ENERGY BUDGET CLARIFICATIONS
Interior Shared Systems Offset
Although base building or DES-provided heating and cooling systems out of scope may be excluded from the energy efficiency calculations for I07, Interior projects must account for a proportionate share of HVAC energy use for the purposes of offsetting the full operational energy of the project.
Teams may calculate this HVAC energy in one of two ways:
- by using air flow meters to measure conditioned air serving the tenant space relative to total conditioned air for the building;
- or by determining a proportionate share of the metered base building loads.
The project team must provide a narrative and calculations explaining how they determined the amount of energy required to be offset, including supplemental calculations, and add the additional loads to the Energy Production and Demand table. When accounting for DES energy, the team must account for energy used by the system, not energy supplied to the project, in order to account for system efficiencies and losses.
Net Annual Energy Balance
Energy use and production do not need to balance each month, but do need to balance to 105% production or better over the course of the 12-month performance period. Additional guidance regarding the performance period is under the Performance Period Clarifications in Imperative 7.
Projects that are not grid-tied do not have to produce energy beyond 100% of the project’s energy demands after taking into account resilience strategy needs.
Surplus Energy
Renewable energy generated on site that is in excess of the net balance required for certification and that goes back to the grid may be applied toward the embodied carbon offset requirement in accordance with all of the following:
- The renewable energy system must have a predicted life of at least 25 years;
- The net surplus energy generated during the 12-month performance period (PP kWh) must be calculated and converted to tCO2e using a regional grid factor from EPA’s Emissions & Generation Resource Integrated Database (eGRID) Summary Tables or equivalent resources for international projects (see Calculations); and
- Up to 10 years’ worth of the converted excess performance period tCO2e (PP tCO2e) may be credited toward the carbon offset.
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.
