Chapter 2
Carbon neutral choices for the built environment
It is widely quoted that the built environment accounts for around 40 per cent of total carbon emissions. Delivering carbon neutral solutions is a complex task but increasingly there are products available that make the task easier. First, it is worth examining what carbon neutral means in this context.
The key to achieving a net carbon zero project lies in the sustainable supply of renewable energy in both the construction phase and the whole lifecycle of the building. A building is deemed to be carbon neutral when the amount of carbon emissions generated during its construction are offset by the use of renewable energy. To maintain true carbon neutral credentials, a building must also be highly energy efficient and powered by renewable energy making it whole-life carbon neutral.
The UKGBC has set out a useful guide to achieving a net zero carbon building which recommends starting with a scoping exercise to explore how to reduce both the impact of construction and the projected operational energy use. Approaching the net zero goal requires a strategic approach from the initial design stage and should be embedded within the initial concept. It requires the collaboration of the entire supply chain and detailed research to identify the most appropriate materials and processes.
The industry is seeing an increasing use of Lifecycle Assessments (LCAs) to determine products’ overall environmental impact. The Carbon Leadership Forum has collaborated with industry professionals to launch a digital calculator which is free to use and enables an assessment of carbon emissions within the construction materials, enabling the reduction of embodied carbon.
Organisations such as EcoAct are working to help business make adjustments in response to climate change objectives while simultaneously boosting their commercial performance. The Better Buildings Partnership seeks to encourage a shift towards energy efficiency within UK office spaces and a move away from a historic tendency towards achieving simple compliance.
Good projects take account of the construction materials used from the extraction of raw materials to their production and transportation. The Environmental Product Declarations (EPD) framework provides a guide to the compliance of most building materials.
It is equally important to take account of how retrofitting can contribute to carbon neutral goals. Four years ago, the UKGBC backed-up their campaign for energy-efficient refits through a successful small scale refurbishment of their London HQ. By considering every aspect of energy use at the concept stage, they were able to cut carbon emissions from lighting by half, reuse nearly all the original fixtures and fittings, and reduce their embodied carbon footprint to just 22 per cent. In addition, they introduced a plant-based ‘living wall’ and improved ventilation and heating.
Retrofitting is in itself a measure of positive environmental action at a time when the average life of a modern building is just 60 years. The desire to create new, ultra-sustainable buildings should be weighed against the option of re-purposing existing buildings to better effect.
Using a brownfield development opportunity, the University of Nottingham worked with Fairhursts Design Group to create ‘the world’s most sustainable chemistry laboratories’ at its Jubilee Campus. The GlaxoSmithKline Centre for Sustainable Chemistry was designed to promote efficient chemistry practices and its iconic building design was sympathetically constructed to embody the same philosophy. Pete Licence, Professor of Chemistry at the University of Nottingham described how its openness and use of natural light in flexible spaces represents the way in which the department is working to provide better access to the discipline of chemistry to inspire future generations.
The building requires a huge number of solar panels to provide its energy and this has resulted in a large, sweeping green roof that boosts biodiversity and provides shelter for an indoor winter garden that has become the focal point of the university science community.
Finally, if the materials you choose are not recyclable, there are ways of creating value and diminishing their impact within the construction lifecycle. Many materials can be incinerated as a fuel to generate electricity or heat small buildings, partially qualifying as a renewable energy source. North Yorkshire Council processes around 320,000 tonnes of waste per year at its Allerton Waste Recovery Park, burning what remains after other recycling processes to produce steam that drives an electricity turbine to supply about 40,000 homes.