Rating System

LEED BD+C: New Construction, LEED BD+C: New Construction, LEED BD+C: Schools, LEED BD+C: Schools, LEED BD+C: Core and Shell

Rating System Version

v2 - LEED 2.2, v3 - LEED 2009, v2 - Schools 2007, v3 - LEED 2009, v3 - LEED 2009

Inquiry

This question is in regards to a nursery and greenhouse project located in Golden Gate Park in San Francisco. Our project intends to use an EPA certified wood-fired gasification boiler as the main heating source for heating hot water (HHW): http://www.epa.gov/woodheaters/models.htm. This HHW will be used for both space heating in the nursery support building and for process loads in the greenhouse and may be used for DHW. The project will be managed by the Recreation and Parks Department, which oversees numerous parks throughout the city and has a readily available supply of wood from fallen trees at no cost except for the costs of wood transportation within the park and maintenance of the boiler. Because 1) EA credit 1 calculates the energy savings through usage and cost of conventional fuels, 2) EA credit 2 accepts biomass as an alternative and renewable energy source, and, 3) we do not have a method to quantify the cost of the fuel we are using, it is unclear how to accurately compare fuel usage. Our team is working off this assumption: The wood fuel for the gasification unit comes from standard tree maintenance and naturally occurring processes of tree life cycle and tree loss resulting from storms. Trees are not removed for commercial purposes and are therefore not defined as part of forestry practices, rather they are part of the Park\'s responsible stewardship of San Francisco\'s public resource and also address public safety. In addition, the wood supply is constantly regenerative, and the carbon emissions are the same as those produced during natural decomposition, and any other emissions are minimized in accordance to EPA standards. We believe this fuel source constitutes a renewable energy source. Our question is: Because the cost of heating water with wood gasification, as compared to a natural gas or propane system, is essentially zero, would it be accurate to exclude all energy costs associated with the gasification boiler?