- Carbon/Climate Change
Bio-Energy Carbon Capture and Storage: applications and limitations
In February 2019, the Drax power station, located in England, became the first biomass plant to capture and store CO2, at a rate of one ton per day and with an objective to reach ten million tons per year in the future. While Carbon Capture and Storage (CCS) technologies have been around since the early 1970s, this event is an important milestone since BECCS (Bio-Energy with Carbon Capture and Storage) was never achieved in the past. It is important to specify that since bioenergy is a flexible source of energy while being highly compatible with CCS technologies, BECCS takes an important part in three out of four of the IPCC 1.5°C pathway scenarios.
Traditionally, CCS technologies were at use on fossil-fuelled power plants, oil and gas fields, and on industrial facilities, allowing to partially reduce the emissions produced by their activities. In other words, new amounts of CO2 keep on adding up into the atmosphere, hence still resulting in net positive emissions, only making such activities a bit “greener” without solving the core issue. One could also argue that in this specific case, CCS technologies contribute to maintaining the use of carbon-intensive energy means of production by making them seem less harmful to the environment.
Biomass does not, however, produce new amounts of CO2 but releases carbon dioxide that had already been captured by organic matter, hence resulting in quasi-neutral emissions. Adding a CCS technology to a biomass plant aims to recapture most of this CO2 and to switch to negative emissions, hence hopefully reducing CO2 concentration in the atmosphere.
However, BECCS technology is not ready to use yet and still faces challenges, the first one being what to do with the captured CO2. For instance, the Drax power station had to release the carbon it had captured back into the atmosphere, lacking solutions to store or reuse it. The most commonly-used storage solution to this day injects the CO2 into depleted oil fields or into saline aquifers (geological formation of porous sedimentary rocks containing salt water), yet this solution faces criticism since its impacts on the environment are yet unknown while the amounts of CO2 to be sequestered would be tremendous. In addition, depleted oil fields and saline aquifers do not offer unlimited room for storage and might be insufficient in the long run.
Other ways of using captured CO2 are being studied, such as selling the CO2 to industries in need for such raw material; yet it could not be considered as storage anymore and this gas could be back into the atmosphere in no time, reducing or even canceling the positive effect of BECCS on its concentration into the atmosphere.
Finally, relying on BECCS and on biomass to mitigate the effects of global warming and to remain on a 1.5°C path could be a tempting idea. However, generalising the use of biomass could lead to conflicts regarding land use, since biomass power requires high amounts of organic matter to function. For example, in 2016 the Drax powerplant consumed approximatively 13 million tons of wood whereas the United Kingdom’s annual wood production added up to 11 million tons. The Drax powerplant therefore had to rely on massive imports from the USA (with the underlying environmental impacts) to cover only 7% of the United Kingdom’s electricity needs. Increasing biomass production could then lead to heightened deforestation worldwide.
In conclusion, if BECCS could be a part of a more diversified solution to tackle climate-risk, it might be dangerous and ineffective to rely too heavily on this solution in its actual state. Taking carbon out of the atmosphere is needed, yet it cannot be done without safe solutions for storage and without monopolizing too much land use. Hence, while this first -temporary – successful CO2 capture at Drax power plant remains positive news, this technology still needs to be improved and carefully forethought.
Ronan Lecarpentier, ESG Analyst
Sources: Beyond Ratings, IPCC