Underground storage – Risk assessment
The German government’s Integrated Energy and Climate Program (IEKP) of 2007 called for a 30% share of renewable energies in electricity generation by 2020 and even exceeded this target by reaching 45%. The electrolytic production of hydrogen and partial feed-in into the natural gas grid (power to gas) is one way of storing surplus energy from renewable sources. According to DVGW guideline G 262, a maximum volume share of 5% hydrogen in the natural gas grid is already compliant with regulations. Higher upper limits are currently being discussed; this limit has already been successfully quadrupled as part of the “20% hydrogen in the gas grid” innovation project.
Several studies have already highlighted the microbial-related technical risks associated with feeding a proportion of hydrogen into underground storage facilities. MicroPro GmbH is addressing this problem by developing a monitoring process for the microbiological risk assessment of hydrogen storage. This risk assessment comprises meaningful chemical, microbiological and molecular biological analyses, which have been compiled under strictly economic and practical aspects.
Microbial risk assessment
- Current degree of colonization of the underground storage tank
- Hazard potential due to hydrogen-utilizing microorganisms
- Assessment of the technical and economic risk
- Prevention and treatment strategies
Further information
The advantages of various analysis techniques are combined for comprehensive microbiological storage characterization. In addition to the molecular biological identification of relevant microorganism groups, the detection of living microorganisms in enrichment cultures has proven to be very informative. With these enrichments, the risk potential can be assessed in model tests under the specific storage.
Risk assessment includes the following tests with original material from underground storage
- Microscopic examination
- Physical/chemical analyses
- Molecular biological detection of relevant microorganism groups
- Enrichment and characterization of living microorganisms
- Model tests under high pressure conditions
- Testing of treatment strategies to combat bacteria
In addition to the actual laboratory analyses, a comprehensive knowledge of the system history and operating procedures is required for the property assessment