Our project will have a biofuel system that utilizes agricultural crops as the biofuel. Per the LEED reference guide this is considered to be renewable energy. If the crops are grown offsite I do not believe the energy production can be subtracted from the proposed model since ASHRAE 90.1, Appendix G and the LEED reference guide specifically require the energy to be either "on-site" or "site recovered".
LEED Interpretation #10020 made on 5/9/11 seems to confirm this.
Could an exeptional calculation method be performed such that the project receives the benefit under EAc1 for the biofuel system?
Thank you.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
December 9, 2013 - 3:08 pm
No an exceptional calculation would not apply. There is some precedence for claiming off-site renewables, like landfill gas. You would need to make a strong case relative to the future availability of the fuel supply. It would probably be hard to do so but maybe not impossible.
Scott Bowman
LEED FellowIntegrated Design + Energy Advisors, LLC
LEEDuser Expert
519 thumbs up
December 10, 2013 - 8:52 am
We were not involved in documenting the credit, but we have a university client that makes significant energy and heating steam using biomass, a waste stream from a local large food producer. This was accepted as renewable energy under EAc2 (v2.2). I looked up the documentation, and a letter declaration from the head of the university physical plant provided overall information on the production of the plant and the share of biomass used. There was a long history they could point to, and plans to increase the percentage going forward to reduce CO2 production. This was also represented in the cost calculations of EAc1 of course.
Dave Hubka
Practice Leader - SustainabilityEUA
LEEDuser Expert
530 thumbs up
December 10, 2013 - 9:22 am
Thanks Marcus and Scott, I appreciate your comments.
I am currently in contact with GBCI. GCBI acknowledges the existing guidance covering this topic is not entirely clear. They have asked me if the biomass would be harvested from a site that is in close proximity to the project site; additionally they asked if the biomass would be harvested by the owner of the building or purchased from a vendor. The harvesting site is relatively close to the project site (within the same country -Kenya) however the biomass is harvested by another owner.
Upon hearing from GBCI I will post the guidance here.
thanks again.
Dave Hubka
Practice Leader - SustainabilityEUA
LEEDuser Expert
530 thumbs up
December 10, 2013 - 1:04 pm
Here is the response from GBCI:
If the biomass is purchased, either one of the following two options is currently available. The same fuel and fuel costs could be modeled identically in both the baseline and proposed case. Alternatively, the baseline may be modeled using a "standard practice" fossil fuel (e.g., natural gas) with applicable costs. At this time, even if the fuel source meets the eligibility requirements of EAc2 as renewable energy, it cannot be modeled as "free" in the proposed case if it is actually purchased. If the fuel source were to be harvested on-site or from the owner's adjacent property and was essentially free to the owner, it would be acceptable to model as free, and to model a different cost rate between the proposed and baseline case for the same fuel.
Scott Bowman
LEED FellowIntegrated Design + Energy Advisors, LLC
LEEDuser Expert
519 thumbs up
December 10, 2013 - 2:41 pm
That makes sense. The case I mentioned above used the same process; it was not “free” to the project, it had a reduced cost as it is mixed into the fuel. Therefore, the energy cost was different for the base case versus the design case for a percentage of the energy used.