Page 188 - The Engineering Guide to LEED-New Construction Sustainable Construction for Engineers

166 Cha pte r F o u r

Calculations and Considerations
The project boundary is an important variable in the calculations since this credit requires
these renewable energy sources to be provided on-site. There may be some exceptions to
this if the building is part of a campus setting where on-campus renewable energies are
shared, but usually large, facility wide renewable energy sources are considered to be a
part of EAc6: Green Power, and are not counted as part of EAc2. There is no rule stating
that the project area must always be contiguous, but justifications for the area being
separated and other special circumstances should be appropriately documented and
approved by the USGBC.
The Reference Guides specifically list the systems that are eligible for applying to
EAc2 as on-site renewable energy (REC). In general, the system must produce electrical
or thermal energy on-site. Other on-site systems that are not included can usually be
used as energy offsets to EAc1, Option 1. If the renewable energy sources come from
off-site, then they are not a part of EAc2, but may be a part of EAc 6: Green Power. The
lists of eligible and noneligible on-site energy sources from the LEED-NC 2.2 and 2009
Reference Guides are summarized in Table 4.2.2. Note that hydrogen fuel cells are not
addressed. This is so because hydrogen fuel cells are not energy sources, but rather are
energy storage devices. Their applicability would be dependent on whether the source for
producing the hydrogen used in the fuel cell came from a renewable or nonrenewable
source.

Energy Source Systems Eligible for EAc2 Systems Not Eligible for EAc2
Solar Photovoltaic systems Passive solar strategies
Solar thermal systems Daylighting
Architectural features
Biofuel energy Untreated wood wastes Wood coated with paints, plastics,
systems or formica or more than 1% treated
with the following with halogen or arsensic-based
fuels preservatives
Wood mill residues Other forestry biomass waste
Agricultural crops or wastes Municipal solid waste
Animal wastes and other
organic wastes
Landfill gas
Ground source Geothermal heating
Geoexchange heat pumps
Geothermal electric
Surface water Low-impact hydroelectric
Wave and tidal power
Wind Wind power

Source: LEED-NC 2.2 and 2009 Reference Guides.
TABLE 4.2.2 Summary of On-Site Renewable Energy Systems