Semi-finished products for construction

Products and by-products

When producing energy at biomass/coal power plants Amercentrale and Eemshavencentrale, residues are released in addition to electricity and heat. These residues are used in civil engineering.

Bottom ash

During the combustion process in the boiler, ash particles are formed and collect at the bottom of the boiler. This so-called bottom ash is used as a foundation layer under, for instance, motorways or sports fields.

Fly ash

The lighter particles of ash heading towards the chimney are electrostatically captured and collected. This so-called fly ash has cement-like properties and is therefore used in the concrete and cement industry to replace the mineral cement.


A final wet cleaning of the flue gases using limestone and water removes the sulphur dioxide, forming the extremely pure gypsum. This so-called flue gas desulphurisation gypsum (ro-gypsum) is used, for example, in plasterboard.

To use these by-products in construction, they must meet Kiwa quality requirements. To this end, RWE issues so-called performance declarations describing, among other things, the composition of the various products. You can download these declarations below.