Net Zero Has Failed. We Need a Universal Carbon Standard for Buildings.
The building sector’s current “net-zero” standards are not credible, not scalable, and don’t eliminate emissions. There’s a better way.
by Joshua Radoff
This is the first article in a five-part series introducing a comprehensive, universal carbon standard for buildings. It explains how “net zero” has failed us. Part Two introduces the six building blocks of a proposed low-carbon standard. And Part Three provides details on each of those six things.
Part Four explains why we need to prohibit offsets and RECs, and eliminate other distractions, and Part Five offers a condensed recap as well as a path toward adoption of this comprehensive low-carbon standard across the building sector.
No one is zero emissions until we are all zero emissions.
Image: Ada Melton-Houghton Net zero has run its course.
We’re going to be mostly talking about buildings in this series, but in the corporate world (or higher ed or city government), claims of Net Zero or carbon neutrality (or really anything that suggests that you’re all done here) are increasingly spurious.
For one thing, achieving “net zero” requires the use of offsets, because it’s mostly impossible for any building or entity today to reduce emissions to zero without them. Offsets are meaningless, and the world is beginning to understand why that is so. You just can’t pay to offset a flight or your corporate footprint in any credible way. All you can do is make reductions and recognize that your path to zero is interdependent with other systems—like the power and manufacturing industries, which need to decarbonize in concert.
For another thing, you need to include emission scopes 1 through 3 (see this primer on the scopes), meaning you have to account for (among other things):
the impact of the products you make
the supplies you use to make them
the way your employees get to and from work or your building
This is especially important where those scope 3 emissions represent the majority of an entity’s total. What if a car company called itself net zero because it had achieved some energy efficiency at its plants and bought some renewable energy certificates (RECs) and offsets, but ignored the fact that their product and supply chains—which are within their control—are one of the largest collective emitters on the planet? We’d all collectively cry foul.
Credible standards include offsets as a last resort
To try and make sense of all this, the Science Based Targets initiative (SBTi)[1] has stepped into the fray and established some important reforms through the Corporate Net-Zero Standard. In addition, a United Nations Expert Group is recommending an “Integrity Matters” approach that aligns with the SBTi approach. At the heart of this approach are the following principles:
an accounting of scope 1–3 emissions
a long-term goal of zero by 2050
a short-term goal of around 50% reduction by 2030
a severe limitation of the use of offsets for anything but what SBTi refers to as “residual emissions”
What is good about the SBTi Net-Zero Standard is that it effectively requires every company or organization to take action to reduce all aspects of its own emissions, without getting to pick and choose which ones they think may be easier or harder to address.
Some people point out that all scope 3 emissions are someone else’s scope 1 or 2.
That’s true! The whole point of the various scopes is to allow multiple entities to claim responsibility for reducing those emissions. Even though the electricity I might reduce in my facility is really a power plant’s scope 1 emissions, I can drive those reductions downward through my efforts.
There are industry-specific versions of the SBTi standard for certain heavy industry sectors, which is appropriate, because not every industry has the same pathway and timeline to decarbonization (think steel or aviation). But if I am a stakeholder or investor, I don’t want to have to figure out what random carbon-neutral standard a company has decided to use, or whether the voluntary actions they’ve decided to focus on are the right ones or not. They’re either reducing all of their emissions or they aren’t.
So while I don’t think the Corporate Net-Zero Standard is perfect, I think it gets a lot of things right, and there is a lot that the building sector can learn from this in terms of the way it thinks about both new and existing buildings.[2]
In many ways, buildings are much more straightforward than corporations, which might vary in business activities and footprint between Whole Foods or Nissan or Burt’s Bees.
Sure, we have zero-energy and zero-carbon certifications for buildings, but these standards are inconsistent and represent a hodgepodge of incomplete accounting and offsetting.
If our cherished net-zero standards were corporate standards, they would rank at the bottom in terms of credibility, despite their best intentions. To understand why, let’s look at the brief history of the net-zero building programs.
The original appeal of net zero: simplicity
Net-zero energy was the original highest ideal for buildings.
Looking back, its appeal was its simplicity: a building produces enough onsite renewable energy over the course of the year to balance the amount of energy used over the course of that year.
I like to think that we always knew that didn’t make sense.
But when the idea was gaining traction (around 2015), the world looked a lot different than it does now. Heat pumps and electric vehicles (EVs) were fledgling, the grid was still looking to be fossil fuel dominated for the indefinite future, and scope 3 emissions were someone else’s problem.
The original U.S. Department of Energy (DOE) definition didn’t stipulate what type of energy you used (whether gas, electric, or other), nor did it concern itself much with the fact that the source of renewables for most projects was (and is) onsite solar, and that one would have to use the grid as a buffer to import and export electricity for most hours of the year.
If you wanted to be NZE, then you needed to use only what you could produce. If you couldn’t produce enough, then you needed to keep cutting and cutting your usage until you could balance it out, or find ways to increase production: to do that, you could put solar panels on parking canopies or integrate solar into the façade.
Why net zero unraveled
The simplicity of NZE really started to unravel when the National Renewable Energy Lab began pointing out that even the most efficient buildings could only be net zero if they were low rise or had low energy density.
Source: B. Griffith et al., “Assessment of the Technical Potential for Achieving Net-Zero-Energy Buildings in the Commercial Sector,” NREL/TP-550-41957 But eventually, people started to realize that some of the best ways to cut usage relative to solar collection area are to use a building less often, make it less dense, fill it with fewer people, or externalize one of your biggest loads by letting Amazon or Google manage your data.
As a result, some of the buildings with the lowest energy use intensity (EUI) are those that are also the emptiest.
With NZE, you also didn’t have to worry about the fact that solar produces during the daytime, and more in the summer than the winter—and in places with a “duck curve,” which will be everywhere at some point in the coming years, the solar you’re adding in the middle of the day is incrementally worth less and less, and doing less and less, to reduce emissions.
But in the current zero-energy and -carbon programs, you can just blithely assume that your daytime “deposits” had the exact same value as your nighttime “withdrawals.”
The simplicity of NZE really started to unravel when the National Renewable Energy Lab began pointing out that even the most efficient buildings could only be net zero if they were low rise or had low energy density.
Ironically, many environmentally minded NIMBYs enjoy the fact that only low-density buildings can meet the traditional definition of NZE. It means that they can effectively reduce growth and housing—and therefore housing affordability—while increasing transportation emissions, all under the pretense of a pro-environment, zero-carbon approach. Appalling!
So a sprawling, non-transit-oriented, relatively inefficient single- or two-story building (imagine a shopping mall) could be NZE simply by adding rooftop solar. Good job, team.
From this recognition came the need to expand NZE to allow for taller and more energy-dense buildings (e.g., from multifamily to labs), leading to the new (albeit subtle) need to allow access to offsite renewables and then define—in laborious detail—the kinds of offsite renewables that would be acceptable.
And since your onsite renewables budget was no longer determining how efficient your building needed to be, you now needed to stipulate a specific efficiency target as well.
Lastly, there is the problem of using the term “zero.” It’s worth noting that when the SBTi references net zero in the Corporate Net-Zero Standard, they are charting out a 2050 goal to truly eliminate all but residual emissions (the latter being the reason to keep “Net” in the name).
When buildings include all of their various emission sources, they too are likely aiming at a true zero target that is some distance in the future. That’s because:
Once you connect to the grid (which you should, since connected systems are far more resilient), then you can’t achieve zero emissions until the grid achieves zero emissions, no matter how many RECs you may acquire (more on this to come in Part Four).
Once you include transportation, refrigerant, and embodied emissions, there’s no longer a zero-emission goal that can actually be obtained until we get to a broader zero-carbon economy. So a zero-carbon economy should be the real focus.
In the future, we will hopefully have:
All-electric transportation
A 100% carbon-free grid
Refrigerants like CO2 or ammonia with a global warming potential (GWP) at or under 1
A manufacturing industry that is zero carbon because of the zero-carbon grid, large-scale energy storage, and renewable-energy-based industrial processes using the same low-cost renewable supply (such as through green hydrogen to produce e-fuels and green steel)
Until then, there is no zero, and branding things as “zero” or “net zero” is misleading. It suggests that emissions can be eliminated or offset in some way, and they can’t.
The truth is that no one is zero emissions until we are all zero emissions.
Shut it down (and then reboot it)
What started as a simple metric to measure the best we could do for building energy—and thus, by proxy, achieve building-related carbon reductions—has become an unwieldy mess that overcomplicates everything and distracts us from what should be a few simple tenets and requirements.
I’ve heard several policy makers, city officials, and project owners effectively say: “I want net zero because we need to act on climate change, and I don’t care if it doesn’t make sense or if we gloss over the more important aspects of climate mitigation that actually move the needle.”
We need to deconstruct "net zero"—both carbon and energy—and rebuild it as a clean, accessible set of basic principles.
To do that right, we’ll have to develop a straightforward standard that every developer, owner, investor, and practitioner in our industry can understand and embrace. A standard that confronts the actual thing we need to eliminate: greenhouse gas emissions.
In the following posts, I will propose a new Universal Low-Carbon Building Standard that does for buildings what the Corporate Net-Zero Standard does for business entities:
It will create a single set of targets that all buildings—new and existing—should meet to be considered on a path to zero emissions.
It will account for all sources of building-related emissions, including the building sector’s version of scope 3.
It will rely on a REC- and offset-free approach to reducing as much carbon from buildings as is possible today while regularly updating to incorporate new opportunities to reduce further.
And it will do all this with the goal of establishing a compliance standard that can be used for any building project, regardless of geography or typology—thus replacing the current “best practice” of certifying or showcasing a few voluntary projects whose owners choose to participate (a la the LEED Zero and ILFI programs).
This series is broken up into the following parts:
Net Zero Has Failed. We Need a Universal Carbon Standard for Buildings. (this one)
[1] SBTi is “science” based, because this pace of reductions aligns with the 1.5C pathway outlined in the Paris Climate Agreement. It’s what the planet needs, not what you think you can deliver, because the planet doesn’t care.
[2] In fact, as of this writing, the SBTi has issued draft science-based target-setting guidance for the building sector, which more or less attempts to outline responsibility among developers, designers, construction firms, and building owners for the various scopes of emissions associated with buildings.
Radoff, J. (2023, August 21). Net Zero Has Failed. We Need a Universal Carbon Standard for Buildings.. Retrieved from https://www.buildinggreen.com/op-ed/net-zero-has-failed-we-need-universal-carbon-standard-buildings
Net zero has driven designers / legislators /politicians / developers / owners to seek carbon offsets as a means of balancing carbon emissions, despite efforts to reduce the carbon imapct -- embodied and operational -- of the built environment. You should have seen the looks I would get when I blurted out 'Net zero is a shell game and not possible without offsets and / or carbon storage.' Maybe that was too direct. Maybe not.
However, we should acknowledge the aspirations and ethos that underpin 'net zero' and the progress / successes going forward. Those need not be diminished because we have learned a few more lessons about what not to do. As well, we can strive for honest, effective and practical solutions that move us along. Humans need to recognize there is just an externalization of emissions caused by offsets. Ultimately, since our planet is pretty much a closed system, it will be about lowering emissions globally, not just defaulting to an unreliable accounting principle that simply makes us feel better.
I'll second this. But that's not surprising given I've been saying the same thing for 12 yrs. Whole Life Carbon needs to be all Scope 1, 2 and 3. LEED Zero, ILFI Zero, ASHRAE 228-2023 and ASHARE proposed Std 240P all omit segments of GHGs in the name of simplicity. ISO 50010: 2023 has tiers which start to get at the whole picture (google "iso 50010 nrdc" to find David Goldstein's blog on the new standard which builds on the paper he and I cowrote). I think standards which address a subset like CIBSE TM65 for MEP embodied carbon and refrigerant leakage are fine, but we need an overarching framework in which to plug all the components. We will have to simplify things to scale the work needed to be done, but codes, policy and rating systems need to see the big picture before assessing a large non-trivial segement of GHGs a value of zero because they elected to ignore it.
It is also important to realize that when we, as professionals, talk about NZE, we understand the nuances. However, most of the decision makers (both on a municipal-national scale, and at the individual developer scale) don't understand the nuances. This can lead to actual environmental harm, which I have witnessed firsthand (in order to make a new school "truly NZE", the city poured 3M$ on a solar facade, which will be shaded for most of the year...)
In military terms, there is an objective, a mission and a means. The means serves the mission, which aims to fulfill the objective. In our case, the objective is reducing GHG. Focusing on NZE turns that into the objective, which will make us miss the real objective and, thus, prevent us from truly tackling the problems we are facing.
Despite very apt critiques, energy efficiency is still the best low-carbon strategy for buildings when paired with low-carbon energy sources. Net Zero energy, even when applied annually, still drives innovation in building design toward energy efficiency. Let's be clear what we're probably for and against: we're not against net zero energy as building-scale renewables and energy efficieny are brilliant together to reduce carbon emissions, reduce the need for new transmission lines, improve resilience, lower land use requirements for the renewable energy grid, etc. It's a great goal but not the only goal because it's myopic. What we're against are zero carbon claims (sometimes based on certifications) that are not true for a variety of reasons articulated in the article. So let's see where this series goes as far as a framework for buildings before we applaud the death of net zero energy. Regardless of what world we'd like to be in, we live in a property-line focused society where on-site energy/carbon claims are very likely to be the most popular.
There are so awesome comments already, and I'm so excited that Josh has started this conversation and given BG the privilege of hosting it. I know there will be plenty of critiques and concerns. But a wide-ranging conversation is desperately needed, including contrary opinions about the "how." I expect great things to come from diverse viewpoints as long as we're all focused on the necessary end point: rapid, mutual, authentic decarbonization. Many thanks to Peter, Jamy, Nadav, and Kjell for jumping into this dialogue. More to come!
I appreciate Josh and Building Green getting this conversation going. There are lots of things comment on with this. I'll pick one.
Josh paints off-site green power with a very broad brush. We can and should be much more nuanced. Decarbonizing requires buildings to be more efficient, (usually) free from on-site combustion, and powered by carbon-free energy. RECS are one tool to help achieve this. However, RECs alone do not encompass the diversity and innovation occurring with energy procurement today. Companies are creating and executing new ways to buy carbon-free power and reduce emissions. We shouldn't undermine these efforts. Rather, we should make energy procurement better: more transparency, more cost effective, more impactful. The solution isn't less energy procurement - it is more, better energy procurement. Here's a bit more on this: https://www.gresb.com/nl-en/articles-rapid-decarbonization-requires-inno...
We'll talk about the other issues Josh raises later.
In our paper "The Limits of Net Zero as a Building Specification", coauthors and I traced the path of 'net zero' from the DOE paper that set the standard for net zero definitions through the complicated and confusing situation we are discussing here. I think it is most useful to be explicit about the EN15978 stage(s) that match the scope needed for the measurement (policy) task. It might be building design/construction-stage scope 1 and scope 2 operational emissions only - that has been a truly valid policy choice to regulate for a generation. The purpose might only be 'cradle to gate' emobodied energy (to minimize material procurement emissions). At ASHRAE 228, we certainly decided to limit the scope to operations (including refrigerant leaks) and not embodied C, but that effort pointed out to me the limits of the net zero concept itself (and hence the paper). I think it is to soon to come up with a reliable summation of carbon emissions across the lifecycle of a building - we need to get the best independent outcomes in reduced carbon emissions (energy/carbon codes for design and building performance standards for operations), cradle-to-gate material emissions (procurement standards and LCA), and eventually duration and end-of-life criteria. And, please, lets not try to shoehorn all of these phases of EN15978 into one calculated net zero value through offsets, RECs, etc. And offsite renewable procurement that is 24/7-based can be more valuable than panels on a roof - lets make sure we use the right criteria to measure the carbon performance of energy supplied to the building. Our efforts should all be to scale the best carbon results at each phase of a building's life through good policy, to come up with easily understandable and eforceable carbon performance tools and rules, and not to wait until we find the perfect definition of carbon neutral.
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