ID#10389 made on
EAc4 - On-site and off-site renewable energy
Rating System Family:
Building operations + maintenance
The project team is planning on installing a Cogeneration System that will take Biogas and turn it into Electricity to be used wholly on-site. The heat produced by this Cogeneration system will also...
The project team is planning on installing a Cogeneration System that will take Biogas and turn it into Electricity to be used wholly on-site. The heat produced by this Cogeneration system will also fully be used on-site to preheat heating hot water and domestic hot water via a heat exchanger and potentially to power an absorption chiller.
The building will receive the Biogas from a local Biogas provider and plans to enter into at least a 10 year contract with this provider to supply enough Biogas to the building to fully power the planned Cogeneration system. The contract will stipulate both that enough Biogas will be fed into the pipeline to meet required demands of the Cogeneration system and that the Biogas will be metered to prove that the actual amount of Biogas supplied meets the contracted requirements at all times.
Though the Biogas is not being piped exclusively to the site (contractually it is supplied exclusively via project ownership funds), it is transported directly to the site in the existing natural gas pipeline. This approach achieves the exact same net result on the Natural Gas grid as piping Biogas exclusively to the project site in its own dedicated pipeline and allows the project to avoid having to dig up 100s of miles of land and lay a brand new pipeline to the project, something that would have a significantly detrimental effect on the local environment. In an urban environment like where the project is located, there is little or no option to be able to refine and extract Biogas on-site or even very close to a site, so the approach the project team is suggesting is the best and most reasonable alternative.
Is this approach acceptable in accordance with the Reference Guide and Addendum 100001081 (November 1, 2011)?
Directed Biogas purchase is not considered on-site renewable energy based on the current EAc2 credit requirements, addenda and LEED Interpretations, because the gas consumed on-site is not the same as the biogas that the project purchased. Please note that the referenced Addendum 100001081 does not allow for the fuel used on site to be different than the fuel that was purchased for the project. The referenced addendum applies for situations such as landfill gas piped directly to the project from a nearby landfill, or wood pellets from wood mill residue that are trucked to the project. In either case, it would not be acceptable for the landfill gas or pellets generated from wood mill residue to be "purchased" by the project, used in another project, and replaced in the project with natural gas or wood pellets produced from tree tops. Also, note that NREL refers to directed biogas as off-site renewable energy.
Related Addenda (Corrections & Interpretations)