Project Profiles

Primary Category: 

The Newport-Mesa Unified School District (NMUSD) covers nearly 60 square miles in Orange County, California. On September 9, 2014, the NMUSD Board of Education approved the installation of solar carports and lunch shelters, as well as a few small rooftop PV arrays, across 32 sites within the district. The board selected Borrego Solar to lead the overall project design, engineering, construction and ongoing O&M services. From an economic standpoint, the district’s primary goal was to reduce energy costs and mitigate the risk of volatile utility rates over the next few decades. The PV installations are net metered, and each school uses the majority, if not all, of the solar energy generated by its respective PV system.

The district leveraged state incentives and loans to secure its PV systems with little capital expenditure up front. The NMUSD did not use any general funds capital on this project, leaving financial resources available for classroom expenses, and paid for the $13 million project with a $3 million interest-free loan from the California Energy Commission, $5 million in funds from the California special reserve funds for capital outlay and $5 million from California’s Proposition 39. In addition, the district will receive a performance-based incentive from the California Solar Initiative program for the first 5 years of system operation. The savings from the installations will provide an income stream over the life of the project.

Borrego Solar designed a portfolio of solar projects for the NMUSD comprised primarily of elevated shade structures that maximize the unused space on school properties throughout the district. The tight schedule and multitude of sites presented many challenges. The slim margin for error required seamless coordination of every step in the process, from meeting interconnection standards and design approvals for Southern California Edison (SCE) to managing permit applications and coordination with the California’s Division of the State Architect (DSA), which provides design and construction oversight for K–12 schools, community colleges and various other state-owned and -leased facilities. Additionally, the multiple parties in the project—including an Inspector of Record, the DSA, construction management firms, subcontractors, the district and SCE—needed to remain updated and involved throughout development and deployment.

At the core of Borrego Solar’s successful completion of the project was keeping things moving forward and on schedule. The team diligently stayed up to date with any changes that SCE made to interconnection requirements, and brought on an engineer to focus on working with the DSA and navigating the process to avoid any snags. The Borrego Solar project manager’s priority was communicating necessary information to the district and its hired construction management firm to avert any unexpected issues that could stall progress.

“While this was the greatest number of sites we have completed consecutively for one district, Borrego Solar has extensive experience working with the DSA and SCE, which proved essential in completing the NMUSD project on schedule. Our experience enabled the team to anticipate elements of the design where utilities occasionally push back. Because of Borrego Solar’s tight teamwork, it was possible to coordinate and complete many tasks across the portfolio, such as shutting off power and interconnecting 24 systems in a single day.”

Karla Martinez, Borrego Solar


DESIGN: Ben Walter, director of engineering for Western US, Borrego Solar,

PROJECT MANAGEMENT: Karla Martinez, project manager, Borrego Solar

DATE COMMISSIONED: Project completed February 2016

INSTALLATION TIME FRAME: 32 sites total, installation time ranged from 44 to 87 days per site, depending on system capacity and site variables

LOCATION: Newport Beach and Costa Mesa, CA, 33.6°N

SOLAR RESOURCE: 5.5 kWh/m2/day

ASHRAE DESIGN TEMPS: 87.8°F 2% average high, 35.6°F extreme minimum

ARRAY CAPACITY: 3,222 kWdc project total, 32 sites total ranging from 23.52 kWdc to 540.96 kWdc


Equipment Specifications

MODULES: 11,508 LG Electronics LG280S1C-B3, 280 W STC, +3/-0%, 8.78 Imp, 31.9 Vmp, 9.33 Isc, 38.8 Voc

INVERTERS: 3-phase, 277/480 Vac services, 42 Yaskawa–Solectria Solar PVI 14TL (14 kW rated output, 600 Vdc maximum input, 180 Vdc–580 Vdc operating range, 300 Vdc–540 Vdc rated MPPT range), four SMA Sunny Tripower 12000TL-US (12 kW rated output, 1,000 Vdc maximum input, 150 Vdc–1,000 Vdc operating range, 300 Vdc–800 Vdc rated MPPT range), 20 SMA Sunny Tripower 15000TL-US (15 kW rated output, 1,000 Vdc maximum input, 150 Vdc–1,000 Vdc operating range, 300 Vdc–800 Vdc rated MPPT range), 12 SMA Sunny Tripower 20000TL-US (20 kW rated output, 1,000 Vdc maximum input, 150 Vdc–1,000 Vdc operating range, 380 Vdc–800 Vdc rated MPPT range), 57 SMA Sunny Tripower 24000TL-US (24 kW rated output, 1,000 Vdc maximum input, 150 Vdc–1,000 Vdc operating range, 450 Vdc–800 Vdc rated MPPT range)

ARRAY: Source circuit parameters and array configurations vary based on array capacity, inverter model and number of inverters deployed per site

ARRAY INSTALLATION: Ground-mounted carports, Borrego Solar DSA Pre-Check design manufactured and installed by Resolute Performance Contracting, electrical installation by HMT Electric

SYSTEM MONITORING: AlsoEnergy portfolio monitoring

Primary Category: 

In August 2016, Mass Renewables of Bellingham, Massachusetts, became the first company in the state certified to install the Tesla Powerwall lithium-ion residential energy storage system. One of its early deployments of the Tesla product is in the Bailey residence, located in Holliston, Massachusetts. The system dc-couples two Tesla 3.3 kW, 6.4 kWh Powerwalls with SolarEdge’s 7.6 kWac StorEdge power conversion system.

Mass Renewables designed the 9.975 kWdc system to offset 100% of the customer’s average annual electricity use. Local utility Eversource permits net energy metering for PV systems in its territory. During the project design phase, Mass Renewables used a Solmetric Suneye to develop a shade analysis for the site. A hipped section of the home’s south-facing roof as well as several plumbing vents complicated the array layout. The installers took the extra time to hide rooftop junction boxes and conduits from view, resulting in a visually clean array installation.

The Mass Renewables installation team mounted the inverter and batteries in the home’s basement. The two Tesla Powerwalls react to commands from the SolarEdge inverter. For the Bailey installation, Mass Renewables programmed the system to maximize self-consumption and to utilize 80% of the battery capacity (20% battery reserve capacity). In the event of a utility power loss, the inverter automatically islands PV generation and energy storage from the grid and provides energy to select household loads, including the client’s refrigerator, gas furnace blower and controls, bathroom lighting, kitchen lighting and outlets, and wireless router via a new backup-loads panel.

Users can manage several system and battery settings remotely from the SolarEdge monitoring portal. For example, Mass Renewables can remotely change the battery reserve capacity and discharge time of day. During the winter months when storms are frequent, users can program the system to retain 100% battery capacity in preparation for anticipated power outages. During extended utility outages, the PV array continues to charge the system’s energy storage and provides a weather-dependent source of critical backup power. 

“Mass Renewables is proud to be an early adopter of both the Tesla Powerwall and SolarEdge’s StorEdge inverter system. Our New England service territory can experience power outages due to winter snow and ice storms. PV arrays coupled with modern lithium-ion energy storage systems present a significant added value for many of our residential customers. We currently have two of Tesla’s new Powerwall 2.0 energy storage systems presold and look forward to installing this new 7 kW, 14 kWh product in Q2 2017.”

Mike Kelley, Mass Renewables


DESIGNER: Mike Kelley, co-owner, Mass Renewables,

LEAD INSTALLER: Jeff Herman, co-owner, Mass Renewables



LOCATION: Holliston, MA, 42.2°N

SOLAR RESOURCE: 4.5 kWh/m2/day

ASHRAE DESIGN TEMPS: 89°F 2% average high, 1°F extreme minimum



Equipment Specifications

MODULES: 35 Suniva Optimus Series OPT285-60-4-100, 285 W STC, +4.99/-0 W, 8.82 Imp, 32.3 Vmp, 9.59 Isc, 39.4 Voc

INVERTER: Single-phase 120/240 Vac service, one SolarEdge StorEdge SE7600A-USS inverter, 7.6 kWac 120/240 Vac output, 500 Vdc maximum input voltage (PV and battery), 400 Vdc nominal input voltage (PV and battery), 5.0 kWac rated output from battery in backup mode with 7.6 kWac 10-second surge capacity; SolarEdge SE-MTR240-2-200-S1 Electricity Meter

POWER OPTIMIZERS: 35 SolarEdge P300 Power Optimizers (one per module), 300 W rated input, 8 Vdc– 48 Vdc MPPT operating range, 48 Vdc maximum input voltage, 5,250 W maximum power per dc source circuit for single-phase applications

ENERGY STORAGE: Two Tesla Powerwalls (3.3 kW, 6.4 kWh each) configured in parallel (3.3 kW, 12.8 kWh total), 350 Vdc–450 Vdc operating range, 100% depth of discharge allowed

ARRAY: One 17-module source circuit (4,845 W) and one 18-module source circuit (5,130 W), 9.975 kWdc array total at 400 Vdc nominal (module-level current controlled by power optimizers)

ARRAY INSTALLATION: Roof mount, asphalt shingle roofing, EcoFasten Solar GreenFasten GF2 mounting and flashing, Ironridge XR100 rails with integrated grounding, 178° azimuth, 31° tilt

SYSTEM MONITORING: SolarEdge module-level and energy storage monitoring

Primary Category: 

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


DESIGNER: Gabriel Molina, project manager, Blue Oak Energy,

LEAD INSTALLER: Chuck Blyth, commercial construction manager, SunSystem Technology,



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



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

Primary Category: 

The Safe Harbor Marina at Buffalo Harbor State Park is home to over 1,000 boat slips, as well as a restaurant and bait shop on Lake Erie’s eastern shore, just south of downtown Buffalo, New York. The 190-acre Buffalo Harbor State Park opened to the public in May 2015. The New York State Office of Parks, Recreation and Historic Preservation (NYS OPRHP) improved the harbor’s break wall in 2016 with the addition of a bike and walking path, landscaping and two custom pergola structures. The artificial peninsula does not have access to ac power. The NYS OPRHP contracted Frey Electric to design and install a stand-alone PV-powered LED lighting system on each of the break wall’s pergolas to provide dusk-to-dawn lighting for park visitors.

The two open-structure steel pergolas feature polyester powder–coated curved beams and arched lattice rafters. The structures’ curved elements presented an inherent challenge to racking and module integration that made it difficult for the installers to mount the rails in the same plane. Frey Electric used one of the end lattice rafters to determine the array orientation’s plane of reference. Each rafter attachment has a custom standoff height to compensate for the arch and orientation angle of each rafter. To prevent possible galvanic corrosion, the installation team inserted Grace Ice and Water Shield butyl underlayment between the aluminum rail attachment brackets and the pergolas’ steel structural members. Due to extreme winds on the lakefront, the team used high-tensile-strength blind bolts to fasten the attachment brackets to the tube steel rafters.

To minimize the arrays’ visual impact on the pergolas, Frey Electric selected Lumos Solar glass-on-glass modules. The modules allow light to pass through portions of the array, helping to maintain the structures’ open feel. The frameless modules mount to the Lumos LSX rail system via four mounting holes in the face of each module. The high-tolerance system required the mounting holes and corresponding rails to line up within about 1/16 inch of each other. The installers constructed module templates from luan plywood and used them to help align the rail’s mounting bolts.

The project site can receive extreme amounts of snow off the lake and experiences long stretches of low-irradiance conditions. With the assistance of National Solar Technologies, Frey Electric designed a dc lighting system that provides 10 days of autonomy. Each pergola has an enclosed BOS package that includes a 24-Vdc nominal 980 Ah Deka AGM battery bank, a Morningstar Tristar MPPT PV controller, a Morningstar Tristar controller configured for load control, MidNite Solar surge suppression and OCPDs for individual components. The systems power Peachtree Lighting’s Cambridge Creek brushed aluminum 5 W LED sconce lights, rated for wet locations. The terminus pergola has 16 sconces (80 W total load), and the intermediate pergola has 12 sconces (60 W total load). The Morningstar load controller uses the PV array as a reference to provide dawn-to-dusk lighting operation.

“Buffalo Harbor State Park is the first state park in Buffalo. It was an honor to be part of one of its start-up projects. It was a team effort, from design to installation. Although the size of the two individual PV systems is small, the design and installation challenges were relatively complex due to the curved structures and the lakefront location. The frameless Lumos Solar glass-on-glass modules keep the openness of the pergola structures. It’s a satisfying feeling to know the project’s LEDs light the way for pedestrians on the break wall and boaters in the harbor.”

Deborah Zarbo, Frey Electric


DESIGNERS: Deborah Zarbo, engineer, Frey Electric,; Paul Vargovich, general manager, National Solar Technologies,

LEAD INSTALLER: Tony Scinta, installation lead, Frey Electric



LOCATION: Buffalo, NY, 42.9°N

SOLAR RESOURCE: 4.1 kWh/m2/day

ASHRAE DESIGN TEMPS: 86°F 2% average high, -4°F extreme minimum

ARRAY CAPACITY: 3,060 Wdc (1,530 Wdc per pergola)

ANNUAL DC PRODUCTION: 1,791 kWh (per pergola)

Equipment Specifications (per Pergola)

MODULES: Six Lumos Solar LSX 255-60M, 255 W STC, +3/-0%, 8.43 Imp, 30.2 Vmp, 8.86 Isc, 37.5 Voc

CHARGE CONTROLLER: One Morningstar Tristar TS-MPPT-60, 60 Adc, 150 Vdc maximum input, 8 Vdc–72 Vdc battery operating voltage range, four-stage MPPT charging algorithm (bulk, absorption, float, equalize), Morningstar remote temperature sensor

LOAD CONTROLLER: One Morningstar TriStar-45 configured for load control, 45 Adc, low-voltage disconnect capability

SURGE PROTECTION: MidNite Solar MNSPD-300-DC, 300 Vdc maximum, NEMA 4X

BATTERY: Deka Intimidator 8A8D, AGM, 12 Vdc nominal, 245 Ah at C20; four series strings of two batteries configured for 980 Ah at 24 Vdc nominal; customized stainless steel equipment enclosure

ARRAY: Three modules per source circuit (765 W, 8.43 Imp, 90.6 Vmp, 8.86 Isc, 112.5 Voc), two source circuits total (1,530 W, 16.86 Imp, 90.6 Vmp, 17.72 Isc, 112.5 Voc)

ARRAY INSTALLATION: Solar pergola mount, custom steel canopy structures, Lumos Solar LSX Rail 1.1 rails, Lumos Solar X Track beam attachment with high-tensile-strength blind bolts, 140° array azimuth (terminus pergola), 210° array azimuth (intermediate pergola), 22° tilt (average)

Primary Category: 

The Ashland Food Co-op has a long history of supplying healthful organic food to Southern Oregon’s Rogue Valley and beyond. The Co-op started as a buying club in 1971 and has grown into a full-service cooperative grocery and deli with over 8,000 owners. It emphasizes locally produced, organically grown and ecologically sound products. While the Co-op has been operating a rooftop PV system for close to a decade, in 2016 it contacted Ashland-based True South Solar (TSS) to evaluate options for expanding the array.

New equipment choices, coupled with decreases in cost, can make high-density array designs that maximize annual production of rooftop systems attractive to integrators and their customers. The original Co-op array included three rows of nine modules mounted at a 30° tilt angle, with large gaps between rows to minimize interrow shading. This section of the array occupied a prime solar resource area on the building’s flat upper roof. A larger low-tilt high-density array would allow the Co-op to offset a greater portion of its annual consumption.

Initial discussions weighed relocating the original system to another area on the building or property. However, when the team compared the cost and benefit of moving the old system to that of replacing it with a new system using current modules and power electronics, it made the decision to decommission the original system. The Co-op plans to donate the equipment to the Ashland Emergency Food Bank in cooperation with TSS, which will donate the labor required to install the system at its new location.

Determining the layout of the new Co-op array was tricky due to all the rooftop HVAC equipment and required setbacks. When TSS considered the locations of the HVAC equipment, the shading and the orientation of the metal roofing panels that run roughly east-west, it determined that an array orientation of 112° with a 10° tilt was optimal. Orienting the array at 180° would have locked the attachment spacing with the spacing of the standing seams, which would have created more small subarrays, reduced the overall number of PV modules and increased labor costs. The arrays consist of nonpenetrating Sunmodo AceClamps, SnapNrack racking and Oregon-assembled SolarWorld modules.

The building’s 120/208 Vac 3-phase service and lack of space to mount inverters in the electrical room or on the building's exterior narrowed the inverter options considerably. TSS determined that HiQ Solar inverters were a great choice for the application due to their 3-phase output and mounting location flexibility. Each 5.75 kWac inverter has two MPP trackers that provide many string length options. To minimize installation complexity, TSS opted to group the six HiQ inverters together and mount them on a strut platform under the far western array. This location is close to the system’s point of interconnection and required only a short ac conduit run. Colocating HiQ inverters with two HiQ Solar AC Splice boxes allowed TSS to use the inverter ac whips to parallel the inverter output, without any additional ac raceways or wiring.

“The Ashland Food Co-op is a very integral and positive part of our community. Designing and installing a PV system for the Co-op was a true honor. It’s been a wonderful experience helping increase the size of this locally owned and operated renewable energy system.”

Ry Heller, True South Solar


DESIGNER AND LEAD INSTALLER: Ry Heller, designer and field manager, True South Solar,

DATE COMMISSIONED: October 26, 2016


LOCATION: Ashland, OR, 42.2°N

SOLAR RESOURCE: 4.9 kWh/m2/day

ASHRAE DESIGN TEMPS: 96.8°F 2% average high, 17.6°F extreme minimum



Equipment Specifications

MODULES: 150 SolarWorld Sunmodule Pro-Series SW 260 Poly, 260 W STC, +5/-0 W, 8.37 Imp, 31.4 Vmp, 8.94 Isc, 38.4 Voc

INVERTERS: 120/208 Vac 3-phase service, six HiQ Solar TrueString TS208-5k75 inverters, 5.75 kWac, 1,000 Vdc maximum input, 325 Vdc– 525 Vdc MPPT range, 3-phase 208 Vac output

ARRAY: 12–14 modules per source circuit, (3,640 W STC, 8.37 Imp, 439.6 Vmp, 8.94 Isc, 537.6 Voc for 14-module source circuits), two source circuits per inverter, 39 kWdc array total

ARRAY INSTALLATION: Low-profile roof mount, standing seam metal roofing, Sunmodo Standing Seam AceClamp A2N Nail Down Kit, SnapNrack 100 Roof Mount System, 112° azimuth, 10° tilt

INVERTER CIRCUIT COMBINERS: Two HiQ Solar AC Splice ACSPL-60, each combining ac outputs of three HiQ Solar TrueString inverters, unfused

SYSTEM MONITORING: HiQ Solar gateway with integrated web server, web-based string-level monitoring

Primary Category: 

Sun Solar is an integrator with operations and service regions in Missouri, Kansas and South Carolina. In September 2016, it commissioned a 93.28 kWdc system for Buzz’s Market, a popular family-owned supermarket that has been operating at its current location in Collins, Missouri, since 1996. The availability of federal tax credits, coupled with a $12,500 incentive from Empire District Electric Company for commercial PV systems, piqued the interest of Ray Marquis, the grocery’s owner. His goal was simple—fit as many modules on the market’s roof as possible.

Array shading is a common concern for many solar projects in southwest Missouri, where PV installations often require the removal or trimming of nearby trees. Localized shading is one reason Sun Solar began sourcing JinkoSolar Eagle MX modules with integrated Maxim cell-string–level optimization from its wholesaler, CivicSolar, in early 2016. These modules use integrated circuits (ICs) to track MPP at the cell-string level. The IC isolates shaded cells within the module and scales up the output current to match the string current. This arrangement optimizes each cell group to operate independently at its unique MPP. JinkoSolar Eagle MX modules provide additional design flexibility by enabling uneven strings and even multiple orientations within a string.

While the rooftop of Buzz’s Market did not have any major shading concerns, roof obstructions—including plumbing vents on one of the roof’s orientations—create some periodic shading. The Sun Solar installation team slightly altered the original array design configuration to compensate for the roof obstructions. JinkoSolar Eagle MX modules are compatible with string inverters such as the Fronius Symo line designated in the design. The modules allowed Sun Solar to mitigate any losses associated with the roof obstructions, and the Fronius Symo inverters offer source-circuit flexibility that made it easy for Sun Solar to adjust the final layout and string design. Installation and commissioning procedures for JinkoSolar Eagle MX modules are identical to those for standard modules, and they do not have any module-specific inverter programming requirements. The string inverter’s MPP tracker or trackers further optimize the output of its aggregated source circuits.

The installation took 11 days from start to finish, including the time required to adjust the array’s design layout. The market’s low-slope trapezoidal rib-metal roof was a great candidate for S-5!’s ProteaBrackets, and S-5!’s PV Kits were a streamlined choice for module mounting. Sun Solar mounted the six Fronius inverters at ground level, in close proximity to the building’s utility service. Once the integrator team members confirmed the final array capacity of the system, they worked quickly to get the job installed and commissioned with the utility.

“Buzz’s Market is one of the bigger jobs Sun Solar had the pleasure of installing this year. The design flexibility of the equipment used made it simple. The combination of JinkoSolar modules and Fronius Symo inverters made it easy on us as an installer and provides the customer with a high-performance solution and increased return on investment, from which they’ll benefit for years to come.”

Luke Arthur, chief operating officer, Sun Solar 


DESIGNER: Jerry Bergstrom, solar designer, Sun Solar,

LEAD INSTALLER: Chris Neal, installation crew lead, Sun Solar

DATE COMMISSIONED: September 14, 2016


LOCATION: Collins, MO, 37.9°N

ASHRAE DESIGN TEMPERATURES: 93.2°F 2% average high, -2.2°F extreme minimum



Equipment Specifications

MODULES: 352 JinkoSolar Eagle MX JKMS265PP-60, 265 W STC, +3/-0%, 8.88 Imp, 29.8 Vmp, 9.51 Isc, 36.7 Voc

INVERTERS: 120/208 Vac 3-phase service, four Fronius Symo 15.0-3 208 inverters (15 kWac, 1,000 Vdc maximum input, 325 Vdc–850 Vdc MPPT range), two Fronius Symo 12.0-3 208-240 (12 kWac, 600 Vdc maximum input, 300 Vdc–500 Vdc MPPT range)

ARRAY: 16 modules per source circuit (4,240 W, 8.88 Imp, 476.8 Vmp, 9.51 Isc, 587.2 Voc), four source circuits per 15 kW inverter (16.96 kW, 35.52 Imp, 476.8 Vmp, 38.04 Isc, 587.2 Voc), three source circuits per 12 kW inverter (12.72 kW, 26.64 Imp, 476.8 Vmp, 28.53 Isc, 587.2 Voc), 93.28 kWdc array total

ARRAY INSTALLATION: Exposed fastener trapezoidal rib metal roofing panels, S-5! ProteaBracket and S-5! PV Kit attachment system, 182° and 2° azimuths, 3° tilt

SYSTEM MONITORING: Fronius inverter-integrated data monitoring, Fronius Solar.web online platform

Primary Category: 

Located 5 miles outside Lincoln, Nebraska, the 4.68 MWdc Holdrege Solar Center is the largest solar installation in the state and a multimegawatt deployment of Solar FlexRack’s TDP Turnkey Tracker system. The project team includes Enerparc, an international solar development company with its US operations based in Oakland, California. Enerparc has developed more than 1.6 GW of PV capacity worldwide and performs O&M for 1.1 GW of PV assets. With 30 years of experience as a general contractor for large-scale projects, Golden, Colorado–based New Energy Structures Company (NESCO) led the on-site construction. In addition to supplying trackers for the project, Solar FlexRack, a division of Northern States Metals, assisted the team with project-specific engineering, analysis, planning and field support. The Holdrege Solar Center is an example of effective collaboration that maximizes on-site productivity.

Early planning efforts mitigated many on-site challenges, but some conditions could not be avoided, such as the dramatic spring weather swings typical of the prairie state. Construction crews dealt with high winds, seasonal rain, thunderstorms and extreme heat. While Nebraska ranks 48th nationally in installed PV capacity, Enerparc reported that it was still able to hire almost 40% of the Holdrege Solar Center’s construction crew locally. The PV plant is located on an active agricultural site with a center pivot irrigation system. The project’s scope included relocating and reconfiguring the irrigation infrastructure in advance of the solar installation to allow agriculture to continue in the areas outside the PV array. The project utilizes approximately 25% of the site for PV generation. The remaining 75% is used for agricultural activities.

Site-specific challenges included the rolling topography, which required a combination of civil engineering and earthwork to support a foundation design compatible with the tolerances of the independent-row tracker system. Layout challenges included avoidance of adjacent wetlands, terrace systems and areas with steep topography. The Solar FlexRack service team worked closely with the installation team well in advance of construction to minimize the impact of these on-site project variables.

NESCO deployed 15,333 Heliene PV modules on 269 Solar FlexRack TDP Turnkey single-axis horizontal trackers, and 60 Sungrow 60 kWac 3-phase string inverters provide power conditioning. Installers aggregated the outputs of the individual string inverters at low-voltage ac panelboards and switchboards. Transformers allow the collected ac sources to interconnect with the site’s 15 kV medium-voltage substation. The electrical design includes integrated relays that ensure PV output operability within utility-required generation parameters, as well as programming for protective settings.

“We selected Solar FlexRack TDP Trackers based on our previous successful experience with Solar FlexRack, and especially because of the great turnkey services packaged with the product, ensuring a smooth installation. Once again, we were not disappointed.”

—Florent Abadie, CEO, Enerparc


DESIGNER: Paul Corteza, project engineer, Enerparc,

LEAD INSTALLER: Ben Searl, construction manager, New Energy Structures Company,



LOCATION: Holdrege, NE, 40.4°N

SOLAR RESOURCE: 5.3 kWh/m2/day

ASHRAE DESIGN TEMPS: 95°F 2% average high, -7.6°F extreme minimum



Equipment Specifications

MODULES: 15,333 Heliene 72P 305, 305 W STC, +4.99/-0 W, 8.29 Imp, 37.06 Vmp, 8.73 Isc, 45.51 Voc

INVERTERS: 15 kV medium voltage substation interconnection, 3-phase 277/480 Vac collection system; 60 Sungrow SG60KU-M, 60 kW, 1,000 Vdc maximum input, 300–950 Vdc MPPT range

ARRAY: 19 modules per source circuit (5,795 W, 8.29 Imp, 704.1 Vmp, 8.73 Isc, 864.7 Voc), 14 source circuits per inverter, typical (81.1 kW, 116.1 Imp, 704.1 Vmp, 122.2 Isc, 864.7 Voc), 4.68 MWdc array total

ARRAY INSTALLATION: Tracked array, 269 Solar FlexRack TDP Turnkey single-axis horizontal trackers, ±45° tracking rotation range

SYSTEM MONITORING: Locus Energy supplied and commissioned DAS hardware, software and performance analytics, including inverter-direct monitoring and revenue-grade metering

Primary Category: 

Fresno, California–based Nova West Solar designed, planned and installed a 10.7 kWdc ground-mount PV system at the Beam residence in Clovis, California. A 5-acre grove of actively farmed navel oranges surrounds the home. In 2008, the Beams had a PV system installed on the roof of their residence. The original system did not offset the customer’s home and business electricity usage, which prompted the Beams to contact Nova West Solar to install an additional array. Combined, the solar arrays offset 100% of the Beam’s annual electrical load. The new PV system will save more than $221,000 over the system’s life cycle and has a 4.5-year simple payback on the family’s investment.

The project presented several obstacles, and allowing for future expansion of the system created additional design requirements. Recent fire codes mandate 3-foot setbacks on rooftop PV arrays, necessitating ground mounting of the new array. The existing electrical panel also presented a hurdle. Nova West Solar landed the single-phase 240 Vac output of the SolarEdge 11.4 kW inverter at a new 60 A breaker in an existing 200 A subpanel. To keep the maximum available current below 120% of the panel’s bus rating, the installer replaced its 200 A main breaker with a 175 A main breaker.

Nova West Solar’s design for the system couples 33 high-efficiency 96-cell Panasonic HIT modules with an 11.4 kW SolarEdge string inverter. A SolarEdge P400 dc optimizer (33 total) monitors and optimizes the output of each individual module. Together, the modules and the power conversion platform maximize energy production and minimize the array’s physical footprint. The result is a system that reduces the area required for the array by approximately 20% compared to an installation using standard modules and power electronics. For the Beams, this meant they needed to remove fewer citrus trees to make space for the PV array. SolarEdge’s module-level optimizer system minimizes the impact of module soiling and shading from the adjacent orange trees and allows for the easy addition of modules down the line, should the family require additional power to run their home and business.

“The combination of Panasonic HIT modules and SolarEdge’s dc optimizers and inverter is a match made in heaven. Panasonic’s high-efficiency module design maximizes energy production, and the modules have an incredibly low failure rate. The costs associated with diagnosing module failures and subsequent replacement and warranty claims can add up quickly and tie up valuable person hours and other resources needed to handle callbacks. High-quality modules and module-level monitoring minimize long-term financial exposure.”

TJ Shelton, Nova West Solar


DESIGNER: TJ Shelton, operations manager, Nova West Solar,

LEAD INSTALLER: Frank Ramirez, installation lead, Nova West Solar




SOLAR RESOURCE: 5.7 kWh/m2/day

ASHRAE DESIGN TEMPERATURES: 102.2°F 2% average high, 28.4°F extreme minimum



Equipment Specifications

MODULES: 33 Panasonic VBHN325SA16, 325 W STC, +10/-0% 5.65 Imp, 57.6 Vmp, 6.03 Isc, 69.6 Voc, 96 cell

INVERTERS: Single-phase 120/240 Vac service, one SolarEdge SE11400A-US, 11.4 kW, 500 Vdc maximum input voltage, 350 Vdc nominal input voltage at 240 Vac; 33 SolarEdge P400 Power Optimizers, 400 W rated input, 8 Vdc–80 Vdc MPPT range, 80 Vdc maximum input

ARRAY: 11 modules per source circuit (3,575 W), three source circuits, 10.725 kWdc array total at 350 Vdc nominal (module-level current controlled by power optimizers)

ARRAY INSTALLATION: Ground-mount IronRidge XR1000 rails, 2.5-inch schedule 40 galvanized pipe substructure, 180° azimuth, 19° tilt

SYSTEM MONITORING: SolarEdge module-level monitoring

Primary Category: 

The Clean Energy Collective (CEC) developed the Garfield County Airport Solar Array project as an 858 kW community solar array (GCASA Phase 1) and commissioned it in 2011. CEC has its roots in Carbondale, Colorado, and has a long-standing and continuing partnership with Sunsense Solar, also based in Carbondale. Equally integral to the project was Holy Cross Energy (HCE), the local cooperative utility. Since the early 2000s and at the request of its customers, HCE has been incentivizing and interconnecting PV systems within its service territory in western Colorado.

After completing this first phase, CEC wanted to expand its community solar reach within HCE territory and approached Sunsense with the possibility of expanding the GCASA site. The size of the expansion, fixed at 826 kW, required developing two sites. The solution (GCASA Phase 2) was to straddle the original array by splitting the new array into Site A (599.4 kW) to the west and Site B (226.8 kW) to the east. This approach proved challenging on several levels. 

From a product perspective, GCASA 1 and GCASA 2 deploy markedly different components that required different design and installation approaches. GCASA 1 consists of helical piers and racking from Solar FlexRack, polycrystalline modules from Hanwha Solar and central inverters from Advanced Energy. In contrast, GCASA 2 includes TerraSmart ground screws and racking, First Solar thin-film modules and a decentralized design that uses SMA America string inverters.

Site A simply extended the original side-of-runway location and featured the same 20° south-facing slope. A portion of Site B has the same south-sloping topography, with the balance relatively flat. While this sloped surface assisted Sunsense in achieving the system design tilt, it resulted in significant issues with construction, particularly through the winter months when ice and snow made things tricky. When the weather warmed up, the mud was equally problematic. The solution was to utilize tracks, chains and other traction methods on all equipment and, during some phases, to wait for drier conditions. Upon completion, the site required significant restoration.

The utility interconnection was an additional challenge. The project team brought utility power to the GCASA 1 site via an overhead line. The team determined that construction of Site B would require excavating a 700-foot trench from the switchgear to the existing transformer at GCASA 1. With the trenching, conduit and conductor installation, and backfilling scheduled to begin during the winter months, the thawing of the ground collapsed the trench in the spring to the point where it required further restoration.

Sunsense considered several strategies, including overhead lines and extensive trenching, for utility interconnection at Site A. HCE proved to be particularly adept at running service lines in a variety of geotechnical conditions throughout the mountains of western Colorado. Ultimately, the utility determined that the best and safest route for the interconnection would be through the adjacent restored Dry Creek drainage.

“With the guidance of our developer partners at CEC, the operations crew at Holy Cross Energy and our subcontractors from Expert Electric and Lyons Fencing, Sunsense Solar was able to address challenges and provide solutions leading to an extremely successful expansion of the Garfield County Airport Solar Array.”

—Mark Item, Sunsense Solar


DESIGNER: Jeff Lauckhart, lead PV designer, Sunsense Solar,

LEAD INSTALLER: Mark Item, commercial site supervisor, Sunsense Solar



LOCATION: Rifle, CO, 39.5°N

SOLAR RESOURCE: 5.8 kWh/m2/day

ASHRAE DESIGN TEMPS: 93.2°F 2% average high, -7.6°F extreme minimum



Equipment Specifications

MODULES: 7,344 First Solar FS4112A-2, 112.5 W STC, +5/-5%, 1.60 Imp, 70.2 Vmp, 1.75 Isc, 87.7 Voc

INVERTERS: 3-phase 277/480 Vac service, 26 SMA America Sunny Tripower 24000TL-US, 24 kW; nine Sunny Tripower 20000TL-US, 20 kW; two Sunny Tripower 15000TL-US, 15 kW; 1,000 Vdc maximum input, 150–1,000 Vdc operating voltage range

ARRAY: 5,328 modules Site A, 2,016 modules Site B; nine modules per source circuit (1,012.5 W, 1.6 Imp, 631.8 Vmp, 1.75 Isc, 789.3 Voc); 28 source circuits (typical) per SMA Sunny Tripower 24000TL-US (28.35 kW, 44.8 Imp, 631.8 Vmp, 49 Isc, 789.3 Voc); 826.2 kWdc array total

ARRAY INSTALLATION: Ground-mount, TerraSmart TerraFarm racking system, 180° azimuth, 30° tilt

SOURCE CIRCUIT COMBINERS: 37 SMA America Connection Unit CU1000-US-10; First Solar four-string fused harnesses combine eight source circuits on each array table into two sets of PV output circuits; each four-string PV output circuit is landed on a 20 A fused input in an SMA Connection Unit

SYSTEM MONITORING: Accuenergy AcuPanel 9100 Series revenue grade meter, AlsoEnergy performance monitoring and portfolio management

Primary Category: 

Mustang Solar is a 3 MWdc solar project developed, designed and constructed by groSolar for the Oklahoma Gas & Electric (OG&E) utility. groSolar is a large commercial- and utility-scale solar development, engineering, procurement and construction firm with more than 15 years of experience. Since inception, the company has built more than 2,000 solar projects for a wide variety of customers, including government, commercial, industrial and utility entities.

Mustang Solar comprises two sites (Mustang South and Mustang North) and deploys both tracked and fixed arrays. groSolar engineers utilized NEXTracker distributed tracking technology on the North site to achieve the project’s desired electrical production on a small parcel of undeveloped land adjacent to OG&E’s Mustang Station, an existing natural gas–fueled power plant. The designers created the Mustang Solar project as a test bed of solar technology for OG&E, while it also provides significant power to the utility’s customers—the project generates enough electricity to power approximately 500 homes.

The Mustang North array has 144 rows of self-powered single-axis trackers with 54 PV modules per tracker. Each tracker has a rotational range of ±60 degrees. Two central controllers communicate with all rows and four weather stations via mesh network, which allows the utility SCADA system to monitor and control the trackers. groSolar included training for OG&E personnel on this first OG&E-owned and -operated single-axis tracker PV project.

The groSolar engineering and construction teams carefully managed the project schedule and partner collaboration to deliver this successful project to OG&E. The energization of the Mustang Solar PV plant represents one of the most significant solar developments in Oklahoma to date and is part of OG&E’s continued commitment to being an affordable, reliable, safe and environmentally responsible energy provider.

“groSolar is proud to be a part of bringing solar to Oklahoma with our partners at Oklahoma Gas & Electric. We’ve built projects all over the nation, and Oklahoma stands out as a state with some of the best solar resources we’ve seen. It has enormous solar generation potential.”

—Jamie Resor, CEO, groSolar 



ENERGIZATION DATE: May 2015 (Mustang South), August 2015 (Mustang North)

INSTALLATION TIME FRAME: 68 days (Mustang South), 116 days (Mustang North)

LOCATION: West Oklahoma City, OK, 35.5°N, 97.7°W

SOLAR RESOURCE: 5.4 kWh/m2/day

ASHRAE DESIGN TEMPS: 96.8°F 2% average high, 6.8°F extreme minimum



Equipment Specifications

MODULES, MUSTANG SOUTH: 2,091 Trina Solar TSM-PD14, 310 W STC, +3/-0%, 37 Vmp, 8.38 Imp, 45.5 Voc, 8.85 Isc

INVERTERS, MUSTANG SOUTH: 18 Yaskawa–Solectria Solar PVI 28TL, 28 kW, 1,000 Vdc maximum input, 500–800 Vdc MPPT range, 3-phase 480 Vac output; inverter outputs collected in 480 Vac panelboards and switchboards; collected output stepped up to 12.47/7.2 kV and connected to an OG&E distribution feeder

ARRAY, MUSTANG SOUTH: 17 modules per source circuit (5,270 W, 629 Vmp, 8.38 Imp, 773.5 Voc, 8.85 Isc), six or seven source circuits per inverter, 648 kW array total

ARRAY INSTALLATION, MUSTANG SOUTH: Fixed ground-mount, Solar FlexRack racking, 195° azimuth, 25° tilt, tables spaced for 10am–2pm winter solstice solar window

MODULES, MUSTANG NORTH: 7,776 Trina Solar TSM-PD14, 305 W STC, +3/-0%, 36.6 Vmp, 8.33 Imp, 45.45 Voc, 8.81 Isc

INVERTERS, MUSTANG NORTH: 72 Yaskawa–Solectria Solar PVI 28TL, 28 kW, 1,000 Vdc maximum input, 500–800 Vdc MPPT range, 3-phase 480 Vac output; inverter outputs collected in 480 Vac panelboards and switchboards; collected output stepped up to 12.47/7.2 kV and connected to an OG&E distribution feeder

ARRAY, MUSTANG NORTH: 18 modules per source circuit (5,490 W, 658.8 Vmp, 8.33 Imp, 818.1 Voc, 8.81 Isc), three source circuits per tracker (16.47 kW, 658.8 Vmp, 24.99 Imp, 818.1 Voc, 26.43 Isc), six source circuits per inverter (32.94 kW, 658.8 Vmp, 49.98 Imp, 818.1 Voc, 52.86 Isc), 2,372 kW array total

ARRAY INSTALLATION, MUSTANG NORTH: Tracked array, 144 NEXTracker SPT horizontal axis trackers, ±60° tracking rotation range

SYSTEM MONITORING: AlsoEnergy DAS systems provide performance monitoring and manage remote monitoring and control via an OG&E SCADA system


Subscribe to Project Profiles