In line with the government target of a net zero carbon target for the UK by 2050, Leeds City Council and the Leeds Climate Commission recently published an exciting roadmap for the city to become carbon neutral by 2050.

Whilst Leeds’ carbon emissions have fallen by approximately 43% in the last 14 years due to changes in the carbon intensity of electricity supplied through the national grid, the roadmap recognises that additional steps will be required to meet the target.

A key behavioural change will be in construction. The roadmap envisages a reduction in consumption of steel and concrete by 33% by 2030, and Leeds’ target is for all new homes to be carbon neutral.

The UK Green Building Council (“UKGBC”) has published a new framework for the construction industry to provide guidance on the definition of net zero carbon buildings and to set a path to achieve net zero carbon status.

The UKGBC guidance sets out two definitions for net zero carbon:

1. Net zero carbon – construction (i.e. emissions from the construction process):Typical carbon emissions during the construction phase can include the transport of waste, the use of temporary offices on site and the inefficient use of construction plant (for example using oversized machines and high carbon fuels).

The framework encourages the industry to: 

  • Undertake a whole life carbon assessment at the start of the project to disclose to other parties, with the aim of parties agreeing reductions; and
  • Measure the carbon emissions and offset at practical completion. The construction company would approach a carbon offset provider, such as carbonfootprint.com, use the online tools to calculate the emissions of the construction process, and then pay the offset company to reduce emissions elsewhere in the world by the same amount. Examples of projects run by carbonfootprint.com include UK Tree Planting and Wind Based Power Generation. 

2. Net zero carbon – operational energy (i.e. in-use operational energy):This relates to how the building consumes energy once built. Practical measures encouraged by the framework include: 

  • Prioritising on-site renewable energy sources, such as solar panelling; and
  • Calculating in-use energy consumption, to be published annually.

There is clearly some way to go: published statistics showed that the amount of carbon dioxide emissions attributable to the construction industry in the UK increased from 8.8 million metric tons in 1990 to 12 million metric tons in 2016. In a typical residential block, 51% of total carbon emissions are created in the lead up to practical completion, 18% are due to the use of the building, 24% comes from operational emissions such as heating, cooling, ventilation and lighting, and 7% comes from unregulated operations emissions (such as appliance usage).

The framework recognises the challenge the industry faces and the UKGBC is encouraging building developers, designers, owners and occupiers to apply the framework and share any knowledge and lessons learnt.

Will a voluntary framework be effective?

Although the framework is a significant step forward, it is merely intended to act as guidance and is purely voluntary. If the government does not make it mandatory, will firms follow it?

There is certainly an argument that it is counter-intuitive for builders to adopt a voluntary zero carbon approach when that may well drive up costs and reduce their chances of winning the work in the first place.

However, changing technologies could assist in bringing down the construction industry’s carbon footprint. Modular construction is increasingly seen as a way of addressing the UK housing crisis, with homes potentially built in as little as 10 days. As modular homes are built in factories according to specific measurements, the amount of waste material is drastically reduced. A 2007 report by the U.K. Waste & Resources Action Programme found that a reduction in waste of up to 90% could be achieved. Once occupied, energy consumption is also typically lower due to the greater use of solar panels.

It is evident that those involved in the construction industry are starting to take the need to reduce carbon emissions and use sustainable sources seriously. Yorkshire is now home to two modular construction factories. It is hoped that these factories and this initiative can help make the region a leading light in the move towards achieving net zero carbon buildings.