Karen,
I gave a presentation on this subject with a member from USGBC and this
exact question was brought up. The answer was to use the local rate for
both systems. LEED/ASHRAE require that the energy rate be the same for
both the baseline and proposed designs. Fuel and electricity rates are
assigned using the local utility rate schedules as they would normally
apply to the building and using the normal ASHRAE and LEED modeling
rules. This line while a little ambiguous means that you should use the
rate that would be applied to the building if it was not connected to
the plant, not the discounted rate that the plant most likely receives.
Thanks
Seth Spangler, LEED(r) AP
I've been interested in the topic of District Thermal Energy treatment,
as well.
My question concerns Step 1 (Building stand-alone scenario): In a
campus setting like a hospital, new buildings are typically served by an
existing CEP, and yet the new building is not charged a rate for CHW or
HW. The USGBC guidance indicates that in this case, "local market rates
as explained in the LEED v2.2 Reference Guide" should be used. However,
I have not found this data to be readily accessible, nor have I found
guidance in the LEED Reference Guide. In my most recent project in
Florida, I've been able to find District Chilled Water plants close to
the project site, but it is my understanding that there is not a single
District Hot Water or Steam Plant in the entire state!
What do I do in this case? And where in the LEED Reference Guide is the
"Treatment" referring to?
Thanks for your help,
Clark Denson
Clark,
I believe the document you are looking for is here:
http://www.usgbc.org/ShowFile.aspx?DocumentID=4176
Let me see if I understand your question correctly: you're not certain what energy rate to apply to the steam or hot water used by the new building since there isn't another example of a hot water or steam plant in the state from which to obtain rates? If that's the case, you don't need to look for rates. As Seth pointed out and as far as I know you only need to find the local rate for whatever fuel the CEP is using to generate hot water or steam. If they are using oil, then the local oil rate (likely the commercial rate, not the residential one) would apply. Ultimately, the CEP is consuming some type of fuel to generate thermal energy and the building is modelled as also consuming the same fuel. I believe the intent of this methodology is to prevent any skewing of results that might arise from the CEP's abilities to use economies of scale to offer lower rates, or conversely charge premiums for capital investment and maintenance. This ensures that only the efficiency of the building, the CEP and the distribution systems factors into the EAc1 calculation.
I hope that answers your question.
Cheers,
Luka Matutinovic, B.A.Sc., LEED? AP
Luka,
I believe Seth was addressing utility rates in Step 2, the Aggregate
Building / DES scenario. In that case, I agree that actual fuel costs
(e.g. electricity and fuel oil) should be used. However, my question
was in regards to Step 1, when fuel costs associated with cooling and
heating equipment in the existing central energy plant are to be
replaced with costs for "Purchased Energy." In this case, what Chilled
Water and Hot Water rates should be used, particularly if there is no
nearby District Thermal Energy provider from which to infer "local
market rates?" Additionally, the USGBC "DTE Treatment" document refers
to the USGBC Reference Guide to answer this question, but I have been
unable to find what part is being referenced.
Thanks,
Clark
Clark,
I encountered this situation once and was told to use the default energy
rate within eQuest. The project did get certified however it was before
the DES Guideline document was released when only step one was required.
The other option is to look into calculating the cost of the thermal
energy which is most likely not a part of your fee. This is a huge
market that DES companies are starting to realize they need in order to
have LEED buildings connect to their systems.
Thanks
Seth Spangler, LEED(r) AP