Date
Inquiry

Our project is a 106,000 SF new laboratory building on an urban university campus. Electricity for this project will be provided from a central campus utility meter with a rate from the local electric power provider that changes in response to on-site co-generation from steam turbine chillers. The expense of purchasing/ generating electric power is then pro-rated and distributed to buildings on campus, including this facility. Our project will use and be billed for electric power from the central plant, so we would not be able to accurately predict the actual utility rate schedule that the building would be paying. Purchased energy rates, as described by the ECB method under ASHRAE 90.1-1999, are those approved by the adopting authority, but not necessarily the actual purchased energy rates offered by local energy suppliers. The LEED EMP takes exception to this by saying that local utility schedules are the default option to compute energy costs. In the absence of a local utility rate schedule, the applicant is directed to use rates from Table 4 of the LEED-NC Version 2.1 Reference Guide, p.144. These rates would not be accurate for this project since the co-generation plant on the campus will provide some electricity for this building and some will be supplied by the local utility. In keeping with the intent of the LEED EMP, our energy modeling proposal is to use the rate schedule from the local electric power provider that would apply if this building were constructed as an independent entity. This same rate schedule would then be used for both the Budget and Design buildings. We would like to clarify that this approach is acceptable by the USGBC for determining the electric energy savings for this project.

Ruling

Your proposed method is acceptable. Note that if a shared campus heating/cooling system serves this building, the chillers and/or boilers should not be explicitly modeled. Rather, an average cost per gpm of chilled water and/or cost per therm of heating should be used in both the Budget and Proposed models.

Internationally Applicable
Off
Campus Applicable
Off