Posted by Adam Smith and Robert Cohen

UKGBC announce new framework to define net zero carbon buildings: a solid foundation, but stronger guidance still required

After more than six months in development, yesterday the UK Green Building Council (UKGBC) launched their new framework definition for net zero carbon buildings at a packed event in Parliament’s energy exemplar Portcullis House. Verco’s Technical Director Dr Robert Cohen has been one of the contributors to the framework. In this article, the Verco team provide their reflections on the new framework and how it might be strengthened to respond to the climate emergency.

Advancing net zero

Emissions arising from energy use in the construction and operation of buildings are a key contributor to man-made climate change. In 2016 the World Green Building Council called on the construction and property sectors to take the lead in pushing for a net zero built environment by 2050 (1). This was driven by the ambition of the Paris Agreement and then reinforced by the IPCC’s special report on 1.5°C of warming published in October 2018, which urged policy makers to target a net zero carbon global economy within the next thirty years (2). To support this transition, the World GBC established an Advancing Net Zero Campaign and developed a set of high-level principles for net zero carbon buildings in operation, with the aim to achieve the target by 2030 for new-build and 2050 for all buildings.

Each country-level GBC is charged with implementing the global campaign in a way appropriate for their local context, and the UKGBC launched its own Advancing Net Zero programme to support the transition, convening an industry Task Group in October 2018. The first job was to develop a definition for net zero carbon buildings in the UK. Five months later in February 2019, UKGBC issued a framework definition for public consultation and received over 150 responses from across the building value chain. The report released yesterday is an important first step towards all UK building industry stakeholders having an agreed understanding of what a net zero carbon building must achieve to warrant this accolade.

The net zero carbon buildings framework is primarily a tool for industry, but there is also a clear role for national and local policy-makers in using the framework to increase demand for net zero carbon buildings. Multiple options for new policies to do this are identified in the Framework. Additionally, both central and local government should use public procurement to encourage net zero carbon buildings.

Scope of net zero carbon – two options proposed

The framework development process raised a number of critical questions about the scope and requirements of a net zero carbon building. A key example is where the line should be drawn in accounting for emissions across the life cycle of a building, which starts with design and development, proceeds to construction using materials and products from multiple sources and supply chains, continues with a long period of in-use operation and maintenance, and is completed by an end-of-life process hopefully aligned with the principles of the circular economy.

The framework initially offers two options. The first is net zero inoperation and the second, for new build or major refurbishment, is net zero construction – where the embodied and operational emissions up to the end of the construction stage are reported and offset. When buildings are efficient in operation, these embodied emissions can in some cases account for half of a building’s whole life carbon footprint (3).

The Task Group and consultation feedback favoured restricting the initial net zero definition to these two options mainly because the exercise of calculating and reporting the start of life emissions can be completed when operation starts. Hence both options can be based on actuality rather than predictions of the future. The general consensus among the task force was that estimated lifetime emissions are still subject to significant uncertainty, and potentially quite an expensive add-on, so may be only affordable by more top-end developments. However, the framework definition makes clear that net zero whole of life emissions is the correct direction of travel for the industry and anticipates a definition being added to the framework within the next five years.

Base build vs whole build – options for landlords and tenants

The framework advises that “…where appropriate, operational energy use should be delineated between the actors who have responsibility and/or the ability to influence energy use.” As such, it appears that net zero carbon for operational energy can be sought not only for a whole building but also for areas of control, such as a base building or a tenanted area in a multi-let commercial building.

Next steps

To maintain relevance and robustness in an ever-advancing area, the framework will need to tighten over time. A number of issues to consider for the future are highlighted by the Framework as priorities.

  • Governance. UKGBC has been reluctant thus far to establish a UK ‘Net Zero Carbon’ scheme. However, the consensus from stakeholders is that such a scheme is needed if the ambition is to be authoritative and independent.

  • Should a minimum level of onsite renewables be mandated? We believe that onsite renewable contributions should be maximised, subject to local constraints.

  • Should there be minimum energy efficiency standards? We support the UK adopting something like the Dutch GBC’s Paris-proof concept (4) as an essential mechanism to ensure each building takes only a fair share of the national (off-site) renewables cake. We anticipate this might mean a minimum energy efficiency standard of something like a DEC B40 or NABERS/LER 5.5 stars rating.

  • Should there be a cap on the amount of offsets allowed? We believe so – perhaps in the region of 5-10% of the total annual carbon emissions arising from a building’s operational energy use to allow for de minimis energy uses or unexpected events. This is driven by concerns around additionality of carbon offsets, and the potential watering down of price signals for decarbonisation if building owners and developers can purchase offsets much more cheaply than pursuing ‘net zero’ strategies built on energy efficiency and on-site renewables. The cap should be less strict for embodied emissions.
  • What types of offsets will be accepted? Should there be an offset standard? In principle we would favour local offsets as is happening in London, although the practicalities appear to be overwhelming the capacity to deliver robustly with credible verification.
  • What about Green Tariffs? We are aware that these have been notoriously viewed as greenwash. They seem to provide an open goal for anyone minded to criticise the framework or indeed abuse it.
  • Time-of-use carbon factors. Accounting for the carbon intensity of electricity at the time of import can give a more accurate value for the carbon emissions over a year. Using ‘time of use’ emissions factors would provide an incentive to shift a building’s energy demand away from times of peak demand on the grid. Earlier this year we undertook a piece of internal analysis to quantify this effect and found a 10 – 15% reduction in emissions compared with using a single annual factor. This is significant and will become more so if used in conjunction with batteries and flexible demand.
  • Whole life carbon. Over time, a lifecycle approach will be required that emphasises the importance of the circular economy in reducing embodied carbon.

As contributors to the framework, we are enthusiastic about the benefits of bolting down clear principles and rules for genuinely zero carbon buildings verified by third party review. We look forward to the next step - setting down some key practical criteria which will turn the framework into a guide to how net zero carbon can be achieved in an exemplary fashion.

For more information please contact Robert Cohen, Technical Director ( 07967 119 541).