Pondera investigates concept of sewage treatment plants as smart energy hubs

The Dutch water boards want to become completely energy neutral by 2025. A shortage of grid capacity could jeopardise this goal. Dutch Pondera is conducting research for the Unie van Waterschappen (Dutch Association of Water Boards) into a sustainable solution to make sewage treatment plants less dependent on the electricity grid. This has led to the idea of a Smart Energy Hub: an electrolyser installed at a sewage treatment plant to produce green hydrogen.

The Dutch water boards operate over 300 sewage treatment plants across the country. These account for over 8 PJ of energy consumption (primary) with ample connection to the electricity grid. In addition, they are one of the largest producers of biogas and green gas (over 135 million cubic metres per year) and there are also many opportunities for installing solar panels and wind turbines.

Combined with a wind turbine and/or a solar park, a sewage plant could form an energy hub together with the companies in the area: a node where energy flows converge and conversion to other forms of energy can take place. All of the generated energy can be exchanged with each other.

By implementing Smart Energy Hubs, the water boards can make a major contribution to the energy transition through the generation of sustainable energy. In addition, they will relieve the burden on the Dutch electricity network

Pilot studies in Harderwijk and Kampen

Pondera has evaluated two pilot projects, in Harderwijk and Kampen, for a combination of a wind turbine and a solar park and an electrolyser. At the Kampern sewage treatment plant there are already plans to realise a solar park of approximately 1 MW and one modern wind turbine of 4 to 5 MW. At the Harderwijk location, in the near future, a solar field (1,8-2,4 MWp) and a wind turbine (±3,5 MW) will be realised on the site.

The availability of sustainable energy and the use of pure oxygen for aeration of the treatment process could lead to large energy savings at the sewage treatment plant and a favourable business case for green hydrogen. Sewage treatment plants are also attractive locations from a licensing point of view, because often a biofermentation plant is already operational here. The installation of a small or medium-sized electrolyser at a sewage treatment plant seems promising, according to the report.

The report ‘De rwzi als smart energie-hub’ (in Dutch) by Pondera was presented on 8 October to a delegation from the Dutch Parliament. Pondera will soon commence with the implementation of the pilots to further investigate this concept. Source: Pondera

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