Carbon capture and storage, or CCS, refers to technologies that allow us to capture CO2 at the source of its production and before it enters the atmosphere. It is therefore seen as a potentially important tool in the battle to decarbonise our global economy and mitigate climate change.
Yet, there is a risk that the comforting possibility of CCS deployment at some stage in the future allows people to avoid thinking about some of the major challenges of the energy transition – and in particular, the unavoidable conclusion that oil, gas and coal use must fall in absolute terms in order to result in a relatively benign climate outcome.
The need for net-zero emissions
Firstly, it is important to note that CCS is integral to most climate scenarios, and not without reason. The ultimate amount of temperature rise that the earth will experience due to CO2 emissions is related primarily to the cumulative amount of CO2 in the atmosphere. This leads to the concept of the “carbon budget”, which is a total figure for the amount of CO2 that can be released – any continuing emissions of CO2 add to this atmospheric stock, hence continue to increase global warming. Therefore, “to stabilise temperatures, at any level 2°C, 3°C, 4°C, requires zero emissions”, i.e. at some point there must be net-zero emissions in aggregate across all sectors of the economy, across the globe. If we accept that there are some processes which are difficult to decarbonise, for example some industrial processes, then CCS probably becomes a necessity in some form.
CCS is not a substitute for using less fossil fuels
23 CCS plants are currently operational or under construction, showing that the technology works. However, CCS remains a long way from large-scale, commercial roll out, and there are limitations to the sectors and geographies where it can be used.
The below charts show total primary demand for oil and gas along with total CO2 captured in two widely used scenarios published by the International Energy Agency (IEA) .
The two scenarios assume that CCS will take off at a rate that can only be described as daunting. In the 1.75ºC scenario, CO2 equivalent to around 20% of current energy-related emissions is being captured annually by the mid-2040s. If we assume that an average size CCS plant can capture 1 mtCO2 per year, to reach these levels we would need to be building CCS plants at a rate of over 5 a week – starting right now. The more generous 2ºC scenario assumes one every other day.
Despite this huge build out of new CCS capacity, demand for oil and gas still needs to fall. In a 1.75ºC world, oil demand halves from 2014 levels by 2045, and gas falls by a third. Under 2ºC, oil demand falls by a third and gas by 10%. Given the Paris Agreement target of “well below 2ºC”, the former scenario is arguably more representative of international aims. Clearly, if CCS cannot be rolled out on the scale envisaged in these scenarios, then fossil fuel use will need to be curtailed even more.
Success in climate change and growing oil & gas are mutually exclusive, CCS or no CCS
This purpose of this note is not to claim that the modelled CCS roll out is unrealistic, although clearly it will be challenging. It is rather to point out that even incorporating such assumptions, there is no escaping the need for a global decline in use of each of the fossil fuels, including both oil and gas.
At a recent oil & gas industry conference, this was pointed out to a panel of experts convened on the topic of CCS; one appeared not to believe it, another seemed to take offence. At a different session at the same conference, an oil & gas industry representative claimed in the same presentation both that the IEA “predicted” oil and gas use continuing to grow for decades, and simultaneously that the industry was “well on the way” to solving the climate change issue through increased efficiency and CCS. The numbers simply do not allow that both of these positions can be held together.
The oil and gas industry has got used to a growth paradigm, which is understandable given the historical context. Indeed, demand for both fuels continues to grow. However, this paradigm will need to be confronted if we are to avoid the worst effects of unmitigated emissions. CCS does not change this picture.
We are supportive of CCS initiatives, and welcome efforts to advance the technology. But it must not be used as a “get out of jail free” card to dodge the really difficult questions.
Andrew Grant – Senior Analyst
 See Glen Peters, “Love it or hate it: Here’s three reasons why we still need CCS”, September 2017.
 The Beyond 2 Degrees Scenario and the 2 Degrees Scenario, both from Energy Technology Perspectives 2017 (published June 2017). They are consistent with 50% likelihood of successfully limiting global warming to 1.75ºC and 2ºC respectively.