Sundance Power Systems: Sierra Nevada Brewing Co., North Carolina

Sierra Nevada Brewing Company is well known for its commitment to preserving the environment and its sustainability initiatives for manufacturing its ales and lagers.  Its Chico, California, brewery is home to one of the largest privately owned PV arrays in the country. When it made the decision to expand to a new East Coast location in Mills River, North Carolina, Sierra Nevada intended to make the new facility as sustainable as possible, with features including a solar component to offset a substantial portion of the site’s electrical usage.

North Carolina has a 1 MWac cap per customer on net-metered systems. This limitation dictated the size of the systems designed for the brewery.  With two planned 200 kW turbine generators, fueled with methane produced from spent grains and wastewater treatment on-site, the total solar inverter capacity had a calculated target of 600 kWac.

The system included nine parking lot canopies with a total capacity of 60 kWdc, custom designed to create shaded parking during the day and provide lighting at night from fixtures integrated on the underside of the canopies. Wire management within the canopy structures posed an installation challenge. Due to aesthetic requirements, the design concealed all of the dc source circuits and ac lighting circuits within the canopies’ structural members, which required fabrication of the structures with internal wiring partitions to keep the ac and dc wires separated throughout. Additionally, aesthetic elements of the canopy design resulted in minimal array shading during certain times of the day. However, the canopies represent a small portion of the total array capacity on-site and create a striking effect for the brewery’s visitors.

The Sundance Power Systems team installed the 650 kWdc rooftop array over nearly two acres of the packing warehouse’s roof. The precast concrete roof provided an ideal surface for laying out Daetwyler’s Eco-Top Rooftop Mounting Structures. Sundance selected the Eco-Top product in part because Daetwyler manufactures it in North Carolina, so it qualifies for local materials credit in LEED certification, an option that Sierra Nevada will be pursuing.

The canopy and rooftop systems interconnect at separate locations on-site. The rooftop system’s 250 kW and 300 kW Solectria inverters are located on the opposite side of the cold storage warehouse from the canopy arrays. The rooftop system’s point of delivery is located at the 480 Vac switchgear on the load side of the MV transformer that feeds the warehouse section of Sierra Nevada’s site grid. The canopy array’s 50 kW inverter interconnects at a 480 Vac subpanel located adjacent to the keg line.

“Delays challenged this installation, including product availability issues, record rainfall for the season and working with custom canopy structures.  However, Sierra Nevada’s familiarity with PV from past installations and its commitment to quality craftsmanship throughout this project were hugely instrumental in the success of the design and installation.”

—Drew Cates, Sundance Power Systems


DESIGNER: Drew Cates, design and estimate coordinator, Sundance Power Systems,

PROJECT MANAGER: Grayson Newell, director of field development, Sundance Power Systems

ENGINEER: Dale Reynolds, PE, senior electrical engineer, McKim & Creed,

DATE COMMISSIONED: January 19, 2014


LOCATION: Mills River, NC, 35.4°N

SOLAR RESOURCE: 4.3 kWh/m2/day

ASHRAE DESIGN TEMPERATURES: 88°F 0.2% avg. high, 5°F extreme min.



Equipment Specifications

MODULES, ROOFTOP: 2,030 Kyocera KD320GX, 320 W STC, +5%/-0%, 7.99 Imp, 40.1 Vmp, 8.6 Isc, 49.5 Voc

MODULES, CANOPIES: 198 Suniva OPT305-72-4-100, 305 W STC, +5/-0 W, 8.45 Imp, 36.1 Vmp, 9 Isc, 45.6 Voc  

INVERTERS: 3-phase 277/480 Vac service, one Solectria PVI 50KW (50 kW, 600 Vdc maximum input, 300–500 Vdc MPPT range), one Solectria SGI 250 (250 kW, 600 Vdc maximum input, 300–500 Vdc MPPT range), one Solectria SGI 300 (300 kW, 600 Vdc maximum input, 300–500 Vdc MPPT range)

ARRAY, ROOFTOP: 10 modules per source circuit (3,200 W, 7.99 Imp, 401 Vmp, 8.6 Isc, 495 Voc), 16–24 source circuits per combiner, 4–6 combiners per inverter, 649.6 kW array total

ARRAY, CANOPIES:  11 modules per source circuit (3,355 W, 8.45 Imp, 397.1 Vmp, 9 Isc, 501.6 Voc), 18 source circuits total (60.39 kW, 152.1 Imp, 397.1 Vmp, 162 Isc, 501.6 Voc), 60.4 kW array total

ARRAY INSTALLATION, ROOFTOP: Ballasted low-slope roof mount, membrane roofing, Daetwyler CE Eco-Top Gen2 Rooftop Mounting Structures, 141° azimuth, 10° tilt

ARRAY INSTALLATION, CANOPIES: Custom-fabricated canopy structures, 141° azimuth, 20° tilt

SOURCE-CIRCUIT COMBINERS: 11 SolarBOS Disconnect Combiners, 15 A fuses

SYSTEM MONITORING: String-level DECK monitoring with weather station

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