APA Racking explains the value of turnkey providers for solar project managers

APA Ground screw

The following post is from APA Racking’s Solar Solutions blog series.

As timelines get delayed and projects overlap each other, project managers can quickly get overloaded by juggling multiple projects at once. Hiring more skilled project managers isn’t as easy as it seems with this skill set in high demand and a severe shortage of qualified individuals. Even with the best project control systems in place and utilizing dashboards, key performance indicators, and critical callout’s, the sheer time it takes to manage such systems can be daunting.

APA has seen more and more companies move toward a turnkey solution. By bringing the manufacturing and installation process under one roof, project managers can breathe a little easier. The turnkey delivery consolidates multiple contracts into a single point of accountability. The result should be certainty of schedule and cost, reduced contract execution time, minimizing change orders, faster decisions, and the ability to communicate with one individual for all things project related. About 80% of APA’s projects are turnkey, and even with material only sales, a project manager is assigned to every project to ensure a smooth process.

RELATED: When augers, ground screws make economic sense for solar contractors

APA is first and foremost a racking manufacturer, but has evolved into a full mechanical turnkey installation partner with many customers. APA works with the customer in the actual design of the project and can mitigate any construction related problems before breaking ground. Changes on paper are certainly easier and more cost-effective than after the installation has begun.

APA’s years as an installation partner provides insight that designers may not have. Issues such as working around underground utilities, topography adjustments, and variations in soil types can be addressed swiftly and creatively. Many times, APA can recommend using multiple foundations on a site to accommodate various soil types and manage costs.

For example, a proposal may include a helical foundation for 60% of the site and a ground screw for the remaining 40% due to areas with rock. The cost savings can be significant versus a 100% ground screw solution.

For the project manager, a mechanical turnkey solution means managing less subcontracts and more time for critical decisions at the highest level without being inundated with minute details. Real time project updates are sent daily and represent the entire project scope with design, manufacturing and installation.

— Solar Builder magazine

Allied Solar Products to distribute CertainTeed’s Solstice Solar System

Solstice System Hi Res

Allied Solar Products, a Beacon Roofing Supply company and one of the nation’s largest distributors of photovoltaic panels, inverters, mounting hardware and solar accessories—has partnered with CertainTeed to expand the distribution of its Solstice Solar System.

Dave Jenkins, national vice president of solar for Allied Solar Products, noted his parent company’s long-standing relationship with CertainTeed’s building products divisions and said extending the relationship to its solar division “builds on our roofing and solar opportunities” and is “a win for both companies and their contractor customers.

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“Allied Solar always looks for ways to improve its supply chains so we can deliver popular products to as many customers as possible as quickly as possible,” said Jenkins. “The move allows us to leverage our logistics, just-in-time delivery, and dedicated solar sales teams to deliver Solstice. With one of the best warranties in the industry, this solution translates into value and peace of mind for installers and their customers.”

CertainTeed’s Solstice system combines high-quality components including modules, inverters, mounting and flashing with a single-source warranty. In addition, when installed by one of CertainTeed’s Credentialed or Master Solar Installers, CertainTeed warrants the installation workmanship on the system for up to 25 years. Considered CertainTeed’s most economical solar solution, Solstice systems are designed to maximize roof space and can be configured to best suit the needs of the client.

— Solar Builder magazine

Market Driver: When augers, ground screws make economic sense for solar contractors

 

auger-ground-screw

The use of augers and ground screws has been of interest in mounting solar systems for some time, and for the right size job, they offer smaller solar contractors an opportunity to grow their business.

Small site factors

For one, with smaller PV systems, one may not need to spend money on a soil engineering analysis and the cost to permit the design separately. The typical soil type in an area may be known from experience. Perhaps local experience with other construction such as a home foundation or a water line installation can provide clues to the soil type.

A method used by some contractors is to use a hammer drill and ground rod available from an electric supply store and see how easily the rod can be driven into the earth. If the rod hits solid rock 6 inches below the surface, or if the rod is very hard to drive, this could either disqualify the use of ground driven foundations, or in some cases lead to using ground screws rather than augers.

Additionally, many counties and states have published maps showing the soil types for many locations. Other sources of data are well sites where there is often a record by the foot of the surface to depths much greater than one would drive a ground-mount.

Selecting a ground-mount

Once a determination has been made as to the type of soil at a site, the installer should select a ground mount to use at a site. If the soil type is not heavily compacted and not rocky, one can consider the use of augers. Most typically, a ground auger driven 7 to 10 ft. will suffice for most 3- and 4-row landscape arrays.

If the ground is compacted, made up of heavy clay, or has small rocks within the first 10 ft., then a ground screw would probably be a better choice. Ground screws offer lower torque when driving them into the soil and are less likely to break in harder ground. However, in soft, loamy soils a ground screw will not provide big pullout values compared to an auger.

If the ground is too rocky, other options such as post and concrete, ballasted arrays, or rock anchors may be a better alternative. Experience with ground arrays will greatly help in the selection of a ground mounting system.

Driving ground mounts

Some form of tractor or track machine is required to drive ground-driven foundations. These machines are easy to rent and use, and depending on the volume you are doing, worth owning. Small arrays with only 8 or 12 posts are probably not worth the investment, but between that and larger arrays that require a specialized company to drive the mounts, there is a sweet spot that makes financial sense.

The machine used will need some form of rotary head such as the small Bobcats used to dig holes for pole buildings and fence posts. Alternately, some farm tractors have a rear-mounted rotary

driver used for fence posts that may be used.
Most equipment rental yards can supply a small track machine normally used with a hole-digging auger. With the hole-digging auger removed, an adaptor can be used to mate the drive head to fit augers and ground screws. A 2 in. hex adaptor that fits the machine can be purchased by the installer if not available from the equipment rental yard with the machine.

The amount of torque required to drive a ground mount should not be more than a nominal 3,000 lbs. If more torque is required, or if the mounts are breaking, than the wrong mount was selected. If augers break, a ground screw should have been used. If ground screws break, then a non-driven mount should be used.

If occasionally a mount breaks due to an undetected boulder or other issue, a traditional post and concrete mounting should be used. In the case of Groundwater, a 50-kW project in Portland, Ore., where over 400 augers were used, eight anchors broke due to large sporadic rocks and were replaced with eight concrete-mounted posts.

Calculations and measurements

There are many resources available covering the use and calculations for commercial construction using augers and ground screws. These include Chance Hubble manuals, and other commercial suppliers of augers. However, there are some general guidelines one can follow summarized below.

Augers have a pitch determined by the blade angle. Our auger is a 10-to-1 auger. Using a 10-to-1 auger, each ft lb of torque driving the auger provides approximately 10 times the uplift capability when driven to 10 ft of depth. For example, if an auger is driven with 500 lbs of torque to 10 ft. the pullout will be approximately 5,000 pounds. Typically, augers are driven much harder, resulting in tested pullup values of 20,000 to 30,000 lbs. Most often, augers driven in reasonable soil values will dramatically exceed the pullout values actually required to resist pullout or overturn of the array.

In the case of ground screws, they are typically applied to more dense soils and solids with rock intermixed. A ground screw should not be used in solid rock.
Ground screws in hard soils have pullout values of 1,500 to 5,000 lbs at a depth of 5 ft., however this estimate is entirely based upon the soil density. The use of ground screws in soft soils will not provide a satisfactory base for a solar array.

The use of a torque measurement gauge is recommended as an additional check on the drive torque and resulting pullout capability. Some modern machines one can rent or buy have a built-in torque gauge. Additionally, there are devices that can mount between the hydraulic head and the ground mount to measure the torque. However, a careful operator will have some sense of the amount of effort required to drive the ground mounts, and in most cases can successfully install and drive ground arrays without a torque head.

Cliff Schrock is an engineering consultant with SunModo.

 


On the Scene

Ready to rack

AP Alternatives’ Ready Rack mounting hardware is designed for both large utility-scale projects and small commercial projects. The small helical anchors and quick-install cross bracing make the simple system robust even for high wind zones. The mini-tilt brackets are adjustable and allow for quick field alignment of the post height. This allows the anchor posts to be installed rapidly and any terrain variation can be accounted for by simply adjusting the tilt bracket up or down to achieve the best aesthetics on an ungraded site. This system is nimbly installed with an attachment that fits on a skid steer.

— Solar Builder magazine

Watch: SnapNrack debuts Ultra Rail System at Solar Power International

SnapNrack debuted its new Ultra Rail System at Solar Power International this year, a lightweight rail solution for mounting solar modules on the roof. Ultra Rail, a lighter rail profile, is a more economical solution for projects in more average load conditions, especially when attachment spacing is already dictated by the existing roof structure and more mounts are needed to disperse the weight of the system.

SnapNrack believes when compared to a railless system, Ultra Rail is a more cost effective solution for customers installing on a mix of roof surfaces rather than one roof type for every install. The entire system is a snap to install utilizing new Ultra Rail Mounts that include snap-in brackets for attaching rail. The spring-loaded roof mounts provide superb full rail leveling capabilities and all components come pre-assembled for a unique install experience and easy tightening.

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SnapNrack’s wire management solutions are still compatible with the Ultra Rail System which features a large top rail channel providing ample room for wires and cables. Furthermore, the system is compatible with all existing module clamps and maintains the same intuitive install experience.

— Solar Builder magazine

Largest landfill solar project in Maryland completed by EDF Renewables, Solar FlexRack

solar flexrack landfill maryland

Led by national engineering, procurement and construction firm EDF Renewables Distributed Solutions, this 18.1 MW dc facility, known as the Annapolis Renewable Energy Park, is located in Anne Arundel County, Maryland and is the largest solar project on a closed landfill in the state. The project is owned by a subsidiary of Building Energy, was developed by BQ Energy, a company specializing in landfill and brownfield renewable energy projects, and used Solar FlexRack racking to complete the job.

The Annapolis Renewable Energy Park is remarkable for its size and complexity. The enormous facility spans 80 acres and was completed in mid-2018. The solar energy park will generate enough clean energy to power more than 12 percent of the city’s homes annually. In addition to gaining the reassurance of fixed, lower-cost clean energy for its clients and partners, the city is estimated to receive more than $250,000 annually by leasing the property to Building Energy.

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Building a renewable energy project on top of a capped landfill is an intricate project, and the expertise of racking provider Solar FlexRack proved invaluable for EDF Renewables. Unable to drill piles into the landfill’s protective membrane cap, Solar FlexRack utilized B3P-X pre-cast fixed tilt racking foundations for the more than 54,000 solar panels.

“Solar FlexRack’s expertise in this important niche market makes the company a perfect partner for landfill projects,” said Jamie Resor, CEO, EDF Renewables Distributed Solutions. “We are pleased to work with a firm that can provide the precise, high-quality product required to execute our vision for the Annapolis Renewable Energy Park.”

“EDF Renewables’ deep experience and technical capabilities make them an extraordinary leader in the field,” continued Steve Daniel, Executive Vice President of Solar FlexRack. “It was a pleasure to collaborate with them on the park, and we look forward to the next partnership opportunity.”

Solar FlexRack offers ballasted solar racking solutions for sites challenged with penetration, weight and other regulatory restrictions. The selection and quality of their products provide a wider choice for solar project engineers to design optimal performance into their solar systems.

— Solar Builder magazine