The Chicago City Council recently passed an ordinance requiring energy benchmarking of large buildings. With the energy use benchmarking ordinance, Chicago joins the ranks of cities such as New York City, Washington, D.C., Philadelphia, Minneapolis, Boston, San Francisco, Austin, and Seattle that have all adopted energy benchmarking ordinances.
As in other cities, the Chicago ordinance requires that building owners use ENERGY STAR Portfolio ManagerTM to report energy use. Portfolio Manager is a free, easy-to-use online tool from the U.S. Environmental Protection Agency (EPA).
Portfolio Manager is widely used across the United States and Canada. As of December 2011, more than 260,000 buildings have been benchmarked in Portfolio Manager. This represents over 28 billion square feet (nearly 40 percent of the commercial market) and all 50 states. The tool is used to track the energy use of a building or portfolio over time and to compare an individual building’s performance with similar commercial buildings nationwide.
Portfolio Manager also makes it possible to track other metrics such as costs, emissions, water usage, and changes from the baseline, while normalizing for weather and operational conditions (such as size of building, hours of operation, and number of employees).
How does Portfolio Manager work?
To begin, users set up an account and enter basic building information such as building age, size, and function. Users then enter 12 months of energy use data. Below, for example, is the information required to enter an office space type. Later, owners can update entries, share information, and run reports.
Portfolio Manager calculates the building’s annual Energy Use Intensity (EUI), a standard metric used to compare buildings. Energy Use Intensity, or EUI, refers to a building’s annual energy usage expressed in kBtu per square foot per year. The lower the value, the less energy intensive the building is. EUI is calculated by converting all reported fuel sources and units (electricity in kWh, natural gas in therms) to thousands of Btus (kBtu). This value is divided by the square footage of the building to allow for easy comparison among buildings of varying size.
Currently, there are fifteen common building types that are also given an ENERGY STAR rating on a scale of one to 100. A rating of 75 or more indicates top performance, meaning that a building performs better than 75 percent of similar buildings nationwide. These properties are eligible to earn ENERGY STAR certification, a distinction that buildings must reapply for each year.
Where can I learn more about Portfolio Manager?
The EPA offers a host of training resources for Portfolio Manager. Chicago will soon offer customized Portfolio Manager training for building owners, in order to comply with the city benchmarking ordinance.
Stay tuned for more information from CNT Energy and other partners for training dates and locations. We’ll also publish a guide to help multifamily building owners benchmark their buildings and a case study of CNT’s ENERGY STAR rated building.