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ASHRAE Net Zero Standard now open for public comment - comment period closes May 17

Kim Shinn

Executive Principal and Senior Wizard

TLC Engineering Solutions

LEEDuser Premium Member

62 thumbs up

April 2, 2021

This is deep nerdy stuff, so don't say you haven't been warned. ASHRAE has opened the first public review to its net zero standard (228). Here's the blurb:

Standard Method for Evaluating Zero Net Energy and Zero Net Carbon Building Performance ASHRAE Standard 228-202x sets requirements for evaluating whether a building or group of buildings meets a definition of “zero net energy” or whether those buildings meet a definition of “zero net carbon.” It provides a consistent method of expressing qualifications for zero net energy and zero net carbon buildings associated with the design of new buildings and the operation of existing buildings.

It doesn't tell you how to create a net zero building - it just defines (in ASHRAE's mind) what qualifies as net zero. It does NOT address embodied carbon and it DOES address impact of fugitive refrigerant emissions. It IS a performance and operation standard, much more than a design standard. If you want to raise hell about the omission of embodied carbon or refrigerant impacts, you are free to do so - just make sure you direct your comments to the appropriate scope statements.

I've uploaded the draft standard to the "Codes and Certifications" folder for you to look through.

If you want to make a comment on the proposed standard, you need to go to the ASHRAE webpage that is the portal for making review comments: https://www.ashrae.org/technical-resources/standards-and-guidelines/public-review-drafts

Once you get there, you have to hit the "ACCESS NOW" button, which will take you to the page that lists all the standards that are open for public review and comment. Since 228 just opened for comment, it is near the bottom of that webpage in a box labeled "45-Day Review Period from Apr 2 to May 17". If you want to download another copy of the draft standard, click on the Standard link. If you want to make a comment, click on the "COMMENT" to the left of the standard title. Doing that will take you the comment page for 228.

The standard draft is more than 40 pages and it is as dense as any engineer's gobbledygook that you have ever experienced. I recommend that you choose to review it in a soft surface environment so that when it renders you unconscious and you faint, you will not be injured in the impact.

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Ramana Koti

Sustainable Design Leader

HKS, Inc.

LEEDuser Basic Member

11 thumbs up

Fri, 04/02/2021 - 18:51

Thanks for the heads up and the caveats, Kim. This brings back memories of a paper by NREL on the same subject from 15 years ago (Zero Energy Buildings: A Critical Look at the Definition; Preprint (nrel.gov)) I'm curious to see how things compare. Both NREL and ASHRAE have since built zero energy research facilities/headquarters. Ramana Koti Senior Associate, BEMP, LEED Fellow LORD AECK SARGENT A KATERRA COMPANY

Jacob Knowles

Director of Sustainable Design

BR+A

LEEDuser Basic Member

0 thumbs up

Fri, 04/02/2021 - 19:40

Hi Kim, Thank you for sharing this. Am a reading the standard correctly that:

The EUI seems to be limited (particularly for buildings that can't install much on-site renewable energy systems, such as an urban highrise) by the limit on the amount of off-site renewable energy that is permitted in table 11.
- For example, if you can't install any on-site renewables, an office in climate zone 5A is limited to 24 kWh/sf-yr of off-site source energy...which is 82 kBtu/sf-yr. So, in New England NEWE with a 2.77 source:site ratio, would limit the site EUI for an all electric building to 29.6 kBtu/sf-yr. Is this correct?
- But, if the building is in the Northwest NWPP with a 1.93 source:site ration, the EUI limit for an all electric building would be 42.4.

If this is correct, this seems like a less than optimal solution. It would be better to limit the site EUI of the building by use type and climate...then apply renewables to get to zero, without limiting the amount of renewable energy needed to get to zero. I may be mis-reading this, since I'm looking at this for the first time....and it is a Friday afternoon. But, I would love to hear your thoughts. Regards,
Jacob

Kim Shinn

Executive Principal and Senior Wizard

TLC Engineering Solutions

LEEDuser Premium Member

62 thumbs up

Fri, 04/02/2021 - 20:35

Jacob Good observation. This is something the committee spent some time debating, and reached the draft language as a compromise. The committee thought about trying to normalize around 90.1 minimum baselines for site energy, but got wrapped around the axle of energy model gaming. You cite the eternal inequity of different locations having different source-to-site ratios. The answer is, without seeming insensitive to those inequities, you need to recognize those location-specific ratios as much a design constraint as climate effects. Consider this as yet another pressure on local grids to decarbonize. I urge you to submit your proposal as a comment to the committee. The commitment to source energy, as the driving metric of concern, is pretty fundamental to the standard (it says so right in the foreword) - with the specific understanding that location then becomes a BIG DEAL. The committee decided that a building is never independent of its location, and that carbon is what really matters. As I mentioned, your concern was the subject of extended debate, and did not have a unanimous consensus. Resolution of your comment could cause some to change their minds.

Kim Shinn

Executive Principal and Senior Wizard

TLC Engineering Solutions

LEEDuser Premium Member

62 thumbs up

Fri, 04/02/2021 - 20:48

Ramana Rest assured that the author of the NREL paper you cite had his influence on the proposed Standard language.

Jacob Knowles

Director of Sustainable Design

BR+A

LEEDuser Basic Member

0 thumbs up

Fri, 04/02/2021 - 21:00

Hi Kim, Thanks for the background. I will definetly comment to ASHRAE...the proposal as written would likely preclude some great projects that I consider to be net zero from being elegible in locations with high source:site ratios. I will also comment that VPPAs from different grid regions should also be eligible. Carbon is carbon...the earth doesn't care which grid zone it came from. Regards,
Jacob

Jacob Knowles

Director of Sustainable Design

BR+A

LEEDuser Basic Member

0 thumbs up

Fri, 04/02/2021 - 21:53

Hi Kim, I submitted both comments, which can be seen here: https://osr.ashrae.org/Online-Comment-Database/DocumentComments/DocItemID/3597?language=en-US/ I also wanted to follow up to say that overall, the standard is excellent. Thank you for your contribution to the industry! Regards, Jacob

Jeremy Shiman

Associate, Building Performance Specialist, Project Architect

WRNS Studio

LEEDuser Basic Member

0 thumbs up

Mon, 04/05/2021 - 13:57

Hi Kim, Would you be willing to share an overview (ideally without the worst of the gobbledygook) of the proposed standards for those of us without the technical wherewithall or requisite quantity of soft surfaces to wade through the full proposal? At a very high level (I'm sure glossing over hours/days/months of sweat and tears), it looks like the standard is saying 2 things. Either (A) produce all of the energy you need on site or (B) here is your maximum source EUI by building type and climate zone, go purchase sufficient renewable energy to offset that. Am I even close to the mark there? Thanks in advance, Jeremy

Kjell Anderson

Director of Sustainable Design

LMN Architects

LEEDuser Basic Member

4 thumbs up

Mon, 04/05/2021 - 14:06

Hi Kim, How many Architects were on the standard 228 committee? -Kjell

Kim Shinn

Executive Principal and Senior Wizard

TLC Engineering Solutions

LEEDuser Premium Member

62 thumbs up

Mon, 04/05/2021 - 14:19

None that I know of.

Kjell Anderson

Director of Sustainable Design

LMN Architects

LEEDuser Basic Member

4 thumbs up

Mon, 04/05/2021 - 14:35

Q: How many Architects are on the 228 Committee? A: Net Zero Since AIA doesn’t write standards and ASHRAE does (and we Architects are subject to these standards more and more) it’s imperative that we step up and participate in ASHRAE committees. While we don’t generally have the depth like other committee members, we have a breadth that may, in fact, be very useful to ensure that the standards that we work under reflect our best intelligence about and stewardship of the built environment. Don’t be intimidated just because engineers can talk part load curves for hours! We can talk for hours about envelopes for existing buildings, embodied carbon, programming, and more. We bring a lot more than we think to the table. Thanks, Kim, for posting this. AIA and COTE (of which I am now a member) can help get architects on Committees, so just let me, COTE, AIA, or Kim know and we can help you find a way to contribute at a national level. Are there any Architects on this list currently participating in an ASHRAE committee or subcommittee? -Kjell From: K

Kim Shinn

Executive Principal and Senior Wizard

TLC Engineering Solutions

LEEDuser Premium Member

62 thumbs up

Mon, 04/05/2021 - 20:55

Jeremy I’m reminded of the old saying, “I would have written a shorter letter if I’d had more time”. I’ll do my best to summarize. I encourage you to read the foreword if you haven’t already – I think it is written without a lot of jargon. Here are the salient points of the Standard:

There is an emphasis and value placed on producing energy on-site. That’s the best way to ensure that the renewable energy is properly accounted for.
Energy use is based on its source, and is tied to the grid serving the project site. As Jacob Knowles points out, there are arguments to be made about this, but the Standard is trying to do its best to tie the project to its greenhouse gas emissions, whether those are emitted onsite or by the sources supplying energy to the project. This will mean that a project served by an electrical grid with a high source-to-site factor will have more carbon emissions associated with its operation than an equivalent project operating in a location served by a utility grid with low carbon emissions.
Source energy can be determined either through grid-specific annualized source-to-site conversions, or hour-by-hour if that information is available (acknowledging the time values of energy generation and consumption).
For the purposes of net zero carbon calculations, the Standard requires that refrigerant leakage during operation be accounted for as carbon dioxide equivalent emissions. For some refrigerants and some system types these greenhouse gas emissions can be significant.
If a project is site-constrained and is unable to produce enough renewable energy on-site to cover its energy consumption, it is allowed to acquire renewable energy off-site to make up the difference. The Standard defines this as “imported” renewable energy.
There are limits to the amount of renewable energy that is imported. This is denominated by building type, climate zone, and the financial arrangment of imported renewable energy source. In short, the more closely the project owner holds the offsite renewable generating source, the greater the allowance for offsite renewable energy.
By way of explanation, I offer a simple example on energy alone, and it doesn’t include complications like on-site combustion, transportation or landscape energy.
- The project is an all-electric 100,000 sq ft elementary school located in Climate Zone 4A.
- It is served by a utility grid with a source to site energy conversion factor of 3
- The procured offsite source energy intensity limit is 25 kWh/sq ft/yr, allowing it to procure up to 2,500 MWh/yr of renewable energy
- The project consumes 600 MWh/yr of site energy, equivalent to 1,800 MWh/yr of source energy
- The project has on-site renewable energy (a 345 kW PV array) that produces 500 MWh/yr of site energy, equivalent to 1,500 MWh/yr of source energy
- This means that the project will have to offset the import of 300 MWh/yr of grid source energy to achieve net zero
- The project has a PPA agreement with an offsite PV farm. The PPA renewable energy is discounted by 25% (I told you that there was a penalty for not directly owning the renewable energy source on-site), so the amount of renewable source energy to be procured through the offsite PPA is 300 / 75% = 400 MWh/yr, which is well below the allowance. In fact, this very energy efficient project could have achieved net zero energy without any onsite renewables, simply through the offsite PPA procurement of 2,400 MWh/yr (1,800 / 75%)
The Standard can be applied to a community or portfolio of sites and projects.