Engineers carry a lot of weight on their shoulders: climate change urgency, getting off gas, the building paradox and constructing for climate disasters are just a few and these were covered in CIBSE’s first seminar in its series on engineering a net zero future.
How on Earth are we going to get to net zero by 2050? Pretty much everyone working in the sustainable built environment field has this question on their minds. The Chartered Institution of Building Services Engineers (CIBSE) is trying to come up with some answers, including running a five-week series of seminars on “The need for speed: Tools to engineer a net zero future.”
The focus of these sessions is entirely practical – providing a toolkit for engineers and designers to envision and put into action their path to net zero, project by project.
The first one on Tuesday last week was facilitated by The Fifth Estate editor Tina Perinotto. it delved into some of the latest findings in climate science and how this is driving urgency in the net zero transition. Presenters included Bruce Precious, principal consultant at sustainable consulting firm Six Capitals, Philip Oldfield, professor of architecture and head of school at UNSW’s School of Built Environment, and Nick Lander, director of climate change, physical risk & resilience at Aurecon.
Bruce Precious – 10 critical years of transition in the built environment
Precious is a well known advisor who works with government and property businesses. His take, with a wry sense of humour, was that “the need for speed in this context is an expression of urgency and not a call to the local meth dealer.
Engineers are critical to the net zero transition, he said. “We won’t science our way to net zero by 2050, we’ll engineer our way there.” Here are some of his highlights:
What’s the urgency?
Various industries are projected to follow different trajectories to net zero. According to Climateworks Centre, the built environment sector is expected to follow an extremely steep decline in emissions by 2035, which means that expectations for this industry are compressed into 10 critical years. The Australian Sustainable Finance Institute also predicts that emissions from commercial buildings will decrease by 88 per cent over the next decade – a trajectory that isn’t out of step with historical performance to date.
The reason behind this, said Precious, is that we already have the technology and systems available to make our built environment ever more energy efficient and to power it with renewable energy. Building engineers have many tools available – from energy efficient design methodologies to measuring systems (such as NABERS), rooftop solar, heat pumps, smart controls, all manner of green building tech, and retrofit options such as Passivhaus.
The regulatory environment is also falling into line, including updates to the National Construction Code that have increased the minimum energy star ratings for various building types, and the Commercial Building Disclosure Program. Engineers and designers just need to be aware of what’s available and know how to use the tools.
Getting off gas and onto solar
The Australian Energy Market Operator forecast that the use of natural gas in residential and commercial buildings will decline by about 40 per cent by 2035. Victoria and the ACT have already banned gas connections for new builds, and other states may soon follow.
It’s now looking likely that with fewer gas customers, those remaining will need to carry the maintenance and supply costs. A similar scenario in the UK has led to forecasts of up to a tenfold price increases on gas network charges that, when coupled with more competition over increasingly limited supplies, will generate further price increases.
“We’re working our way into a bit of a death spiral for the gas network,” Precious said.
He also discussed the “transition risks” in this space, including:
- As large commercial property owners transition to all-electric and commercial tenants increasingly require this in their lease conditions, buildings still connected to gas by 2035 may become expensive to run and difficult to lease.
- Tipping points where particular sections of gas pipeline will become unviable and need to be decommissioned.
- Expensive gas appliances will likely become redundant before the end of their lifespans.
As solar continues to grow, with over 3.7 million rooftop installations in homes and businesses nationwide to date, Precious said paying for a gas connection to be “an extravagance”.
The electricity grid is also decarbonising, albeit more slowly than expected, with solar, wind and hydro all making increasing contributions.
All of these facts “deflate the arguments against immediate electrification of the built environment,” he said, and indicate that the transition to renewables and electricity in this sector should be almost complete by 2035. Hence the urgency.
Philip Oldfield – The building paradox
Oldfield’s research examines how the built environment sector can meet the needs of society while limiting environmental impact. His presentation was a provocative, whistle-stop tour through the magnitude of the global challenge of decarbonisation in the construction industry, including some big-picture paradoxes and inequities.
To summarise a complex and informative session:
- Building is a necessary societal good to provide homes, hospitals, schools and other important facilities for the world’s growing population. UN-Habitat says we need to build 96,000 new homes daily to meet the future need for safe and affordable homes worldwide
- Building is also an “environmental bad.” There are almost always negative environmental impacts, with the building and construction sector responsible for 37 per cent of global greenhouse gas emissions
- Globally we’ve already dominated nature through construction, with the total weight of buildings and infrastructure worldwide now exceeding the weight of all living natural biomass
- Worldwide we’re constructing the equivalent of all the buildings in Japan every year
- According to the Global Carbon Project, we’ve already consumed around 90 per cent of the carbon emissions “budget” required to have a 50/50 chance of staying within 1.5 degrees of warming. Building the number of homes needed in the future alone will rapidly blow the rest of that budget
- According to UNEP, we’re on track to double the total global floor area of buildings by 2050 – in exactly the same timeframe that Australia is aiming to get to net zero
The global building paradox lies in the fact that the maths here simply doesn’t work, as current construction projections don’t match our net zero targets.
Oldfield believes this means we need a major rethink, including drastically reducing new building, and ensuring that all new and existing buildings are net zero in both operational and embodied carbon by 2050. No small task.
How can we solve this paradox?
The second and more optimistic part of Oldfield’s session focussed on solutions. He said we need to:
- Shift away from thinking about efficiency, which is driven by technological improvements, towards sufficiency, which is about considering what we really need
- Recognise that the most sustainable buildings are the ones that don’t exist
- Find ways to use unoccupied homes, for example the estimated 65-80 million vacant apartments in China
- Build smaller houses – relevant in Australia, which has some of the biggest homes in the world
- Encourage multi-use buildings, for example school buildings, which are only used during the day could become community centres in the evenings
- Retrofit and refurbish old buildings to produce huge embodied carbon savings
- Upcycle building materials and components from “donor buildings,” which creates more efficiencies than recycling (for example reusing tiles and floor slab sections rather than smashing up concrete for roadbeds)
- Rental systems for fixtures and fittings in buildings (think lighting, elevators, bathroom fittings) to encourage reusing, recycling and a circular economy
- Reduce material waste in construction with new technologies such as 3D printing
- Rethink buildings at the design stage, particularly for elements that need high embodied carbon materials such as steel in cantilevers and trusses – do we really need these?
- Have open conversations about the public and social benefits of specific buildings versus their environmental costs, to decide which are necessary and which aren’t
- And the most confronting: include the human mortality cost of carbon in construction decisions. Research shows that adding 4,4000 tonnes of carbon dioxide to the atmosphere in 2020 caused one excess death globally, which means that a skyscraper (50,000 tonnes of embodied carbon) “costs” 11 excess deaths.
Oldfield finished with a snapshot of the extreme infrastructure inequalities and gaps between the global north and the global south, which make the challenge of achieving an equitable transition to net zero in the construction sector even more difficult for developed nations like Australia.
He argued that 2050 is too late from this perspective – we need to get there by 2040.
“For us in the global north, we have a responsibility to reduce our emissions much, much quicker. This will allow other countries around the world to build the necessary infrastructure that we already benefit from, to improve life for everybody on Earth.”
Nick Lander – Climate risk and resilience planning
Lander has been working in the field of sustainability in the built environment for 25 years. His presentation focused on equipping the built environment for the climate risks that we’re already experiencing, as well as those in the future. He emphasised that “climate change isn’t just about big events, it’s also about incremental worsening.”
We all know the major climate risks – including extreme heat, dangerous levels of humidity, dryness, dust, bushfires, storms and cyclones.
Lander said that engineers are used to assessing discrete risks, but climate change is different. “It’s a transverse risk. It affects lots of things and the risks cascade through the system. This means that the biggest risks may not be the most obvious ones.”
He recently did some work with the Victorian Health Building Authority , looking at the climate resilience of hospitals and healthcare buildings. Some examples of the system-wide risks identified during climate-related emergency scenarios include:
- The need for backup power beyond a generator, as fuel supply for generators can break down with blocked roads, fuel pumps not working without power etc.
- Parts of a hospital’s supply chain that are less resilient and don’t have backup power can fail – for example catering, cold chain, emergency services and communications.
- Digital administration, information and communication systems don’t work without power.
- Road closures due to floods and bushfires severely impact healthcare, as essential supplies such as fuel and food can’t get through.
- Many communities in Australia are accessed by a single road which increases their vulnerability, including remote towns and newer housing developments.
For engineers, this means that it’s vital to look at the whole ecosystem around a project, including supply chains. The buildings of today need to be constructed and equipped for diverse current and future climate risk scenarios, including the ability to survive in disasters. His suggestions include to:
- Avoid construction in flood plains and high-risk bushfire zones where possible
- Build in flood and fire defences such as green infrastructure, water reservoirs and vegetation breaks
- Design buildings so they can be swept out and activated as soon as flood waters recede or bushfires pass, rather than needing a full refit
- Locate backup equipment (like standby generators) on higher floors or in safer areas
- Include independent fresh water supplies (such as rainwater tanks) and food gardens
- Design infrastructure and landscaping to retain water in soils to reduce bushfire risks and drought impacts (dry soils crack which can crack buildings)
- Design public buildings to act as community refuges – for example maximising natural cooling and ventilation in areas prone to heatwaves
According to Lander, sustainable and climate resilient building design is “not just about reducing energy consumption to make net zero. It’s also about how [the buildings are] going to handle it when things go to custard.”