BECCS (BioEnergy with Carbon Capture and Storage)

China, the world’s largest emitter of CO2, plans to become carbon neutral by 2060. EU, UK, Japan and South Korea have announced their intent to go carbon neutral by 2050. Many big corporations too have declared that they will be carbon neutral by middle of this century or even earlier. Amazon plans to achieve this goal by 2040. Microsoft is even more ambitious and hopes to become carbon negative by 2030.

Becoming carbon neutral means achieving “Net Zero Emission” of CO2. This requires removal of CO2 equivalent to amount emitted. One way of achieving this is to grow more forests or improve land management though better farming practices and thus enhance the natural sinks for carbon. But natural processes cannot achieve carbon neutrality and technological interventions are necessary.

The most practical and scalable technological solution consists of disrupting the carbon cycle by capturing the CO2 released while using biomass as fuel and locking it away permanently in a secure geological formation. The CO2 that is absorbed by the growing biomass thus does not get back into the atmosphere.

There are 3 techniques to capture the CO2: post-combustion, pre-combustion and oxy-combustion. The post-combustion approach uses well proven solvents like potassium carbonate and amines to scrub out the CO2 from the flue gases. In the pre-combustion approach, the fuel is subjected to partial oxidation and the resulting syngas is processed in a shift reactor to produce a mixture of H2 and CO2. The higher CO2 concentration makes the capture easier and cheaper. The oxy-combustion technique uses pure air for burning the fuel and results in flue gas that is nearly pure CO2, thus making capture simpler.

BECCS is not without critics. The land required for cultivating biomass for use as fuel is a serious limitation. Achieving carbon neutrality only via BECCS would require land equivalent to the area currently used for agriculture – 1.5 billion hectares.

Carbon Capture

Elon Musk, who became the richest man at the beginning of the year, has announced $100 million towards a prize for the best carbon capture technology.

CO2 concentration in the atmosphere has increased from 280 ppm at the start of the industrial revolution in 1760 to 417 ppm in 2020, a 49% jump. This is believed to be the highest since 3 million years ago, when the earth was significantly warmer and the sea levels were 15-25 meters higher than today. In the last few years, we have been adding 2.5 ppm each year.

With CO2 continually building up in the atmosphere, more carbon capture and sequestration (CCS) projects are necessary. Without CCS, net-zero emission is practically impossible to be achieved. Currently about 40 million tonnes of CO2 are captured and stored annually. This has to increase more than 100 times to 5.6 giga tonnes by 2050 if we have to meet the IPCC guidelines on limiting the global warming to 1.5 degrees C above preindustrial levels.

CCS capacity increased by 33% last year and currently there are 26 CCS facilities in operation. 65 projects are under various stages of development. The slew of projects currently in pipeline will take the CCS capacity to 110 million tonnes by 2026, a pitifully low value. ExxonMobil recently announced the formation of a new business unit to build as many as 20 CCS projects across the world. 

CCS projects are highly capital intensive and are not presently viable without fiscal support and incentives from governments. CCS technology is rapidly evolving and larger capture volumes will drive down costs and spur the much needed competition and innovation.

Many environmentalists are not too happy with CCS projects, because as much as 80% of CO2 captured so far has been used to pump out more oil in Enhanced Oil Recovery (EOR) projects. The irony of this is all too evident.