Latest news on our biggest ever sustainability project
The investigation phase of University Hospital Lewisham's Ground Source Heat Pump (GSHP) project has now been completed, and we wanted to provide an update on progress.
Since works began in June, we have been carrying out drilling and testing activities within two temporary work areas in Ladywell Fields. The aim of this phase has been to determine whether groundwater beneath the park could support a future low-carbon heating system for University Hospital Lewisham.
This test phase is now complete, and demobilisation of the work sites in Ladywell Fields is expected to be completed by Friday 21 August 2026.
The plan to restore the park is being finalised and agreed with Glendale, the park maintenance contractor, to ensure that the restoration works have the best chance of success (when we finally get some rain!) We will provide further updates on the timeline for this, as soon as these arrangements have been made.
Progress to date
- All planned drilling works have now been completed.
- Both sets of test boreholes have been successfully installed, and the necessary testing has been carried out to assess whether the system could work at this location.
- Additional pumping and cleaning work was required to fully clear natural cracks and channels within the chalk aquifer, which allow groundwater to flow into the boreholes.
- As a result, some testing activities and programme dates needed to be adjusted, but the overall investigation phase has progressed largely as planned.
Discharge of chalk into the River Ravensbourne
During one of the initial pumping tests, an unexpected release of chalk sediment entered the Ravensbourne River.
The pumping test was stopped immediately, the relevant authorities were notified, and additional controls and filtration measures were introduced before testing resumed.
The project team worked closely with the Environment Agency and our specialist contractor to enhance the mitigation measures for the remainder of the works. Ongoing monitoring during subsequent testing confirmed that these measures were effective in preventing further chalk release to the river.
What happens next?
Following completion of the site works, the results from the investigation phase will be analysed by the project team and technical specialists. These findings will determine whether a ground source heat pump system is technically viable at University Hospital Lewisham and whether the project should progress to the next stage of development.
Analysis of the test phase results is still underway. The data collected from the boreholes and pumping tests is currently being reviewed by the project team and technical specialists.
Further updates will be provided once this analysis has been completed and the findings have been fully assessed by the Trust.
If the project is technically viable, then a full business case will be developed and considered through the Trust’s governance processes. We expect this decision would be made by mid-October 2026.
If the business case is approved, the project would then proceed with appropriate applications for licensing with the Environmental Agency, Lewisham Council as the landowner, and the Local Planning Authority. The Trust would also hold regular community liaison group meetings to provide a forum for project updates and discussion with local stakeholders.
We would like to extend a big thank you to local residents, park users and all stakeholders for their patience and understanding throughout the investigation works. We are well aware that major site works in the park during summer is not ideal! However, we really hope our rationale has been clear and worthwhile: reducing the hospital's carbon footprint, improving local air quality, and helping to provide a more sustainable and resilient heating and hot water system for our patients, staff and community.
Please do get in touch with any questions by contacting lg.sustainbility@nhs.net.
