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Billings Public Library solar array: "A gamble with no losing side"

Return to:Community Scale, Rooftop Solar

The brand-new Billings Public Library, which opened in January 2014, features on its roof a 30 kilowatt solar photovoltaic array installed by MREA member business Bozeman Green Build. The solar array is net metered, meaning that when the solar panels produce more electricity than is needed in the building at any given moment, the excess power flows out onto the grid and the city receives a credit on its power bill for the library. The array was funded in part by a Universal Systems Benefit grant from NorthWestern Energy.

The solar array was incorporated into the new library building with the intent of achieving LEED Gold certification. LEED, which stands for Leadership in Energy and Environmental Design, is the most widely used green building certification program worldwide. The solar array is just one of many sustainable elements incorporated into the new library building. Others include waterless urinals, reduced use of paint and carpeting, water-wise landscaping, and emphasis on task lighting rather than ceiling lights. The building is currently undergoing LEED review, and final certification is expected this summer.

Solar array on the library's roof

The solar array will offset about 5% of the building's power use, reducing the city’s power bill for the library over the long term. John Palm, owner of Bozeman Green Build, points out that ultimate dollar savings are hard to predict, since they will depend on how much the price of conventional energy rises in the coming decades. As he puts it, “you buy solar today and it’s sort of a gamble, but it’s a gamble with no losing side.”

Quick Stats

  • Location: 510 North Broadway, Billings MT
  • Owner: City of Billings
  • Installer: Bozeman Green Build
  • Capacity (kW): 30
  • Incentives: USB Grant ($50,000)
  • Equipment Used: 120 Trina 250 Watt modules; Three Fronius IG Plus10.0 inverters; Solarmount racking with heavy duty rails and Quick Mount standoffs; SolarBOS disconnecting combiners