Tracking Trackers: We look at what’s new with these seven solar trackers

What are you looking for in a tracker? Longer rows with fewer spans? A two-up bifacial module setup? A simple central drive configuration with reliable bearings? More self-powered options? There are a lot of trackers in the segment, and we wanted to highlight some of the cool, innovative features outside of the market share leaders that reduce costs, ease installation or improve reliability.

Arctech

arctech

Three tracker styles to match every solar site

Arctech offers three tracker designs: The Arctracker Pro is its centralized tracker with push-pull design that is the best for flat land. The SkySmart is a single-row design with two modules in portrait that has fewer posts and is perfect for bifacial modules, and the SkyLine is a single-row design with one module in portrait.
Arctech makes the majority of its products with the support of two enormous factories, with a third on the way in 2019, to better control costs and quality.

Key hardware

  • All of Arctech’s trackers have its new D-shaped torque tube that adds stability and saves material.
  • Single-row trackers are powered from the string rather than from the batteries.
  • A beefy bearing was recently added that can handle a 20 percent N-S slope and stop the translation of weight.

Software

“Most of what we are doing is ensuring interfaces to client’s SCADA systems,” says Guy Rong, president of Arctech Solar. “We have a number of alarms in the rare case something happens to the system. Beyond this we are building software to create more accuracy on a row-by-row basis. We will announce when this is available.”

Case study

A 172-MW project in Telangana, India, had three main challenges that were solved by the design of the Arctracker Pro.

Challenge 1: Rough terrain and uneven slope. Solution: Arctech took advantage of special linkage and different post lengths to offset land contour variations and, at the same time, keep the high density of PV modules in available land and maintain high energy yield. Moreover, tracker sizes were specially designed to make best use of corner areas of land.

Challenge 2: High wind. Solution: Arctech Solar reinforced the tracking system by adding 25 percent more dampers to ensure stability and reliability of general operation and avoid damages caused by strong wind.

Challenge 3: Installation within timeline. Solutions: Installing 172 MW at a single site within the timeline was a challenging task for the EPC. In India, it’s not always easy to find skilled man power in remote areas. To solve these issues, the Arctech engineering team collaborated with the EPC to finalize installation phases well before shipping. Posts were shipped first to make sure the civil work started early while Arctech’s project managers gave tutorials on demo tracker installation so that all teams could start work simultaneously.

Nclave

nclave

Recently acquired by TrinaSolar, this international tracker has beefed up its design

Spain-based Nclave keeps on expanding. Founded 12 years ago by the Clavijo Family, it integrated with MFV in 2017. Nclave has installed over 2.5 GW worldwide. Earlier this year, the company teamed up with Trina Solar, a Chinese supplier of global solutions for the solar sector, to be a part of its TrinaPro utility-scale solution, which eventually led Trina to acquire a controlling interest in Nclave.

Structure

Nclave has developed and patented a module mounting design, the Nclave Clamp, that reduces assembly time of modules by more than 75 percent with as low as 50 manhours per MW. It also lessens the weight of the material by more than 30 percent. It includes UL-compliant integrated grounding features and has been load tested to UL and IEC standards.

Nclave separates the tracker assembly from the module assembly process to ease installation. The registered purlin allows the system to be pre-assembled on the tracker so modules can be installed with only a nut driver. Installers get rid of dedicated hardware for module installation (no more clips, bolts or rivets) as the U-bolt brackets secure module, purlin and clamp all together with just two nuts: a sandwich-like concept.

Software

The Nclave tracker controller is part of smart PV solution TrinaPro. The tracker controller is connected with the inverter in order to boost energy yield production: the optimized matching among components and the “Edge Computing” algorithm integration of TrinaPro can improve system stability with higher power generation.
The controller is empowered with a smart O&M system on a cloud platform that analyzes and processes data to optimize the system’s operation model and ensure the system runs smoothly and efficiently.

Solar FlexRack

solar flexrack

We featured this in more detail right here.

Tough, reliable, and cost-competitive, Solar FlexRack introduces their new, advanced TDP 2.0 Solar Tracker for commercial and utility-scale ground mount solar installations. The TDP 2.0 Tracker’s new BalanceTrac design offers more modules per row (up to 90), a rotational range of up to 110° and is compatible with 1,000V and 1,500V crystalline and thin film modules. This solution allows for shorter piles and lower per-unit fixed costs for balance of system savings. The combination of complete project support services and this next-generation technology enables solar power plants to increase energy yield while significantly reducing project risks. The results are cost savings across your solar project budget.

Soltec

soltec

Smartly designed structure offers slick wire management

Soltec, a manufacturer and supplier of single-axis solar trackers and related services, has installed its trackers all over the globe for more than a decade now, but the company says 2017 was its best year so far, showing over 200 percent revenue growth. The strategic move to the United States in 2015 has coincided with additional market share in 2017, amid market uncertainties and strong competition.

Structure

The DC Harness StringRunner wire management solution is a proprietary standardized component of Soltec’s SF7 tracker. It performs the functions of combining fused PV source circuits and cabling a homerun trunk circuit, all enclosed within the tracker torque tube, to a DC power switch for off-take. It eliminates the traditional fused combiner box and other cable management materials and controls the power output of eight trackers typically around 240 kW.

Soltec says the cost benefits come from the reduction of materials and related operations in manufacturing, power plant design, purchasing, supply and installation. The net cost benefit is a 30 to 35 percent reduction of installed first-cost compared to the traditional exposed installation of bundled copper wire circuits with a traditional combiner box. Installation labor is reduced by 75 percent thanks to less material and fewer manual operations including wire connections.

There are yield-gain benefits too with a reduction of IR cable losses, reliable low-resistance connections and factory dimensioned trunk cable sizing. The elimination of cable-management backside shading increases tracker compatibility with bifacial module technology.

Software

Comparative tracker yield-gain elements are both standard and site-dependent. Principal to site-dependence is asymmetric backtracking control to modify tracking position in the case that terrain irregularities cause inter-row shading in morning and afternoon hours, a case that is avoidable on flat terrain.

Soltec’s TeamTrack asymmetric backtracking control solution achieves both yield-gain and cost reduction benefits in tracker technology, achieving up to 6 percent yield-gain over the alternative of standard tracking on irregular terrain, and enabling cost reduction of earth-grading on contours and steps. The TeamTrack differs from other backtracking solutions that incorporate an auxiliary PV module and feedback response mechanisms that can add cost and vulnerability by instead performing the task straightforward with programmed operation and robust tracker position control.

The TeamTrack control algorithm works with NREL sun position data versus programmed constants of local irregularities (that never change) to calculate and execute backtracking movements and avoid inter-row shading. TeamTrack is part of comprehensive tracker positioning control that includes sensing and response to cloud cover, snow cover, standing water level and wind regime.

Schletter

schletter

New tracker product with self-locking mechanism now available

Although the U.S. arm of Schletter filed for bankruptcy, the Germany-based headquarters is still chugging along. At this year’s Intersolar Europe, Schletter Group presented its new tracking system.

Hardware

The core feature of the new Schletter tracker is that it combines the stability of a fixed mounting system with the additional yields of a tracking system. This is achieved by the drive concept: While most other tracking systems use hydraulic dampers or similar supporting structures to mitigate the vibrations and torsional forces caused by the wind, this Schletter system features a drive system with a self-locking mechanism. Each post locks as soon as the row has stopped moving. This newly-developed and soon to be patented drive system fully eliminates vibrations over the entire row which can be caused by wind. Therefore the system, while at rest, has the properties and durability of a fixed mounting system and is designed to withstand wind speeds of up to 161 mph. It thus completely avoids the dangerous galloping effect.

The second feature that stands out is its efficiency, achieved through its large wing-span and ground cover ratio. Each row can be up to 393-ft long and is driven by one centrally located motor. At 13 ft in width, each row is wide enough to hold either two panels oriented vertically or four horizontally, thus up to 574 sq yds of solar array can be installed per row and motor. This allows operators to make optimal use of the available land and a ground cover ratio of more than 50 percent can be achieved.

Software

The tracker has a rotational range of 60 degrees and is controlled through wireless technology, which completely obviates expensive wiring for both power supply and communication. The motor and the control systems are selfpowered by a dedicated PV panel in each row with a battery pack. To make O&M easier, mechanical connections between the rows have been deliberately avoided. This allows unhampered vehicle access between the rows, for instance during servicing and maintenance work.

GP JOULE

gp joule

GP JOULE’s single-axis tracker passes 20-year reliability test

The PHLEGON single-axis tracker from GP JOULE Canada Corp. passed a series of accelerated life-cycle tests conducted by the Southern Alberta Institute of Technology (SAIT) in Calgary. The Institute’s Green Building Technology Lab and Demonstration Centre confirmed PHLEGON’s long-term reliability within a wide range of environmental conditions and proved its performance in extreme northern climates. SAIT’s Accelerated Life Test Report shows that GP JOULE’s active tracking technology provides proven results in the Northern Canadian and U.S. markets where fixed-tilt PV has been dominant.

SAIT cycled PHLEGON’s mechanical components continuously 7,305 times over a 19-day period to simulate two decades of functionality. PHLEGON initially underwent the tests without environmental factors, and then went through another round that simulated extreme conditions including grit, freezing rain and sleet. The test included a deep freeze below -20C, confirming sensitive components function under extreme temperatures. “Freeze-thaw” tests mimicked the effects of spring and fall on the tracker, flooding moving parts with water before immediately exposing them to below-zero temperatures. The actuator, responsible for controlling and rotating the solar panels, completed both the mechanical and environmental rounds of testing — essentially 40 years without failure.

“GP JOULE wanted SAIT to test two things. First, how the system will operate in Alberta’s climate and second, what the cost of operating and maintaining the PHLEGON over a 20-year lifespan will be,” says Tom Jackman, SAIT’s principal investigator. “Our testing protocol introduced freezing conditions that were not considered in their original test plan, resulting in substantial ice buildup and additional weight. All components tested without failure.”

SunLink

SunLink Tracker

Updates strengthen the TechTrack design

SunLink’s single-axis tracker TechTrack is one of the quickest mounting systems to install, largely due to the simplicity of every component designed to eliminate inefficiencies and optimize energy production. The company is responding to the current environment, with customers looking for faster installation to keep up with their volume of solar projects and ultimately reduce field labor and associated installation costs, with some tweaks to its tracker design.

Hardware

One change is a new bearing and pivot design that arrives on site preassembled. The new and improved bearing design provides enough room in the stabilizer stroke (SunLink active damper) so that the system no longer needs to be rotated. Instead, the stabilizer mount position can be set from a measurement, saving substantial installation time. And with the preassembled bearings, installation crews can immediately install the component, saving valuable time in avoiding additional assembly of multiple parts in the field.

An additional design benefit enables drop-in torque tubes, eliminating the requirement for specialized jack equipment. SunLink also improved the durability of its pivot and bearing to withstand the rigors of construction crew handling on the project site.

“Another way we’re is reducing installation time is by revisiting our slew arm,” says Kate Trono, SVP of product, SunLink. “With a more streamlined design, we’ve eliminated the need for multiple or expensive custom tools and install kits that can sometimes add another $10,000 to a project. Our redesigned slew arm can be installed with standard tools, reducing the number of components, labor time and additional expenses.”

Feature enhancements like these may seem like small improvements, but the pay-off is big when you consider the reduction in labor, installation time and reducing your overall solar project cost.

— Solar Builder magazine

Submit your projects to our Project of the Year awards

 

Solar Builder Project of the Year awards

I started to sum up our July/August issue by saying “it’s all about innovation!” and nearly barfed. Ugh. Innovation. You know what I mean? For one, it’s a word overused to the point of being meaningless. But my gag reflex is caused more by the aura around it. Everyone wants to innovate. It is an overly sought-after objective, in my book. So much time is spent trying to innovate that we don’t invest enough time and energy perfecting what’s already working and maintaining what we all actually need. Like, endless funds and brainpower get pumped into building a car that drives itself while the plan for maintaining and improving the infrastructure underneath is left to rot.

Solar innovation is different though. It’s not just innovation for innovation’s sake. Much of the new technology and concepts have the possibility to evolve and strengthen our existing infrastructure.

The most prime example of solar’s practical innovation (SEGUE) is our Project of the Year awards. Past winners have included a large craft brewery trying to be eco-friendly, a school looking for a shading solution, a utility-scale project that provided clean power on tribal land. All of them a refreshing blend of practical problem-solving led by, well, you know what.

Submit your project this year

Any PV project, big or small — we want to hear about it. Was the installation innovative in some way? Did it help a community? Does it just look really awesome? If it stands out, it’ll qualify for our Project of the Year awards. To nominate a project (construction completion date must fall between Oct. 1, 2017 and July 31, 2018):

Step one: Click here.

Step two: Fill out the form by Aug. 31, 2018.

That’s it. From there we compile the entries and put them up for an online vote in the following categories:

  • Residential (pending enough submissions)
  • Commercial & Industrial
  • Utility-scale
  • Solar + Storage

Projects with the most votes win each category, but ALL nominees are also eligible for Editor’s Choice awards. All winners are then featured in our year-end magazine and on the site. Head here for more details and to enter.

— Solar Builder magazine

Install Inequality: Nearly half of U.S. residential rooftop solar potential is currently out of reach

poor apartment buidlings

One of the largest barriers to solar adoption on a wide scale is the wealth gap, and it will require more problem-solving than a mandate to overcome it. A new report released by the National Renewable Energy Laboratory (NREL) shows that nearly half (42 percent) of all the United States’ residential rooftop solar technical potential (see pg. 15 for definition) is on the dwellings of low-to-moderate income (LMI) households, representing 330 GW of potential solar capacity — a number the researchers admitted was much higher than they expected at the outset.

“Understanding the potential size of the LMI market in detail offers new insights and opportunities to serve these communities,” said David Mooney, executive director, Institutional Planning, Integration and Development for NREL. “The potential electric bill savings from the adoption of rooftop solar would have a greater material impact on low-income households compared to their high-income counterparts.”

Although residential solar adoption has increased over the past decade, adoption among LMI households (defined as 80 percent or less of the Area Median Income) and affordable housing providers continues to lag.

The obvious issue here is the lack of capital, cash or credit for such an investment among LMI customers, but the NREL report also shows how solar financing strategies and the long-time inability to penetrate the multifamily sector specifically leaves behind the LMI segment.

Segment spotlight

Across the entire U.S., all income levels mushed together, the rooftop potential of residential single-family is much higher than multifamily — 68 percent versus 32 percent — but the high-income category is doing the heavy lifting to get that outcome. Splitting this chunk another way, into owner-occupied and renter-occupied, reveals where the LMI segment diverges from higher income categories. After doing this, the largest modality of potential is single-family owner-occupied (SFOO) at 177 TWh, but is closely followed by multifamily renter-occupied, with 140 TWh of potential.

Said another way, although deployment of rooftop has been concentrated on SFOO, about 60 percent of potential is in the other three combinations. This means over half of LMI technical potential for solar is in underrepresented housing combinations, like single-family renter-occupied and multifamily buildings, which means the barriers of solar deployment in these categories is really an additional a barrier for an LMI individual’s access to solar.

The study shows the quantity of residential technical potential is highly concentrated in urban and densely populated areas with more building stock, which makes sense intuitively. But many of these areas with high levels of potential already have significant levels of residential deployment, like California, Maryland, Massachusetts and New Jersey. Several states cited to have high potential with low levels of deployment were Illinois, Ohio, Florida, Pennsylvania and Texas.

RELATED: Solar for All: How to incentivize community solar projects to benefit low-, middle-income customers

At a high level, patterns of LMI potential mirror overall income trends. LMI solar potential percentages are greatest in the lower income communities and higher in rural counties. Spatial trends in the potential for solar to offset LMI consumption most strongly reflected regional variation in per-capita electricity consumed, primarily due to which fuels are used for building heating and cooling loads.

Impact on the future

The Solar Energy Technology Office of the U.S. Department of Energy updated the cost targets of 5 cents per KWh for residential solar by 2030. Using these costs and making forecasts, NREL estimated that achieving them would result in 970 GW of PV capacity 2050, or 33 percent of the generation mix. But can we hit that target leaving the LMI solar rooftop segment in the dust?

Using this data set, NREL examined the feasibility of rooftop offsetting that much in each county in the United States given the technical potential.

Offsetting 33 percent of LMI household electrical consumption (“offset target”) with rooftop solar is technically feasible on a national scale when only considering households in SFOO buildings, although to do so requires buildout on essentially all SFOO buildings — an impractical and unforgiving market challenge. In contrast, on a technical basis, there is more than sufficient roof space to meet the 33 percent offset target when including single-family rental-occupied (SFRO), multifamily owner-occupied (MFOO), and multifamily renter-occupied (MFRO) buildings.

attack-the-tariff-300x250

Using only the popular SFOO segment, 60 percent of counties would have potential to meet 33 percent of LMI electricity consumption. Said in reverse to belabor the point: 40 percent of U.S. counties have insufficient rooftop potential to offset 33 percent of LMI electric consumption in just single-family, owner-occupied. The current path to 2050 will not achieve the target generational mix. But including rental and multifamily there is “more than sufficient rooftop space to meet the 33 percent target.” NREL believes 99 percent of counties would meet the 33 percent threshold in just residential rooftop capacity.

Reaching this potential requires deployment models other than those commonly found today. Such models would need to ensure the rental owner had incentive to install solar on their own buildings, like bundling utility expenses with rent payment as a means of passing the costs and savings along to tenants. These models would also need to address diverging requirements and energy burdens of owners and tenants in multifamily. Here’s a great example of one new concept in our Attack the Tariff Series.

It takes a village

The NREL study shows that most LMI electricity consumption (especially with the LMI segment requiring a lower threshold to offset onsite) can be met with rooftop solar, but again 100 percent deployment is unlikely. To get to these high levels of penetration would require deployment on non-traditional building types.

NREL posits one way to increase LMI access to solar is through the vast network of nonprofits that connect to this segment. What if PV systems on government buildings, public housing, schools, shelters and places of worship were intentionally oversized to benefit their LMI communities with the excess generation? The NREL team estimated this opportunity for three cities — Chicago, San Bernardino-Riverside and Washington, D.C. — based on building size, average electric consumption and solar technical potential for outsizing each of those buildings segments. They found enough gross generation potential on those selected building types to meet between 10 to 30 percent of LMI consumption, but only about 1.5 to 9 percent after accounting for the onsite consumption.

Schools have the greatest opportunity to export to the community because of their typically large flat roofs and lower levels of electrical consumption in the summer when irradiance is highest. Places of worship came next because of low levels of consumption year round and moderately favorable roofs. Public housing sites and homeless shelters likely have insufficient rooftop areas to offset 100 percent on site consumption.

National nonprofits GRID Alternatives and Vote Solar updated their Low-Income Solar Policy Guide which explains some proven strategies for expanding solar access being used in states and cities across the country. In multifamily, for example, successful strategies include:

  • Net metering or other incentives to ensure full value of solar
  • Financial incentives to reduce upfront costs, overcome split incentives scenarios and ensure benefits reach tenants
  • Measures to reduce barriers to financing
  • Technical assistance to affordable housing providers, participating contractors and service providers
  • Pairing solar with energy efficiency programs
  • Facilitating waivers from regulatory utility and rent allowance requirements to maximize tenant benefit. (Under a utility allowance formula, a resident’s rent plus utilities equate to a certain percentage of the resident’s income. When a resident’s utility bills decrease, as can happen with solar, the rent portion will automatically increase under the formula)
  • Integrating job training and employment opportunities in the solar energy and energy efficiency sectors of the economy

California and Washington D.C. are the only examples of active programs in place specifically targeted to deploying solar for multifamily affordable housing. California has an incentive program dedicated to affordable housing multifamily, with requirement that half of energy generated on site be used to serve tenants loads. Other states have included incentives for multifamily solar adoption in their broader solar programs. In Colorado, the Denver Housing Authority’s 2-MW LMI solar garden model has shown a scalable model through utility partnerships for offsite generation. In Massachusetts, the SREC II program has awarded a higher price for solar renewable energy credits that are generated by projects that are considered community shared solar projects or that serve affordable housing. When the SREC II program ends, it will be replaced by the new Solar Massachusetts Renewable Target (SMART) program that will award a higher incentive for solar projects that serve affordable housing.

Final thought

It is a big opportunity, though there are clear market and economic barriers. Ignoring this segment and these potential barriers could significantly limit the long-term size of the rooftop solar market.

“Solar can have tremendous benefits for low-income communities in addition to diversifying and de-carbonizing our national energy mix,” said Tim Sears, chief operating officer for GRID Alternatives. “We hope this research will give more states the data they need to develop effective low-income solar programs and build a more equitable clean energy economy.”

The report is accompanied by a web application (maps.nrel.gov/solarforall) that enables users to assess solar technical potential for their communities. This tool makes it possible to visualize the amount of low-income solar potential in a specific neighborhood, for example, while also enabling identification of neighborhoods with both high solar potential and high electricity costs where rooftop solar could provide cost-effective electricity generation. Check it out and see if it sparks any new ideas. The potential is there, it just needs to be tapped.


Methodology

Using LIDAR data from Homeland Security to examine 23 percent of U.S. building stock, the researchers inferred the solar potential of building footprints and unshaded roof area, azimuth, tilt and roof plane. Age cannot be detected so was not considered. This was then matched with socio-economic demographic data from the Census and building stock data to understand total usable rooftop area for LMI households. A statistical model was then created to make estimates of areas not covered by the available LIDAR data (stuff like household counts, number of suitable buildings, etc.) They then dove into three representative regions to infer more in-depth information.

— Solar Builder magazine