Combustible waste that cannot be sorted or reused is processed in the waste-to-energy (WTE) incineration plant.

The current WTE plant, with its two incineration lines, has been in operation since 1997. It is one of the most modern WTE plants in the world. With an average temperature of 1000°C, waste is incinerated here 24 hours a day, seven days a week.

The current plant can process 300,000 tonnes of waste on an annual basis. As a result, Twence now produces about 190 GW of electricity each year, 36 GW of which go to supply its own operating needs. The rest of the electricity produced is supplied to the public electricity grid. With the combustion of waste, Twence achieves a savings of 41 million m³ of natural gas each year, as well as a reduction of CO₂ emissions by 72,000 tonnes.

Twence is currently building a third incineration line, which is expected to be operational by the end of 2008. With an annual capacity of over 220,000 tonnes of waste, this new incineration line will be able to produce 135 GW of electricity and 180 GW of heat. The new line will therefore save 59 million m³ of natural gas and reduce CO₂ emissions by 104,000 tonnes each year.