Thank you for the email with the results from my FoI request. I was wondering if it would be possible to clarify a detail from my request; please could you explain what the process of Energy Recovery by Incineration involves, and whether there is a particular site that the non-recycled waste from the Underground goes to to undergo this process?

---

TfL Ref: 2927-1819

Thank you for your follow on request to 2462-1819 received by Transport for London (TfL) on 1 February 2019 asking for information about the process of Energy Recovery by Incineration relating to newspaper waste on the London Underground.

Your request has been considered in accordance with the requirements of the Freedom of Information Act and our information access policy.  I can confirm that we hold the information you require.

Energy recovery by incineration, also known as energy from waste (EfW), is where waste is burnt at high temperatures (850 degrees C and above) to generate electricity for the national grid. There are a few variations to how this process creates electricity but typically the heat generated causes steam and carbon dioxide which powers a turbine to form electricity. Below is a step by step to how this process works in more detail.

1. Solid and liquid waste is delivered to an EfW facility and stored for processing.

    

2. The waste is transferred to a combustion chamber where self-sustaining combustion is maintained at extremely high temperatures. The facility maintains the building around the tipping and bunker area under negative pressure and uses this air in the combustion process to control odor.

    

3. The heat from the combustion process boils water.

    

4. The steam from the boiling water is used directly or drives a turbine that generates electricity.

    

5. Electricity is distributed to the local grid.

    

6. Ash from combustion remnants is processed to extract metal, which is then recycled. The remaining ash is then combined with residue from the air pollution control process (see steps 9 and 10).

9. All gases from the combustion process are collected, filtered, and cleaned with current air pollution control technology that operates to strict standards set by the Environment Agency.

10. The combined residue is beneficially reused. The material is typically used by the aggregate industry to make asphalt for roads.

11. Emissions and other operating criteria are closely monitored by the Environment Agency to ensure compliance with permit conditions.

The waste generated from London Underground is sent to various energy from waste plants however dependent on the location where pick ups of waste have been made however a large proportion is sent to a plant in Kent. Material is taken from transfer stations to this site on barge along the Thames to minimise road use and decrease vehicle movements.

Material is also sent to EfW plants in Germany, Sweden and other Scandinavian countries where by energy from waste is treated as a much more widely used form of renewable energy. The movement of waste in this way is really dependent on market conditions.

If this is not the information you are looking for, or if you are unable to access it for any reason, please do not hesitate to contact me.

Please see the attached information sheet for details of your right to appeal as well as information on copyright and what to do if you would like to re-use any of the information we have disclosed.

Yours sincerely

Sara Thomas

FOI Case Management Team

General Counsel

Transport for London

Back to top

---