The six winners of the second annual Minneapolis Building Energy Challenge Awards cover a wide variety of building types and energy needs, but they all have one thing in common. Every building receiving recognition this year either incorporated a lighting retrofit into their energy-slashing strategies or plans to conduct one in the near future.
The Building Energy Challenge requires participating buildings to benchmark energy use with Portfolio Manager to track progress toward a goal of a 15% reduction in greenhouse gas emissions by 2020. The focus on emissions instead of consumption allows a more flexible approach, the city explains; participants can improve energy efficiency, install or purchase renewable energy or a combination of the two.
All of this year’s winners focused heavily on energy efficiency improvements, a strategy that can deliver considerable savings to be used on future projects. The winning strategies include:
Stinson Ramp: This 800-stall parking structure in northeast Minneapolis received an LED lighting upgrade that cut its electricity usage by more than 46%. The large footprint of parking ramps and a requirement for round-the-clock lighting can add up to high energy consumption, so upgrades like this can deliver big savings quickly.
Basilica of Saint Mary: The Facilities Assessment and Ecological Stewardship volunteer committees have spent the last three years working with staff and contractors to identify energy savings opportunities, including replacing the original 1913 boilers with efficient models, replacing 35 window air conditioning units with central air, and using LED lighting throughout the campus, bell towers, church sanctuary and lower level. The lighting change also helped save on cooling thanks to the lower heat output of the LEDs.
Hennepin County Government Center: This facility improved its ENERGY STAR score by six points over the last three years, reaching an all-time high of 84. A host of improvements fueled this growth, including tinting atrium glass to control solar gain; updating lighting controls and installing LED lighting in much of the building; replacing old appliances, computers and monitors with efficient versions; opting for new pump motors with VFDs to more accurately control pool operation; and renovating the exterior revolving doors and curtainwall doors to reduce energy loss.
Wells Fargo Home Mortgage: This four-building campus has reduced its greenhouse gas emissions by 12% since 2014, due in part to a lighting retrofit that reduced the parking garage’s electricity consumption by more than half. Wells Fargo also restructured its central heating and cooling plant to better serve the three office buildings, and it now groups employees with similar schedules together to optimize space and energy use.
Butler Square: This building is more than 100 years old, which makes its low energy use (50 kBTU per square foot) particularly impressive. The thick masonry envelope helps prevent waste, but the equipment inside was of varying vintages and efficiency. Butler Square staff installed over $1 million in new pumps and drives and converted the pneumatic building management system to direct digital control.
The one large chiller was replaced with five smaller ones that can be selectively ramped up or turned off. Upcoming plans include replacing track and exterior lighting with LEDs.
Calhoun Square: This shopping center managed by the Ackerberg Group upgraded the lighting in its large parking ramp in 2015, then followed suit in common areas. The management company also swapped out two oversized 60-ton HVAC units with one 40-ton and one 20-ton unit and installed programmable thermostats. Between the lighting and HVAC upgrades, the shopping center’s energy use has decreased by half.