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Waste water turned into asset in green hydrogen production

The planned PtX plants in the municipality of Esbjerg will be able to utilize large volumes of waste water in their hydrogen production. Local utility company, DIN Forsyning, H2 Energy Esbjerg and HØST PtX Esbjerg recently signed a development agreement to further mature the technical solution needed.

In the future, the citizens of Esbjerg will be contributing to the production of Power-to-X (PtX)-based green fuels whenever they flush the toilet. A development agreement between DIN Forsyning and the two largest PtX plants is going to commit the three companies to work together on a technical solution which will enable the use of waste water in the so-called electrolysis process.

Waste water as valuable resource

The production of green hydrogen takes place in a Power-to-X plant, where electrolysis converts electricity into hydrogen by splitting water(H2O) molecules into hydrogen(H2) and oxygen (O). This requires large amounts of electricity and large volumes of water; something like 4 million m3 for the two PtX plants in Esbjerg alone. In order not to drain the ground water resources and protect the drinking water, alternative thinking has been needed. Managing Director in DIN Forsyning, Helle Damm-Henrichsen explains:

- The basic idea is to clean waste water, purify it, and then turn it into a valuable resource which can create value to society. Also known as upcycling. We will never run out of waste water. In Esbjerg alone, we produce more than 15 million m3 every year. Apart from protecting our precious drinking water resource, this model also means we do not need to spend resources pumping any extra water out of the ground. The water is already in our treatment loop, explains Helle Damm-Henrichsen, who is looking forward to the cooperation with HØST PtX Esbjerg and H2 Energy Esbjerg.

Stong co-operation benefits the environment 

Both HØST PtX Esberg and H2 Energy Esbjerg are thrilled that comprehensive studies have deemed it possible to use waste water in the electrolysis process. Generally, sector linkage and the co-operation across companies is key to the energy systems of the future.

- Society can benefit hugely from intelligent sector linkage, and the use of waste water is yet another example of that. In this case we apply a previously useless resource and turn it into an asset which benefit us all. We have already entered into an agreement with DIN Forsyning about the provision of climate friendly district heating from our plant, and it’s an example that showcases some of the great options offered to the industry by the city of Esbjerg.

We believe in the good partnerships, and we are convinced that PtX in Esbjerg will mean more jobs, increased security of supply and benefits to the environment, says HØST Project Director, David Dupont-Mouritzen.

Legislation needs to support green transition initiatives

Utility company, DIN Forsyning is already moving ahead with the plans. However, there are still some obstacles that need to be tackled, in particular within the current legislation for municipal water treatment:

- The financial boundaries in the Danish Water Sector Act are designed to protect citizens against price increase, while at the same time ensuring that the Danish utility companies work as efficiently as possible. But the framework becomes a challenge in the formation of new, innovative solutions benefitting the green transition. We need a different framework when we enter into commercial agreements, for instance offering cleaned waste water to the PtX industry. We hope that the legislation will follow the development and going forward support the green transition projects, concludes Helle Damm-Henrichsen.

Facts about DIN Forsyning:  

  • DIN Forsyning cleans approx. 24 mio. m3 of waste water annually – hereof 15 mio. m3 in Esbjerg alone
  • It is expected that the two PtX plants will consume 3-4 mio. m3 of water annually
  • In comparison, the total consumption of drinking water provided by DIN Forsyning (Esbjerg and Varde) totals approx. 8 mio. m3 annually
  • Large-scale PtX consumers will be offered waste water, and if more water is required, they will be offered groundwater unfit for drinking