Podcast: How NEXTracker ‘decapitated the duck’ with its new solar-plus-storage tracker design

solar builder buzz NEXTracker photo

Being the No. 1 tracker worldwide according to GTM Research, I will assume you’ve heard of NEXTracker and its decentralized tracker design by now. What you may not know about is the company’s giant leap into the storage arena with two solutions — NX Drive, a standardized battery enclosure system for generation-plus-storage or stand-alone storage applications, and NX Flow, a modular, integrated solution designed for long duration solar-plus-storage applications.

NX Flow in particular intrigued us – a solution so unique the company worked on and created a new UL standard to test for and prove what it does (more on that below). We stopped by the Fremont, Calif., offices to chat with Chief Technology Officer Alex Au about the concept, maximizing MWh over pure MW, decapitating the duck curve and the effect tariffs might have on all of this.

Be sure to download the full podcast interview below (and subscribe!), but here are three big takeaways.

1. The NEXTracker NX Flow is a 30-kW tracker row with a battery coupled just to that row, making it a modular power plant that achieves a renewable base load. There are two keys to its value proposition. One is the battery.

Au: “Two years ago we started an RFP called ‘Decapitate the Duck’ specifically to address the storage market. We reviewed north of 40 technologies. We had an aggressive demand profile, tested units and agreed to move forward with the Avalon battery — a vanadium flow battery. As of Christmas last year, we were able to pass the point of 10 years worth of cycles. Approximately 1.25 cycles per day, 100 percent depth of discharge. We haven’t been able to detect any degradation. With other batteries there are maintenance cycles and equalization time, but we haven’t had to do any of that either.”

“The Avalon product mates perfectly with one of our 30-kW rows; it is a 6,000 lb unit, can ship completely wet and has actually gone through a burn-in cycle in the factory. That testing and burn-in period means you literally just plug in the DC wires for the modules and then the AC grid. Takes less than an hour and 15 mins to do the full installation with piers and everything.”

2. The second key is the work done with PG&E and UL to create a testing standard that proves the system is only using the grid to power a few electrical components and not charging the battery or sending electrons back into the grid.

Au: “The NEM program, the (self-generation incentive program) SGIP and ITC, have a common theme: If you’re going to participate, you cannot take the energy from the grid and sell it back. You have to have 75 to 100 percent of the power generated from a renewable energy source. To do that, you need meters to show how much of the PV is being produced, and how much is being put on the grid.

“That’s not an integrated solution. You literally have to split everything out and have to put a meter there for added cost. And then to govern that, there is additional labor and time required. We wanted to do everything natively. We took our Self-Powered Controller and put it inside the battery, so we’re talking to the battery and to the inverter, which is on our native SCADA platform.

“Two weeks ago the utilities and PUC came in and said we could start moving forward with this. This is a true milestone for us. We said we will take on the extra burden of creating a power plant – a renewable base load – and we’re going to get it approved by utilities and we’re moving forward with that. We’ve essentially changed the industry.”

3. In the end, NX Drive isn’t necessarily generating more power, but smoothing out production much better over time. But, because of the modularity and the system’s tracking algorithms and data analytic capabilities, more production is possible too.

Au: “You no longer have clipping loss. A lot of guys design DC to AC ratios north of one. In our case, any time you go north of one, it gets stored and could be used in the later part of the day. That’s why we called our RFP ‘Decapitate the Duck’ because the energy is stored and shifted to later times when the head of the duck [curve] would pop up.

“We can go out and apply for an SGIP type program and can put more than 1 MW of PV panels out there because a flow battery actually falls into the fuel cell category. All we care about is nameplate rating. So we have a UL listed inverter with guts that are 30 kW but de-rated to 15 kW. So, instead of 40 tracker rows, we have 60 tracker rows and take a lot more of the energy produced in the day, store it, and then release it later in the day when the sun sets.”

Be sure to listen to the full interview for more on the concept of TrueCapture, what NEXTracker is doing with its advanced analytics and more on the complicated but game-changing proposition of including storage at the point of generation.

— Solar Builder magazine

S-5! 2018 Attachment Solutions & Products brochure now available

S-5! has published its 2018 Attachment Solutions & Products brochure and made it available for download. You can access it right here.

What’s in it?

S5!_ASAP_Brochure

The Attachment Solutions & Products brochure contains information about what S-5! attachment products can be used for and how to correctly use them. The S-5! line of aluminum and brass attachment products are extremely versatile, fitting most standing seam and exposed fastener metal roof profiles, including most structural and architectural profiles.

In the brochure, find solutions for attaching solar panels, snow retention systems, signs, banners, pipes and conduits, HVAC and rooftop equipment, satellite dishes, lightning protection, fall protection and more.

— Solar Builder magazine

PV Pointer: How to optimize PV system structural design for environmental hazards

snow-covered solar panels

According to a recent study by SolarPower Europe, new solar photovoltaic (PV) capacity installed worldwide in 2016 reached more than 76 gigawatts. This was largely due to dramatic growth led by the United States and China, with both countries almost doubling the amount of solar added from 2015. Globally there is now more than 305 GW of solar capacity, and with the increase of solar projects around the world, different climates, topography and other geographic considerations are making design for the environment increasingly important to ensure the integrity of the system over its lifetime.

PV plants are subject to a multitude of threats from the physical environment over the span of their lifetime. These threats must be taken into consideration during structural design in order to mitigate the risk to the system. With PV plants now being installed all over the world, the applicable risks will vary greatly depending on the geographic location. Therefore, the design of each plant must be thoroughly evaluated for its unique set of potential environmental hazards.

Environmental Loads

The first decision to make in determining the environmental loads on a plant is to identify the appropriate risk category for the plant. Building codes around the world use this categorization to determine the probability of occurrence of the design loads, or in other words, how extreme the design loads are. More critical solar project facilities can be designed for a higher risk category, and therefore, for loads with a lower probability of occurrence and a larger magnitude. For example, a rooftop system at a hospital that is required to remain operational after a design level event will be designed to higher loading conditions than a utility-scale facility behind a fence that is not supplying critical power to the grid.

Check out all of our PV Pointers here

Evaluating Different Types of Environmental Loads

When designing a PV plant, the environmental loads that usually first come to mind are wind and snow loads. However, certain architectures or geographical locations will necessitate consideration of seismic, ice or thermal loads as well.

Due to the large surface area and low weight of PV arrays, wind loads are often the most critical environmental forces. Consideration must be taken for both the potential wind magnitude at the site as well as surrounding topographic features that may amplify or weaken the wind as it approaches the PV plant. In many designs, wind tunnel test data is used to most accurately predict the resulting loads on a particular architecture. More accurate prediction of the wind loads allows for optimized structures that still meet the desired levels of performance and reliability.

Snow is another common critical design load on many PV plants. Rooftop and fixed-tilt ground-mounted systems are particularly vulnerable due to the relatively shallow slope of the modules. In addition to the snow’s weight on the tables, the designer must consider snow accumulation between tables, drifting and the potential need for an elevated system to allow for snow shedding. Tracker systems allow for some mitigation of the snow loads by tracking to maximum tilt to shed a large portion of the snow.

Seismic loads are less discussed in the solar industry, but they can be a significant concern in locations with high snow load and moderate to high seismic risk. Since the snow weight is considered part of the seismic mass, the resulting loads can be significant as snow accumulates (force = mass x acceleration). Many PV plants use wide flange post sections which have significantly lower strengths in one direction than the other. As earthquakes act in all directions, this is a vulnerability that needs to be expressly accounted for in design.

Ice, temperature and flooding are additional environmental risks that need to be examined for PV plants in some locations. Ice can add weight to a table and can be a concern for freezing up moving parts. Temperature becomes a concern with systems like trackers where there are long continuous members such as torque tubes. Thermal swings such as those found in desert climates can cause enough expansion or contraction of the steel along a row to result in non-trivial forces on the system. Finally, systems in floodplains must take the expected flood levels into account in the architecture and evaluate whether to design an elevated system.

Designing for these potential load effects helps to mitigate the risk to a PV plant from environmental hazards, thus increasing the overall reliability of the system throughout its lifetime and providing better value to the plant owner.

Lauren Busby Ahsler is a structural engineering manager at SunLink. She works on project engineering as well as tracker product development for SunLink.

— Solar Builder magazine

Global solar tracker shipments up 32 percent, another 30 percent increase expected

Solar trackers continue to take more market share in large-scale PV design, and the #TrumpTariffs may even encourage more tracker deployment, in order for more conservative investors who traditionally installed fixed-tilt under pre-tariff pricing look to boost long-term project value. Even before accounting for that possibility, according to new data from GTM Research, global solar tracker shipments hit a record 14.5 gigawatts in 2017. This represents growth of 32 percent year-over-year.

The data comes from GTM Research’s new report, Global Solar PV Tracker Market Shares and Shipments 2018.
The report notes that NEXTracker maintained its spot at the top of the shipment rankings, accounting for a third of all solar PV trackers sold worldwide in 2017. Array Technologies ranked second, and Soltec third. For the first time, Latin America was the largest market for solar trackers, followed closely by the United States.

GTM solar trackers

“Mexico and Brazil are two of the fastest growing solar markets in the world, each accounting for over 1.5 gigawatts of tracker shipments in 2017, notes Scott Moskowitz, senior analyst at GTM Research and author of the study. “The U.S. utility-scale market was significantly stunted last year due to tariff uncertainty, so it took a backseat to Latin America.”

GTM Research solar tracker shipments

In spite of strong growth, GTM expects to see continued consolidation in the industry. The report notes that vendor margins continue to compress as the market grows, making profitable growth a significant challenge. There has already been one significant acquisition in 2018, with steel giant ArcelorMittal acquiring Exosun out of French bankruptcy court in January.

However, analysts at GTM Research remain optimistic. “Fundamentals in the global utility-scale solar industry are excellent, and trackers are an obvious choice in most developing solar markets,” said Moskowitz. “We expect 30 percent growth in 2018, with shipments approaching 20 gigawatts.”

— Solar Builder magazine

Quick Mount PV debuts QRail — a rooftop racking system to pair with its mounts

QRail Quick Mount

QRail!

Quick Mount PV is simplifying your supply chain, today announcing QRail, its new rooftop racking system featuring patented QClick and QSplice technologies that simplify and speed installation. QRail combines with Quick Mount PV’s waterproof mounts to create a complete, fully-integrated racking and mounting solution for installing solar PV modules on any roof.

“With QRail, we now have what our customers have been requesting: a comprehensive, cost-effective single-source solution for solar installation on all roof types,” said Quick Mount PV CEO Claudia Wentworth. “And because of the QClick and QSplice technologies, solar installers will find that QRail exceeds their expectations for quality and ease of installation.”

How it works

Quick Mount rail

The patented QClick technology enables module clamps to easily click into the rail channel and remain in an upright position, ready to accept the module.

Quick Mount Q Splice

QSplice

QRail’s QSplice is the fastest, most efficient splice in the industry—a tool free, bonded, fully-structural splice that installs in seconds with no tools or extra hardware required.

Electrical bonding is fully integrated into every system component. All electrical bonds are created when the components are installed and tightened down. QRail is fully code compliant, certified to UL 2703, and backed by a 25-year warranty.
QRail is designed and engineered for strength and versatility.

The aluminum QRails come in three sizes, Heavy, Standard and Light, to match all geographic locations. QRails are available in 168-inch and 208-inch lengths, and in both mill and black finish.

Quick Mount Universal End Clamp

For optimal versatility, the QRail system is compatible with virtually all PV modules and roof attachment systems. Modules can be mounted in portrait or landscape orientation in either standard or shared rail configurations.

QRail comes with QDesign, a free online design application that enables quick and easy design of solar arrays, producing a precise bill of materials and all necessary engineering reports.

RELATED: We Look at the Pros and Cons of Rail and Rail-less Racking Systems 

— Solar Builder magazine