What is sustainability – The pitfalls of carbon as a proxy for our buildings performance
“Sometimes we can’t measure what we need, so we invent a proxy, something that’s much easier to measure and stands in as an approximation” – have we done this with carbon emissions as a measurement for sustainability in the built environment?
And if we have, what implications does gaming the proxy have on our built environment and what is the solution?
False Proxies and Rating Systems
I love Seth Godin‘s work, he has written a lot of great business and marketing books and also blogs every day. On a recent post about the dangers of false proxies, I saw many parallels to green rating our built environment.
Seth first gave two examples
“TV advertisers, for example, could never tell which viewers would be impacted by an ad, so instead, they measured how many people saw it. Or a model might not be able to measure beauty, but a bathroom scale was a handy stand in.”
“A business person might choose cash in the bank as a measure of his success at his craft, and a book publisher, unable to easily figure out if the right people are engaging with a book, might rely instead on a rank on a single bestseller list. One last example: the non-profit that uses money raised as a proxy for difference made.”
OK, so we needed to reduce the environmental impact of our built environment. With such a range of buildings and uses, and not knowing the right metric to use, energy, carbon, footprint against what measure per area or per person, we chose carbon emissions per meter squared as the right proxy.
“You’ve already guessed the problem. Once you find the simple proxy and decide to make it go up [or down], there are lots of available tactics that have nothing at all to do with improving the very thing you set out to achieve in the first place. When we fall in love with a proxy, we spend our time improving the proxy instead of focusing on our original (more important) goal instead.”
So, we have our proxy – carbon emissions per meter squared and our proxy goal is to reduce this through NABERS, Green Star, Basix and House Energy Ratings.
Some implications of our carbon proxy?
NABERS Six Stars and Site Boundary Limits
We have seen an industry shift it’s average carbon emission with the introduction of NABERS and then the introduction of mandatory disclosure through the CBD. So how do you keep it going – increase the scale.
The introduction of NABERS 6 Stars has been designed to keep the proxy going. The response has been most new CBD office buildings are now targeting 6* NABERS, some are seeing the commercial reality and limiting to 5 stars NABERS.
The limit of carbon per meter squared as a proxy is that any carbon emission savings outside the buildings boundaries cannot be accounted for when designing a new building. There was a recent ruling that district trigeneration could be accounted for, but when it comes to renewable energy anything offsite cannot be accounted for.
Existing buildings, yes you can buy green power. New buildings, no you cant take account of green power. But what about if you have made the building as energy efficient as possible and you want to improve its carbon by investing in off site renewables? No, sorry you cant do that. Yes I understand thats its to stop someone designing a really energy inefficient building. But its now encouraging the industry to focus on carbon not energy efficiency.
The two main implications.
The first is that almost all new CBD office buildings are now being installed with trigeneration. The result of carbon per meter squared as a proxy is that we are now installing disconnected decentralised power generation. Is decentralised a good idea? Yes. Is it a good idea for these to not be connected and controlled centrally? No.
The second implication is the multiple issues and challenges of trigeneration – see my tri harder series for some of these issues. These issues can be overcome, create a far greater long term benefit to the environment, reduce localised emissions, all at a lower cost if we were to invest the same money in offsite renewables. But our proxy won’t let us.
Carbon proxy versus Energy Efficiency
Carbon emission reduction should be focused on after we have maximised energy efficiency, installing a carbon emission reduction mechanism to meet a NABERS rating can sometimes counter the energy efficiency opportunities. The most energy efficient air conditioning system is one thats turned off, unless of course you have a trigeneration system.
If you install a trigeneration system and want to payback the financial and carbon investment you have made in installing the system then you want it to run all the way through the year. If you naturally ventilate your office, the airconditioning will be off which means the trigeneration system will be off. No one would do that if they invested over $2million in trigeneration.
Per person rather than per meter squared
The current trend in office buildings is to have more people per meter squared of office space, activity based working (ABW) and more combined common areas means that new tenancy fitouts are more like 1 person per 10 meter squared rather than the average 1 person per 15 meter squared from NABERS ratings benchmarks.
In the landlords case more people per meter squared is a bad thing for our carbon proxy, the carbon emissions per metre squared of the building increases but the carbon emissions per person decreases.
Our impact on the environment is more related to the number of people not the size of the buildings. Almost everything related to our impact on the environment is measured per person, except for our buildings. Buildings are inherently more efficient with more people in them, we should measure our carbon emissions per person not per meter squared.
Seth’s last comment was “Gaming the system is never the goal. The goal is the goal.”
NABERS has generated a huge and significant step change in our industry but once we start gaming the system we lose the focus of the original goal. The original goal was to reduce the environmental impact of our buildings.
NABERS and Green Star were created some 10 plus years ago, our industry has changed a lot in that time. We understand energy in buildings a lot more than we did, we know about the environmental impact of building materials, we design in 3D and use BIM, and we have collected a lot of data.
The need for a proxy as an approximation is not there anymore – we can now measure the total lifecycle environmental impact.
We need to be able to account for offsite renewables, we need to assess energy and carbon not just carbon, we should include the embodied energy and carbon of buildings not just operational, and we need to be account for it per person.
We need to change from a proxy of carbon emissions per meter squared to total lifecycle environmental impact per person.
We fell in love with carbon per meter squared as a proxy but the industry has moved on.