Hydrogen in Underground Gas Storages for Natural Gas Open Questions

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1 Hydrogen in Underground Gas Storages for Natural Gas Open Questions Dr. Stephan T. Hatscher Wintershall Holding GmbH

2 Hydrogen in Natural Gas Storages What is it all about? Hydrogen could be one answer to the challenges of the growing energy demand Storage of hydrogen in the natural gas infrastructure is discussed Where do German storage operators still see some open questions? 2

3 Types of Gas Storages Salt Caverns Solution mined containments Usage: peak load coverage Pore Storages Natural storage reservoirs in depleted oil/gas fields Artificially developed reservoirs in aquifer structures Usage: base load coverage 3

4 Natural Gas Storages in Germany Germany: 21,3 Giga (10 9 ) Nm 3 storage capacity In operation: 23 pore storages, 24 cavern storages Planned/under construction: 1 pore storage 24 cavern storages total capacity 13,9 billion Nm 3 Storage capacity to consumption ratio: 22% Source: LBEG Report (31 Dec 2010) 4

5 Natural Gas Storages in Europe Working gas volume in Giga (10 9 ) Nm 3 5

6 Natural Gas Storages in the World Country Working gas volume Number of storages in Giga Nm 3 US 110,7 389 Russia 95,6 22 Ukraine 31,9 13 Germany 20,8 47 Italy 16,8 11 Canada 16,4 52 France 11,9 15 Netherlands 5,0 3 Other countries Worldwide Source: EGU (2009) 6

7 Gas quality: Situation for the time being Long term gas supply contracts with producers Constant gas quality and compositions Homogeneous gas composition injected and withdrawn Operation is based upon gas quality standards/recommendations by DVGW G260 and/or EASEEgas 7

8 Gas quality: Upcoming changes New additional supply sources Biogas plants (oxygen, carbon dioxide, microbiology) Electrolytically produced hydrogen Thermally produced regenerative gases Odorized gases from neighbouring countries Feed-in of additional sources is not necessarily constant New gas components of varying composition Consequences on storage facilities expected Integrity Performance 8

9 Gas quality: Critical gas components Identified critical gas components and some major concerns: Oxygen Potential oxidation processes (development of elemental sulfur, precipitation of iron compounds), corrosion, degradation of production chemicals Odor / sulfur components Souring of reservoir, corrosion, plugging of pore throats by polymerization, odour nuisance in surface facilities Microbiology Souring of reservoir, corrosion, plugging of pore throats by biofilms Carbon monoxide / carbon dioxide Corrosion, toxicity Hydrogen 9

10 Component Hydrogen Possible effects Storage process Lower energy density of hydrogen Changed compressibility Effect on p/t relation Heterogeneous composition injected, heterogeneous composition withdrawn? 10

11 Component Hydrogen Possible effects Reservoir, especially for pore storages Hydrogen as substrate for biological activity Reactions of hydrogen with reservoir water and/or with reservoir rock Integrity of wells/cementation/completion and of caprock has neither been constructed nor checked for hydrogen 11

12 Component Hydrogen Possible effects Impact on steel and wellbore equipment Embrittlement Change in corrosion mechanisms Leak tightness of packers Influence completion elements 12

13 Component Hydrogen Possible effects Surface installations Effect of fuelgas on gas turbines Change in explosion range Reduced ignition energy Higher detonation velocities Change in Joule Thompson effect Leak tightness against smaller molecule gas 13

14 Gas quality: Gas storage operators Majority of German gas storage owners and operators are organized in WEG KUGS (Wirtschaftsverband Erdöl- und Erdgasgewinnung e.v.) In 2009, WEG KUGS founded a Work Group concentrating on potential effects due to change in gas supply sources for storages Way ahead of Work Group Identification of potentially critical components from alternative supply sources Identification and analysis of potential influences on subsurface and surface storage facilities Definition of topics for further research Development of limiting values for associated gas components 14

15 Summary Gas chain has been operated smoothly up to now Consequences of gas changes in associated gas components have to be analyzed, limits and guideline have to be determined There are open questions to be addressed and solved before we start injecting hydrogen! The integrity and the performance of storage facilities has to be maintained, as it directly affects the security of supply Any other open questions? 15

16 Backup 16

17 WEG Workgroup KUGS WEG Workgroup KUGS BEB (Wallbrecht) DBI (Schmitz) E.ON Storage (Zenner) EWE (Berger) GdF Suez (Wubs) RWE Dea (Schulze) VNG (Höcher) WEG (Grundmeier) Wingas (König/Sander) Wintershall (Hatscher) 17

18 Hydrogen and Methane Properties Parameter Hydrogen Methane Flamability in air 4,0 to 75,0 vol.% 5,3 to 15,0 vol.% Detonability in air 18,3 to 59,0 vol.% 6,3 to 13,5 vol.% Ignition energy in air 0,02 mj 0,29 mj Flame temperature in air 2318 K 2148 K Burning velocity in air 265 to 325 cm/s 37 to 45 cm/s Joule Thompson inversion -68 C (at RT: warming with expansion) Above RT (at RT: cooling with expansion) 18

19 Hydrogen embrittlement Hydrogen attack increases with High hydrogen partial pressure Increasing temperature Increasing carbon content in the steel (carbon steel often applied in non-sour gas wells in Germany) Increasing grain size of metals Cold worked metals With presence of moisture, traces of hydrogen sulfide, carbon monoxide 19

20 Hydrogen stress cracking Hydrogen stress cracking tendency strong With high tensile strength of metal With welds and hard spots in situations with cyclic loading In presence of traces of hydrogen sulfide and carbon dioxide Small concentrations of oxygen compensate the effect of hydrogen (reason for the stability of town gas storages?) 20

21 Chemical reactions Literature stated potential reactions with reservoir material: Sulfides to Hydrogen Sulfide and elemental metals Anhydrite to Calcium Oxide and Sulphurous Acid H 2 SO 3 Gypsum to Calcium Hydroxide and Sulphuric Acid H 2 SO 4 Iron Oxides to metal and water 21

22 Literature recommendation Underground Hydrogen Storage (Stephen Foe et al., Department of Energy and Environment, Brookhaven National Laboratory, Upton, New York, US, 1979) Generally pro hydrogen storage in natural gas storages, but Concludes that there is still research to be done Investigations are limited to low temperature and low pressure (< 1200 psi, < 100 F) 22