For Building Owners and Managers, it is important to understand the benefits of ongoing energy monitoring, as well as the ever-increasing legal requirements for public energy benchmarking disclosure. This article will cover the basics of how to use ENERGY STAR Portfolio Manager, and the various benefits of energy benchmarking.
ENERGY STAR is commonly recognized as the label to look for when purchasing new appliances or fixtures to signify that it’s energy efficient, much like the WaterSense label for water efficient fixtures. However, also managed by the US EPA, is ENERGY STAR Portfolio Manager, an online tool for tracking and comparing whole-building energy use in buildings.
The premise is simple: based on 12 months of energy data, one can compare a building’s energy performance with like buildings across the US; based on energy use per square foot, and building location/operating characteristics. This has been used to celebrate energy achievements, certify buildings that are high performers, and set goals for energy efficiency based on anticipated energy projects. The benefits of benchmarking can be seen at the building level and at the municipal or utility level. At the building level, owners and managers can track month-by-month data for anomalies, leaks, or savings opportunities; and recognition for certified buildings can be a value-add. At the municipal level, benchmarking transparency and reporting can help identify road-maps to city, county, or state-wide greenhouse gas reductions and energy efficiency goals. Between 2008-2011, over 35,000 benchmarked buildings observed a 7% energy savings documented through ENERGY STAR Portfolio Manager (PM).
Let’s take a look at the various uses of a tool like this.
Ongoing Monitoring and Benchmarking
The benefit of tracking data is two-fold, to have numbers to react to, and to compare performance. The raw data used in ENERGY STAR PM is 12 months of occupied energy data, divided into a per-square-foot energy density: Energy Use Intensity (EUI) is kbtu/sf-year. The Site EUI is generated by adding all fuel sources in kbtu (electricity, natural gas, district steam/chilled water, solar, etc). This allows you to compare buildings of different sizes, normalizing for energy per square foot. From there, you can compare more detailed operational efficiencies based on breakdown of property type, climate zone and associated impacts, operating hours, occupancy, and other type-specific details such as data centers. For 12 eligible property types (office, bank, multifamily, data center, etc), this all rolls up into a 1-100 ENERGY STAR score that represents a building’s percentile ranking; i.e. a score of 60 means a building performs better than 60% of like buildings. Those with a score of 75 or higher are eligible for ENERGY STAR certification.
The tool also allows for tracking impact in different ways. From a site EUI and zip code, ENERGY STAR PM also generates a Source EUI, using local grid efficiency data from the national dataset eGRID. This tells you how much energy must be generated at a power plant to deliver the energy you use, also tied to greenhouse gas emissions tracking. Additionally, you can track water, waste, and sustainable policy data directly in ENERGY STAR PM, whether for internal tracking or for 3rd-party green building certifications like LEED, BREEAM, or Living Building Challenge.
Estimating and Goal Setting
For new construction or retrofit projects, ENERGY STAR Portfolio Manager has a tool called Target Finder, that can be used to estimate a score based on modeled or potential Energy Use Intensity (pEUI). Conversely, if a building is targeting a particular ENERGY STAR score or performance level, Target Finder can be used to estimate a target EUI for comparison with results from an Energy Audit or Commissioning (Cx) report (see screenshot of Target Finder below). This can help in doing a ‘reality check’ for any energy goals discussions, and can be a crucial step in early energy planning for new construction or major renovations projects.
Since ENERGY STAR Portfolio Manager is used so widely for tracking energy data, its robustness and data security continues to improve and has grown to be the foundation of both public and private tracking tools and rating systems. This makes it a great data collection resource for benchmarking and energy transparency policies. The Institute of Market Transformation in partnership with organizations such as local Better Building Challenge groups has monitored the positive effect and impacts of these policies over time. The IMT map below shows a top-level view of Benchmarking Ordinances across the US as of January 2017.
In California, we have state-wide and local leadership pushing the energy efficiency continuous improvement cycle through a combination of annual energy data reporting and 5-10 year cycles of energy audit or energy reduction requirements. In our state and nation-wide, these policies vary widely on transparency, in some cases only requiring energy data during building transactions (as was required by AB1103 during building sale, lease, etc); where in others annually-reported data is kept confidential or annually published.
Statewide AB 802 is slated to go into effect for buildings over 50,000 sf next April, requiring annual energy reporting for whole-building aggregate energy data. This requires either building owners to collect tenant-level data and enter into Energy Star PM, or collect aggregate data now required to be accessible through the utility by the building owner.
In Los Angeles and San Francisco the same type of ordinances exist, pushing even further with building sizes, down to 20,000 sf in Los Angeles for all buildings and 7,500 sf for public buildings. It is highly likely that San Diego will see a similar ordinance in the very near future.
In summary, whether you use EnergyStar portfolio manager or an outside tool, benchmarking a building’s energy or other resources can help in identifying a building’s performance or validating a resource-efficiency project in planning or implementation. Building owners and managers have a vested interest in improving building efficiency for operational cost savings and competing with an ever-improving building stock for market presence. As state and national sustainability goals come on line, that same concept of “you can’t manage what you don’t measure” is leading to more benchmarking and disclosure ordinances important to take note of. For national portfolios, make sure to plan accordingly, as building size requirements, reporting deadlines, and other requirements vary from city to city.