D8.1 & D8.2 State of the art technologies in the current gas grid and gap definition with the future hydrogen grid

The Dutch government’s central goal with the National Climate Agreement is to reduce net greenhouse gas emissions in the Netherlands by 55% by 2030 compared to 1990 levels and 100% by 2050. Hydrogen will carry out a number of critical functions within energy and raw material systems.

The Distribution System Operators (DSO’s) in the Netherlands may play an important role delivering (green) hydrogen to the built environment via their existing gas transport network for sustainable heating of homes and business.

Replacing natural gas by hydrogen in the existing DSO infrastructure will give several challenges (next to safety aspects, social acceptance, etc.) on the security of supply of energy to the end-users, related to the physical aspects of the assets in the hydrogen network. We would like to analyse where digital technology can contribute in accelerating the natural gas grid transformation. The scope of the research is limited to 100% hydrogen grids.

As a research methodology to execute work we chose for the following approach:

1. Get insight in the state of the art of digitalization of the current DSO gas grids, by sending a questionnaire and interviewing DSO representatives. The same questionnaire has been sent to TSO Gasunie to get a benchmark.
2. Get insight in the needed digitalization of the future hydrogen grid. This was done by:
   • Literature study, mainly regarding foreign DSO’s.
   • A workshop with Dutch DSO representatives.
3. Both the literature study and the outcome of the workshop with the DSO’s give an indication of the desired situation of digitalization of the (future) hydrogen grid.The concrete topics can be compared with the current situation regarding Modelling, Monitoring and Control. Within in the scope of this research, we will give a qualitatively description on the technology gap, and a (preliminary) prioritization of the gaps.

Main results from the state of the art investigation for three systems are given below.

Modelling

All DSO’s use commercial tools for capacity calculation, designing the gas grid and determining risk levels regarding delivery. All capacity simulations are based on worst case scenario’s, like maximum demand at -12 or -13 °C. No dynamic hourly demand profiles are used. For risk analysis the N-1 approach (omitting one asset) is used, in most cases for design reasons. The tools are able to work with different gas compositions, but are only used for natural gas at this moment.

For most DSO’s the capacity calculation tool is validated based on pressure measurement data at district stations and total flowrates at GOS. The data from measurements in the grid is not yet directly integrated to the capacity simulation tool. Currently the data is used as a manual input of the tool or by manually comparing the value in Excel table.

Monitoring

Pressure is the most common parameter being measured in the network. Mostly, there is no sensor placed in the pipeline, only a limited number of stations are being measured. Need for flow data has been observed and most DSO’s are working on that topic. Data from GOS and green gas suppliers is available.

Most of data is manually accessed by the DSO by sending people to onsite location or a manual download from the website. Some station data of some DSO can be retrieved automatically via Remote Terminal Unit (RTU) unit.

The use of smart meter data at small consumers is limited. Individual demand of small consumers is predicted by ‘Standaard JaarVerbruik’ (SJV) or by contract values for large consumer.

Control

The grid control at DSO’s is autonomous on pressure. The pressure setting is changed manually. The grid is robust with respect to capacity. DSO’s recognize no huge need for advanced control of the grid capacity in normal operation. More advanced control might be needed  in some cases of green gas supply in the grid, e.g. boosters and dynamic pressure management.

Most activities regarding Control are on green gas feed-in. Control is done by closing the valve in case of deviating gas quality. Manual control of the GOS pressure is done by request, to allow green gas feed-in in low demand period.

From the workshop with the DSO’s we found the main challenge of operating a hydrogen grid is about balancing the hydrogen grid. There are several factors that contribute to this challenge:

1. Increasing dynamics in supply and demand, like changing user profiles, increasing local supply and local storage and line-pack
2. From a stand-alone gas grid to a multi-connection grid. Observed trends are: connection to other DSO’s, connection to Gasunie backbone and connection to E-grid (bi-directional)
3. Get access to real time data, on both Demand and Supply.

The workshop delivered many ideas on how to address the main challenges:

1. Monitoring. Real-time data of Supply, Demand and Storage. Measurements in the grid (stations, pipes): Flow, Pressure, Quality and Temperature.
2. Modelling. Real-time capacity models with coupling to externals: E-grid, Gasunie, other DSO’s. And tooling for short term transition planning from natural gas to hydrogen.
3. Control. Controlling the priority of suppliers which can feed into the network.

The main results of literature study on mainly foreign DSO’s are globally in line with the results from the Dutch state of the art investigation and the main outcomes of the workshop.

Both the literature study and the outcome of the workshop with the DSO’s gives an indication of the desired situation of digitalization of the (future) hydrogen grid.  Especially, the ‘HOW’ topics can be compared with the current situation to come to  a qualitatively description on the technology gaps.

From technology point of view we come to the following summary of the technology gap in digitalization of the hydrogen grid.

Combining the technology readiness and timing, results in a preliminary prioritization of the technology gaps for modelling, monitoring and control.

To provide more quantitively information regarding the development of the main technologies for digitalization of the hydrogen grid, in the second part of the current HyDelta 2 project we will investigate a selection of the gaps in use cases:

1. Investigation on the number of flow sensors and pressure sensors needed in the grid. Investigate the added value of flow sensors?
2. Investigation on the added value of using demand profiles and intermittent supply profiles for balancing the hydrogen grid using storage by utilizing producer priority and grid pressure regulation.