Pilot project on hydrogen injection in natural gas on Island of Ameland in The Netherlands

Abstract

The Netherlands, as many other countries, strive for a more sustainable energy mix and efficient energy consumption. Hydrogen, which is one of the energy carriers of the future, plays an important role in this respect. The use of hydrogen, when produced in a sustainable way on a large scale (for instance by means of wind and solar energy) considerably reduces the CO2 emissions, compared to fossil fuels. Injection of hydrogen in natural gas is one of the possibilities on the route to sustainable gases. The aim of the injection of hydrogen into natural gas in this pilot project was to obtain knowledge regarding the electrolysis, the mixing process and the behaviour of the gas grid and gas appliances. Different types of mains, joints, service governors, gas meters, boilers and cooking devices were tested. The experiences and the opinion of the end-users were an important part of the pilot project since successful energy transition requires a broad social basis. This pilot project is part of progamme "Sustainable Ameland". The project was executed by Joulz, together with Kiwa Gas Technology as subcontractor, on behalf of GasTerra and Stedin. It was the first time that the influence of the injection of hydrogen in the natural gas supply was tested in an actual situation in the Netherlands. This took place in a small scale natural gas grid which supplies the apartment complex "Noorderlicht" in the town of Nes on Wadden Sea island Ameland, of the northern coast of the Netherlands. Apartment complex "Noorderlicht" houses 14 families. Each apartment has its own gas meter and heating system. Gas boilers and cooking appliances have never before been exposed to a hydrogen-natural gas mixture for such a long time. The duration of this project was four years. Hydrogen was mixed in the natural gas supply from 5% to 20% (volume), increasing the hydrogen content in steps of 5%. After assembling the housing for the electrolyser, the hydrogen supply was switched from hydrogen bottles to on-site production by electrolysis. The electricity needed for generating the hydrogen was produced by solar panels on the nearby new building of the "knowledge and innovation centre". Thus, the hydrogen used came from a fully sustainable source. For pipeline materials testing a reference grid and a test grid were added to the existing natural gas grid. These similar grids were constructed especially for this project. The grids were made of components originating from the same batch. The grid contained different pipeline materials for mains, joints, service governors and gas meters. The selected pipeline materials and accessories are commonly used in the Dutch gas network. The boilers and cooking appliances were selected based on burner principle. These selected appliances are also commonly used in the Netherlands and were not adjusted for hydrogen enriched natural gas. Beforehand all gas appliances were tested by means of test gases containing 30% of hydrogen. This 10% safety margin over 20% was applied to overcome dynamic behaviour (overshoot) of the mixing unit. The initial state of service governors, gas meters, boilers, cooking devices and opinion of end-users were saved in a baseline measurement. The test data was compared to the baseline data. In case of mains and joints the test measurements of the test grid were compared to the test measurements of the reference grid. In this paper the influence of the injection of hydrogen in the natural gas supply on the gas grid and gas appliances has been evaluated.