Tapping Freshwaters for Methane and Energy

Energy supply limits development through fuel constraints and climatic effects. Production of renewable energy is a central pillar of sustainability but will need to play an increasingly important role in energy generation in order to mitigate fossil-fuel based greenhouse-gas emissions. Global freshwaters represent a vast reservoir of biomass and biogenic CH₄. Here we demonstrate the great potential for the optimized use of this nonfossil carbon as a source of energy that is replenishable within a human lifetime. The feasibility of up-scaled adsorption-driven technologies to capture and refine aqueous CH₄ still awaits verification, yet recent estimates of global freshwater CH₄ production imply that the worldwide energy demand could be satisfied by using the "biofuel" building up in lakes and wetlands. Biogenic CH₄ is mostly generated from biomass produced through atmospheric CO₂ uptake. Its exploitation in freshwaters can thus secure large amounts of carbon-neutral energy, helping to sustain the planetary equilibrium.