The issue of climate change couldn’t be more topical. But what is “net zero carbon”? Is it just another buzzword and what does it really mean? The UK Green Building Council has this week published its Framework Definition on Net Zero Carbon Buildings. To see a copy of the new Framework Definition click here and to understand how it will work in practice read on. This document is a critical first step in the UK property and construction industry’s aim to make new and existing buildings net zero carbon by 2050. Political, investor and popular pressure is driving the real estate industry in this direction, and the transition to net zero carbon buildings is seen as a key part of ensuring that investments are “future-proofed”. Whether you are a developer, an investor, an occupier or a funder of real estate, the UKGBC’s framework is well worth a read, and is an important contribution to this vital ongoing conversation within our industry.

In her introduction, UKGBC Chief Executive Julie Hirigoyen describes climate change as “undoubtedly the greatest challenge of our times” and explains that “we need to take urgent action to almost halve global emissions by 2030 and eliminate them completely by the middle of the century“. That is a commendable aim, but the industry lacks consensus on how it should be achieved. The UKGBC’s framework tries to address this in a practical way: by providing an overarching framework of consistent principles and metrics that can be integrated into tools, policies and practices. This should enable the industry to build the consensus that is needed.

It does this by setting out two definitions of “net zero carbon”, one that applies to construction and the other that applies to operational energy. A building is net zero carbon in construction “when the amount of carbon emissions associated with [its] product and construction stages up to practical completion is zero or negative, through the use of offsets or the net export of on-site renewable energy.” It is net zero carbon in its operation “when the amount of carbon emissions associated with [its] operational energy on an annual basis is zero or negative” and if it “is highly energy efficient and powered from on-site and/or off-site renewable energy sources, with any remaining carbon balance offset.

The framework also describes three overarching principles, which are:

  1. “the polluter pays”, i.e. whoever is responsible for creating emissions should also be responsible for the costs of addressing them;
  2. measurement and transparency should be improved, so that as far as possible building emissions should be based on measured rather than estimated data, using the most accurate data available; and
  3. action should be encouraged today, with the requirements tightening over time, in order to ensure that a “whole life carbon approach” is taken.

These two definitions and the three overarching principles are then applied in five steps to achieving a net carbon building. These steps represent the “whole life carbon approach” and so not all of them will be relevant to every building all of the time.

The first step is to establish the net zero carbon scope. This is not just a question of deciding which definition to use, but also to identify the boundaries of what is being measured, depending on how much operational control the building owner has in practice.

The second step is to reduce construction impacts (which can only apply where the first definition is being used and the building is being newly constructed or undergoing a major refurbishment).

The third and fourth steps are to reduce operational energy use and to increase renewable energy supply. Whilst these are mainly operational matters, they are still relevant to construction because the framework requires that new buildings and major refurbishments are designed to achieve operational net zero carbon by considering them. The fifth step is to offset any remaining carbon. These three steps have been deliberately ordered so that the priority is to reduce energy demand and use, to supply any remaining demand from renewable sources as far as possible and only then to offset carbon.

The framework also contains a number of areas for “future development”, where standards can be raised and additional processes developed to assist and measure performance. The framework cannot be static, and there is a clear intention to update and improve it regularly over the next decade, “in order to increase robustness and provide sufficient stretch for industry to lead the transition to net zero whole life carbon buildings“.