The need to hold the global temperature rise below 2 degrees Celsius, in accordance with the Paris Agreement, necessitates being addressed through various perspectives. The conventional method is to reduce the amount of carbon that is emitted into the atmosphere. Another way is to create carbon storage and sinks, so that the carbon that is already in the atmosphere can be reduced. The latter needs to work along with the conventional, former to fulfill the emission requirement for its reduction. The second method uses innovative technologies to catalyse emission reduction and are known negative emission technologies.
To achieve the 2 degree target it is necessary to have negative emissions. This can be accomplished through the increase in natural carbon sinks which include reforestation or other nature-based interventions that lead to carbon sequestration. It can also be achieved using specific technologies such as carbon capture and storage. The reduction in carbon emission is a global target as it affects every country. Emission from one place affects another. Countries that can handle it must move forward with the plans for net-zero emissions while taking into consideration their income as well as developmental level. In this way, positive emissions in one country may be balanced by negative emissions in another and this may lead to carbon neutrality.
Negative emission technologies involve two steps – removal of carbon from the atmosphere and their storage for longer periods. They require resources like land, water, or energy which puts limits to their scaling capabilities and location of their implementation. These methods require a price for carbon and future projection of a carbon process of $100 per ton of carbon would make these methods feasible in the economic sense. These methods require monitoring and maintenance from time to time and cannot be successful without a meaningful global response or policy solution.
Bioenergy with carbon capture and storage (BECCS) is a negative emission technology, as producing the biomass fuel involves the absorption of carbon from the atmosphere and returning that to the atmosphere on combustion can be avoided by capturing it from flue gases and storing it in geological reservoirs. It involves growing energy crops such as fast-growing perennial grasses, or short-rotation coppicing or increasing forest biomass which is equivalent to afforestation and reforestation. The biomass grown also act as a carbon sink. The area of land and water requirement for the cultivation of these biomass is huge and may not be feasible at times, which creates difficulties in its scaling capabilities. To remove a gigaton quantity of carbon, it would require a very large land area of about 1 to 1.7 hectares for each ton of carbon equivalent removed each year for forest residues, about 0.6 hectares for agricultural residues, and 0.1–0.4 hectares when purpose grown energy crops are used.
One of the targets among India’s NDC is to create an additional carbon sink of 2.5-3 billion tons of carbon equivalent by scaling forest and tree cover by 2030. The target can only be achieved with the help of the inclusion of negative emission technologies to increase the carbon sink capacity. The technologies of carbon sequestration and carbon capture need to be taken into consideration. These targets have been set by keeping 2005 as the baseline year. The targets are defined in such a way to include 1.9 billion tons of CO2 sequestration and its exclusion would entail the conservation and improvement of existing forest. The report on India’s NDC also states the land availability for the measures and has given out different scenarios for land allocation. Availability of total land is given as 75.8 Mha most of which is taken for the restoration of forests and afforestation of the wasteland.
In the case of BECCS, the cost may occur in three stages – 1) during the capture of carbon, 2) during transportation and 3) during storage which also includes monitoring and verification. The positive impacts of BECCS in a socioeconomic sense include economic diversification, technology development, and a rise in market opportunities. Its positive impact in the environmental sense includes the substitution of GHG emissions. The negative impacts of BECCS in a socioeconomic sense include impacts on health, and in the environmental sense include Biodiversity losses, deforestation and forest degradation, and air pollution through CO2 leakages.
Some of the issues related to it include inadequate information to assess the technological needs, weak institutional infrastructure, lack of subsidies, and difficulty in mainstreaming the environment into development plans. Other issues include a lack of development in carbon capture and storage infrastructure. At the moment, it has low efficiency compared to conventional power generators and leakage in the CCS storage is a major concern. The amount of residual emission potential is not clear and there are issues with its investment in the developing countries.