Biomethane Acceptance in Underground Gas Storage Facilities
16 February 2022 | News
In its latest technical report, MARCOGAZ examines the acceptance of biomethane in Underground Storage facilities (UGS). It delves with the implications of biomethane injection into the gas transport grid and UGS facilities, although some peculiarities to certain types of storages, especially aquifers, are specified.
MARCOGAZ highlights the significant role of oxygen existence in biomethane due the gas treatment process of biogas. Indeed, the increasing level of biomethane injection into storage facilities, alongside the accelerating energy transition and decarbonisation of the gas industry, may require handling of oxygen ingresses due to sensitivity of storage facilities, particularly aquifers.
MARCOGAZ’s conclusions determine that the storage of renewable gases in UGS and close monitoring of oxygen levels in UGS facilities are essential in order to support the energy transition and to further achieve the aims of a decarbonised gas sector and green deal objectives.
Key Preliminary Conclusions of Biomethane and Oxygen impacts on UGS Facilities
- Should the composition of biomethane be compliant with standards and regulations, its storage in deep aquifer should not create significant impact on the water quality of the aquifers.
- Depending on whether the usual required natural gas specifications are met, Biomethane can be injected in UGS facilities as an exchange gas equivalent to natural gas.
- Permissible oxygen content is dependent on the specific facility and must therefore be assessed case by case.
- An Oxygen limit of 100 ppm or more is acceptable for some UGS facilities. More sensitive storage facilities or oxygen sensitive industries require a permissible oxygen concentration of 10 ppm at most.
- The amount of Oxygen in the gas grid and storage facilities should be kept as low as possible.
‘As other components defining the gas quality according to local standards, the oxygen content should be monitored before the injection into the grid and into UGS. A detailed analysis, with special attention to the interaction of critical components such as oxygen, carbon dioxide and hydrogen sulphide, is mandatory in order to ensure integrity and safety of the facilities’.
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