London North West University Healthcare NHS Trust

Northwick Park Hospital - in progress

Executive summary

We are helping London North West University Healthcare NHS Trust’s transition to net zero by 2040 through the design and implementation of a fully integrated, self-funding, multi technology energy solution at Northwick Park Hospital. The innovative solution comprises air and water source heat pumps, a Battery Energy Storage System (BESS), solar PV, and a host of energy conservation measures (ECMs). As well as reducing the Trust’s carbon footprint by over 2,500 tonnes a year, they’ll achieve guaranteed energy savings of £1.9m a year, and the local community will benefit from the creation of a local smart grid.

  • reducing-carbon
    2500+ tonnes of carbon reduction per annum
  • battery-storage
    2MW battery energy storage system
  • heat-pump
    Air and water source heat pumps
  • solar
    1,642 solar panels

Project Overview

The Trust came to the market with the requirement for an innovative solution that addressed the concerns associated with their end-of-life energy systems. The existing 50-year-old steam system was reaching end of economic life, inefficient, and impacting on the reliability of essential heat supplied to the acute hospital estate, which could impact on patient care. These inefficiencies also resulted in higher carbon emissions and increased energy costs for the Trust.

Our Solution


As part of the 15-year performance based contract, we converted the existing steam heating system to a Low Temperature Hot Water (LTHW) distribution infrastructure, and developed a unique energy solution which includes a combination of water and air source heat pumps and a BESS, which was designed to facilitate the integration of heat pumps and other renewable technology into the hospital’s energy infrastructure. Working closely with the hospital’s facilities teams, we put together a three-phase plan to enable the hospital to make a genuine operational change towards its net zero ambitions assisted by the BESS infrastructure.

The BESS will initially enable the site to maximise the use of onsite generation and help the hospital avoid import electricity at the most expensive times. It is also capable of providing a range of grid services such as frequency response which can provide another source of income to the hospital when the BESS is not providing other onsite services.

The LTHW will be supplied by a gas-fired combined heat and power unit (CHP) with integrated water source heat pump, complete with LTHW boilers and solar photovoltaic arrays. Most CHP units have a second stage intercooler that produces 40-degree heat that needs to be rejected via the dry air cooler, and we are tapping into this circuit with the water source heat pump.

We’ve also implemented a range of ECMs, including the installation of a 649.74kWp solar PV array across 8 roof spaces, optimisation and upgrades to the existing Building Management System, pipework insulation, and the retrofit and upgrades of existing air handling units and chillers, all specifically designed to reduce the energy consumption and the overall carbon emissions of Northwick Park Hospital.

Solution detail

The financial savings and the eradication of high-risk backlog maintenance cannot be underestimated at an NHS Trust, however we are extremely proud to be part of a team that will save 2,500 tonnes of carbon every year in London. This was only deliverable through complete collaboration, an innovative commercial model to maximise value, and an expedited project delivery within a long-term partnering arrangement.

Mark Trumper, Director of Estates & Facilities at the Trust

Key benefits

Northwick Park Hospital

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