WSP designed an energy efficient Paddington Square in London

WSP developed the initial design by Renzo Piano Building Workshop to prioritise greater energy-efficiency and ensure emissions will decline as the electricity grid decarbonises.

Location

London English GL

Client

Sellar

Project Value

Project value

Project Status

Completion 2022

Is it possible to exceed sustainability aspirations while meeting the architect’s vision for a glass building that ‘hovers’ 18 storeys above 1.35 acres of public realm? We did.

By using electric heat pumps instead of gas-fired combined heat and power (CHP) – along with a host of other features such as a double-skinned façade – we reduced carbon emissions by 39% on Part L requirements. As more low-carbon energy generation is connected to the grid, the building’s emissions are expected to continue to fall to an estimated 28% of the Part L 2013 CHP option by 2050.

Images Copyright Great Western Developments

carbon reduction on Part L requirements

39% 39%

further reduction in carbon emissions by 2050

37% 37%

of space heating met by heat pumps

67% 67%

The project was guided by sustainability from the outset, aiming to achieve BREEAM Excellent and to comply with the significant emission reductions required by the London Plan. We then took this a step further by examining how heat pumps could cut carbon compared to CHP

Chris Hempsall Technical Director, WSP

In focus: making use of a greener grid

From 2022 Paddington Square will present a new gateway into London from Paddington Station, a public transport hub serving six rail links including the new Elizabeth line. Designed by Renzo Piano Building Workshop, Paddington Square is a centrepiece development for the wider district’s regeneration – to include a world-class mix of shops, cafes, West London’s highest rooftop restaurant and a pedestrianised piazza – centred around an 18 storey glass and steel building for which WSP is providing multidisciplinary services.

The consented scheme for the building used gas-fired CHP to produce electricity on site that was intended to be less carbon-intensive than the grid. But by 2018, with renewables already gaining a larger-than-anticipated share of UK energy generation, it was no longer certain that this would be the case by the time the building was complete. So we took the initiative to rework the design to replace the CHP with electric heat pumps and gas backup.

Alongside this, we strived to make every element of the building as energy-efficient as possible. With a large area of glass, overheating through solar gain can increase energy use for cooling. We used a double-skin façade to trap the heat between the layers and transfer it out of the building through small ventilation pockets.

Blinds within the double-skin façade open and close automatically to optimise solar gain, while smart features such as daylight controls improve energy efficiency further. The result is a 39% carbon reduction on Part L requirements, and the building’s emissions are predicted to fall to 28% of the Part L 2013 CHP option as the grid decarbonises by 2050.

When we started looking at this back in 2018, it was clear the grid was getting greener but planning policies didn’t yet reflect this. We pre-empted this change, examining the carbon-reduction benefits of electric heat pumps on our own initiative.

Jacob Cox Senior Energy Engineer, WSP