Defining net zero

This is a really interesting topic. tl;dr: From a communications standpoint, I think it's most important that we encourage folks across our industry to be as transparent as they can be in defining just "how net zero" a building or space within a building is. Longer version: all of the things you mention above sound, in most instances, to be taking really positive action. I think we risk cutting our noses off to spite our faces if we say "nope, that doesn't count" to any of these, though at the same time, "net-zero" in and of itself should mean no footprint when you do the math. So, getting comfortable with the nuance is important, especially as there are plenty of customers and owners out there that might need the incremental jump. We can get really into some weeds, otherwise. If a building generates enough energy onsite to meet and go beyond its power needs, but just pushes that into the grid and the bulk of energy in the grid is coming from fossil sources, there are a lot of hairs to split on carbon measures, but "net zero energy" still holds. Same if the "offsets" are kinda questionable rather than purely backed up by data. Really... I think it's just a matter of being upfront about it and running at the fact that the building makes the local grid more green. Water is a whole other situation, too, and plainly, it's getting lost in the net-zero and carbon-tracking narratives. Maybe it's just too cheap a resource in most markets? That bill will come due, though. And even if we have net-zero energy and carbon buildings (down to the emobodied carbon), we still are right to ask about water if we're calling something "net-zero." At the very least, there are stakeholders out there who will ask and, as a communicator, I think instead of running from it, just being clear about the steps and systems a given building takes, where the trade-offs are and more might actually advance the larger discussion.

Hi Chris - I'm glad you've asked, because I've been thinking about this too... I've had a sense for some time that what we need (and the best we can reasonably hope for) is a "Net Zero Spectrum" that communicates, from least effective to most, the full range of certifications and measuring methodologies out there for "Net Zero". I think there would be real value and power in groups like ours, and eventually for industry as a whole, to agree on such a spectrum and the rationale behind why one certification is "lesser" than another (similar to the breakdown you laid out in your question). This notion crystalized for me when I went to Mahesh's USGBC presentation last spring on the new LEED Zero program (Program Guide attached). As I listened, I started seeing a spectrum that is bracketed with LEED Platinum certification on the left side and full Living Building certification on the right side. I realized that the chasm between these two points is rather vast, and that the USGBC had correctly determined that they could have a role to play in the market by filling in some of that void. (Interestingly, this is not how they portrayed their new creation, instead they proposed that their's was THE new standard in Zero certification, and no mention was made of work in this arena by NBI, Architecture 2030, ILFI Zero and Living Buildings, alas.) When you review the LEED Zero "net zero source energy+RECs" approach, you quickly realize that it is "less than" (and more accessible than) the ILFI certification requirements, as we might expect, but it seems to me that the USGBC still has a credible claim that achieving one or more of their "Zero" certifications is an improvement on just achieving LEED Platinum certification. If that is the case, one can start to diagram a credible full-spectrum for the array of choices in front of out clients, and a uniform language and criteria for describing the differences for each position. If we had that, we could then map our client's project goals/ambitions over the spectrum, and probably find the right landing spot (or zone) fairly easily. I genuinely don't believe that we will develop one net zero definition to "rule them all" because there are too many variables in play across the certification systems and the energy market as a whole, hence the need for a "spectrum". That's as much thinking as I've done on this, but it seems like one way to deal with your quandry - what do you think? Clark

I agree, Clark. We recently presented such a spectrum to a client and noted that there are very different ramifications for the design and renewables depending on the flavor of net zero; we also distinguished between net-zero energy and net-zero carbon. The spectrum we presented included self-certified net-zero carbon (dubious), to LEED Zero Carbon, to Net-Zero energy onsite + LEED Zero Carbon, to ILFI Zero Carbon (including fossil fuel free). To Chris’ point, we should also have a floor such that low-quality offsets/renewable purchases are not considered a major part of something that is called ‘Net Zero Energy’ or ‘Net Zero Carbon.’ We work a lot in Higher-Ed, and have seen that many campuses claim net zero carbon; it’s tough to sort through what is being done and what is not. If any new building on a campus is inherently Net Zero carbon due to cheap offsets… -Kjell From: Clark B

Kjell - I agree that the same kind of diagram/thinking should be applied to carbon, and water (though as Jay notes, water will be a bit trickier), so that we're communicating clearly and consistently about where a given project lands in regards to it's multiple net zero goals and ambitions.

And it gets even trickier if we are considering total carbon, which includes embodied and operational....we just finished this for concept phase in a project. BTW and we did not consider waste, water or transportation. What is truly carbon neutral? Best, Pablo Pablo La Roche Ph.D. LEED AP BD+C Associate Vice President Sustainable Design Lead +1 213 633 1194 Direct | +1 213 631 6203 Cell

I love that we've gotten to the point of needing to clarify all the different ways our buildings are trying to be net-zero! I agree with the need for transparency and like the spectrum ideas, but also agree with Jay's warning about cutting our noses off. This may be an oversimplification, but I'm comfortable with a "net-zero energy" label on any project resulting in a demonstrable addition to the grid of a renewable energy source - that wouldn't otherwise be there - that produces at least as much energy as the project consumes on an annual basis. Mike Manzi RA, CSI, CDT, LEED BD+C Associate Principal he/him Bora Architecture & Interiors Working from home, please use email

Adding an industry perspective I came across via Schneider Electric's weekly email:  https://perspectives.se.com/digest/net-zero-carbon-neutral-climate-positive-or-carbon-negative It provides a decent summary of the confusion, and a helpful framing (via questions and answers) to parts of this discussion.  

Great discussion. One more thing to consider is the time frame of your zero carbon building. We need buildings to be zero carbon now, or at least within ten years. That's pretty much our window. If you are off-setting embodied carbon with carbon positive performance, ideally you want to pay back that initial carbon investment within ten years. Reusing and upgrading existing buildings is one way to do this: the embodied carbon for a renovation is a lot less than a whole new building and you can actually lower the existing building's emissions with electrification, heat pumps and efficiency upgrades. Merry Christmas and a Zero Carbon New Year Larry Strain, FAIA LEED AP S I E G E L & S T R A I N A r c h i t e c t s 6201 Doyle Street, Emeryville, CA 94608 510.547.8092 x103 fax 510.547.2604 (Enter on 62nd Street) lstrain@siegelstrain.com www.siegelstrain.com

Interesting to see these comments, and I do have to say it feels like ILFI has worked very diligently to address most of them over the years.  ILFI has allowed high grade offsite renewables for around five years now as long as onsite renewables are reasonably maximized and aggressive energy targets are met.  The Zero Carbon certification allows maximum flexibility on renewables provision anywhere in the world as long as it is additional, and a strong long term contract connects the project to the renewables.  The Zero Carbon certification is getting its feet wet with embodied carbon as well.  ILFI and Architecture 2030 have been quietly collaborating now for years in terms of aligning energy targets and tools, and the Reveal label offers a platform for demonstrating compliance with the A2030 Commitment.   I was truly excited to see USGBC take on zero energy + carbon, but completely lost me on the offset topic.  Very disappointing.  I personally don't support source energy approaches, UNLESS they are actually connected to something that the building can respond to or include in its function, ie grid optimal or grid beneficial.  That is actually where the certifications need to go.  Google is also setting the path now around 24/7 zero energy, which gets into the same area.   Given my background at ILFI I have a pretty particular perspective, and hopefully not just being a fanboy loyalist.  I just think there isn't the need to reinvent the wheel but rather really dig into what's there now.   This TrimTab article might be of interest - https://trimtab.living-future.org/blog/the-state-of-zero-energy-zero-carbon-through-the-eyes-of-a-pioneer/. Thanks all and appreciate the conversation!

Thinking a little about the embodied vs operational carbon effects of this 'net-zero' discussion... has anyone worked on setting or meeting targets for projects which take credit for existing building embodied carbon on the path to 2030 targets? This isn't really a fully baked question, but certainly there are some potential credits that could be taken for an existing building made to operate more efficiently as part of a renovation compared to a demo / new construction project that operates at a - perhaps lower - EUI and purchases RECs? 

Thinking about a current RFP I saw that requested 'net zero building emissions (carbon neutral) by 2030' but utilizes an option for the developer to either reuse existing structure or redevelop the property to maintain a similar aesthetic. So, asking another way, how can the carbon value of the existing building be quantified in comparision with a 'net zero operational' carbon goal?

Hi Sarah, I’m not sure I have a specific answer to your question, but I’d love to chat through this with you, as similar questions have been rattling around in my brain. Email me at Kristy.walson@tlc-eng.com if you feel like talking through this. Kristy Kristy M. Walson, PE, LEED Fellow, BEMP Principal kristy.walson@tlc-eng.com TLC ENGINEERING SOLUTIONS® 255 South Orange Ave., Ste 1600 Orlando, FL 32801 Direct: 407.487.1118 Cell: 352.514.5920 Main: 407.841.9050 www.tlc-engineers.com TLC is supporting building owners through COVID concerns with recommendations for multiple building types, as well as providing building health and safety rating certification in line with best practices. Click here to read more. [cid:HotFirm_2020-1024x1024_fd37754b-0f7a-4b86-b60d-e956a2817e38.png][cid:BFTWF_2020-01-1024x1024_8a048aff-5295-459f-88a9-c614f5eef475.png] [cid:TLCtriangle_48_5fcae4e3-b2cd-4e9c-88ca-7cc0976751ff.png] [cid:LinkedIn_b59db350-de64-46db-826b-6e945ffd8396.png] [cid:Facebook_eced6e55-89bc-4c58-b1c5-ae1f5b610c02.png] [cid:Twitter_6ce39de6-37fa-451d-bda4-ae51e1e3aabd.png] From