Background This credit interpretation request is in reference to LEED-EB requirements for a 497 000 s.f.g. Convention Centre located in Quebec City (Canada), winner of the 2006 AIPC Apex Award for the World\'s Best Congress Centre given by the International Association of Congress Centres. The Quebec City Convention Centre (QCCC) has for mission to welcome conferences, meetings and large-scale exhibits by offering an international convention facility. In the first project analysis for the energy performance prerequisite, we deduced that Conference Centres are not addressed by ENERGY STAR program. We did not find any comparable building in terms of use, square footage and localization. We thus chose the Option A for the buildings not addressed by ENERGY STAR (Reference guide LEED-EB, p.184). The procedure to determine the building energy baseline (Reference guide LEED-EB, p.183) specifies that the historical average energy use must be calculated from 3 consecutive years selected within the 6 years of the performance period beginning. The section Strategies & technologies (reference guide, p.182) show that the objective of this prerequisite is to encourage the owner to make improvements in the building energy performance either by commissioning or by doing systems/equipments improvements. In years 1998 to 2000, the QCCC carried out a series of actions (retro-commissioning) to decrease the building energy consumption such as: 1. Temperatures optimization of the air-conditioning and heating networks by modifying the coolant temperature according to the outdoor temperature in order to avoid the losses of energy produced by too large temperature variations. 2. Optimization of the ventilation and lighting system schedules operation according to events. 3. Employees educational program including practical actions such as: i. Using elevators instead of the service elevators ii. Closing the light by leaving the rooms iii. Informing the operations service when the ventilation is no longer necessary iv. Start up mobile escalators only in period of events. 4. Procedures to follow to reduce the natural gas consumption by closing some steam networks in summer period. The improvements made during this period of time showed an optimization of the energy performance close to 20% and are always in function today. Since the year 2000, the QCCC maintained this performance as required, for example, by a LEED-EB recertification. Calculations proposal These improvements made by the QCCC between 1998 and 2000 can be listed with supporting documentation demonstrating an energy consumption reduction close to 20%. QCCC kept this level of performance since year 2000 which represent a long term engagement to sustainable energy practices. Is it acceptable to push back the building energy baseline beyond the 6 years window as prescribed by the EA Prerequisite 2-Minimum Energy Performance? Our calculation methodology would be: - Energy performance period: April 2006 to march 2007 - Building energy baseline: o LEED-EB - 6 years window for historical data: April 2000 to march 2006 o Our proposal : - 9 years window for historical data: April 1997 to march 2006 - 3 years to determine the historical average energy use: April 1997 to march 2000 Is this an acceptable alternative calculations methodology to meet the requirements of the EA prerequisite 2 - Minimum Energy Performance?