Source VS site EUI

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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

Farid Pour's picture
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Joined: 2014-12-15
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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] *On
Behalf Of *Farid Pour
*Sent:* Tuesday, January 06, 2015 10:05 AM
*To:* 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

Nicholas Caton's picture
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Joined: 2014-12-09
Reputation: 0

The eQuest SITE Energy is that which is measured at the meter, that which you are billed. SOURCE Energy is an estimate of what the energy is at the power plant or the gas works. I believe eQuest (DOE-2) has a multiplier of three on it, so 1 million kWh SITE becomes 3 million kWh SOURCE.
Energy Star probably has its OWN multiplier for Carbon footprint, so use your bills (Site Energy)---unless it has already calculated SOURCE energy for you. SOURCE energy will be the one stating how much of a power plant use YOU cause.
Hope that helps.
John R. Aulbach, PE

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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John Aulbach's picture
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Dear Nick, 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

Farid Pour's picture
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Joined: 2014-12-15
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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

David Eldridge's picture
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Joined: 2012-05-08
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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

Farid Pour's picture
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Joined: 2014-12-15
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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

David Eldridge's picture
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Unless I am missing something, if you are using the Energy Star target
finder / portfolio, I belive it is pretty clear you are intended to input
the site energy consumption, and the web tool/interface will apply the
factors to determine source emissions.

If you are trying to perform these calculations yourself, without using
energy star?s interface, then you would need to apply such factors to come
up with a source emissions estimate.

Hope that helps,

~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:* Farid Pour [mailto:farid.pour at hok.com]
*Sent:* Tuesday, January 06, 2015 12:10 PM
*To:* David Eldridge; Nicholas Caton
*Cc:* equest-users at lists.onebuilding.org
*Subject:* RE: [Equest-users] Source VS site EUI

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
*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

Nicholas Caton's picture
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Classification: UNCLASSIFIED
Caveats: NONE

Not a complete answer. May not even be correct, but it may stir discussion.

1. When running an 80% furnace, the 'sight energy' may be 100,000 btu, but the actual energy delivered to the site is 125,000 btu. But you also have to factor in the energy used to deliver the gas which makes the 125,000 btu go up slightly higher. Since gas doesn't require very much energy to transport the 125,000 btu does go up, but not by much.

2. Electricity for heating is 100% efficient, but it has a lot of transmission loses, so the 100,000 btus goes up a lot more.

Jeurek's picture
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