Deep water supersaturated with methane can be degassed by lifting it to the surface. This process can be self-sustaining once initiated.
Deep water in lakes or seas exposed to local methane sources may have a partial pressure of methane greater than atmospheric. When depressurised (lifted), it becomes supersaturated and effervesces methane-rich gas, permitting recovery or flaring.
This ebullition changes buoyancy, and therefore flow in continuous pipes can be self-sustaining, creating fountains. Installations using this principle manage CO2 concentrations in lakes, e.g. Nyos, Cameroon.
Kivu in DRC is undergoing comparable methane projects, for fuel extraction. This technique is potentially profitable for near-term scaling. Availability of suitable sites requires research.
In the asbsence of any such treatment, the methane may ultimately travel to the surface by diffusion, bulk movement or ebullition - thus escaping to the atmosphere.
Category of the action
What actions do you propose?
Who will take these actions?
Where will these actions be taken?
What are other key benefits?
As the KivuWatt project shows, commercial exploitation of recovered methane is a realistic possibility in particular cases.
What are the proposal’s costs?
Instances of this technology are expected to be brought into use without any subsidy targetting environmental co-benefits (KivuWatt). Accordingly, the 'costs' associated with geoengineering deployment are largely a matter of supporting deployment in marginal or uneconomic locations.