Grid impact of hydrogen is a system architecture matter – ETIP SNET

Hydrogen electrolysers are not treatable merely as a new load on the grid and must form part of the system architecture, a new review from ETIP SNET states.

Electrolysers are most likely to be realised as industrial investments primarily by private bodies, having secured their business case based on purchases of hydrogen or its derivatives from off-takers. They will then submit a request for connection to the grid in a location and with characteristics according to their needs and constraints.

However, in the perspective of large-scale integration of electrolysers, in the range of hundreds of GW in Europe, their impact, both on the local grid and the broader energy system, is not treatable as requiring just a connection solution.

It is instead a question of system architecture, which must be addressed from the start as a coordinated energy system development among hydrogen operators, gas operators and power grid operators, as well as the private investors making those large investments.

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The report points to four overarching issues that arise, of which one is the relationship between the supply and demand-driven aspects.

On one side, one can consider building electrolysers for exploiting excess renewables, but on the other one can develop additional renewables for exploiting green hydrogen decarbonisation capacity and system flexibility.

Both approaches have to match the final users’ demand evolution, therefore a virtuous loop between supply needs and demand needs has to be set up under a coordinated holistic development of a whole energy system.

Others are the use cases and their impact on the grids, the potential for flexibility from the hydrogen ecosystem and the impact on scenario definition and system planning methodologies with projects still uncertain in time, number, size, locations, grid interaction and operation mode, etc.

Among the key findings of the study are that hydrogen is complementary to electrification for decarbonisation targets and not a target in itself.

The first applications of green hydrogen are likely to be for substituting grey hydrogen in present industrial processes. However, electrolysers shall progressively become an additional system element, which implies they are planned and operated in synergy with the rest of the energy system.

Grid operation and planning

Regarding the impact on grid operation, the hydrogen system can provide both short-duration flexibility and grid services and long-duration flexibility, adequacy and resilience.

The former is dependent on technologies and on hydrogen off-take agreements and the latter on the ecosystem, i.e. final uses, logistics, storage options and markets.

In terms of grid planning hydrogen projects should be designed and assessed starting from the end use case, volumes and costs, rather than from the supply side, which must follow the needs of the end user.

Moreover projects should be assessed with an end-to-end approach, i.e. in economic terms, energetic terms, decarbonisation effect and cost-effectiveness, with the viability both case and country-dependent.

Ultimately win-win solutions matching business needs with system requirements must be found in order to maximise the benefits for all stakeholders, the report states.

Coordinated planning, from scenario-building to system impact and to consistent cost-benefit analysis of single projects, is necessary in order to best exploit existing infrastructures, avoid stranded assets and bottlenecks.
Repurposing the gas grid, also through initial blending, is a viable and smart option to enable a gradual phase-out of natural gas and set-up of an hydrogen market.