The Leadership in Energy and Environmental Design (LEED) recognizes the contribution that photovoltaics (PV) make to the sustainability and efficiency of a building project through its Green Building Rating System for New Construction & Major Renovations (LEED-NC Version 2.1). This system was developed by the U.S. Green Building Council (USGBC) and is the criterion for getting a building project LEED certified. Within this rating system, there are three ways that the project team can earn points toward LEED using PV. These three credits are all in the LEED Energy & Atmosphere (EA) Category and are as follows: EA Credit 2/Renewable Energy, EA Credit 1/Optimize Energy Performance, and EA Credit 6/Green Power.
EA Credit 2 is the most direct way that a PV system can contribute to the LEED certification of a building. This credit directly recognizes the incorporation of renewable energy sources into the building design and provides points for the amount of conventional energy supply that these sources displace. Points can be earned toward LEED certification by incorporating one or more of these systems into the building project.
The project team can earn up to three points from EA Credit 2 depending on the amount of energy that will be displaced by renewable energy sources based on annual energy cost. The incorporation of on-site renewable energy sources that supply at least 5 percent of the building's total annual energy use will be awarded one point toward LEED certification.
Similarly, if on-site renewable energy sources supply 10 percent or more of the building's annual energy use, then two points will be earned. A maximum of three points is awarded for EA Credit 2 if on-site renewable energy sources supply 20 percent or more of the building's annual energy use.
EA Credit 1 addresses the optimization of building energy performance. Prerequisite 2 for the EA category requires that the building meet the requirements of ASHRAE/IESNA Standard 90.1-1999 entitled Energy Standard for Buildings Except Low-Rise Residential Buildings as a minimum for LEED certification.
EA Credit 1 allows the project team to earn up to 10 points toward LEED certification by reducing projected annual energy costs beyond the baseline established by ASHRAE/IESNA 90.1-1999 in EA Prerequisite 2.
The points are earned based on 5 percent increments of calculated annual energy savings between 15 and 60 percent for new buildings and between 5 and 50 percent for existing buildings.
To qualify, the project team needs to demonstrate that design energy costs (DEC) have been reduced in comparison to the baseline annual energy costs established by ASHRAE/IESNA Standard 90.1-1999 using the energy cost budget (ECB) method prescribed in Section 11 of the standard.
The exception to Paragraph 11.2.3 addresses the incorporation of on-site renewable energy sources such as PV into the calculation of the DEC. Essentially, energy supplied by a PV system or other renewable energy sources is deducted directly from the calculated DEC for the building without the renewable energy sources.
The cost reduction provided by PV would be calculated using the cost of electricity. The projected average amount of annual energy produced by the PV system and included in the DEC calculation would need to be documented as part of the project team's application to the USGBC for LEED certification.
LEED EA Credit 6 promotes the purchase and use of off-site renewable energy sources that include grid-source PV, wind, low-impact hydro and other alternative power sources.
EA Credit 6 is worth one point toward LEED accreditation and requires that at least 50 percent of the building's electric energy needs be supplied through a two-year green power contract with a local utility or power supplier.
To qualify, a Green-e accredited utility program must supply the power or other source that meets the Green-e certification requirements. Information about the Green-e Renewable Electricity Certification Program can be found on the Green-e Web site at www.green-e.org.
The installation of on-site PV can help the project team earn points toward LEED certification. This is important because more private and public building owners are seeking various levels of LEED certification for their building projects.
Electrical contracting firms that have the knowledge and expertise to install PV systems, relationships with manufacturers of PV materials and equipment, and employees that are certified PV installers by the North American Board of Certified Energy Practitioners (NABCEP) should market their services to owners and designers involved in LEED projects. EC
GLAVINICH is an associate professor in the Department of Civil, Environmental and Architectural Engineering at The University of Kansas and is a frequent instructor for NECA’s Management Education Institute. He can be reached at 785.864.3435 or firstname.lastname@example.org.