Page 18 - North American Clean Energy May June 2018 Issue

solar power
Cost-E ective PV in Northern Climates
Getting it done right from the start
by David Pichard, Rob Souliere and Eugene Koval
New benefits and installation certification
Fronius is expanding its Fronius Solutions Provider (FSP) program, a network of solar installers who are certi ed and trained directly from the manufacturer. Formerly known as Fronius Service Providers, the renamed loyalty and training program o ers solar installers the ability to provide
quality service to their customers in both installation and service. e Fronius Solutions Provider trainings now
also include design and installation aspects of Fronius solutions in the residential and commercial segment. With this quali cation, FSPs are able to provide their customers with high-quality solar solutions and can support them seamlessly over the lifetime of a system. e unique
O&M solution of the FSP program eliminates the need for inverter exchanges, which typically causes wait times for the new unit and potential re-wiring and re-inspection. Quali ed installers can service inverters directly on site, with only one truck-roll, guaranteeing maximum system uptime as well as satis ed system owners. In addition to providing better solutions to their customers, FSP certi ed installers receive a multitude of bene ts, including higher reimbursements for warranty work, a direct phone line to Fronius technicians, regular visits from the Fronius team, continuing education, and opportunities for beta testing of upcoming products. Fronius also supports FSPs with joint marketing activities and sales trainings.
Fronius USA LLC | www.fronius.com
Fully integrated mounting and racking solution
Quick Mount PV introduces the QRail rooftop racking system, a comprehensive, cost-e ective single-source solution for solar installation on all roof types. Combined with the company’s waterproof mounts, Quick Mount
PV now o ers a complete, fully integrated racking and mounting solution for installing solar PV modules on any roof. QRail features patented QClick and QSplice technologies to streamline the installation process. Mid- and end-clamps with QClick technology simply snap into place and remain in an upright position, ready to accept the module. QRail’s QSplice is a tool free, bonded structural splice that installs in seconds with no tools
or extra hardware required. External splices are also available. QRail is designed and engineered for strength and versatility. e aluminum rails come in three sizes, Heavy, Standard and Light and are available in 168” and 208” lengths, in mill and black nishes. e QRail Series
is compatible with virtually all PV modules and L-foot attachments. Modules can be mounted in portrait or landscape, in either standard or shared rail con gurations. QRail also comes with QDesign, a free online design tool to enable quick and easy design of solar arrays,
as well as produce detailed bills of material and all necessary engineering reports.
Quick Mount PV | www.quickmountpv.com
What works in the desert won’t last on the northern prairie. As utility-scale PV grows beyond its traditional sun-soaked environments, developers and EPCs have faced a steep learning curve. Experience gained in the desert doesn’t necessarily translate into designing for the geotechnical and environmental challenges of northern frost, snow loads, and strong winds. What is accepted as cost-e ective in traditional settings, can prove disastrous under extreme conditions.
2.7MW Project in Lake Waconia
This fixed-tilt system in Minnesota was constructed during winter 2017. Winter construction poses many challenges, including poor irradiance, cold temperatures, snow load on the modules, low PV production, and impaired road access to the site. Ideally, all civil work should be concluded before the seasonal ground freeze.
Fixed Tilt System in Snow
This photo is typical for Canadian snow accumulation. Leading edge ground clearance for fixed tilt and tracking systems in the north must take snow accumulation into account.Typically, minimum required clearances are one meter, but that is not always sufficient for heavier snow loads.
per hour works well). Trackers also need to hold up against heavy snow loads - 50 psf is ideal.
Push back against any suggested use of I-beam or C-channel foundations in place of helical piles. While cheaper than deep-set helical piles, these foundations have a history of failing in northern soils.
The right execution
EPCs who know the region can work through the winter without compromising quality. For example, the north’s construction season usually coincides with the rainy season, making trenching tough, expensive, and harmful to the environment, if not planned well. Ideally, trenches should be dug up and back- lled during dry, storm-free periods. During the spring thaw, special attention must be paid to sediment and erosion control measures.
Don’t overlook the working environment. In one case, the construction trailers used throughout a cold winter had no source of heat; with no way to warm up, on-site crews ended up making mistakes they likely wouldn’t have in better working conditions.
Local building codes in emerging markets, where standards are still being developed, are frequently older, and ill equipped to accommodate solar. In the case of one 10-megawatt solar farm, the original pile contract was $1.6 million for materials and installation, with a six-to-eight-week installation schedule. To save money, however, the contractor put pilings in only to the minimum required depth. By the time spring rolled around, frost heave had displaced nearly every piling. Remediation costs climbed to nearly $8 million -- more than four times the cost of the original contract -- and stalled the facility’s operational date for six months.
Seek out an EPC who schedules time for documentation, training, O&M preparation and QA/ QC processes, long before the nish line is in sight.
The right partner
An EPC partner familiar with the region, particularly in newer markets like those in the Midwest, Northeast, or Canada, can o er designs and products suited
to snow, wind, uctuating temperatures, and uncertain topology. ese regions may not yet have solar-speci c building codes, leaving data open to interpretation. Don’t look for the lowest short-term costs. Instead, do careful total cost analysis from start to nish. Experienced partners know that a project’s true cost requires factoring in the lowest mean time between failure, and avoiding remediation costs for issues that should be addressed during installation.
Trench, MN
This open trench in Canada flooded during heavy rains and required 24 straight hours of pumping before the cables lying next to it could be placed. Flooding like this is common during spring and autumn, particularly during thaws.
Choosing the most bankable partner helps establish the best possible backbone to support a plant’s 20-year lifespan. EPCs with an integrated PV solution, combining proprietary products with a turn-key installation package, can o er substantial advantages over a piecemeal approach.
David Pichard is Vice President and COO, Rob Souliere is Director of the Product Division, and Eugene Koval if Director of Engineering – EPC Division at GP JOULE. GP JOULE is a global renewable energy company with an extensive
track record developing, engineering, constructing, operating, and nancing commercial and utility-scale photovoltaic ground mount installations. GP JOULE provides a full range of PV products and services with complete in-house and local execution that includes civil, mechanical, and electrical expertise. Globally, GP JOULE has installed over 500 MWs of PV projects and manages 600 MWs of assets across Germany, France, Italy, Canada, and the United States.
GP JOULE | www.gp-joule.com
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The right engineering
Making the numbers work is one thing, but making sure you’re using the right numbers is something else entirely. Use the standard engineering
ASCE 7 guidelines, but research local standards carefully. In areas where PV development is new, engineers need to consider regional building codes for other types of projects, to help them learn about local snow loads, wind shear, and frost heave potential.
Foundation designs in particular must take geotechnical forces into account. When water freezes and expands in subsurface soils, it can create ice lenses that shift and push upward, carrying solar rack foundations along with them. Unfortunately, the rate of this frost heave is dynamic and can occur at over
an inch per day, depending on local conditions, including the soil’s moisture depths. Heaving foundations can ex structures, crack modules, and cause catastrophic damage to conductors and grounding.
Check what historical records show for the depth of subsurface frost. Designs that stipulate a range of three to nine feet, for example, are not speci c enough to counter frost heave. Pile lengths must be long enough to meet the deepest frost numbers. How much snow accumulates in the region? Di erent foundations and designs can accommodate varying weights. What are the region’s maximum wind speeds? Mounting designs can handle the stresses if local data are taken into account.
Key design features and decisions should include:
• Install as much pile material as necessary (size, depth) after running a proper
pre-production test program. Reduce frost heave risk by installing accurately engineered helical piles, which minimizes the true cost per kWh produced, without compromising on the ground anchoring of the PV system and increasing maintenance costs. Driven piles aren’t suited to areas with deep subsurface frost.
• Reduce mechanical connections. Avoid systems that require lubrication, and use bearings, which can fail during the natural expansion and contraction cycles in areas with extreme temperature ranges.
• Select enclosures, cabling, conduits, wire management etc. adequately rated for a wide range of temperature variance and exposure to harsh conditions - which most people do. But also ensure the installation and placement of BOS fully takes advantage of the higher spec products: installed right with easy access, wherever preventative or curative maintenance is needed.
• Limit cut-and- ll operations to preserve existing grades. Precipitation and wide temperature swings destabilize disturbed soil more readily than untouched ground. Look for state-of-the-art top of pile engineering, combined with advanced racking, that adapts to challenging topography.
The right products
Resist the temptation to go with the least costly options; seek out quality components that have withstood a range of third-party testing and certi cation processes. Choose parts
built to tolerate the maximum stresses recorded in the region. Wind tunnel checks, accelerated life-cycle testing, and cyclic corrosion studies show proof of quality.
Temperature range studies are a vital tool. Inverters, cabling, and mounts should show both lab-based and in-situ performance measures. Panel stringing components and designs should take both snow load and temperature extremes into consideration.
Select racking structures or trackers with the right corrosion resistance,
from galvanizing applied to the steel components. For single axis trackers, speci cations should include how well the system holds up in sustained winds in any operating position (ideally over 40 kilometers per hour) and in stow position (a base design rate over 140 kilometers
• LowProfile Construction
• LargeO set Adjustment
• Unique Cutting Swing Arm Prevents Damage
• HeavyDuty
CAL-AG ENTERPRISES
2020 S. Golden State #106, Fowler CA 93625 Cell: 559-779-8703
Email: [email protected] Contact: Jose Sanchez
SUPERB HORTICULTURE
2811 Michigan Rd, Plymouth IN 46563 Phone: 800-567-8264
Email: [email protected] Contact: Keith Norman
34 MAY•JUNE2018 /// www.nacleanenergy.com
North American Clean Energy 35