Rating System

LEED BD+C: New Construction

Rating System Version

v2 - LEED 2.0

Inquiry

We have used the LEED" Energy Modeling Protocol, including a central plant model and applicable time-of-use utility rates, to determine the percent energy cost savings achieved by our proposed building with reference to the budget (reference) case. Our local energy standard is California Title 24-2001. We calculate 56% energy cost savings, which would appear to qualify for the maximum 10 EA1 credits per Amendment #LEED 2.0-EAc1-133. Our proposed building and plant emphasizes design features that provide efficiency during periods of summer peak electricity demand (e.g. lighting systems, cooling systems). These periods have the highest electricity costs under the applicable time-of-use rate schedule. Our proposed plant includes chilled water thermal energy storage which shifts electricity used for cooling to off-peak periods with lower electricity costs. Thus, the time-dependent value of the electricity accounts for a significant portion of the energy cost difference between the budget (reference) and proposed cases. The corresponding calculation for source energy savings (performed for the California "Saving-by-Design" utility incentive program) indicates a 37% savings from California Title 24-2001 for the proposed building. The time-dependent energy cost savings is a proxy for substantial environmental benefits which are captured off of the proposed building site. There is reduced need for expansion of power plant and electric transmission facilities. Use of environmentally undesirable power plants ( including both old plants or peaking plants) is also avoided with further reduction in emissions and further reduction in use of energy resources. Transition to renewable resources may also be facilitated by minimizing peak power demand. Please note that the DRAFT 2005 revision to California Title 24 (currently close to adoption by the State of California) includes the use of time-dependent electricity valuation as the basis for savings calculations. This implies that future Title 24-based calculations will inherently recognize the value of the energy cost based calculation for proposed buildings like ours. The environmental benefits associated with the time-dependent energy cost savings for our proposed building appear to meet both the letter and the spirit of the credit intent. We would like to confirm that our use of the protocol and our high credit count will be considered valid if some of the savings are derived from the time-dependent energy cost savings.