To have any chance of achieving net zero buildings we need a sea change in approaches to design, writes Susan Roaf

Sue Roaf_cropped

Source: Christiaan Krop

Susan Roaf

As COP 28 commences in the United Arab Emirates, running from 30 November to 12 December, we urgently need truthful answers to questions around why we currently have ZERO chance of meeting the UK’s net zero targets by 2050.

At our September ICARB conference on Measuring Net Zero: Carbon Accounting for Buildings and Communities we were joined in Edinburgh by experts from 27 countries. Here are some of our reflections from there on this planet-threatening challenge:

The bad news: climate chaos is predicted by 2029

The runaway climate change tipping point is currently predicted to occur when the global mean temperatures exceed 1.7°C above the long term average. This year we already hit 1.5°C in what will be the hottest year on record. At the current emission rates the climate will tip into chaos around 2029. If you think the weather is bad now, wait till you see what it is like by 2030! Why no urgency?

Reality: UK PLC bets on a decarbonised grid

The UK is apparently betting the house on decarbonisation of the National Grid to reach net zero, ignoring investment in building stock upgrades. Hence the push into all-electric energy markets to power industry, buildings and transport. Mark Jacobson from Stanford showed it is theoretically possible to run grids on 100% clean renewable everywhere, globally. So how best to do that?

Everyone has their opinion. Some enthuse over using biomass with carbon capture and storage (CCS) in geological reservoirs as a key transition technology on the path to a fully renewable grid. Jacobson rules out CCS in the USA, citing a lack of suitably located reservoirs. Edinburgh’s Camilla Thompson presented a sensible scheme to add CCS to a local waste to energy electricity plant near a good underground store.

Many countries like the UK are now sharing HS2 moments

Solar energy on buildings is incredibly still discouraged in the regulations, rating schemes and design guidelines. The one thing everyone did apparently agree on is that new nuclear won’t work as plants take over 20 years to build and will provide electricity at up to four times the cost of wind, solar or hydro generation.

So what is UK PLC doing? Pouring millions into new nuclear and CCS while discouraging solar and wind investment with fickle market incentives and subsidy barriers!

Many countries like the UK are now sharing HS2 moments, realising that in a heating world with flat-lining economies, growing populations and fuel poverty, cost effective optimisation of low carbon energy investment is vital for climatic, economic and political stability.

Reasons to be sceptical

Buildings are responsible for around 40% of global greenhouses gasses (growing annually) yet government policies to reduce emissions can range from the ineffective to non-existent, while many architects bewail the fact they have been stripped of so much of their agency in contributing, in part because:

  • Net zero decision-making processes are often dominated by engineers promoting energy efficient technologies and big ticket / profit systems like heat networks.
  • Tone deaf government departments currently push only electric solutions like heat pumps, which are good in new-building but unsuitable in many traditional buildings that are often unaffordable to upgrade by occupants.
  • The HVAC industry has captured, ring fenced and shapes building performance regulations.
  • Net zero for architects is often reduced to ticking boxes in rating schemes developed in 20th century climates and economies like BREEAM, LEED, EPCs or Passive House schemes.
  • Building integrated solar, especially with batteries, that promises far higher emission reductions as a first step addition to homes than heat pumps, but is actively sidelined by developers, designers, planners, regulations, policy makers and national grid interests. Why is it not mandatory on most new homes? Is the democratisation of energy generation threatening?
  • Architectural education eschews courses in basic building physics, materials and passive design for training in simulation models that do not deal easily with thermal mass, natural ventilation, occupant comfort or local site and climate conditions - key features of resilient design.
  • Building regulations are stuck in the 1990s, still dwelling on issues like air leakage, cold bridging and U-values (the old Fabric First mantra). Regulations even promote unnecessary technologies like mechanical ventilation on greenfield sites and actually impede progress with an impossibly slow and inflexible process that is then often compromised by enforcement via private companies.
  • Governments are in thrall to, and occasionally in the pockets of, lobby groups from engineering, the HVAC industry, developers, landowners, materials and product manufacturers, and groups like the Passive House movement, all working to influence building, planning and energy policy and legislation.
  • Governments invest in research that justifies favoured policies, managed by ‘buddy’ consultancies more focused on profit than the common good.
  • Explicit or implicit questioning of engineering-first market-led narratives are absent.
  • Real people are lost in the huge gap between expensive market-led technology-facing solutions and the Martin Lewis approach of ‘heat the person not the building’.
  • Regulations ignore energy sufficiency that eliminates energy demand through good design.
  • The need for resilient buildings is ignored in policy as schemes are permitted that overheat, flood and fail as shelters during the grid outages that increasingly occur during extreme weather events.

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Source: Shutterstock

Reasons to be cheerful

  • Eliza Hotchkiss showed the US leading the way in the face of their accelerating climate change impacts there with policies now prioritising building resilience as well as net zero targets.
  • Daniel Overbey explained the idea of “passive survivability”, increasingly popular with US architects as people invest to survive during weather extremes when grids fail. He asked for:

i) Publically accessible future climate data

ii) All new buildings to be simulated with the “HVAC/off” functionality to prove they have “well-behaved” indoor micro-climates without mechanical heating or cooling

iii) Good passive solar heating and natural cooling simulations must be easily accessible 

  • Timothee de Toldi demonstrated the importance of thermal mass in dampening temperatures in a hotter future to affordably protect people without air-conditioning systems.
  • Rolf Frischenecht dwelt on the role of embodied energy in materials in getting to net zero. He and other speakers highlighted exciting progress made in high mass, low emissions materials like low carbon concrete, brick (eg. K-briq) and natural fibre insulation.
  • Rajan Rawal showed that even in hot dry Ahmedabad or hot humid Mumbai, energy use in an office building can be halved operating them as mixed mode buildings, using natural ventilation and fans for cooling for much of the year, when perceived to be necessary by occupants. Simply using the wider Indian Adaptive Thermal Comfort standards rather than the narrow temperature limits of the US air-conditioning engineering industry radically reduces emissions.
  • Marius Peters from Germany explained that PVs systems emit almost no CO2 over their lifetimes and Matthias Hasse from Switzerland demonstrated that the optimal amount of solar on any building is as much as you can fit on the roof.
  • Jimmy Jia dealt importantly with how to correctly cost emissions reductions for projects.
  • Prashant Kapoor works with cities around the world and showed that three things are needed to make change happen: knowledge, financial resources, and political will power.

Key concerns included the fashionable topic of embodied energy as more accessible assessment methods are being promoted. Whole life accounting is more difficult to calculate, but is essential for achieving net zero over time.

The 1990s mantra of ‘fabric first’ is no longer fit for purpose due to its use of simplistic assumptions around measures like U-Values. Jia defined embodied energy as the energy consumed in the past from which one derives future energy benefits. For example, a solar cell has embodied energy that (+) generates future energy. However, an air-conditioner has embodied energy but (-) consumes future energy.

The future must lie in designing buildings that work with natural energy, not against it

Some embodied energy is more useful than others to reducing emissions over time. A high mass wall provides insulation and also absorbs energy, so dampening the amplitude of temperatures in a space, storing it so it can be reemitted later, and so extending the hours that the building can run on local natural energy from wind and sun. A low mass wall just provides insulation.

One wall is much more useful than the other, but they can have the same U-value. A building is not a cardboard box with a machine in it! It is a living breathing part of a local landscapes and its energy flows. The future must lie in designing buildings that work with natural energy, not against it.

Messages from ICARB 2023

Buildings First: for net zero buildings architecture is what truly matters.

Energy Sufficiency: net zero buildings must work for as much of a day, season or year as possible, running on local or imported zero carbon renewable energy.

Community Scale endeavours are very effective. For example on university estates where data driven planning for the long term across a range of buildings can radically reduce emissions.

Architects need good clients, vision and determination to work with in agile teams with evolving skills, capable of overcoming the inertia of 20th century thinking. A quantum leap in climatic design skills is vital when designing future-facing buildings that can keep occupants safe for as long as possible as temperatures soar to over 450C, even in the UK.

Access some great research and presentations on net zero buildings and communities on the ICARB 2023 website.

To get anywhere near net zero by 2050, we need urgently to refocus on investment in upgrading our building stock to save future lives, not least because buildings are our first line of defence against ever more extreme weather events – not machines and not the grid.

>> Also read: Want to know about Net Zero? Take a short hard look