesis gas – carbon monoxide plus hydrogen), gas handling (both carbon dioxide and hydrogen), gas separation, gas compression, geology, drilling and well monitoring. The use of bio matter for energy may also utilise gasification, but also a range of other chemical processes and of course large scale flammable liquid distribution.

Perhaps the irony in all this is that as society moves to a more electricity based low CO2 emissions world, the oil and gas industry could end up, at least in my view, competing with the electricity sector anyway, but I don’t think solar and wind will be the pathway that takes us there. As gasification of coal and other energy feedstocks becomes more commonplace in power generation with CCS, the power companies will find themsleves handling synthesis gas and hydrogen. Synthesis gas can be a primary feedstock for all manner of chemical products, including synthetic transport fuels and hydrogen will almost certainly play a role as an energy carrier somewhere in the economy. The power generators will also be selling electricity directly to transport consumers for their plug-in hybrid cars. But the oil and gas industry won’t be just sitting on its hands whilst this happens (well I hope not). Not only will many of the technologies needed in the power sector come from the oil and gas industry, but the refinery of the future might look very much like a power station, taking in a range of energy feedstocks, gasifying them, using the syngas to produce certain liquid products such as synthetic fuels, storing CO2 underground, producing hydrogen . . . . and generating electricity. Need I say more.