One of the long-time criticisms of the U.S. Green Building Council (USGBC)’s Leadership in Energy and Environmental Design (LEED) rating system has been its inability to track and enforce building operational efficiencies post-occupancy and post-certification. Since its inception in 2000, the rating system’s credits mainly have addressed the design of a facility and its projected energy savings, while more recent versions have included measurement and verification credits in an attempt to bridge this gap.
This year the USGBC will be launching the latest edition of the LEED rating system (LEED 2012) across all certification types: Building Design and Construction (BD+C), Interior Design and Construction (ID+C), and Existing Buildings Operations and Maintenance (EB: O+M). While this article focuses on BD+C, a review of the draft reference guides located at www.usgbc.org reveals that the USGBC is taking a big step toward furthering the goal of making accountability a key component in all certification types with a new emphasis on verifying design calculations with performance-based credits and a pledge to increase its auditing of certified buildings. Additionally, new requirements and certification options for data centers and hospitals hope to give buildings with high energy loads the ability to achieve certification for a variety of energy reduction strategies. Here’s a quick look at the anticipated design and performance changes to the Energy and Atmosphere section of LEED BD+C 2012.
Energy and atmosphere design credits
Mirroring ASHRAE’s newest energy code 90.1-2010, which is 18% more efficient than ASHRAE’s 90.1-2007 (required for LEED 2009), LEED 2012 heightens its baseline for energy savings. The following changes are related to the performance path options for all prerequisites and credits. Prescriptive path options are similar to those available in the 2009 editions of the reference guides.
EA Prerequisite (EAp1): Minimum Energy Performance requires energy/cost performance to be better than ASHRAE 90.1-2010 by 10% for new construction, 7% for major retrofits, and 6% for core and shell projects. Additionally, this new percentage reduction from the baseline will now be measured by the average percentage of energy cost savings and source energy usage intensity savings. (Previously, LEED 2009 measured compliance using only energy cost savings.) This reduces score inflation for buildings with multiple fuel sources with different utility rates and increases the incentive for building designers to decrease overall building energy consumption. For example, in Chicago, electricity is considerably more expensive per Btu than natural gas. Therefore, reducing electric consumption in Chicago has a greater effect on cost and future LEED points, versus reducing natural gas consumption under the current version of LEED.
EA Credit: Optimized Energy Performance allows buildings to earn points if energy/cost savings exceeds the requirements of EAp1 above. Beyond energy/cost index savings, project teams must analyze a minimum of nine efficiency measures during the design process and account for the results in the project’s design decision making. During the schematic design phase, a minimum of six energy-efficiency measures focused on load reduction strategies must be analyzed. Before the completion of the design development phase, a minimum of three additional energy-efficiency measures (which can include passive measures) focusing on HVAC-related strategies also must be analyzed.
EA Credit: Demand Response allows a building to earn one point for having a manual demand response program and two points for an automated demand response program. This is a new credit.
Energy and atmosphere performance credits
LEED 2012 used commissioning prerequisites and credits as well as Measurement and Verification credits to place more of an emphasis on building performance and verifying actual metered data. Attempting the performance credits will require an ongoing commitment from the building design and ownership team for confirmation of completion of these activities 10 months post-occupancy. As can be seen in the following prerequisites and credits, the goal is to emphasize building performance through the updated credit structure and further increase the transparency of the entire LEED certification process.
EA Prerequisite: Whole Building Energy Metering requires whole building design and construction projects to use building-level meters or submeters that can be aggregated to provide building-level metering. This prerequisite also requires the sharing of energy consumption data and electrical demand data acquired from energy resource meters on the project with the USGBC, extending for a five-year period beginning on the date the project accepts LEED certification or typical occupancy. At a minimum, energy consumption must be tracked at one-month intervals or in accordance with utility billing intervals. This is a new prerequisite.
EA Prerequisite: Fundamental Commissioning and Verification will include the same commissioning process as LEED 2009, but the scope of systems required to be commissioned has increased beyond energy-using HVAC systems and energy-generating renewable energy systems to include the building envelope and plumbing.
Additionally, the project team must document the following: current facility requirements in its operation and maintenance plan, including the sequencing of building operations; the building’s occupancy and equipment run time schedules; setpoints for all HVAC equipment; building set lighting levels; minimum outside air requirements; any changes in schedules or setpoints for different seasons, days of the week, and times of the day; a systems narrative describing the mechanical and electrical systems and equipment in the building; a preventive maintenance plan; and an ongoing commissioning program to include the periodic commissioning requirements and ongoing commissioning tasks.
It is important to note that this documentation closely matches the requirements of EA Prerequisite: Energy Efficiency Best Management Practices—Planning, Documentation, and Opportunity Assessment of LEED 2012’s Existing Buildings Operations and Maintenance certification program. This parallel between the rating systems is a powerful example of the importance the USGBC is now placing on documenting operating procedures in order to truly understand the energy performance of a building. Additionally, it is a further indication that the USGBC will be encouraging ongoing certification maintenance using the Existing Building program for new construction projects that achieve LEED 2012 certification.
EA Credit: Enhance Commissioning intent remains the same as in LEED 2009, which includes verification of documents created as a part of fundamental commissioning as well as completing contractor submittal reviews; incorporation of systems manual requirement and owner training into construction documents; verification systems manual delivery and of owner training; seasonal testing; and development of an ongoing commissioning plan. LEED 2012 also hopes to provide more guidance regarding the schedule of deliverables during the design and construction phases of a project.
EA Credit: Monitoring-Based Commissioning profiles the development of monitoring-based procedures and measurement points to be included in the building’s commissioning plan, including determining points and parameters to meter and trend; appropriate trending frequency for points monitored; the review of trend data at least quarterly for unusual behavior like variations from sequence of operation and higher-than-expected energy and water consumption; and identifying criteria for alarm, including tracked points and metered values, and finally the development of a plan for corrective action. Part of this credit was a component of the EA Measurement and Verification credit from LEED 2009.
EA Credit: Advanced Energy Metering outlines the installation of advanced energy metering for all whole-building energy sources and major end uses that represent 10% or more of the total annual building consumption. This is a new credit.
EA Credit: Reconcile Projected and Actual Energy Performance includes developing and implementing a Measurement and Verification program in accordance with Option D: Calibrated Simulation (either Savings Estimation Method 1 or 2), as specified by the International Performance Measurement and Verification Protocol (IPMVP), Concepts and Options for Determining Energy Savings in New Construction, Volume III, 2006. Additionally, an executed contract must be in place at the time of certification to ensure that this work will be completed. Part of this credit was a component of the EA Measurement and Verification credit in LEED 2009.
With LEED 2012, the USGBC has taken a significant and worthy step to ensure that modeled and projected energy savings will play out beyond just design and construction. Reconciling real performance with design goals will redefine high-performance buildings as we know them today.