Sustainability and resilience have never been more important in transport infrastructure than now. The ambition for a megaproject such as HS2 has always been to build the most sustainable railway of its type in the world. Representing companies with relevant experience and an interest in high speed rail, the High Speed Rail Group is acutely aware of the challenges to industry that the government’s net zero carbon target brings. As part of its commitment to managing carbon footprint, HS2 has also set ambitious targets for its supply chain to minimise the whole life carbon emissions of its assets including buildings. For stations this includes achieving net zero carbon in operation for regulated emissions and achieving a 50 per cent reduction in whole life carbon emissions against a baseline for a typical station.

Arup has produced a design for HS2’s new Interchange station, to be built near Solihull and the NEC in the West Midlands. The station will be one of the best-connected places in the UK, with customers able to reach London Euston in just 38 minutes. The station will be made up of two 415 metre long island platforms, offering 4 platform faces, as well as 2 central high speed through lines for non-stopping services. The station will be linked to the NEC, Birmingham International Station and Birmingham Airport via an automated people mover (APM) carrying up to 2,100 passengers per hour in each direction. In addition to the APM, the station will be fully integrated with other local buses, taxis and private vehicle options as well as provision for cyclists.

The design focuses on sustainability, maximising natural daylight and ventilation and a station roof design which can capture and reuse rainwater – and has become the first railway station globally to achieve the BREEAM ‘Outstanding’ certification.  BREEAM offers a holistic and globally recognisable benchmark for sustainability performance in building design and construction terms, and achieving this certification puts the station in the top one per cent of buildings in the UK for sustainability credentials. Its application on the Interchange Station for HS2 was embraced by the Arup led design team, who used the standard not only as a sustainability yardstick but as a quality indicator, challenging the designers to consider innovative and unconventional technical solutions that were brought together with a collective intent to mitigate impact upon the environment and natural resources.

Arup’s design minimises embodied carbon through the use of life cycle assessment reporting for key building materials and waste at source through material efficiency analysis. Energy efficient technology will be incorporated, such as air source heat pumps and LED lighting. In addition, the station and APM maintenance facility have over 2,000m2 of solar panels generating zero carbon electricity. Directing rainwater from the main station building via a network of underground pipes into a rainwater harvesting tank will assist in providing part of the building’s water requirements, which will reduce the mains water demand for the station. The landscaping features sustainable drainage systems to reduce the burden on surface water drainage whilst naturally irrigating planted areas, and there will be new natural habitats created around the station, leaving a legacy of biodiversity and an enhancement of native species.

Alongside a focus on energy and climate change that set out a clear intent to meet net zero carbon targets through intricate passive design features and renewable technologies, the design proposals embraced lowering material impacts through investigation of embodied carbon within key building components, developing material efficiency strategies through use of modular and volumetric design principles and considering deconstruction and end of life impacts within structural and building envelope research. The use of glu-lam timber with the design offers a significant embodied carbon saving and is a prime example of how an engaged design team can use emerging life cycle carbon software analysis to influence their design decisions.

The Interchange project team and its BREEAM Assessors at GWP Project Services showed that even the most complex of projects, with many stakeholders and constraints to consider, can meet exemplar standards through teamwork and expertise within each area. The project will now move towards construction phase where the same level of collaboration and attainment will be widely encouraged so this fantastic achievement – reached by less than 1% of all new buildings in the UK – can be fully delivered.