• European Green Cities/Site Development

Stad van de Zon, the first CO2-neutral district in the Netherlands

Updated: Apr 14

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Project information summary

Source: Nautilus Eco-solutions bv


‘De Stad van de Zon’ is the first CO2-neutral district in the Netherlands; moreover, a great deal of attention was put into the district’s water mission. The large water presence in ‘De Stad van de Zon’ (approx. 33%) serves as water storage and for recreation. ‘De Stad van de Zon’ takes its name from the large number of solar roofs, which generate enough energy to cover all the electricity consumed by the 1400 homes.


The active solar energy is produced by applying 2.45 MW photovoltaic (PV) solar panels on the roofs of the houses and the various facilities. This is part of the 5 MW PV-project in which the municipalities Alkmaar and Langedijk participate. ‘Stad van de Zon’ in Heerhugowaard was with 2.45 MW power capacity realised the biggest partner in the European SUN city project. The goal of this project was to increase the use of PV panels and to bring the European energy targets closer. The district itself produces the same amount of energy that it needs for living, working and traffic. In addition to the realised active solar energy houses, three wind turbines were installed in the recreation area.


The large pond surrounding the district’s Central Square is of swimming pool quality and acts as a recreational pool and a rainwater buffer. A specific water system has been created for the area, which is not connected to Heerhugowaard’s food-rich and polluted polder water. The system is fed almost entirely by relatively clean rainwater running off from the district’s roofs. The ground level in De Stad van de Zon is raised to prevent seepage of polluted water.

The district’s area is divided into three parts: one part is reserved for water, one part is built-up and one part is used for nature and recreation. The area reserved for nature includes a labyrinth of streams for purifying the district’s water. In that labyrinth, with its natural banks and large quantities of water plants, the water is purified in a natural manner. A circulation pump has been positioned on the southern edge of the pool. The form of the central square creates several blind corners in the flow pattern. The water quality is monitored: if the water becomes too polluted, it can be pumped through the purification system at the inflow point to improve the water quality.


In this project, Nautilus Eco - solutions BV was involved in the second phase, where a crooked ecological corridors for elongating the water path was built. This makes the water treatment method totally nature - based, only hydrophyte was applied to purify the water, by increasing the water retention time, the excessive nutrient (phosphate and nitrogen) can be removed from the stream. The project is an example of our nature - based solution and an ambitious for us to apply this concept on bigger scale.




Source: Urban Green-blue

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