IEA's Proposals for Buildings Should Be Adopted Right Now

Buildings have a big role to play in their Net-Zero emissions scenario.

Glass tower with red light
No more of this please.

Chris Jongkind/ Getty Images

The International Energy Agency's (IEA) recent report Net Zero by 2050 is subtitled "a roadmap for the global energy sector" and that is what is getting all the attention with their calls for an immediate halt to all new fossil fuel projects. However, buried in the 225 pages are lots of other interesting details, including sectoral pathways for energy-consuming industries often discussed on Treehugger, such as transportation and building.

The Transportation Sector

Transportation CO2 emissions


Road Transportation does not present many surprises. The report calls for rapid electrification of road vehicles, calling for EVs to be 70% of all cars sold by 2030. They recognize this will create challenges for the electrical grid, but do not think they are insurmountable.

Aviation is tougher, but the IEA expects that aviation growth will be constrained by "comprehensive government policies that promote a shift towards high‐speed rail and rein in expansion of long‐haul business travel," such as high taxes on commercial flights. There will be continued incremental improvements, and maybe "revolutionary technologies such as open rotors, blended wing‐body airframes and hybridisation could bring further gains."

Rail's share of transportation is expected to double and "all new tracks on high‐throughput corridors are electrified from now on, while hydrogen and battery electric trains, which have recently been demonstrated in Europe, are adopted on rail lines where throughput is too low to make electrification economically viable."

The report also encourages "transport mode switching" in their section on behavioral change.

"This includes a shift to cycling, walking, ridesharing, or taking buses for trips in cities that would otherwise be made by car, as well as replacing regional air travel by high‐speed rail in regions where this is feasible. Many of these types of behavioral changes would represent a break in familiar or habitual ways of life and as such would require a degree of public acceptance and even enthusiasm. Many would also require new infrastructure, such as cycle lanes and high‐speed rail networks, clear policy support, and high-quality urban planning."

These are not included in the transportation section, which is unfortunate, as is the examination of the embodied carbon in making all these vehicles.

The Building Sector

Emissions reductions


The report assumes that the buildings sector is going to grow by 75% by 2050, most of which is in emerging markets and developing economies. The main drivers of decarbonization will be energy efficiency and electrification. The report states: "That transformation relies primarily on technologies already available on the market, including improved envelopes for new and existing buildings, heat pumps, energy‐efficient appliances, and bioclimatic and material‐efficient building design."

The report calls for building code changes to ensure that new every building is "zero carbon ready" by 2030 and that every existing building is retrofitted by 2050.

"A zero‐carbon‐ready building is highly energy-efficient and either uses renewable energy directly, or uses an energy supply that will be fully decarbonised by 2050, such as electricity or district heat. This means that a zero‐carbon‐ready building will become a zero‐carbon building by 2050, without any further changes to the building or its equipment."

This includes building operations "as well as emissions from the manufacturing of building construction materials and components." –that is the embodied carbon. The report doesn't call out the passive house or Passivhaus standard and uses confusing wording with the phrase "passive design" which is something else entirely. But the intent is clear:

"Zero‐carbon‐ready energy codes should recognise the important part that passive design features, building envelope improvements and high energy performance equipment play in lowering energy demand, reducing both the operating cost of buildings and the costs of decarbonising the energy supply."

That last point about how reducing demand also reduces the cost of decarbonizing the energy supply is critically important and is one of the best selling points of Passive House—it is much easier to address the reduced demand with renewables, both on-site and from the grid.

"Whenever possible, new and existing zero‐carbon‐ready buildings should integrate locally available renewable resources, e.g. solar thermal, solar PV, PV thermal and geothermal, to reduce the need for utility‐scale energy supply. Thermal or battery energy storage may be needed to support local energy generation."

This section concludes with the identification of embodied carbon and a call for "bio-based materials" which one might just call wood or mass timber.

"Zero‐carbon‐ready building energy codes should also target net‐zero emissions from material use in buildings. Material efficiency strategies can cut cement and steel demand in the buildings sector by more than a third relative to baseline trends, and embodied emissions can be further reduced by more robust uptake of bio‐sourced and innovative construction materials."

Most of the reductions in energy used for heating and cooling will come through building envelope improvements, and remaining heating and cooling needs should be met with heat pumps. Then they get fancy:

"Not all buildings are best decarbonised with heat pumps, however, and bioenergy boilers, solar thermal, district heat, low‐carbon gases in gas networks and hydrogen fuel cells all play a role in making the global building stock zero‐carbon‐ready by 2050." They also write that "by 2025 in the NZE, any gas boilers that are sold are capable of burning 100%􏰧 hydrogen and therefore are zero‐carbon‐ready. The share of low‐carbon gases (hydrogen, biomethane, synthetic methane) ingas distributed to buildings rises from almost zero to 10%􏰧 by 20􏰄30 to above 75%􏰧 by 2050."

This is all a distraction and comes from not understanding the full implications of radical building efficiency or Passive House.

As Monte Paulsen of RDH Building Science tweets, with insulation, airtightness, and energy recovery, one can go straight to zero emissions. Hydrogen and an entirely separate distribution system are not necessary at all. But one thing that nobody can disagree with is the need for urgency:

"Near‐term government decisions are required for energy codes and standards for buildings, fossil fuel phase-out, use of low‐carbon gases, acceleration of retrofits and financial incentives to encourage investment in building sector energy transitions. Decisions will be most effective if they focus on decarbonising the entire value chain, taking into account not only buildings but also the energy and infrastructure networks that supply them, as well as wider considerations including the role of the construction sector and urban planning. Such decisions are likely to bring wider benefits, notably in reducing fuel poverty."

The report stresses the need to start renovations right now.

"Making zero‐carbon‐ready building retrofits a central pillar of economic recovery strategies in the early 2020s is a no‐regrets action to jumpstart progress towards a zero‐emissions building sector. Foregoing the opportunity to make energy use in buildings more efficient would drive up electricity demand linked to electrification of energy use in the buildings sector and make decarbonising the energy system significantly more difficult and more costly"
Jarrett Walker Tweet

The report does conclude with a point that we have tried to make so many times on Treehugger, expanding on Jarrett Walker's tweet of the decade, that transportation, land use, and also energy are really all different manifestations of the same thing. They write: "The systemic nature of the NZE means that strategies and policies for buildings will work best if they are aligned with those being adopted for power systems, urban planning, and mobility."

It continues by noting that "policies incentivising dense and mixed‐use urban planning coupled with easy access to local services and public transport could reduce reliance on personal vehicles."

But it misses the opportunity to build on this, to present a coherent vision of a net-zero energy world where you don't need so many electric cars because you can walk, where they don't need elaborate power systems because they don't need much power. Perhaps they ran out of gas at the end of the chapter, because this is the real opportunity for designing a net-zero world.

Oil Industry reaction screenshot

It's likely that the IEA report will evoke the same response from the development, concrete, and steel industries as it did in the oil industry if they read it at all.

But designers, authorities, governments, and the public who care about keeping climate heating under 1.5 degrees C should sit up and pay attention: We have to start code reviews right now, make these standards mandatory. According to the IEA, we have run out of time.