SunSystem Technology: Golden1 Center

Sacramento’s Golden1 Center is home court to the Sacramento Kings professional basketball team and hosts a wide range of events, including concerts, ice shows and rodeos. Opened in September 2016, the arena is the first indoor sports venue to earn a LEED Platinum designation and is pioneering progressive sustainability initiatives for an arena of its size, including a farm-to-court program that requires restaurant partners to source 90% of their ingredients, and the majority of the arena's beer, wine and spirits, from within a 150-mile radius. For the electricity required to power the Golden1 Center, the arena relies on generation sources within an even closer radius of 50 miles. While the Center obtains the bulk of its electricity from the Sacramento Municipal Utility District’s (SMUD) Rancho Seco Solar Power Plant, an on-site 700.5 kW rooftop PV array generates approximately 15% of the arena’s load. The array is a dominant feature of the facility's roof and highlights the Center’s commitment to sustainability.

Sacramento-based SunSystem Technology (SST) served as the EPC firm for the Golden1 Center PV system installation. SST teamed up with Blue Oak Energy to develop the project’s mechanical and electrical engineering. The array layout comprises a 16-block, eight-faced columnar shape that neatly conforms to the arena’s domed roof. This complex module configuration consists of 3,417 SPI Energy PV modules. To secure the AET Rayport-B ECO racking system to the arena’s rooftop, the installation team screwed 1,975 Johns Manville Enrgy Anchors into the roof system’s structural decking. The Enrgy Anchor product consists of a mounting plate and stud that are heat fused to Johns Manville TPO and PVC roofing systems, creating a waterproof seal for commercial projects that require penetrating attachments.

The project engineering team broke up the electrical system into two groups of modules (1,708 and 1,709 modules per group). Five SunGrow 60 kW string inverters provide power processing for each of the two array sections. SST aggregated each inverter group at a 600 A, 600 Vac Square D panelboard. It routed the two panelboards' output circuits from the rooftop to an electrical room on the facility’s ground floor, through a disconnect and to a SMUD meter cabinet before landing the combined inverter output circuits at a 600 A breaker in the system’s metal-enclosed switch and breaker combination switchgear. A Trimark T1-S Solar Controller SCADA system provides monitoring. The Golden1 Center awarded SST the O&M contract for its solar project, which it adds to an O&M portfolio that includes Staples Center and Microsoft Theater (formerly Nokia Theater) in Los Angeles.

“In addition to being high-profile, the Golden1 Center system came with some technically unique installation challenges. The array is very much a part of the Center’s overall architectural aesthetic, which was something we were all very aware of. Incorporating the geometry of the Center’s dome-shaped roof into our layout plans left no margin for error. The AET racking system was originally a ballasted system that we converted into a penetrating system to meet the unique requirements of the roof. We worked closely with Blue Oak Energy and AET to convert the racking and achieve a solution that perfectly matched the technical and architectural demands of the project. We couldn’t be more pleased with the outcome.”

Derek Chase, CEO, SunSystem Technology

Overview

DESIGNER: Gabriel Molina, project manager, Blue Oak Energy, blueoakenergy.com

LEAD INSTALLER: Chuck Blyth, commercial construction manager, SunSystem Technology, sstsolar.com

DATE COMMISSIONED: September 2016

INSTALLATION TIME FRAME: 65 days

LOCATION: Sacramento, CA, 38.6°N

SOLAR RESOURCE: 5.5 kWh/m2/day

ASHRAE DESIGN TEMPS: 100.4°F 2% average high, 26.6°F extreme minimum

ARRAY CAPACITY: 700.5 kWdc

ANNUAL AC PRODUCTION: 1,057 MWh

Equipment Specifications

MODULES: 3,417 SPI Energy ES205PCFW, 205 W STC, +5/-0 W, 8.39 Imp, 24.4 Vmp, 8.83 Isc, 30.3 Voc

INVERTERS: 3-phase 480 Vac service, 10 SunGrow SG60KU-M, 60 kW rated output, 1,000 Vdc maximum input, 550 Vdc–950 Vdc MPPT range

ARRAY: 30 modules per source circuit typical, (6,150 W STC, 8.39 Imp, 732 Vmp, 8.83 Isc, 909 Voc), 11 source circuits per inverter typical (67.65 kW, 92.29 Imp, 732 Vmp, 97.13 Isc, 909 Voc), 700.5 kW array total

ARRAY INSTALLATION: Roof mount, Johns Manville PVC roofing system, Applied Energy Technologies (AET) Rayport-B ECO racking, 164° azimuth, 5° tilt

INVERTER CIRCUIT COMBINERS: Two Square D 600 A, 600 Vac panelboards, 100 A breakers

SYSTEM MONITORING: Trimark T1-S Solar Controller SCADA system

Article Discussion