855773520-LEED-v5-ID-C-Reference-Guide-Launch-Edition-1 - Page 193

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PATH 2. PERCENTAGE REDUCTION INCLUDING ON-SITE RENEWABLE CONTRIBUTION

Path 2 applies primarily to project types that have limited opportunities for incremental energy savings beyond the referenced standard, such as unconditioned warehouses, and to projects that generate a large proportion of total project energy from on-site renewables.

Consistent with ASHRAE 90.1 G2.4, this path credits the on-site renewable contribution for the project. Prior to calculating the PBP, subtract eligible on-site renewable energy generation from the proposed design energy consumption. Total savings documented for on-site renewable electricity generation can be up to 100% of project electricity use on an annual basis. To qualify for credit compliance, the on-site renewable energy must be installed and commissioned within the project scope of work, or an earlier scope of work on the base building or the site of a contiguous campus, with all renewable attributes allocated to the project.

Plug and process efficiency For EAc2: Enhanced Energy Efficiency, projects may document credit for plug and process efficiency using ASHRAE 90.1 G2.5, Exceptional Calculation Method .

Document that each process efficiency measure is not conventional practice and provide detailed calculations and narrative justification supporting the future source energy savings claimed. (See additional guidance from Option 1, Path 3, Case 3 Plug and Process Load Exceptional Calculation). To convey the magnitude of impact associated with process efficiency measures, the energy analyst must separately report the PI, Performance Index Target, and all associated terms with and without the process efficiency savings.

District energy For EAc2: Enhanced Energy Efficiency, energy analysts may optionally replace prescriptive purchased heat and purchased CHW efficiencies modeled per ASHRAE 90.1-2022, Addendum A with improved virtual DES efficiencies representative of the DES purchase heat and purchased CHW systems serving the project.

Provide an engineering analysis based on monitored data and/or energy simulation to justify the improved virtual DES efficiencies modeled for the project. For each DES source, virtual DES efficiency must account for total annual energy required to generate and distribute the district energy. Include all pump energy use from the DES and within the project, thermal distribution losses, heat rejection, and all operational effects influencing efficiency such as standby losses, equipment cycling, equipment staging, and partial-load operation. When thermal distribution losses are not measured or modeled, estimate default losses of 5% for CHW, 10% for hot water, 15% for closed-loop steam, and 25% for open-loop steam.

U.S. Green Building Council LEED v5 Reference Guide for Interior Design and Construction, April 2025 Launch Edition 182