We are working on a building connected to a campus central plant (DES). The local campus has a GBCI approved DES calculator which is used to document LEED v4 Optimize Energy Performance (cost) savings for any project receiving energy from this plant. This calculator converts the building’s energy consumption to DES gas consumption (per DES guidance) and utility provided electricity consumption.
The project includes Tier 2 & Tier 3 renewable electricity for the LEED v4.1 Renewable Energy credit. However, the reference guide indicates that the renewable electricity and EACs may only be applied to electricity usage. Since the DES generates most of the electricity (~80%) and the DES uses gas, it does not appear that the point thresholds for Tier 2 & Tier 3 Renewable Energy can be met.
Is our understanding that under LEED v4.1, renewable energy contribution should be calculated as a percentage of the total energy consumption (i.e., DES’ gas usage + utility provided electricity), prorated the building, correct?
Tyler Thumma
7GroupLEEDuser Expert
61 thumbs up
April 5, 2024 - 10:40 am
Your understanding is correct, except that renewable electricity and EACs may be applied to project electricity use or district energy use (as of the November 2020 Addendum).
Gail Hampsmire
Technical Director - Energy/HVAC TeamGreen Business Certification, Inc. (GBCI)
4 thumbs up
April 8, 2024 - 9:21 am
@Hans Marman,
If you are documenting credit for the District Energy System performance in EAc Optimize Energy Performance using Path 2 Full DES Performance Accounting Method, and the majority of the energy used to generate the electricity for the project is from natural gas, you are correct, the project will be significantly limited in the credit available under LEED v4.1 EAc Renewable energy.
Per the LEED v4.1 BD+C Referene Guide, EAc Renewable Energy, Further Explanation, Project Type Variations, District Energy Systems:
District Energy Systems (DES)
The method for documenting EA Renewable Energy credit must be consistent with the method for documenting EAp Minimum Energy Performance. If the project is using a prescriptive path to document EAp Minimum Energy Performance, OR applies ASHRAE 90.1 Appendix G to model district energy using identical purchased energy rates (i.e. $/unit of delivered energy) and Greenhouse gas emissions factors (i.e. lb CO2eq emissions per unit of delivered district energy) in the Baseline and Proposed case for EAp Minimum Energy Performance, renewable electricity and EACs may be applied to offset the site energy use of the district energy (e.g. district steam, district hot water, district chilled water) in EAc Renewable Energy.
If the project documents a performance improvement for the district energy system within EAp Minimum Energy Performance using the LEED District Energy Guidance Path 2 or 3, the modeled results in the EAp Minimum Energy Performance will indicate the estimated natural gas, electricity, and/or other fuels associated with the district energy generation; and district energy will not be reported as an energy source in the modeled results. In this case, renewable electricity and EACs may only be applied to electricity (either in the building or associated with the district energy system) and captured bio-methane may only be applied to the fossil fuel or other fuel used in the building or associated with the district energy systems.
https://build.usgbc.org/bd+c_guide