OPINION
HOW NEAR IS NEARLY ZERO?
Vast numbers of buildings are missing energy targets by up to 250%. To hit nearly zero carbon targets by 2019, clients need to provide low carbon briefi ngs within a year, says Ian Taylor
We are heading inexorably towards zero energy buildings.
Article 9 of the recast Energy Performance of Buildings Directive (EPBD) introduced ‘nearly Zero- Energy Buildings’ (nZEB) to be implemented from 2019 onwards for public buildings, and from 2021 onwards for all new buildings. The advised CO2
emissions from a new
building to meet the long-term EU climate targets are recommended to be below 3kg CO2
/(m2 yr).
This initiative raises signifi cant challenges. In Europe, more than one quarter of the building stock that will exist in 2050 is still to be built. The energy consumption of these new buildings will need to be close to zero to reach the EU’s highly ambitious
carbon targets, while the existing 75% will need signifi cant upgrade. Is there an appetite for such
a radical shift in our building procurement? How many buildings might actually be able to achieve such low targets? Society’s expectations are mixed,
with a desire to do the right thing for the world becoming worryingly over- ridden by concern over short-term damage to regional economies and personal wealth. A longer-term view of the typical lifespan of the buildings we are designing – it is only 37 years to 2050 – demands our immediate action.
The evidence The performance gap between design expectations and the reality of operation is becoming better understood. Clients and design teams are beginning to share building performance-in-use data. Standardisation of analysis tools is enabling comparative studies and data sets to be established to benchmark performance. Technology Strategy Board (TSB)-funded
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target of 50kg CO2 operate at above 75.
/(m2 yr) and
And yet the Buildings Performance Institute Europe (BPIE) is targeting nearly zero – 3kg CO2
/(m2 yr). This
is 13 times lower than the university design target, which is already being missed by 250%. It is the scale of mismatch that is worrying between a) what our planet can accommodate and what our clients aspire to; and b) what building users need and what industry can deliver. This is after we have taken into account ‘in use’ reported fi gures that may lie outside the nearly zero target parameters, for example plug loads, unregulated energy and operational hours.
Architect Feilden Clegg Bradley Studios is carrying out a post-occupancy evaluation for Brighton Aldridge Community Academy
research projects, including post- occupancy evaluations and Carbon Buzz, are providing valuable insights into how far our new buildings are from meeting ambitious targets. Indeed, they show how far we are from our own design targets now. A review of data currently uploaded to the Carbon Buzz dataset demonstrates that current operational carbon impacts from offi ces, schools and university buildings all miss their design targets by between 50 and 250%: ● Schools have an average designed target of 30kg CO2 operate at above 50.
/(m2 yr), yet
● University buildings have an average designed target of 40kg CO2
/(m2 100. ● Offi ces have an average designed yr) but operate at above
● IAN TAYLOR is partner studio leader at Feilden Clegg Bradley Studios
It is not a small tweak to our designs that is needed, but a wholesale jump to get anywhere near
bridging the gap
The action needed Client engagement is critical, and building owners need to be ahead of demand and policy. To achieve lower operational carbon performance targets, clients need to provide low carbon building briefi ngs at least fi ve years in advance. It takes this length of time to design and construct the building, and optimise performance after a period of operational monitoring. It means targets for 2020 would require a change in building briefs by 2015. Successful buildings come from working innovatively with committed clients. Building management systems need to become simpler. We must target low energy use, while becoming more aware of increasing occupant small-power energy use, with potential increases in cooling loads exacerbated by climate change temperature increases. It is not a small tweak to our designs that is needed, but a wholesale jump to get anywhere near bridging the gap.
May 2013 CIBSE Journal
19
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