Delta helps Chicago’s Prudential Plaza earn LEED® Gold-Existing Buildings (EB) certification from the U.S. Green Building Council (USGBC)
The Prudential Plaza is an iconic Class A office tower that overlooks Chicago’s Millennium Park and East Loop commercial district. The Delta Institute worked with owners BentleyForbes for the past two years to achieve the certification, which resulted in substantial improvements in sustainable building operations, recycling and tenant services, as well as an annual savings of $1 million on energy costs through energy efficiency measures.
Delta Institute has a long history of leading sustainable certification of complex and challenging commercial structures. In 2007, the organization famously helped the Merchandise Mart, the world largest commercial building, achieve LEED-EB. Delta also helped 350 West Mart Center earn LEED-EB Gold Certification in 2009 and the NBC Tower earn LEED-EB Silver certification in 2010.
BACKGROUND
Prudential Plaza is a Class A commercial office and retail building in Chicago, Illinois, owned and operated by BentleyForbes of Los Angeles, CA. The Plaza sits on prime real estate over looking Millennium Park, with excellent vistas of Lake Michigan and the Chicago Loop. Prudential Plaza consists of two buildings, Prudential One (Pru 1) and Prudential Two (Pru 2). The smaller and older of the two buildings, Pru 1, has 44 stories and was built in 1955. At 58 stories and 995 feet, Pru 2 is an iconic building in Chicago’s skyline. The architect of Pru 2 was Loebl, Schlossman & Hackl. Pru 1 was heavily renovated when Pru 2 was built, and mechanical systems and lobby areas between the two buildings are shared.
Prudential Plaza is home to myriad tenants, from law offices, publishing, insurance, energy firms, and data centers. This three million gross square foot (approximately 2,460,000 sq ft net) building is a Chicago landmark visited by over 1,500 outside visitors per day.
PROJECT HIGHLIGHTS
• 86 Energy Star Portfolio Manager score for the Campus
• A building-wide Free Cycle (PruCycle) reuse initiative, through which tenants can post items and purchase used items from other building tenants
• A building website, Green Pages, dedicated to the sustainable activities of the building and providing green tips to tenants
• Advanced green cleaning program and near universal use of green cleaning products and equipment
• A building-wide Purchasing Consortium to encourage tenant participation
• An almost 30% electricity use reduction over 2 years (in real kWh, see below)
• Seasonal farmers market at Prudential Plaza to promote sustainability and access to locally grown produce and artisan crafts.
SPECIAL CHALLENGES AND SOLUTIONS
Two challenges were apparent from the beginning of the project that were significant barriers to LEED certification. First, a cursory review of the water consuming fixtures in Pru 1 mandated several upgrades in advance of certification. These upgrades are ongoing as Pru 1 continues to update its systems.
Second, the energy use of the building did not meet the requirements of LEED, and required a very deep look at both the systems in use, and how they were used in the building. The building, through this process, was able to reduce its energy use by approximately 29% from 2007 by operating the building more efficiently and making relatively minor changes to mechanical systems, resulting in $1 million in annual savings in utility costs for the property.
An additional 16% of the building’s usage was reduced from the discovery of a faulty smart-meter, a reduction of 5.8 million kilowatt hours, as a direct result of a close look at the building’s meter loads. The building was able to recoup the loss and credits the LEED process with a cost-avoidance that results in a $600,000 utility refund to the property. Many of the energy efficiency measures are highlighted in the Commissioning documents submitted under the Energy & Atmosphere credits.
A typical and often unresolved issue with LEED for multi-tenant buildings is tenant participation and documentation collection. This is especially important with the Materials & Resources credits, with a significant portion of the opportunities coming from consumable purchases. With the help of the Delta Institute, Prudential Plaza was able to begin a building-wide purchasing consortium with Office Depot. Participating tenants are able to purchase LEED compliant products from a specially created green website. As Office Depot has over 2,500 green products in its catalog, this was the first step in getting the entire building to improve its purchasing. To date over 30 tenants have signed up for the program.
The building has also taken advantage of the ComEd Smart Ideas for Business and the ComEd Energy Insights online software to analyze individual meter data and identify opportunities for savings by studying interval data and the corresponding mechanical systems. The building completed a retrofit of VFDs and a retrofit of most of the common areas to T-8 lighting. The building has also creatively removed one bulb from fixtures in building service areas, reducing the load by approximately half while still maintaining sufficient security light to meet local building codes. In the building service areas and parking garage areas, this has reduced its light bulb consumption by over 1,000 lightbulbs while saving energy.
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