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Study: Most fossil fuels unburnable without carbon capture

Posted on 14 June 2016 by Guest Author

This is a re-post from Simon Evans at Carbon Brief

The majority of fossil fuel reserves are unburnable if the world is to avoid dangerous climate change, but carbon capture and storage (CCS) could “unlock” greater use, a new study concludes.

The white paper, from Imperial’s Sustainable Gas Institute, challenges previous findings that CCS makes little difference to the quantity of fossil fuels that can be burned, within a 2C carbon budget.

Carbon Brief runs through the report’s findings and what it might mean for fossil fuel firms.

Fossil framing

CCS has a decidedly mixed reputation. Some strongly support it, whereas many view it with suspicion, as a technological fix that promises to allow existing energy firms to continue business as usual.

Indeed, oil and gas majors, such as BPShell and ExxonMobil, are among the loudest CCS advocates. So it’s worth noting that the Sustainable Gas Institute was set up in 2014 with an £8.2m grant from oil and gas firm BG Group, which was recently bought by Shell.

Setting out its purpose, the new report says:

“This white paper has considered whether carbon capture and storage (CCS) technology has the potential to enable access to more fossil fuel reserves in the future, where these reserves would otherwise be ‘unburnable’.”

Note that this explicitly frames the question in terms of enabling access to more fossil fuels, rather than in terms of securing the energy the world needs while avoiding dangerous climate change. Fossil fuels are useful, but using them is not an end in itself.

In contrast, bodies such as the Intergovernmental Panel on Climate Change (IPCC) have asked if the world could limit warming to 2C without CCS (the IPCC says it could), and whether the alternatives would be more costly (the IPCC says it would cost twice as much without CCS).

Unburnable carbon

Moving on from how it chooses to frame the issue, the Sustainable Gas Institute report follows a well-worn path that starts with the carbon budget. This is the amount of CO2that can be released for a given chance of remaining below a chosen temperature limit.

For instance, the IPCC says cumulative emissions must be no more than 1,300bn tonnes of CO2 (GtCO2) after 2011, for a 50-50 chance of staying below 2C. This is much less than the 3,683GtCO2 that would be released if all fossil fuel reserves were burned, leading to the concept of “unburnable” carbon.

An influential paper published last year found more than 80% of coal reserves, 30% of oil and 50% of gas is unburnable if the world is to avoid warming of more than 2C. This paper also said that CCS made little difference to the share of fossil reserves that would be unburnable.

It found that CCS would allow just 6% more of the world’s known coal reserves to be burned, with an even lower figure for oil and gas. It said:

“Because of the expense of CCS, its relatively late date of introduction (2025), and the assumed maximum rate at which it can be built, CCS has a relatively modest effect on the overall levels of fossil fuel that can be produced before 2050 in a two-degree scenario.”

The new report challenges this argument. While it agrees that CCS allows only a relatively modest increase in the use of fossil fuels before 2050, it finds a much larger impact by 2100: two-thirds of known reserves could be burned, if CCS is available, compared to just one-third without.

Share of known fossil fuel reserves that could be burned within a 2C carbon budget

Share of known fossil fuel reserves that could be burned within a 2C carbon budget (GtCO2 and %). Note that the totals include cumulative emissions from coal, oil and gas between 2005 and 2050 or 2100. Without CCS, the amount of burnable carbon to 2100 is similar to the remaining carbon budget for a 50/50 chance of remaining below 2C, see above. Source: Sustainable Gas Initiative white paper.

The impact is particularly large for coal and gas, the study says. That’s because centralised coal- or gas-fired power stations could be fitted with CCS, whereas oil is used in millions of vehicles where carbon capture would be impractical.

Gas equivalent to 150% of current reserves could be burned by 2100 if CCS is available, it says, compared to 68% without CCS. For coal, the fraction of reserves that can be burned also more than doubles from 14 to 32%.

A summary of the report says:

“CCS technology underpins the future use of fossil fuels in scenarios that limit global warming to 2C.”

The amount of gas that could be burned within a 2C carbon budget would rise even further, the report suggests, if CCS technology could be improved. CCS doesn’t capture all of the CO2 emitted: in general, the higher the share captured, the more expensive it becomes.

Most models assume CCS would only capture 85-90% of emissions. This is a key constraint on the use of CCS because emissions need to fall to net-zero if global temperatures are to be stabilised. Even a 90% reduction in the CO2 emitted by fossil fuel burning might not be enough to get there.

If the capture rate could be increased to 95% or more, the report says, then the amount of gas that could be burned by 2100 would roughly double.

Interpreting the results

Before asking what the new findings mean, it’s worth raising an important caveat, which is that the study is based on the remaining carbon budget for a 50-50 chance of limiting warming to below 2C.

Many would prefer to aim for a likely chance — a 66% probability — of remaining below 2C. Moreover, the 2C limit is out of step with the Paris climate agreement, which says warming should be kept “well below” 2C and that efforts should be made to hold temperatures 1.5C above pre-industrial levels.

Meeting these aims would entail sticking within a smaller carbon budget, which in turn would mean much less of our fossil fuel reserves are “burnable”. The fact that CCS captures less than 100% of CO2emissions becomes more of a problem, if the carbon budget is tightened.

It’s also worth noting that the impact of CCS lies far in the future. Luke Sussams, senior researcher at theCarbon Tracker Institute, tells Carbon Brief:

“CCS only makes a meaningful contribution after 2050…But we know that the 2C carbon budget is spent by 2040 on our current trajectory. So CCS will do little to slow warming over the most critical next few decades.”

In terms of what the results mean for fossil fuel firms, this timeframe is significant, because investment decisions tend not to look further than a couple of decades ahead.

After sketching out a below-2C scenario for the first time last week, Shell said it had “no immediate plans to move to a net-zero emissions portfolio over our investment horizon of 10–20 years”.

The study’s central finding, that the burnable share of current reserves would double by 2100 if CCS is available, has little relevance in this context. Sussams explains:

“A reserve in 2100 has no value today, so companies cannot base any strategic decisions today around such a finding.”

He adds that there are “many outstanding questions” about the modelled findings based on today’s assumptions of the future cost and availability of technologies.

Another issue is that some experts argue against using CCS to decarbonise power stations, saying it should be reserved for industrial uses, or negative emissions.

Ben Caldecott, director of the sustainable finance programme at the University of Oxford’s Smith School of Enterprise and the Environment, tells Carbon Brief:

“Even the successful deployment of CCS for power generation – a questionable outcome and priority given the costs relative to other options – does not mean business as usual for carbon-intensive assets. Companies and consumers will have to pay directly or indirectly for the very significant costs involved.
CCS attempts to address risk on the one hand by extending carbon budgets, but creates it on the other hand through new and uncertain costs. It should not be seen as a deus ex machina that will ‘save the day’. Investors should view CCS for power generation with a healthy dose of scepticism.”

This seems to get to the heart of the problem with CCS. Modellers tell us it isindispensable if we are to avoid dangerous warming cost-effectively, but that the upfront development costs will be high. Meanwhile, others warn it should not be seen as an excuse to continue business as usual.

Given this context, and the fact that its potential benefits lies so far in the future, it is, perhaps, unsurprising that progress on developing the technology is stuttering in the UK, even if developments elsewhere show more promise.

Dr Sara Budinis, research associate at Imperial and part of the Sustainable Gas Institute team that authored the report, tells Carbon Brief:

“None of the technologies that we have available at the moment is the super-winning one. We think every technology has to play its role and CCS is part of the solution.
We are basically running out of carbon budget. I understand there are concerns about CCS but to me it is something that could help us to access fossil fuel reserves without endangering climate change even more.”

New Carbon Brief analysis shows just how quickly the carbon budget is running out, with around five years of current emissions remaining for a likely chance of staying below 1.5C.

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Comments 1 to 5:

  1. The same folks who tell us renewables are too expensive keep pushing CCS. I would be very surprised if the cost of CCS isn't 10 to 20 times more expensive than simply using renewable energy instead.

    The way I view this:: The house is on fire (global warming). The guys who keep pouring ever more gasoline on the fire, (the fossil fuel industries) are telling us to not worry because they have a small, handheld fire extinguisher, (CCS), and if we just allow them to keep pouring more gasoline on our burning house for a few more years, (or decades), they will eventually use their small, ineffective fire extinguisher to put out the fire (promise!).

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  2. BHHY, A minor clarification of your view. The ones wanting personal reward from throwing gas on the house on fire are not going to bring their fire extinguisher. They expect someone else to develop the fix for the problem they want to enjoy making bigger.

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  3. "Sustainable Gas Institute"? Well it seems they aren´t impartial here; they have a hard stake in the matter.

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  4. It is pretty clear that Carbon capture is not on.  I've seen estimates that you have to burn 30% more carbon to catch and store the Carbon dioxide.  That is just silly.  We would use all the renewable energy we have developed and then some to store the carbon from our coal fired power plants.  Equally clearly, a huge step would be to transition to electric cars as fast as possible while balancing our grids with demand balancing rather then supply balancing.  However, going out on a limb a bit here, we see that the Northern Hemisphere Atmospheric CO2 levels go up 8 and down 6 each year.  Clearly, the natural systems have a huge ability to suck up carbon.  We would be far better advised to facilitate all these systems including some we could tweak.  For instance, we could burn all wood waste for energy only to the charcoal stage and incorporate all the charcoal into our soil.  We could reforest, cutting down the trees at the appropriate stage to be built into long lasting buildings, furniture and so forth.  We could adopt agricultural methods that increase the organic content in soils (which we have depleated over the years with chemical fertilizers) and we could rewild large areas both in the sea and on land and simply leave them alone.  Oh, and we could insist on spreading the beaver throughout our catchments and leaving them to get on with saving our sorry selves from ourselves.  We might even sink whaling ships (after removing the crews).  Look at Monbiots TED talk to get an idea how much carbon they can remove from the atmosphere.  At the very bottom of all this is one common problem.  We have to get big vested interest money out of politics all over the world and especially in America.  We could have had Bernie but that looks to be over now.  We have blown our best chance and it may be too late.  Have you seen the Carbon increase from April to April in the Mana Loa web site.  4.16ppm.  We may have already passed the point of no return.  Our carbon output didn't go up last year and yet we have this jump in atmospheric CO2.

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  5. There is somewhere between 35 and 40 Gt CO2 emissions yearly worldwide. To draw down CO2, (decrease the stocks in the atmosphere) we must adjust the flows into and out of the atmosphere until we achieve a net negative flux.

    There are approximately 5 Giga Hectares of land in the world currently being used to produce food for human populations. (only ~1%+/- is in permaculture or other ecofriendly management) Agriculture has been proven to be capable of being an emissions source or a sequestration sink depending on the methods used. Currently right now agriculture is an emissions source. (99% being managed by either industrial or traditional subsistence methods)

    Working backwards, for agriculture to offset emissions and achieve a net negative flux for atmospheric CO2 worldwide each hectare of agricultural land producing food would need to sequester long term into the soil over approximately 8t CO2/year. 8t CO2/ha/year X 5 Gha = 40Gt CO2/year

    Can we do that? According to Dr. Christine Jones we certainly can.

    Liquid carbon pathway unrecognised

    The case studies mentioned by Dr. Christine Jones above show a range in results between 5 & 20 tonnes CO2e/ha/year increases in soil carbon by using permaculture pasture cropping methods. (direct seeding grain crops into perennial pasture and cell or pulse rotational grazing integrated together)

    Why pasture cropping is such a big deal

    In no way is this example alone or even out of the ordinary. There are multiple case studies on people getting similar results with other carbon farming practises.

    So quite likely if done on enough land we could offset between 62% and 250% of all emissions worldwide. That is VERY conservative BTW, because it doesn't even include the oceans or the forests which already are removing about 1/2 of the ~35 to 40 Gt CO2 emissions yearly worldwide.

    Makes me wonder why CCS technology is even being discussed? We know soil degradation is a very serious problem. 

    Only 60 Years of Farming Left If Soil Degradation Continues

    We also know renerating degraded soils includes restoring Soil Organic Carbon (SOC)

    Soil regeneration

    So no, CCS technologies is a fail from the start whether it works or not. We actually need that carbon... But we need it in the soils worldwide, not some CCS technology. It's a very bad idea and pulling resources away from where it needs to be...implementing the infrastructure required to change agricultural models of production to regenerative systems.

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