Heating of Amsterdam: every source needed

Vattenfall currently has two heat grids in the Amsterdam area: one in the north-west and another in the south-east. They will eventually be joined by the Amsterdam South Connection, which is currently under construction.

Making the heat grid sustainable and independent from natural gas is a major challenge, says Bart Dehue, Programme Manager Sustainable Heat:

"Recently, a lot of attention has been devoted to the development of a potential biomass-fired plant for this heat grid. Along with this plant, though, we are working intensively to develop a number of other sustainable sources."

Diemen is ideal for an electric boiler

Vattenfall currently has a 120 MW electric boiler in Berlin, but none yet in the Netherlands. An electric boiler converts electricity into heat that can be supplied to household and business customers or stored in the heat buffer already present in Diemen, south east of Amsterdam city.

"We received the permit for a boiler with a maximum capacity of 200 megawatts in early October," says Michelle Poorte, project manager for heat projects at Vattenfall Heat Nederland. "We will determine the actual capacity by the end of the year, because it depends on the technical feasibility and sustainability impact of the boiler on the district heating grid."

Here, the impact means that the larger the electric boiler, the more sustainable heat can be generated. The electric boiler only operates when the electricity mix is sustainable, produced from solar and wind power, and has a low cost.

"The location in Diemen is ideal for the electric boiler because it is close to the electricity and heat grids, and because we can store excess heat in the heat buffer," says Poorte.

Results of geothermal study expected in 2021

While the permit for the electric boiler has been issued, authorisation for extracting heat from deep underground in Diemen and near-by Almere – known as geothermal energy – is yet to be awarded.

"We are exploring the possibilities together with the municipality and the energy company HVC. HVC has extensive experience in drilling geothermal wells, so we are pleased to have them as a member of the consortium," explains Dehue. "The first step now is to obtain the exploration permit. This will give us the exclusive right to conduct a study into the possibilities for geothermal heat in this area.”

An important input for this is the national government's SCAN seismic survey programme, which maps underground features up to a depth of 6 km to see if there is a suitable stratum for extracting geothermal heat. The results of the survey are expected to be available in the course of next year.

Using residual heat from data centres in the heat grid

Amsterdam is one of the largest data centre hubs in the world, and data centres produce a great deal of residual heat. Now the first studies on the use of residual heat from the cooling water of existing and future data centres have started.

"The challenge is that the temperature of the residual heat from data centres is currently around 30 degrees Celsius. For large-scale application in the heat grid, the temperature often needs to be 90 degrees Celsius or higher. This means we would need heat pumps to raise the temperature of the water," Dehue says.

Poorte adds: "We are presently talking with a data centre developer to see how we can make the systems compatible. By using new cooling systems higher residual heat temperature could be achieved, so less electricity would be needed to boost the heat to the right temperature, making it more sustainable."

Lake water can be used for heating

Another source of energy could be water. The aquathermal potential is, in principle, very large because the enormous amount of surface water available in the Amsterdam area.

"The challenge is that the surface water is relatively cold, so a relatively large amount of electricity is needed to raise the temperature to a usable level. Even so, aquathermal could certainly play a role in the energy mix for the heat grid," states Dehue.

Poorte concludes:

"It would be great if all these different types of energy generation came together soon in a single heat grid, because all are necessary to make the heat system sustainable as a whole. Of course, we have to keep a critical eye on how we use the various sources to make fossil-free living possible within one generation."