I know that the 90.1 and the LEED Reference Guide generally tell you to use the same utility rate structures for both the Proposed and Baseline models. But what happens when the Proposed model uses Full Accounting of DES and includes DES-CHP-supplied electricity and steam, while the Baseline uses On-site Boilers and grid-tied electricity? The DES is charged $0.45/therm while a new gas service at the Baseline Project Building would be charged $0.73/therm due to inherently different rate structures).
I've provided a link below to a CHP LEED Calculator (provided by the EPA CHP Partnership) which instructs the user to use $0.45/therm in the Proposed model since it is a special price for CHP gas and $0.73/therm in my Baseline model (See Inputs tab, rows 14 and 17). Is this acceptable from a USGBC perspective? Thanks!
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5907 thumbs up
March 13, 2017 - 11:51 am
The rates must be identical for LEED. The Baseline system in this case is a virtual DES so it must use the same rate as the Proposed case.
Raphael Sperry
Associate Principal, Global Social Equity Skills LeaderArup
2 thumbs up
August 29, 2017 - 2:53 pm
Hi Marcus,
The online reference for project type variations says "Exception: For DES plants that operate under specific and atypical rate structures and actively take advantage of those rates through strategies such as load management or energy storage, use the rate structures as they apply to the DES."
It sounds to me that if you are using available rate schedules to save energy cost then you should calculate that for LEED, no?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5907 thumbs up
August 29, 2017 - 3:20 pm
The rates still must be identical. For example, suppose you have a time of day rate or an off-peak rate to save energy cost. That rate is used in both models. This is what the last part of the sentence means. The proposed should still benefit as the systems are designed to take advantage of the rate. You cannot use a special rate schedule for the Proposed and a different rate schedule for the Baseline.
Raphael Sperry
Associate Principal, Global Social Equity Skills LeaderArup
2 thumbs up
August 29, 2017 - 4:38 pm
Thanks!