Few technologies are considered by experts to be as important in addressing the risks of climate change than carbon capture and storage, or CCS.
Why is it important?
By 2030, global energy demand will rise by 50%, while CO2 emissions must decrease by 50%. The International Energy Agency has reported that the Paris Agreement targets cannot realistically be achieved without some form of carbon capture technology.
Due to the rising global population, and the continued increase in fossil fuel-based power plants, CCS may be the only way to curtail emissions. Considering 60% of global emissions come from industrial sites and power plants alone, CCS has the potential to drive down the number of polluting fossil fuel plants extensively by working alongside the world’s biggest polluters.
So how does it work?
The CCS chain consists of three parts: capturing the CO2 emission before they leave the plants or industrial site, transporting that CO2 in liquid form via pipelines, and finally storing the CO2 deep underground in depleted oil and gas fields or aquifers.
The CO2 can be captured either before or after combustion by splitting out the CO2 from the other gases in the combustion process, or capturing the CO2 in a solvent before it is finally emitted.
Currently, both versions of the technology are costly. Most projects often find the cost per tonne captured around £50 – £70. With that being said, this method is still in fact cheaper than not capturing the CO2.
The cost of capturing CO2 without CCS will be dramatically higher, according to the IEA, over 70% higher. And the technologies capable of pulling CO2 from the air are still nascent and not scalable.
So what else can it do?
If CCS is coupled with biomass plants (wood pellets etc), the technology actually becomes carbon negative. Trees that are used for bio-energy generation have, throughout their life cycle, sequestered tonnes of carbon from the atmosphere.
This in turn is then burned to produce energy, but the carbon doesn’t return to the atmosphere, it is stored deep underground via the method mentioned above.
This method could answer the intermittency problem associated with traditional renewables such as wind and solar, and provide a future that actually works on removing excess CO2 from the atmosphere over time.
Okay, so what’s the catch?
It is estimated that CCS uses anywhere between 10 – 40% over a power plant’s energy to capture the carbon emissions. Some argue that due to the limited energy efficiency of plants with CCS, the technology will actually increase emissions overall.
CCS does not factor in the CO2 produced during the mining and transporting of the coal or fossil fuel to the power plant. If a power plant needs to produce 10 – 40% more electricity to make up for CCS, more coal will be required from source and therefore more CO2 will be generated from extraction and transport.
Others groups such as Greenpeace say that money spent on CCS will mean less investment in actual renewable generation, which they believe is the clear winner in technologies that will help the planet meet the mitigation targets.
What’s the verdict?
The Intergovernmental Panel on Climate Change has used biomass generation with CCS in its mitigation target scenarios for a 1.5 C increase, which shows a support for the technology from scientists. From our perspective, CCS from fossil-fuel based power plants may only exacerbate the problem. It may push the growth of power plants in areas of increased population demand further with a future view to implement CCS.
But what if that promise isn’t carried out? What if the technology does not reach maturity and cannot be implemented? Large areas will then have no alternative but continue to emit harmful emissions without the infrastructure of renewables to compensate.
However, there is a greater argument for biomass, or bio-energy with carbon capture and storage (BECCS). The carbon negative element of the technology is promising. With scale and genuine investment, BECCS may play a monumental role in reaching the Paris Agreement mitigation targets.