[Equest-users] Source VS site EUI

David Eldridge DEldridge at grummanbutkus.com
Tue Jan 6 12:23:58 PST 2015


It sounds like you should use site energy to start with.

If you are using ENERGY STAR portfolio manager, then all of the source energy and emissions numbers will be output to you based on your site energy inputs and building characteristics.

For a calculation that you are performing yourself, you will start with your site energy use and apply the conversion factors from ESPM, eGrid, or other references.

Source energy implies that losses for the generation and transmission are included in the total.

Likewise "lbs/kWh" or similar emissions factors include the generation efficiency (and maybe transmission efficiency...check the footnotes).

If you convert to source energy, and then apply lbs/kWh factor, you will double-count.

DSE Mobile

On Jan 6, 2015, at 2:10 PM, Farid Pour <farid.pour at hok.com<mailto:farid.pour at hok.com>> wrote:

thanks for your reply.
I understand that for each eGRID sub-region there is a different emission factor. My confusion is about using source EUI instead of site EUI. I was wondering all eGrid emission factors are calculated based on generated energy (Site energy) and not delivered energy (site). Therefore we might need to first convert the site EUI to source EUI and then use the converted number in the calculation. However, the energy star methodology specifically mentioned to use site EUI.
What do you think.
Thanks


From: David Eldridge [mailto:DEldridge at grummanbutkus.com]
Sent: Tuesday, January 06, 2015 2:08 PM
To: Nicholas Caton
Cc: Farid Pour; equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: Re: [Equest-users] Source VS site EUI

I believe that source energy figures in ENERGY STAR use one set of national conversion factors to calculate source energy from site energy for everyone. (Not sure about international locations.)

"Emissions" reported by ENERGY STAR for a facility can be specific for eGrid regional differences.

DSE Mobile

On Jan 6, 2015, at 1:23 PM, Nicholas Caton <ncaton at catonenergy.com<mailto:ncaton at catonenergy.com>> wrote:
To my best understanding, EnergyStar's portfolio normally takes in your site energy usage and uses the project's regional location to come up with source figures.  A building located in an area powered largely by hydroelectric will report differently than one located somewhere powered largely by coal plants, all else being equal.

The database which comes up with those regional factors is a bit opaque, however, and the regional resolution have changed over time.

~Nick

NICK CATON, P.E.
Owner

Caton Energy Consulting
  1150 N. 192nd St., #4-202
  Shoreline, WA 98133
  office:  785.410.3317
www.catonenergy.com

From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org<mailto:equest-users-bounces at lists.onebuilding.org>] On Behalf Of Farid Pour
Sent: Tuesday, January 06, 2015 10:05 AM
To: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: [Equest-users] Source VS site EUI

Hi,
Sorry  this question is not about eQUEST, but I thought you might be able to help me. I am in process of calculating the carbon foot print of my building. I have the values for electricity and fossil fuel EUIs.
I also have a report from energy star (https://portfoliomanager.energystar.gov/pdf/reference/Emissions.pdf ) that explain how to calculate the carbon footprint of the building. however, I am not sure that I need to use source EUI in my calculation or site EUI.

Can you please explain?
Thanks,
Fred
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