Contributing to the energy transition by being flexible

The FlexInWater cases were structured around various challenges at the intersection of water and energy. An important overarching issue is grid congestion, i.e. that the electricity grid in the Netherlands can no longer meet demand. Drinking water companies are also experiencing the consequences of this.

Limits of grid management

Abel Heinsbroek of Vitens explains: “For us, grid congestion means that some projects are delayed or cannot go ahead. Examples include connecting new treatment plants or expanding existing installations. Distribution System Operators (DSOs) try to help where possible, but are reaching their limits. That is why we asked ourselves: how can we help each other?”

Alleviating congestion

Together with KWR, Vitens has made calculations for various locations to see how the drinking water company can help alleviate grid congestion. It turned out that the power requirements of drinking water companies and DSOs peak at the same times. “For us, the greatest power requirement is in the summer,” explains Heinsbroek. “Our drinking water production then runs at full capacity, because households demand a lot of water. At the same time, DSOs have plenty of power available in the summer, because solar panels generate a lot of it. This often means they also have sufficient local transport capacity available. But in winter, DSOs have a shortage of transport capacity because a lot of power is being used, while we need to produce less water. How wonderful would it be to adjust our contract with  our DSO to these fluctuations? Currently, our contract is still based on the maximum amount of electricity we are allowed to purchase. This value applies throughout the year. Greater flexibility in this area would be highly desirable. I look forward to this with our DSO.”

Creating space

Based on this insight, Vitens will conduct a trial at one of its locations this winter. Heinsbroek: “We want to see how we can adapt our operations in such a way that we can help the DSO. Of course, this must not be at the expense of our water quality. And the customer should not experience any adverse effects. But perhaps this will create exactly the wriggle room the DSO needs to connect that one additional residential area or factory.”

Further reducing our carbon footprint

PWN’s participation in FlexInWater was motivated by a different need, explains John Vrijbloed, who works for this drinking water company. We generate our own solar power using floating solar islands on our reservoirs. We use most of this power for our business processes, but there are also times when we have a surplus, which we feed back into the grid. Our question was: can we use this power somewhere in our purification process to further reduce our carbon footprint?’

Surprising result

The idea was to make the UV lamps work harder and reduce the dosage of peroxide in PWN’s purification process during periods of surplus electricity. ‘KWR looked at the CO₂ load per hour,’ explains Vrijbloed. “Because that varies, of course. During the day, there is a lot of solar power, which reduces the footprint. But at night, the electricity has to come from the grid and the footprint increases. The calculations confirmed this pattern, but there was also a surprising result. It turned out to be beneficial for our carbon footprint to use more peroxide at night. The resulting footprint is lower than that of the electricity generated at that time, which could be generated by a coal-fired powerplant. Of course, this difference will become smaller as we move towards renewable energy. We thought the project was a good exercise to see what is possible.”

Drinking water quality

Like Heinsbroek, Vrijbloed emphasises that applying flexibility must not adversely affect the end product. “Varying the ratio of UV to peroxide means that there will be a difference in drinking water quality. You can’t just do that. But I think one of the most important results is that we have investigated the potential. We are starting to think about our business processes in a new way. In the future, the energy supply will no longer be a constant. This will have an impact on drinking water production and requires a different mindset. FlexInWater has certainly contributed to that.”

Flexible train

Drinking water companies could also investigate whether flexibility in energy management could lead to cost savings. ‘We wanted to know how flexible we are at the start of our drinking water production,’ says Hylco van Engelen of Dunea. To explain how it works, he compares this process to a train. “It starts with the intake from the Meuse, at Brakel. From there, the water goes to Bergambacht, where it is pre-treated so we can infiltrate it into the dunes. There, the water ends up in dune basins. With nature in mind, we are reluctant to vary the water level in the dunes. Instead, we have investigated how much we can fluctuate our intake at Brakel and our pumping at Bergambacht, to help us connect better to cheaper energy or reduce grid congestion.”

Security of supply

Although the calculations show that there are certainly opportunities, Van Engelen also points out the snags. “On paper, you can run the pumps harder at cheaper moments. But you also have to consider the pipe conditions, for example. Are they able to withstand this? In addition, Dunea – like any other drinking water company – is focused on security of supply. That must never be compromised. This study was extremely useful because it allowed us to review all our process steps carefully. We could ask ourselves: why have we been doing it this way for a hundred years? With thorough knowledge, you can engage in that discussion and take new directions when circumstances require it.”

Water in the Cirsular Economy

FlexInWater was carried out on behalf of the  Water in de Circulaire Economie (WiCE) research programme. In WiCE, water companies and KWR, together with partners in the water chain, develop applied knowledge for the transition challenges in energy supply, water availability, climate and the circular economy. In WiCE ontwikkelen waterbedrijven en KWR, samen met partners in rond de waterketen, toegepaste kennis voor de transitieopgaven op het gebied van energievoorziening, waterbeschikbaarheid, klimaat en circulaire economie.  

Final symposium

On September 23^rd, the project results have been shared during the Symposium on Flexibility in the Water Sector.