[Bldg-sim] Defining Utility rates - proposed building different than reference building?

David Eldridge DEldridge at grummanbutkus.com
Wed Sep 19 13:53:42 PDT 2012


I'm not familiar with LEED Canada specifically, so these thoughts are applied to Appendix G modeling in general. The rate structures should be the "same" based on the utility tariffs that apply to the building.



Each of the proposed and baseline cases will set their own demand "ratchet". So the Baseline will have a 65% of its maximum, and the Proposed will have a different 65% of its own maximum. When you calculate the average $/kWh for each of the two models, they could be different between the two cases.



I'm not sure if EE4 includes this ratchet capability as a built in feature, but many other software programs do. If the baseline system selections end up with equipment that suffers under the ratchet, while the Proposed case minimizes the penalty, the Proposed model would justifiably be rewarded.



To take this credit the actual tariff will have to be modeled with all of the demand and energy based components. Credit probably wouldn't be allowed if you had used a weighted average utility price including all factors. If that was the case, then the rates should be identical in both models. I'm not sure how this impacts LEED Canada projects.



Under some scenarios the Proposed and Baseline cases might fall into different tariffs with the utility, this would also be allowable if you can provide the documentation on each being subject to different requirements. Similarly it would not be allowed if you use a weighted average utility price instead of modeling the actual tariffs.


David

David S. Eldridge, Jr., P.E., LEED AP BD+C, BEMP, BEAP, HBDP
Project Manager

Direct: (847) 316-9224 | Mobile: (773) 490-5038

Grumman/Butkus Associates | 820 Davis Street, Suite 300 | Evanston, IL 60201
Energy Efficiency Consultants and Sustainable Design Engineers




-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Genest, Frederic
Sent: Wednesday, September 19, 2012 3:30 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Defining Utility rates - proposed building different than reference building?



Hello everyone.



A quick question for you.



We're modeling a building to evaluate its performance for LEED Canada-CS, using EE4/MNECB as the modeling tool.



My question is whether or not if we should/need to define different utility rates for the proposed building and the reference building. Is this allowed?



The motivation for this is because the electrical utility rate for our region is set with a minimum kW to pay each month, which is equal to 65% of the max demand over a period of 12 months. So, if a given monthly kW demand is lower than that minimum, you pay a "penalty" for un-demanded kW.



Since both proposed and reference buildings have a different monthly demand profile, the min kW to pay, and the total "penalty", would differ. This influences the total energy costs for both building, and the % energy savings used to evaluate the LEED points.



So, can we set different rates, defined to match the actual utility demand of each case? My guess is yes, but I want to check...



Thanks.



Frederic Genest, P.Eng.

Pageau Morel.

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