Why Net-Zero Energy Is a Goal We Can All Get Behind

BuidingGreen’s recent report critiquing net-zero energy may be fighting the wrong battle.

By Brad Liljequist

The McKinstry Catalyst building, which is registered for both ILFI Zero Energy and Zero Carbon certifications, is served by the brand-new South Landing heating and cooling district, which includes substantial thermal storage to enable load shifting.

Photo: Benjamin Benschneider
Reading BuildingGreen’s provocative “Net-Zero Energy Isn’t the Real Goal: 8 Reasons Why” sparked a lot of emotions and thoughts—ranging from strong agreement to a fair amount of “Yes, but….”

Zero energy by itself has never been the full, holistic goal—which instead perhaps is best stated as: “to reconstruct our human community to use and generate energy in planet- and climate-positive ways.” Achieving this goal will require a narrative of positive change over time, in which zero energy (ZE) and its successors have played, do play, and will continue to play an important role.

We need to remember there are still only several hundred truly zero-energy buildings, which at this point are hardly a Godzilla threatening to bring down the grid. Solar energy is only 2.3% of U.S. electricity production, and the oft-replicated California duck curve (complete with its faulty y-axis solar generation net-zero point, as shown in the article) represents a single (worst-case) day in a specific, solar heavy grid. It’s not close to universally applicable nationwide. In addition, utilities have solutions too, particularly in large-scale vertical mechanical storage such as rail or two-cell hydro, meaning buildings don’t have to solve grid renewable variability on their own.

Zero Energy’s Successes

Establishing a positive, accessible brand and well-defined performance goal for built environment climate solutions—Most of the people reading this have struggled at some point to build enthusiasm for efficiency with mainstream audiences. Zero energy’s greatest strength may be as a tangible marketing concept that has already gained buy-in across all levels of the built environment. In 2001, we had 10,000 visitors to zHome (the first certified Zero Energy community in the United States), who came from all walks of life, responding to the gee-whiz, high aspiration, can-do message of zero energy. Today, zero energy, zero carbon, and zero emissions have become common parlance, all the way to President Biden. We must appreciate that ZE and its kin are a hard-won, collectively held brand, of which our community is the collective steward. Yes, we should evolve it conceptually, but we should also protect its market resonance and have care with our critiques.

Creating a portfolio of technically compelling, human-scaled examples of deeply efficient clean-energy buildings that catalyze climate-positive change—The hundreds of zero-energy buildings now serving their occupants provide an incredible sample of fully electrified, deeply efficient buildings that use 70%–80% of the energy typically consumed. That as a collective they are also beautiful, functional, cost-effective, and loaded with co-benefits clinches the deal. The strength of this vanguard in providing living proof that deep efficiency is not only possible, but even yields a better building, cannot be underestimated. Washington State’s adoption of a commercial energy code that effectively requires super-efficient, electrified, heat-pump-based heating was successful in part by having compelling, real examples to point to.

It is also critical to recognize that our entire built environment climate regulatory framework is based on energy, not carbon metrics at this time—and zero energy is the stretch performance goal for these tools. Washington State and, just last week, Colorado have adopted energy benchmarking legislation as a tangible first step in driving carbon mitigation. Do not discount the driving role energy savings performance contracts and similar funding mechanisms play in pushing code and legislative requirements. These metrics and tools are just starting to shift to carbon. We should not make a broad language transition from energy to carbon until the whole infrastructure of carbon-based funding mechanisms and international standards is in place.

Closing the circle on climate responsibility through a full renewable offset—Zero-energy buildings, which demand a 100% renewable energy offset, have been a key part of helping people to take full responsibility for their carbon footprint. As “zero” language has made its way into the mainstream, this is perhaps its strongest conceptual kernel. Also, the cohort of zero-energy buildings sporting a full solar rooftop helped seed the growth of commercial rooftop solar, which is well underway.

My primary reservation with the article—focused on some very specific phraseology—is the use of strong declarative statements in the eight key points, i.e., “NZE buildings use energy at the wrong time,” or “NZE buildings lack the flexibility to shift loads in real time” (which could have been easily ameliorated by the inclusion of “can,” as in “NZE buildings can…”).

There is nothing inherent in zero-energy definitions or practice that enforces these outcomes, and in fact, I’d argue the opposite. For example, every zero-energy building I am aware of includes some form of higher-performance envelope. This, combined with also-typical heat-pump-based heating, radically reduces the energy demand of the buildings not only overall, but at the peak grid-demand points the article highlights. The midday solar trough is a somewhat different matter, and applies to every electron generated by net-metered solar in the world, not just those located on zero-energy buildings—leading to the grid optimization discussion below.

A Note on Embodied Carbon

Finally, with regard to zero energy not addressing embodied carbon—well, yes, that’s why the International Living Future Institute (ILFI) launched the Zero Carbon certification four years ago, including embodied carbon requirements. The time is right to further strengthen embodied carbon standards, reducing construction carbon and addressing carbon sequestration opportunities (such as through forestry practices). Many project teams are doing the type of embodied/operating carbon tradeoff analysis pioneered by groups like the Carbon Leadership Forum and KieranTimberlake, which will influence design at the outer limits of efficiency as well. It is likely these will start to be internalized in zero-carbon systems. 

Moving Forward

Zero carbon is the future, but zero energy still plays an important role

I believe zero carbon is the brand and metric of the future. We should continue to evolve and build on it to include not only grid optimization, but also neighborhood-based and other solutions. As mentioned above, however, so much of our built environment climate-solutions infrastructure is based on the language and metric of energy (e.g., energy codes, energy efficiency, energy use intensity, energy services contracting, etc.), that we need a locomotive to continue to pull that organizational and cultural train forward. While energy currently plays a surrogate role for carbon in most of these settings, the shift is just starting.

Zero carbon should include grid optimization

I think the best, core point of the article, which it addresses from numerous angles, is that it is time for these zero systems to address the energy-using and -generating framework as an ecosystem—and it absolutely is.

The impulses of zero-energy and zero-carbon approaches that internalized grid-source carbon loading, but included no way for a project to respond, were understandable but misguided. Grid optimization turns this on its head with a positive, holistic structure to improve the interactivity of the whole system. The good news is that there is an array of fairly-easy-to-implement solutions. In particular, using water as thermal storage should not be underestimated as a solution due to its low cost, ability to be delivered as a retrofit, and in particular its benign, commonplace nature (just wait for our first lithium war). To echo the point made by Cara Carmichael at the Rocky Mountain Institute, the high carbon grid peaks of today will be different tomorrow, and we should be careful to not build those into building design, but rather provide for flexible response over time. And I would suggest that, given the strength of the “zero” brand, grid optimization be included into the zero carbon concept, rather than running alongside. I fear it is too specific and obscure to gain traction on its own, and to echo the article, it is time to pull all the pieces together under one integrated system.

The best buildings are already incorporating grid-beneficial load shifting, often simply in response to peak demand and rate structures established by utilities to promote building/grid integration. For example, the McKinstry-developed Catalyst building, registered for ILFI Zero Energy and Zero Carbon certifications, is heated and cooled by the brand new all-electric South Landing energy district, which includes thermal storage to fully enable off-peak heating and cooling. Similarly, McKinstry is supporting a large municipal school district in its pursuit of zero-carbon energy use. The district’s local utility has both peak demand and rate structures which significantly incentivize use of off-peak grid electricity, as well as self-use of onsite solar generation. In response, through thermal storage, solar angle, combining night flush with delayed mechanical cooling, switching, and other strategies, McKinstry is creating a grid-responsive portfolio.

Wrapping Up

Let’s not inadvertently kill the goose that lays the gold egg. We have spent years building acceptance for zero energy, which now has traction in the broader culture. As a community, we are sometimes too ready to forget narrative and solve for all problems at once. We have a terrific start; let’s build on it and adjust. Timing is everything: just as offsite zero-energy renewables and zero carbon had their right launch times, so do these new topics. Now is the time to expand our zero-carbon approaches. But zero energy has some good runway left too.

Brad Liljequist leads Zero Carbon and Energy programs for McKinstry, which has nearly two dozen zero-carbon and -energy projects underway. Previously, Brad led Energy and Carbon programs for the International Living Future Institute, where he launched the Zero Energy offsite renewable pathway, as well as the Zero Carbon standard. He also developed zHome, the first certified Zero Energy community in the United States (now celebrating its tenth anniversary) and wrote The Power of Zero: Learning from the World’s Leading Net Zero Energy Buildings.  

Published July 6, 2021

(2021, July 6). Why Net-Zero Energy Is a Goal We Can All Get Behind. Retrieved from https://www.buildinggreen.com/op-ed/why-net-zero-energy-goal-we-can-all-get-behind

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July 9, 2021 - 12:29 pm

Agree with all for sure! I've also been thinking a lot about how a building's embodied carbon footprint will improve as the grid decarbonizes. For example- 100% recycled steel that is from 100% renewable powered arc furnaces changes the equation pretty significant. 

July 12, 2021 - 12:25 pm

I think this article, plus the original, both make valid points, but also maybe miss the crux of the matter. I'll summarize in some bullets:

1. I agree that onsite solar wont bring down the grid. Utlities are generally required to upgrade their substations and transmission if the solar is behind the meter, although the size and conditions of what utilities may have to accept varies by state. And if curtailment is the concern, then batteries are always an option. 

2. However, NZE (or NZE 1.0) has become a confusing and misleading goal, because we no longer mean all energy should be produced onsite. That was never a good definition, even if it was simple and easy to understand. It excludes most buildings and ignores important site contexts (and rewards low density and surface parking for solar). 

3. The components of NZE 2.0 are really important and we should just talk about those, namely make buildings efficient (but I'd argue if you're at IECC 2021, you're probably good there, and if not, then we're only talking about a few EUI points difference), electrify buildings,  adding onsite renewables, and procuring the rest from offsite renewables. You should also address the embodied carbon content, shift to low GWP refrigerants, and add charging infrastructure. But for the building itself, if you meet code, electrify (which many jurisdictions are trying to make code anyway), and add renewables, then is NZE really worth touting anymore when what we mean is that we achieved electrification and that we added some onsite renewables? 

4. The last component which is all about getting renewables from an offsite source is extremely fraught with complexities and barriers that arguably shouldn't be the concern of a building owner. Most states don't have community choice aggregation (CCA) or community solar garden programs. If they do, yes, buildings should sign up if there is availability, but there may not be given the way utilities allocate their development. Or projects may not be able to keep RECs which is an accounting nuance that building owners also shouldn't have to navigate. Similarly green tarrif programs vary widely in terms of credibility and value, and I don't think I'd make a NZE certification depenent on signing up for a utility program of questionable and dubious value. There are still other mechanisms that exist in certain places, like virtual net metering, but most owners don't have access to additional land in another location on which they can develop renewables. And yet, this is often the main barrier between achieving NZE and not doing so, even if a project has contributed the value of #3 above.

5. I would advocate for a universal zero carbon building checklist. This would include the elements above as well as non building operational elements such as embodied carbon (including adaptive reuse) and transportation management and electrification. And it would allow for an 'NA' if there is not a good option available for off site RE procurement. But NZE in its current form should go away, and we should emphasize the things that matter and try not to confuse everyone in the process. 

July 12, 2021 - 4:47 pm


July 12, 2021 - 6:17 pm

Moving away from costly utility NZ programs and looking towards community infrastructure hardening may be the new paradime. Small towns rural in particular need to look at all buildings from homes to schools, shopping centers and municiple as potential energy sources. Combining solar, storage and EV charging to become a local power plant when climate breaks our utility connection becomes more than feel good NZ posturing. The inevitable future of large scale blackouts that may last days to weeks and possibly months is on the horizon. We need to move away (not completly) from the large power grid as the final word and look towards local power generation as the next step towards energy independence.

July 12, 2021 - 7:33 pm

While NZE doesn't capture embodied carbon impacts and is perhaps outdated, deep energy efficiency as well as on-site generation/storage provides significant resilience benefits. In places with low carbon electricity and abundant wood such as the Washington State or British Columbia, it is much easier to achieve a low carbon building and still not provide adequate resilience during a winter or summer power outage. The recent heat wave in the Pacific Northwest where peak hourly electricity demand in British Columbia set new records (even though many don't have air conditioning) demonstrates that energy efficiency metrics are still critical.

July 14, 2021 - 9:15 am

It is excellent that the original article was pulished (though I agree adding "can" to the declarative statements would have been been appropriate) and that this counter article has been published to broaden the discussion.

Between them both there is much useful information, and a call to think at a systemic level, which is the key to accelerating good, holistic, ZNE projects that are designed to support grid transition and reduce embodied carbon as well. And maybe, just maybe, these can be be built in established cities or be renovated from our valuable building stock (at least in the Upper NE, where we have so many valuable yet neglected existing buildings)!

July 14, 2021 - 10:23 pm

Shanti - thanks - I have to confess generally that the embodied carbon revolution took me off guard and was humbling.  I am thrilled that wood is making a comeback, as long as the harvest is done appropriately.  I do wonder if enough attention is being paid to weatherproofing - we are definitely expanding the potential rot bubble with larger potential structural consequences (high rises, etc.) - a lot of attention was paid to fire, but I wonder if in the long run structural rot will be a bigger concern.  

Josh, your title cracked me up, as it was what I nearly suggested for the piece.  Appreciate your thoughtful response.  A couple thoughts:

  • It's easy to forget the substantial majority of the US significantly lags the code innovator jurisdictions.  In WA State, where I am located, the 2018 energy code requires DOAS ventilation, heat pumps, and essentially requires electrification (except for kitchens, and I'd bet that's next).  Working nationally, I am really struck by how what is standard practice in WA is avant garde elsewhere (had recent conversations in a small Western city about the viability of VRF due to lack of contractor knowledge - that would never happen in Washington). I still think ZE provides a great aspirational goal for most of the country.  
  • Availability of credible offsite renewable purchasing is incredibly variable across the country - I think if I could pick one thing nationally to do right now, it would be to mandate that every utility provider provide an easy renewable option.  This would force the utility to provide it and accomodate/integrate it into their larger system.  Strangely, WA State is really bad in this regard - if only we could consolidate the "best of" regulations and programs nationally.  

Scott and Ilana, I really agree that non-powered, or less powered, independent and flexible systems are where it's at.  A ZE building may have some of the elements, but sometimes misses, and in some cases just minor changes would improve non powered flexibility a lot.  

Jodi, thanks!  I agree - I really appreciate BuildingGreen's willingness to have the dialogue - we have a lot to do - the more we can support each other, the better!