Energy Modeling and Tools
Although there are no specified energy efficiency targets that must be met to achieve Zero Energy Certification, project teams must submit calculations at the Ready Audit showing that the building is projected to operate at net zero performance.
It is best practice to prioritize energy efficiency in the building design and equipment, and energy baselining and modeling tools are useful for setting performance targets. The Zero Tool and the EDGE tool are recommended simple tools for calculating energy baselines and establishing energy targets. Baselines should be established by using a typical building with a comparable climate, floor area, use, and occupancy.
Projects registered under the Existing Building typology that have consumption data for a previous continuous 12-month period for the building in the same condition and operating at full occupancy may submit that data in lieu of calculations for the Ready Audit. Note that previous data may not be used in lieu of data that was generated during the designated performance period for the Final Audit.
Interior
The project’s total energy use reported for certification should align with the end uses that are within the project boundary, meaning the systems and associated loads that are within the tenant’s space and within their control. Any energy loads that are associated with a shared system outside of the project scope, for example, a central heating and cooling system, should be included at a prorated portion of the energy associated to the project scope. Interior projects may not exclude energy-consuming loads within their tenant space because the systems were not upgraded within the project scope. If the loads are within the tenant space and within the tenant’s control, they must be included in the project’s total energy use.
Metering
Projects must meter their project’s energy use and report it in the Energy Production and Demand Table. Although sub-metering is best practice and strongly encouraged in order to better understand and troubleshoot energy end uses, it is not required for certification.
Interior projects must only meter energy associated with their interior scope. In cases where that data is unavailable, a tenant-proportionate share of the energy metering data from the whole building may be used. If whole building data is not available, project teams should propose a metering approach and submit a Request for Ruling for preapproval. In either case, ensure that the metered loads coincide with the loads included in the target EUI calculations.
Net Annual Energy Balance
Energy use and production do not need to balance each month, but do need to balance to net zero production or better over the course of the 12-month performance period.
Project Energy Needs
All energy-using equipment and systems related to any part of the building program (including process energy) and used during building operations must be included in the energy budget for the project. The building must function as intended and meet the energy requirements over the 12-month performance period. Energy used during construction does not need to be included in the project’s operational energy budget.
Note that use of exception EC-014 Emergency Power Systems requires that any energy used by an allowed generator be included in the project’s energy consumption calculations.
Vehicle Charging Energy
The project energy budget may exclude any vehicle charging energy associated with the project, as long as separate metering demonstrates that the amount excluded from the overall energy use of the 12-month performance period is equal to that used for vehicle charging. This exclusion is to encourage projects to have public charging stations that support non-project or non-tenant-owned electric vehicles.
If separate metering of charging stations is not feasible, project teams may track the miles driven by the vehicles over the performance period and convert miles driven into electricity using the rated mileage of the vehicles charged. If distance tracking is not possible, projects may use an average efficiency rate as an alternative.
