Researchers at the University of Sheffield have been studying the process of biomethanation to determine whether it could be used effectively by the wastewater industry and the wider industrial and domestic heat sector as an alternative to fossil fuels.
Working in partnership with United Utilities, Dr Stavros Michailos and a group of fellow researchers from the University's Energy 2050 group carried out a techno-economic assessment of four methods of biomethanation, part of a group of processes known as Power to Gas (P2G).
In order to reduce the amount of gaseous carbon compounds released by (or decarbonise) industry processes, improve long-term energy storage and deliver an energy system that can support a balanced grid, there first needs to be an efficient and cost-effective method of creating the same gases and other outputs made by fossil fuels. One potential method is to upgrade biogas to biomethane through P2G.
Recently, the biomethanation of CO2 has emerged as a promising biogas upgrading technology. The tests run by the research team aimed to determine whether biomethanation is a viable option for businesses, and the most effective way implementing it.
Furthermore, the group wanted to test the additional process of using digestate to reduce the waste products created by biomethanation. The utilisation of sludge digestate as fertiliser is usually avoided due to high contents of heavy metals, however using digestate in the process of biomethanation would contribute towards a circular economy and increase the benefits of biomethanation for businesses.
The results of the study found that whilst biomethanation is not currently competitive with the price of fossil fuels, there is a future where Power to Gas is a viable and profit-generating option for businesses. However, the future of these new processes depends on equipment cost reductions, renewable energy incentives and other policies which encourage businesses to focus on decarbonising their operations.
Speaking about the project, Dr Stavros Michailos said, "Biomethanation and its associated processes under the umbrella of Power to Gas give us an opportunity to make industry far better for the environment, producing less emissions and using renewable sources of energy.
"Although our study shows that there's a long way to go before wastewater plants and other facilities could efficiently make use of biomethanation, the more we research into different methodologies, the more we can highlight the importance of long-term policymaking and investment in new technology. We hope our study can evidence the possibilities of biomethanation and the circular economy."
Read the full paper from the journal of Energy Conversion and Management