A version of this article first appeared on the Sustainability Talk & News website, published 28 February, 2013.
Smart-city strategies are rethinking the rôle of buildings in terms of their ability to generate, share and store energy, rather than just consume. In addition, energy efficiency and carbon offsetting are shrinking footprints ever further. As a result, the ultimate built-environment question of the carbon era seems to be:
‘How low can we go?’
In February this year, construction voices followed the lead shown by the UK Green Building Council in calling on government to provide clarity on plans for changes to building regulations and to confirm its support for zero carbon. In commercial markets, delay is the enemy of investment and without a strong policy steer, there is a fear innovation could stall, as business confidence falters.
Ever since government ambitions were announced back in 2006, the zero-carbon target has proved the subject of much debate. Many supporters argue that as the pin-up for the overall campaign to decarbonise the built environment, a ‘zero hero’ project exemplar inspires achievement across the board, fuelling demand for excellence and boosting belief in delivery. Energy efficiency meanwhile seemed the Cinderella of the low-carbon story, until, with austerity biting and pragmatism on the rise, a nascent retrofit revolution began to weave its magic wand, bringing belated transformation of existing stock.
Helping construction to cross the low-carbon finishing line has been the impact-minimising rôle of carbon offsetting. Once every effort feasible has been made to reduce consumption and emissions, then it appears perfectly reasonable to offset the unavoidable remainder. The key word in that sentence, though, is ‘feasible’: Who or what decides what is feasible?
Typically, cost is the determining factor and so the extent of what is ‘feasible’ is not a technical matter, rather a business decision. Profit margins are dependent on where the line is drawn between the feasible and the commercially uneconomical, or undesirable. Lack of transparency in this grey area is arguably the cause of much of the concern about abuses of offsetting as a means of managing impacts responsibly.
The carbon scale does not however start, or even end with zero. Never mind impact-neutral solutions, a number of structural building materials billed as carbon-negative have been available on the UK market now for some time: These range from hemp-based blocks, to prefab straw-bale panels.
At project level, the built-environment sector has also witnessed a flurry of below-zero ‘firsts’ in recent months alone: Australia has seen completion of its first carbon-negative commercial building, in Melbourne, for example; whilst in South Shields, England, the tenants have moved into Britain’s first carbon-negative street. It is fair to say, that the rôle of (successful) high-profile projects in driving forward the agenda for a low-carbon built environment has almost as much to do with media coverage, as it does design excellence, or build quality – aspiration is, in part, a function of awareness.
Taken out of context, however, carbon targets can lead to cases of unintended consequences, or even be used to justify false accounting for building impacts. In effect, marketable ‘zero-carbon’ status has sometimes been pursued at the expense of broader sustainability goals and metrics, as Ant Wilson, Director, Building Engineering, Aecom, explains: “You could almost say it is dishonest of designers to pass the buck back in time to earlier materials and construction phases of development, loading buildings with embodied energy in order to minimise performance-in-use figures and get carbon ‘off the books’, so to speak, in the operational phases.
“The new, true focus should be on energy reduction, not just zero carbon. In reality, lower-carbon buildings sometimes use more energy, not less. Overall resource efficiency is the key to sustainability in the built environment.”
In built-environment parlance, the terms energy and carbon are often erroneously used as if interchangeable. They are not: Energy is a resource or an asset; carbon is an impact or a liability.
In the race to zero and below, low-carbon ends do not justify high-energy means.
Mindful of this maxim, the true sustainability question seems not to be ‘How low can we go?’, but rather, ‘How can we best go low?’.
To view the original article in full on STN, a Carillion PLC initiative, please click here.
Author: Jim McClelland