80 Charlotte Street – our first net zero building

At 80 Charlotte Street, Derwent London challenged the design team to create a building that would accelerate progress to a low carbon future. As the Group’s first all-electric building, it will use air source heat pumps for all heating and cooling needs. To ensure the building is net zero carbon, it will be powered by renewable electricity and optimise energy efficiency in operation; embodied carbon was also reduced during development and Derwent London will offset residual carbon emissions that cannot be eliminated.

• On track to achieve BREEAM Excellent and LEED Gold
• 28% lower embodied carbon intensity than the RICS Carbon Database (offices) average
• All office space pre-let prior to completion

Introduction

Derwent London’s ambitious sustainability goals include achieving a net zero carbon portfolio by 2030, in line with the United Nations’ goal of keeping global warming to no more than 1.5°C. The Group plans to do this through reducing energy demand, investing in renewable energy and offsetting residual emissions that cannot be eliminated.

80 Charlotte Street in Fitzrovia is a leading example of Derwent London’s net zero carbon approach in practice, as well as the active role the Group plays in the local community. The mixed-use scheme is one of three developments currently under construction that the Group has committed to delivering as net zero carbon, with all remaining buildings in the portfolio transitioning to net zero carbon by 2030.

Completed in June 2020, 80 Charlotte Street comprises 35,300m2 of office, retail and residential space, including affordable housing, along with a new public pocket park. It has been designed by architects Make and delivered by Multiplex. Arup is the mechanical and electrical (M&E) and sustainability consultant for the project, and will also be one of the main occupiers, together with Boston Consulting Group, Elliott Wood and Lee & Thompson.

Advancing net zero carbon

80 Charlotte Street is Derwent London’s first all-electric building, with central heating and cooling provided from air source heat pumps, significantly reducing carbon emissions compared to traditional gas boilers. The Group is now targeting all-electric heating and cooling systems for new development projects, as part of its net zero carbon ambition. 80 Charlotte Street will be used as a reference point for designing low carbon heating and cooling in future projects.

Arup carried out a detailed embodied carbon study early on, which has been tracked throughout the project. To further reduce embodied carbon, the Sustainable Procurement Policy focused on use of responsibly sourced materials, materials with a high recycled content and regional materials, along with waste minimisation and recycling. Informed by this project, all future Derwent London projects will undergo carbon appraisals, as well as financial appraisals.

Features to reduce operational energy demand at 80 Charlotte Street include an optimised façade design, so there is a good balance between allowing daylight to enter the space, whilst limiting solar gain. High efficiency building services and fittings include an all LED system for main landlord areas and daylight sensors that enable light fittings to be automatically dimmed in response to ambient light levels.

Once the fit-out is complete and the building is fully occupied, in-use electricity data will be analysed and compared against TM54 modelling calculations completed by Arup at the design stage. As Arup will be one of the main occupiers, Derwent London has a unique opportunity to work with them to optimise operational energy performance. The building will also be supplied by electricity purchased from renewable sources and 80m2 of solar thermal panels will heat all the domestic hot water.

Growing social value

80 Charlotte Street is located in Fitzrovia, where Derwent London has a long-standing relationship with local residents and community groups through its Fitzrovia & West End Community Fund and employee volunteering programme. Derwent London and project partners has been available throughout the construction phrase for local residents, businesses and groups to contact and talk to in person, including through regular neighbourhood liaison meetings. In addition, the project team has issued regular newsletters to keep people informed of the scheme’s progress and provide essential contact information.

The project has been under development for a number of years and its impact on the community has been a key consideration during this process. Over the course of construction, the project has supported 30 new apprentices and carried out 46 educational engagement events. Through various activities, the project team has raised £69,430 for charity. As the scheme moves forward, Derwent London’s building management team will work with local groups and collaborate with future occupiers to ensure the building contributes positively to the neighbourhood.

Supply Chain

Derwent London is a relatively small organisation that operates an outsourced business model for the design, delivery and maintenance of its buildings and spaces. As a result, the Group works closely with supply chain partners to deliver market leading spaces and achieve its ambitions – be they environmental, social, ethical or financial. Its Sustainability Framework for Developments, launched in 2014, sets out Derwent London’s approach to designing and delivering buildings responsibly. This Framework provides design teams and contractors with a clear overview of sustainability expectations for new developments and is a key tool in working to achieve net zero carbon. Derwent London’s science-based carbon reduction targets are embedded within the Framework and there are plans for new embodied reduction targets to drive down the carbon footprint of its schemes even further. Other tools and support for supply chain partners include briefings, contract clauses, project-specific sustainability plans and its Supply Chain Sustainability Standard.

Financial

In 2019, Derwent London became the first UK Real Estate Investment Trust (REIT) to issue a Revolving Credit Facility with a ‘green’ tranche. This makes £300m of funding available for qualifying green expenditure. The completion of 80 Charlotte Street will be financed using this green tranche.

Benefits

• 28% lower embodied carbon intensity than the RICS benchmark, with estimated embodied carbon of 850kg CO2e per m2, versus the RICS Building Carbon Database (offices) average benchmark of 1177kg CO2e per m2.
• All office space let prior to completion to Arup, Boston Consulting Group, Elliott Wood and Lee & Thompson. Arup is one of Derwent London’s long-standing customers and has been based in the area for over 50 years.
• Advancing progress towards Derwent London’s net zero carbon goals, both by achieving net zero carbon at 80 Charlotte Street and by providing a reference point for future projects.
• Making positive socio-economic contributions to the local community, including employment opportunities, reflected in 45/50 score on the Considerate Constructors Scheme, rated Exceptional on every aspect.
• High sustainability ratings, including BREEAM Excellent achieved at design stage. The project is on target to achieve BREEAM Excellent post construction, LEED Gold and Energy Performance Certificate (EPC) B.