Gas in the Decarbonising German Energy Space
For quite a while many have overlooked the contribution that fossil natural gas and – lately – ‘green gas’ can make towards Germany's decarbonisation effort. This is partly due to the considerable complexity of a multitude of studies and reports where the acknowledged relevance of gas is ignored. But it is also because gas is frequently put in the ’dirty fossil corner’ all too quickly.
Against this backdrop research institute ‘ewi ER&S’ and consultancy ‘The Gas Value Chain Company’ have extracted the considerations and arguments addressing the long-term relevance of gas in the decarbonising German energy space in various studies.
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They compare a scenario labelled Electrons, implying a high degree of electrification and lower use of gas with a scenario labelled Molecules, the latter implying a higher degree of direct gas use in all sectors. Gaseous molecules as energy carriers will be instrumental and indispensable in both the Electrons and the Molecules scenarios all the way towards 2050. Fossil natural gas demand can remain at current levels up to CO2 reduction targets of 65% to 70%. For deeper decarbonisation beyond 70%, gas has to become ‘green’, i.e. non-fossil. In the Molecules scenario, demand for green gas reaches ~800 TWh in 2050 in order to achieve a -95% CO2 reduction.
Synthetic methane, produced by the power-to-methane process, is the most likely option for greening gas in large quantities. Therefore, and also in the face of further rising significant ‘overproduction’ of green power otherwise curtailed, it appears crucial to develop this technology on an industrial scale sooner rather than later.
Gas and the existing gas infrastructure will be pivotal for ensuring the security of electricity supply in more than one way: gas acts as a ‘permanent synchroniser’ for intermittent wind and solar; it satisfies peak power demand (rising towards 160 GW in ‘EL95’) stemming e.g. from heat pumps during cold spells and steps into the breach supplying significant quantities of power (total power demand rising towards ~930 TWh in ‘EL95’) during protracted periods of ‘Kalte Dunkelflaute’ – no wind and short days.
While gas-fired power generation capacity will rise from 30 GW in 2015 towards 57 GW (‘TM95’) and 107 GW (‘EL95’) towards 2050, peak gas demand will decline in both the Electrons and the Molecules scenario. Hence, existing gas infrastructure by and large suffices, with the caveat that certain adjustments and re-enforcements may be necessary to accommodate the additional gas-fired generation capacity.
Seasonal gas demand patterns as we presently know them will diminish. However, volatility stemming from renewables intermittency will rise substantially, implying a greater need for short-term flexibility such as ‘line-pack’ and multiple-cycle peak storage.
Gas-based decarbonisation strategies are significantly less costly than those based on electrification. The Molecules scenario achieving 80% CO2 reduction (‘TM80’) in 2050 causes additional costs of €1.2 trillion ($1.4bn) (€600bn cheaper than ‘EL80’), while the Electrons scenario achieving 95% CO2 reduction (‘EL95’) causes costs of €2.2 trillion (€500bn more expensive than ‘TM95’).
The paper, by Drs Harad Hecking and Wolfgang Peters, may be read here.