Beyond net-zero buildings: ‘Carbon-negative’ homes and a ‘net-positive’ logistics centre completed

Image: St Modwen

The three-bedroom houses from St Modwen Homes are located in its ‘Heathy Wood’ development in Copthorne, a village around four miles outside of Crawley. The developer claims that the homes deliver a 125% reduction in CO2 emissions compared to similar homes built to average industry standards.

Built-in features which reduce energy consumption and operational emissions include highly efficient insulation and ventilation; air-source heat pumps; ‘smart’ hot water tanks; heat recovery systems for air and wastewater and smart radiator valves. The homes are built to Passivhaus standards of energy efficiency.

To take the operational emissions of the buildings to negative, they are fitted with rooftop solar panels and a small battery energy storage unit. Electricity generated and stored can be used to power the homes’ activities and/or to charge electric vehicles (EVs). British Gas is working with St Modwen Homes on some of the built-in energy solutions.

To reduce the embodied carbon associated with the homes, St Modwen Homes used low-carbon concrete for the foundations and selected timber frames. The UK Green Building Council (UKGBC) is advocating for a greater industry and policy focus on the embodied emissions of buildings. At COP26 last November, it launched a new Whole Life Carbon Roadmap for the sector to assist with the measurement and reduction of carbon from materials, processes and demolition, as well as operations. It subsequently published a study demonstrating how the developers of low-rise residential developments could achieve a 20% reduction in embodied carbon.

“With energy prices continuing to rise, creating energy-efficient homes that are affordable to build is more vital now than it ever has been,” said St Modwen Homes’ managing director Dave Smith. The company estimates that families living in the homes will see a reduction in their energy bills of up to 79%. Bills could come in at less than £290 per year for residents.

Smith added: “Over the course of this year, we will be analysing the results of this latest trial to aid us in our objective to build these new homes at scale for the benefit of homeowners and the environment.”

Back in 2020, St. Modwen announced a commitment to deliver net-zero operations by 2025 and to become a fully net-zero business by 2040.

Logistically speaking

Image: Prologis

Also this week, logistics parks developer Prologis has announced the completion of a new building at its Apex Park near Daventry, Northamptonshire. The firm claims that the 435,000 sq ft unit has “gone beyond net-zero carbon in construction and operation”.

The building has achieved BREEAM ‘Outstanding’ certification and has achieved an Energy Performance Certificate (EPC) rating of A+. Built-in sustainability features include rainwater harvesting and a 1.4MW rooftop solar array, which will generate more than enough electricity to serve the building’s own energy needs. Excess electricity can be used by other buildings at the site.

It is this solar array which will take operations beyond net-zero. Also to cover embodied emissions and any other operational emissions, Prologis has financed the protection of 310 acres of rainforest in Papua New Guinea, as part of a partnership with the charity and climate service provider Cool Earth.

Prologis’s vice president and development manager Martin Cooper said: “This is a milestone for Prologis and shows what can be achieved when like-minded businesses work together to realise their vision for a building that delivers a net benefit for the environment. All of our new warehouses in the UK have been net-zero carbon in construction for the past 14 years, but this building at Apex Park takes carbon reduction to a new level.

“The dialogue around net-zero is progressing rapidly and businesses are beginning to look beyond operational carbon to find other ways to make their buildings more sustainable. Reducing the embodied carbon of new buildings requires intense collaboration across the supply chain, from engineers and architects to material and product suppliers, plant hire firms and contractors. Moving as a country towards being net-zero by 2050, we look forward to seeing many more logistics projects that are net-positive for the environment, and we’re extremely proud to be leading the way.”

Action inspires action. Stay ahead of the curve with sustainability and energy newsletters from edie