Part 1: Site Grading and Design Optimization
By Samuel Laughlin and Bill Reaugh
When developers consider a piece of land for a large-scale ground-mounted PV power generation asset, the costs for grading and earthwork can be significant drivers of project viability. The project developer’s or owner’s goals determine in part when, where and how much to grade. These decisions must also fit the requirements of the site with respect to AHJ controls and the mechanical limitations of the equipment the developer may use.
The best approach to this puzzle is one that integrates a holistic view for these requirements across multiple engineering disciplines, including civil, structural, electrical, mechanical and geotechnical, and water resources. A few of the first questions to ask are: How does the topography behave? Is the proposed equipment capable of dealing with the site in its current state or are modifications required? If the requisite site modifications are significant, are there other solutions that align better with the project’s financial goals?
To Grade or Not to Grade
Grading typically includes two major activities: cutting, the process of removing quantities of soil, and filling, the process of building up quantities of soil. Ideally, the amount of soil imported to or exported from the site is near zero to reduce both costs and environmental impacts.
The needs and conditions of the land underlying the solar array structure make each project unique. Depending on site conditions and construction requirements, a piece of land may need no preparation, minor surface clearing and grubbing of subsurface plant roots, smooth grading or full grading. Generally speaking, developers perform grading because the site requires it or because doing so will support plant optimization.
In certain circumstances grading is unavoidable. The most common reasons for grading are to meet AHJ requirements or best practices for access roads or storm water management. Grading may also be required to conform to vendor-specified mechanical tolerances for the mounting system.
On-site access roads. AHJs and industry best practices dictate minimum and maximum slopes for access roads, as well as compaction and surface maintenance requirements. Grading is required where the existing topography does not meet these longitudinal or cross-slope requirements. While the local fire department typically has the final say on access roads, the local building department or the site owner may also have applicable requirements.
Storm water management. Site-specific hydrologic characteristics are a critical factor in determining grading requirements and plant design. If a site lies in a flood zone, for example, the flood depth determines the minimum height for electrical equipment. Storm-induced runoff and scour affect minimum pile embedment depths. The contributing watersheds and historical water flows may dictate detention basins or improvements to the existing storm water channels. Local environmental agencies may have requirements related to dust or water quality that impact these grading activities.
Mechanical tolerances. In general, fixed-tilt mounting systems are more capable of dealing with topographical changes across a site than are single-axis trackers. However, many large-scale ground-mounted systems use trackers to maximize energy production from the available land area. Trackers have a maximum slope (% grade) associated with the north-south axis of the torque tube and, if applicable, the east-west elevation of the driveline. Should existing slopes fail to accommodate the maximum slopes of the torque tubes or drivelines, grading is one possible solution.
While tracker equipment manufacturers specify maximum slope values, installation guidelines or product datasheets do not always provide these design criteria. Instead, some manufacturers provide a grading requirements document or similar reference upon request that details civil engineering needs for sites. This document provides information about mechanical tolerances to help engineers determine project-specific design criteria, including maximum slopes and maximum and minimum pile elevations above grade.
GRADING FOR OPTIMIZATION
Site preparation impacts solar power plant optimization in a variety of ways. For instance, minimizing the amount of steel in the foundation or the time required to wash the modules can offer potential benefits. Maximizing the ground-cover ratio (MW/acre) or specific energy yield (MWh/MW) can also yield benefits. Rather than focus on a single variable, a well-integrated engineering effort develops the best result holistically by evaluating all these variables in concert with the goal of achieving the lowest levelized cost of energy.
Steel piles. A combination of subsurface soil conditions, torque tube height requirements, tracker reaction forces on the pile and terrain variation determines the amount of steel required for driven pile foundations. The higher the torque tube height, the more steel the project requires. The larger the terrain variation from one end of a tracker row to the other, the more steel the project requires. Strategic grading has the potential to compensate for both of these conditions. For example, grading to channel water across the site can reduce flood depths and equipment height, whereas smooth grading can compact soils or minimize terrain variations.
When optimizing a pile foundation plan, the design team generally seeks to minimize the total amount of steel the client must purchase or to optimize logistics by minimizing the total number of pile types and lengths. The former activity reduces the material cost for the steel, while the latter reduces the cost to transport and distribute piles across the site.
Soil volume. Another optimization variable for the design team to consider is the volume of soil that heavy equipment will need to move around the site. On one hand, reducing the required amount of earthwork has the advantage of speeding up the site preparation time, which allows the contractor to start installing equipment sooner. It is also beneficial to reduce site disturbance in areas that have the potential for below-grade archaeological or paleontological resources. On the other hand, minimizing earthworks could limit the area of land available for modules and other electrical equipment or increase the total amount of steel required. If the design must space rows further apart to account for terrain features, that restriction reduces ground-cover ratios.
Operations and maintenance. Site designers should also consider the amount and type of O&M activities required to keep a solar project operating optimally. For example, it may be beneficial to use a ground-cover ratio that allows maintenance personnel to wash two rows of modules at the same time. In addition, locating serviceable equipment—especially combiner boxes, inverters and transformers—close to maintenance roads makes O&M activities more efficient.
Available area. The design team also can employ multiple site or soil preparation variables to maximize the available land area for PV modules. These include placing detention basins under PV array fields, strategically routing storm water, developing flood-control channels, leveling hills and filling valleys, and so forth. Whereas locating detention basins below tracker arrays tends to increase the torque tube height and the required amount of foundation steel, smooth site grading generally allows the use of shorter piles. Further, more-extensive earthwork and site preparation activities lead to higher levels of pre- and post-construction monitoring for environmental quality impacts.
Specific yield. The goal of optimization exercises is to maximize the energy harvest per unit of installed power. For instance, the design team might adjust the ground-cover ratio or increase site slopes to increase the amount of incident sunlight. The potential downside is that more-extensive site preparation activities tend to increase grading costs.
Part 2: Ground Mounts on Landfills
By Bryan Morrison
Over the past 20 years, towns, municipalities and other entities have closed and capped nearly 6,000 landfills. Since the land at the majority of these sites is contaminated or contains remediated soils, they are not suitable for typical residential or commercial uses. However, these capped landfills can still provide value for municipalities as host sites for ground-mounted PV power plants.
A capped landfill typically becomes an expense for the community, requiring annual maintenance and continual monitoring. By leasing the land for PV project development, municipalities can recover maintenance and monitoring costs as well as generate revenue. Project developers also benefit because these tracts of land are often offered at exceptionally low lease rates compared to land suitable for commercial development.
To capitalize on the low cost of land, however, project developers need to address some unusual design challenges and unique risks associated with deploying a ground-mounted PV power plant over a landfill cap.
GROUND MOUNTS ON LANDFILLS
The first thing that project developers must consider is the construction of the landfill itself.
Landfill cap. Several different types of landfill cap designs appear in the US. Modern-day landfills commonly feature a Standard Subtitle D Cover cap design, as shown in Figure 1. This type of cap uses either a high-density polyethylene (HDPE) or a linear low-density polyethylene (LLDPE) geomembrane liner in concert with several layers of sand, soil and vegetation. A 12- to 18-inch drainage layer and a 6-inch soil layer are commonly found above the liner. The thickness of these layers determines the allowable bearing pressure on the liner.
A Standard Subtitle D Cover landfill cap provides allowable temporary bearing pressures (for vehicular traffic) of up to 7 pounds per square inch (psi) and permanent bearing pressures of up to 5 psi. Allowable bearing pressures dictate foundation designs for mounting systems and other equipment, as well as access road designs for plant construction and maintenance. Bearing pressure also determines what types of vehicles can safely operate on top of the landfill. Since a damaged or punctured membrane would be costly to repair and would cause significant project delays, bearing pressure is an extremely important design consideration.
Storm water management. Landfills are designed to maximize municipal solid waste storage capacity and therefore result in large dome-shaped plateaus with steep side slopes. Given these terrain features and the minimal amount of cover material, storm water runoff is another critical PV system design consideration. Landfills rely heavily on both vegetation and drainage swales to manage storm water and prevent erosion. It can be extremely costly and time consuming to modify these existing storm water management features to accommodate a PV system.
Gas vents. PV system designers also need to consider landfill maintenance features such as gas vents, settlement plates and monitoring wells. It is especially important for installers to pay attention to gas vent locations. Since a large percentage of the gas emitted from a landfill is either methane or carbon dioxide, workers in the proximity of a passive vent risk exposure to flammable gas or a zero-oxygen environment. Landfill gas can also contain ammonia and hydrogen sulfide, both of which can cause a variety of respiratory issues. Since landfill vents often emit odorless gasses, workers need to rope off vent pipes in close proximity to the PV array to ensure that no one accidentally gets too close to these vents. To prevent gas from migrating into enclosures, workers should locate electrical equipment away from landfill vents. Smoking is prohibited when working on a landfill.
Vegetation control. Mowing is the most common form of routine landfill maintenance. If certain species of trees, shrubs or brush are allowed to grow on the landfill, their root systems will eventually penetrate the geomembrane liner. Regular mowing prevents this from happening. When preparing a PV array layout for a landfill, designers need to understand and consider how maintenance personnel mow the site and ensure that all sections of the landfill remain accessible to the mowing equipment.
Fencing. Many existing landfills are already fenced, and some of these fences require only minor modifications to comply with National Electrical Code requirements. Unfenced landfills can present significant design and budgetary challenges. The landfill membrane often extends for many acres beyond the usable array area. Fencing this long perimeter is a costly and time-consuming proposition. More often than not, project developers need to contend with wetlands located at the perimeter of the landfill that could require additional permits through local conservation committees, extending the project mobilization timeline. If it is not practical to build a conventional fence, system designers can consider adding a ballasted fence at the array boundary, provided they factor the fence location into the array layout.
PV SYSTEM CONSIDERATIONS
After taking landfill design into account, project developers need to adapt their PV system design and installation practices to the site.
Build from the vegetation up. It is a good idea to hire a site contractor who has experience with landfill closures or making landfill repairs. Given the minimal amount of material above the geomembrane liner, the most productive design and construction strategy is to build the PV system up from the vegetation layer. This means that the array foundations, equipment pads, electrical infrastructure and access roads are all installed above grade. The goal of this design approach is to maintain the existing protection of the cap and to preserve the functionality of existing storm water controls.
Prior to commencing construction activities, an authorized agent should inspect the existing landfill conditions to ensure that both the gas vents and storm water controls are intact and that no depressions due to settlement exist. The developer needs to remedy any depressions under the supervision of the AHJ prior to construction. During construction, crews need to immediately remediate any ruts or divots caused by construction traffic and weather events. The contractor can alternate construction activities among different areas or project phases to allow the protective layers of the landfill to dry out between weather events or while the crew is repairing them in an effort to minimize project delay.
Road layout. The first step in the design process is to determine the proper location of the construction road. Placing the access road along the spine (the highest points) of the landfill reduces or minimizes impacts to existing storm water controls. If space and landfill topography permits, it is ideal to have a road entering one side of a landfill and exiting the other, as this is beneficial for project logistics and project velocity. At a minimum, PV designers need to provide a sufficient number of turnarounds to accommodate construction traffic and material delivery.
Array layout. Designers determine the usable array area flanking the access road based on the slope of the terrain and the mechanical tolerance of the mounting system. Since ballasted mounting systems are susceptible to sliding forces and constrained by the allowable bearing pressure on the landfill cap, these systems are commonly limited to a 5°–7° slope. Once designers have identified existing landfill features and areas with acceptable slopes, they can begin to lay out the array, keeping in mind maintenance activities and cap protection.
Mounting system selection. Developers also must consider differential settlement when designing this type of system. As the landfill decomposes, the surface naturally settles differentially due to the varying types of material decomposing below. Landfills will settle 10–20 feet over their lifetime, and settlement of 1 foot per year in the first years of closure is common.
To tolerate this settlement, designers should use a statically determinate mounting structure that they can analyze using static equations of equilibrium to determine reaction forces. A structural design with two foundations per array table that allows for future in-field adjustment is generally best for withstanding settlement over the life of a system. By comparison, a structural design with three or more foundations may be subject to intolerable stresses that result in module deflection and possible destruction.
Cable tray. Landfill projects have unique electrical infrastructure requirements in two ways: The design needs to account for settlement, and the site has insufficient cover material to allow burial of conduit or cables. Since landfill applications require an above-grade solution, designers typically specify cable tray. Cable tray comes in 10- or 12-foot sections that installers do not have to physically connect to one another, so it can tolerate differential settlement, provided the conductors offer adequate slack.
Each cable tray section generally has four independent height-adjustable feet, allowing for installation on uneven ground. The base area for these feet is often adequate to disperse the weight of the cable tray and conductors, as well as keep the point loads below the maximum allowable bearing pressure. As an added benefit, cable tray remains visible to the landscaping crew even when the grass grows tall between mowings, and physically protects the electrical cables from both mowers and string trimmers.
Electrical equipment pad. As is the case with typical ground-mounted systems, centralizing the location of the inverters offers cost and performance benefits. The optimal location is typically somewhere along the access road near the center of the array. The shoulder of the access road serves as a means of bringing in the medium- or high-voltage circuit to the distribution transformer from the point of common coupling. Since the road is subject to both vehicular traffic and differential settlement, system designers generally call for a reinforced concrete duct bank to protect these circuits.
Concrete equipment pads for landfill applications may have to be quite large, given the extreme weight of the electrical equipment and the relatively low allowable bearing pressure. A typical 1 MW liquid-filled medium-voltage transformer usually weighs more than 1,000 pounds. In many cases, it makes sense to install a single reinforced concrete equipment pad that supports all of the equipment, rather than multiple smaller concrete pads, as the larger pad will save preparation and installation time. Using a single pad also protects the conductors against damage due to differential settlement, since the single pad will move uniformly as a single unit.
System grounding. Opting for a single equipment pad also provides a means for system grounding. Given the shallow depth of the landfill cover material, it is obviously not possible to install an 8- or 10-foot ground rod as a grounding electrode. Instead, a copper ground ring with supplemental copper grounding plates typically offers adequate system grounding. The thickness of the concrete pad, plus the depth of the fill material beneath it, provide the burial depth required for the ground ring.
Part 3: Bonding and Grounding
By Marvin Hamon, PE
To provide a safe PV system, designers and installers need to understand the fundamentals of bonding and grounding. Whereas proper bonding ensures that a ground-mounted PV array is free from stray shock hazards for the life of the system, proper grounding prevents dangerous voltage differentials between the PV array and the ground on which installers or service technicians stand. Since people often confuse these terms and practices, here I define each individually, consider its intent, and review hardware options and installation methods.
Per the definition in Article 100 of the National Electrical Code, equipment is bonded when it is “connected to establish electrical continuity and conductivity.” Employing an equipment-grounding conductor (EGC) is one way to make this low-impedance connection. Another way is to make a mechanical connection by, for instance, bolting two pieces of conductive material together.
Intent. As described in NEC Section 250.4, bonding establishes a low-impedance connection between conductive equipment and materials to conduct fault current safely and minimize potential voltage differences between conductive components. By providing a low-impedance path for line-to-line or line-to-ground faults, the designer ensures that fault currents quickly rise to a level that activates an overcurrent or ground-fault protection device.
Hardware. In the 1990s and early 2000s, installers used thread-forming screws, UL-listed grounding lugs and bare copper EGCs to connect all the conductive parts of a ground-mounted PV system. While straightforward and easy to verify during inspection, this bonding method is also relatively expensive. It requires a lot of lugs and copper, and it is time-consuming to implement in the field. In other words, this approach is not well suited to deploying PV systems at low prices and high volumes.
About a decade ago, companies such as Wiley Electronics (now Burndy) introduced specialized bonding clips for PV applications to address this pain point. These products have sharp or serrated surfaces that bond the exposed metal module frames and other electrical equipment to the metal mounting structure during installation. Though these new bonding products allowed quick and easy installation, some AHJs and industry stakeholders were skeptical that they could effectively replace conventional hardware and copper EGCs. These (often single-use) components also make system inspection challenging since they are invisible once installed.
UL convened a Standards Technical Panel to develop the UL 2703 product safety standard—which covers PV module-mounting systems, clamping devices and ground lugs—in part to address these concerns about effective bonding. Mounting systems listed to this standard include bonding components designed to establish electrical conductivity between PV modules and other electrical equipment connected to metal racks. Further, a Nationally Recognized Testing Laboratory has certified the efficacy of these bonding connections.
EGC sizing. NEC Table 250.122 provides guidance for identifying the minimum allowable EGC size. But, many people fail to read the note that states the following: “Where necessary to comply with 250.4(A)(5) or (B)(4), the equipment-grounding conductor shall be sized larger than given in this table.” In other words, choosing a conductor based on Table 250.122 is no guarantee that the design will provide an effective path for fault currents. However, the NEC offers no further guidance about how to upsize an EGC.
Engineers need to account for a number of variables—incident energy ratings, available fault currents, overcurrent protection device (OCPD) time-current characteristics and so forth—to ensure that a fault will not damage an EGC. Fortunately, the unique electrical characteristics of PV systems work in their favor. For example, the available fault current in a PV array is much less than that from even the smallest utility service; the maximum fault current from a 500 kW PV array might be 1,000 A, whereas a 600 A utility service might easily have an available fault current of 50,000 A or greater. Conductors can carry a high amount of current for a short time without incurring damage. Therefore, Table 250.122 is very conservative for the purposes of PV array design. In most applications, a 10-gauge EGC is more than adequate.
Table 250.122 also provides installers and inspectors with a convenient basis of comparison for UL 2703–listed PV mounting systems, which should be bonded at least as well as those bonded with an EGC. As a quick bonding test, for instance, an installer could take a resistance reading between two points in an array, such as between one row of modules and an adjacent row. Assuming that these module rows are 100 feet long and spaced 10 feet apart, the installer should see a resistance reading equivalent to 210 feet of 10 AWG copper. According to NEC Chapter 9, Table 8, which details conductor properties, a single-strand 10 AWG copper conductor has a resistance of 1.21 mΩ per foot. So if the row-to-row resistance measurement is in the vicinity of 254 mΩ (210 feet x 1.21 mΩ/foot), that suggests the equipment is properly bonded. A significantly higher reading means a poor mechanical connection somewhere in the path probably needs correction.
Maintenance. It is not that difficult to create a good electrical bond in a new mounting system. The challenge is maintaining that connection over time in an outside environment. This is precisely why PV designers need to specify UL-listed equipment and assemblies, as UL product safety standards define test procedures intended to determine how bonded connections will age. While measuring bonding resistance during system commissioning is important, it does not indicate what the resistance will be after 6 months or 10 years in the field. Therefore, O&M providers should review bonding resistance as part of their scheduled maintenance activities.
Per NEC Article 100, equipment is grounded when it is “connected to ground [the earth] or to a conductive body that extends the ground connection.” A grounding electrode establishes the actual connection to ground. A grounding electrode conductor extends the ground connection to the EGC or the conductive equipment.
Intent. Grounding is sometimes referred to as earthing, since it ensures that conductive equipment is at the same electrical potential (voltage) as the earth. Eliminating voltage difference between ground and conductive surfaces such as PV module frames and mounting systems mitigates shock and fire hazards. As long as the aluminum frames and steel racks, for example, are at earth potential, electrical current will not flow to ground through a person who is installing or servicing the array. In this scenario, the source of the voltage difference could be a cross-connection fault with another power system—perhaps an overhead power line falling onto a PV array—or a lightning strike. Proper setup of a ground-mounted array prevents any shock to service personnel because they will never provide the best electrical connection to earth.
In the field. Normally an electrical system is grounded at one point only: the point of supply. This connection to ground might be located at the utility service entrance or on the secondary side of a transformer. The Code also requires a connection to ground on the dc side of transformer-isolated inverters. However, this single-point approach to grounding can cause problems in large-scale ground-mounted PV systems, where the farthest reaches of the PV array may be located a great distance from the grounding electrode system.
While designers can extend the grounding electrode system throughout the PV array with buried electrodes—as is done with substations—this is very expensive. Alternatively, NEC Section 250.54 allows the use of auxiliary grounding electrodes, which do not have to comply with electrode-bonding requirements. The steel foundation members often serve as auxiliary grounding electrodes. Section 250.52 covers electrodes permitted for grounding. Ground-mounted PV array foundations may comply with Subsections 250.52(2) or (3), depending on whether the system uses driven piles or posts embedded in concrete. Designers can increase the overall connection to earth in a ground-mounted PV system by specifying a foundation with one or more posts per array table or row of modules that qualifies as a grounding electrode.
Some in the PV industry feel that auxiliary grounding electrodes can actually make a PV system less safe in areas prone to lightning strikes. When lightning strikes the ground, localized voltage increases in the earth but normally dissipates over time. If there are auxiliary grounding electrodes in the area of increased voltage, however, the voltage rise can cause current flow up one auxiliary grounding electrode through the PV array and out the nearest auxiliary grounding electrode that is at a lower voltage, which could put people or equipment in harm’s way. In a grounding electrode system, the buried bonding jumpers that connect each of the individual grounding electrodes into a single system would carry this current below the surface of the earth.
[Editor’s note: For information on system grounding, which is a design consideration not covered here, see “Grounding Compendium for PV Systems,” SolarPro, April/May 2013.]
Part 4: Scalable Mounting Solutions
By Keith Beisner and Sara Jacobs
The increased rate of solar adoption is opening up new markets to solar providers and ramping up project volumes. Developers, EPC firms and solar providers are seeing an increased number of project opportunities as well as a wider range of project sizes across their portfolios. In addition, the solar industry’s footprint is expanding into all regions of the US, from the remotest rural areas to the tightest urban spaces.
Rapid market expansion means that solar solution providers must streamline their designs across a wide range of environmental conditions. Solar installers have to be prepared to deal with variable surface and subsurface conditions. At the same time, the industry is under great pressure to lower costs. These realities require new solutions. Solar providers and EPC firms require a new generation of efficient, cost-effective solutions that enable them to better react and adapt.
The key to making solar happen in more places while driving costs down lies in having a mounting-system design that is centered upon built-in environmental adaptability, construction flexibility and predictable costs. Developing customized solutions on a site-specific basis is not a scalable strategy. Instead, the industry needs racking systems composed of standard components that installers can assemble in a variety of ways to meet each project’s unique challenges. This mass customization approach will allow the industry to accelerate most rapidly because it is both highly configurable and cost effective.
Foundation design. Installers need different foundation options to avoid costly delays caused by variable soil conditions and unpredictable subsurface obstructions within a project portfolio. To achieve economies of scale, however, it is essential that these foundation options be part of a standardized product solution. Taking the need for foundation flexibility a step further, soil conditions can vary dramatically within a site, meaning even a single project may require a range of optimal foundations. The key is to provide a range of standardized foundation options that developers can easily interchange without having a negative impact on the overall system design or aesthetics.
If project developers discover the need for diverse foundations during the engineering design phase or preconstruction pull tests, mass customization allows designers to optimally specify different foundation types before construction starts. Often, though, EPC firms do not discover these soil variations until installation work is already in progress. When installers must quickly react to problems without a ready-made solution on hand, delays and escalating costs are the norm.
Product designs that allow for swap-in foundation changes can equip installers to make on-the-fly changes during construction without incurring high costs for replacement parts and project delays. For example, if installers hit a refusal while driving a post on-site, they might quickly swap in a cast-in-place ballasted foundation on top of the soil while utilizing the same superstructure. Readily available and interchangeable foundation options can help eliminate expensive in-field modifications.
Mounting structure. When it comes to the racking structure itself, mass-customized solutions provide design flexibility to accommodate project variations, including different modules, terrains, and wind or snow loads. Although 72-cell modules are the de facto standard on ground-mount projects, each module frame has its own distinct set of mounting dimensions. Mounting systems that are adaptable to different modules without component modification eliminate the need for last-minute change orders.
Similarly, standardized products with terrain-following capabilities reduce not only site preparation and installation time, but also PV system cost and complexity. In recent years, the scope of projects has grown to include not only flat, level and prepared sites but also more-challenging sites with undulating slopes or hilly terrain. Mounting systems that installers can deploy without making major site improvements or modifications can reduce preconstruction civil work and improve project economics.
As solar projects expand into regions with higher wind and snow loads, mounting systems must also adapt to these environmental conditions. Standardizing products to accommodate higher loads without the need for custom components simplifies both the design and the supply chain processes. This simplification allows optimal project delivery timelines and improved cost efficiencies.
Soft costs. Beyond material costs, mass customization also shaves project soft costs. Many developers and customers are seeking better-integrated electrical and mechanical designs across their project portfolios. Mounting solutions with standardized table sizes—such as two-high in portrait configuration—make this integration possible. Different foundation configuration options, meanwhile, can accommodate changing environmental factors while keeping other variables, including table size and mechanical and electrical components, consistent across multiple project sites. Standardizing these mechanical and electrical design processes can lower costs and increase engineering efficiency while allowing for easy preparation, installation and O&M.
THE DOMINO EFFECT
A domino effect begins to take place when product design and engineering become more efficient. Solar providers, large and small, can take on more projects in more locations. While these growth factors place a high demand on materials, mass customization also streamlines supply chains. It allows companies to inventory components and reduce lead times. It accommodates short-notice schedule or design changes. This adaptability is critical to companies with aggressive and sometimes simultaneous or competing construction schedules.
Furthermore, the ability to use the same system and components on all sites, regardless of environmental and site conditions, allows installers to implement best practices more consistently and can dramatically improve installation efficiencies. On-site crews learn to quickly troubleshoot unpredictable situations and implement rapid, cost-effective mitigation solutions while also reducing punch lists and mitigation work.
With the combined advantages of mass customization, solar providers gain maximum efficiency and achieve economies of scale across projects of all sizes. Mass customization reduces costs and allows rapid growth in nonresidential markets where ground mounts are typically deployed. The result is more successful solar projects and a faster technology adoption trajectory.
Keith Beisner / SunLink / San Rafael, CA / sunlink.com
Marvin Hamon / Hamon Engineering / Alameda, CA / hamonengineering.com
Sara Jacobs / SunLink / San Rafael, CA / sunlink.com
Samuel Laughlin / Blue Oak Energy / Davis, CA / blueoakenergy.com
Bryan Morrison / Borrego Solar / Lowell, MA / borregosolar.com
Bill Reaugh / Blue Oak Energy / Davis, CA / blueoakenergy.com