5 things you need to know about… unburnable carbon

CCS plant02_2012-115Meeting growing energy needs around the globe whilst slashing carbon emissions is a monumental challenge. SSCP-DTP student Clea Kolster discusses a new report that provides fresh evidence of how technologies including carbon capture and storage can help.

The International Energy Agency (IEA), the IPCC and the World Bank all agree: carbon capture and storage (CCS) technology is key to reducing the greenhouse gas emissions responsible for climate change whilst minimising the impact on world economies.

The Sustainable Gas Institute’s recent white paper, Can technology unlock unburnable carbon?, goes one step further by showing how CCS can give us access to the energy locked up in fossil fuels without jeopardising the future of the planet.

Here are 5 things you need to know about unlocking unburnable carbon:

1. What is ‘unburnable carbon’?

This refers to the remaining fossil fuels that would cause global warming above 2°C if they were extracted and burnt for industry or power. In order to stand a reasonable chance of keeping the temperature warming below this level, scientists estimate we can emit an additional 1,000 Gt of carbon dioxide (CO2) emissions, which would last roughly 30 years at current rates. Unburnable carbon is also known as ‘stranded assets’ or fossil fuel reserves that are known and commercially (or economically) extractable but would surpass the carbon budget if consumed.

2. Why is it critical to unlock more carbon?

Global energy demand is skyrocketing as nations around the world build more fossil fuel power plants and populations in many developing countries grow at unprecedented rates. While energy demand has been declining in the European Union – the UK and Portugal achieved their first coal-free periods during the last week – it continues to increase year by year in the rest of the world in parallel with a growing appetite for fossil fuels. Consumption of coal in India increased by 11.1% in 2014 for example – the highest increase on record.

Whilst a transition to renewable energy sources is the only viable long-term solution to meeting global energy needs, fossil fuels are likely to remain a substantial part of the energy mix until the end of the century. Hence, it is critical to reduce the amount of fossil fuel reserves that would otherwise be stranded by limiting global carbon emissions associated with fossil fuel usage.

3. CCS can make 37% of unburnable carbon burnable by 2050.

View full size infographic

CCS is widely considered to be one of the key ‘direct approach’ technologies to unlocking unburnable carbon. Other solutions include improving the energy efficiency of power plants and switching from coal power generation to gas (with the latter resulting in 50% less emissions). CCS involves capturing CO2 from power plants and industrial plants, then purifying and compressing the gas for transportation to a storage site (view infographic). Applying CCS to fossil fuel powered plants would allow them to generate energy whilst locking away 85-90% of the CO2 produced, thereby reducing the amount of unburnable carbon by approximately 400 GtCO2.

4. Models show that CCS will unlock more carbon by the end of the century.

The results discussed in this report are drawn from integrated assessment models (IAMs). These are used to show various scenarios of technology deployment, energy usage and other elements of global change, and the effect these have on climate change. This report considers scenarios from models that deploy CCS from 2020 whilst limiting atmospheric CO2 concentration to 450ppm, with a high probability of keeping temperature rise below 2°C.  The IAMs considered in this study revealed that given the early uptake of CCS and assuming its deployment continues to ramp up past 2050, the proportion of fossil fuel reserves that can be burnt by 2100 increases from 33% without CCS to 65% with CCS.

5. CCS is expensive upfront, but the investment is better value than paying for an overshot carbon budget later on.

It’s clear that CCS is needed in order to secure a realistic chance of avoiding substantial temperature increase around the world, yet the technology is still not deployed on anywhere near the scale at which it needs to be. The reasons behind this sluggish uptake do not relate to the technology itself; instead, a lack of market incentive and commonly held misconceptions are the key obstacles that CCS must overcome. Upfront costs of CCS are currently high, with only 13 projects in operation globally. However, the cost of reducing greenhouse gas emissions and mitigating climate change once the carbon budget has been exceeded would be 4-8 times higher than the current cost of adopting CCS, leaving no economically viable excuse for not deploying it.

Find out more in the Sustainable Gas Institute’s white paper, Can technology unlock unburnable carbon?

2 thoughts on “5 things you need to know about… unburnable carbon

  1. I am as keen as anybody to minimise CO2 production. However, CCS leaves me confused. I attended a lecture promoting CCS. I asked about the energy usage of CCS. The speaker gave a very detailed explanation of the percentage by explaining that that one would need to build a third power station to provide energy for CCS for the first two. This seems a very large proportion of the energy generated by burning the fossil fuel. In effect, to release usable energy from 100 tonnes of fossil fuel, we would need to burn another 50 tonnes. I am not sure if the figure included CCS for the third power station. Also, unlike photosynthesis, for every 12 tonnes of sequestered carbon we are locking away 28 tonnes of oxygen and thus affecting atmospheric gas concentrations. Further, the storage volume required for CCS is far greater than the original volume of the fossil fuel thus limiting the process . I would be grateful if somebody could explain.

    1. Hi Andrew,
      Thank you for your message. Could you please tell me what lecture it was that you attended to get this information?

      In order to capture the carbon dioxide that is otherwise emitted to the atmosphere by fossil fuel burning plants does indeed require energy. This is because depending on the type of fossil fuel and the method of combustion, the gas that is emitted does not only contain CO2, in fact the concentration can range from 10% to 70% CO2 typically. And therefore this gas needs to be stripped in order to get a high concentration of CO2 as well as compressing the gas to a high pressure in order to transport and store it. But this does not require an additional power plant, it will use the energy that is produced by the original power plant but this is around 20% or less of the energy produced by the original plant. So yes, this will cause that energy to be more expensive in the near term as more of it will need to be produced in order to meet the same energy demand whilst being able to capture the CO2. But, as we would expect/hope that policies would come into place making it more expensive or taxed to emit CO2, this loss of energy/value will be offset.

      I am not sure where you got your figure with regards to locking away oxygen when sequestering carbon via CCS… The gas that is emitted when burning fossil fuels is essentially made up of CO2, O2, N2, Ar and some Sox and Nox. And when CO2 is captured it is purified so as to not contain any of these other gases particularly O2, N2 and Ar which indeed make up our atmospheric gases. Furthermore, storage space for CO2 around the world is abundant and in fact a majority of the storage spaces considered for CO2 are depleted oil and gas reservoirs that have already been exploited. These are deep geological reservoirs typically kms below ground or below sea level.

      Finally, CCS is a transition technology, it is needed to help the transition of the power sector from fossil fuel heavy technologies to low carbon and renewable energy until the end of the century as well as being crucial to the decarbonisation of sector such as heavy industry (steel, cement, iron production etc…) in order to meet any of the global targets for greenhouse gas emissions reduction and avoid dangerous climate change. But it is not a long term solution over centuries to come.

      Hope this helps.
      Best regards,
      Clea Kolster

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