Pared-down MLPE: How Empower Micro Systems does residential solar with two SKUs

empower-genesys-8k-powerbridge-1In its early days, the U.S. residential solar market was dominated by high-volume buyers like Sunrun, Solar City and Vivint, which means they bought most of the equipment, with the remaining market being served through distribution channels. But big-time growth going forward in the residential solar segment will be driven by the local installer, and the growth of that local installer market will come through greater simplicity, in both process and systems. That’s how we see it at least, and that’s the thesis driving a new PV electronics platform from Empower Micro Systems, a technology company that is currently licensing its new patented solar platform to larger established brands.

“With more financing options available, there is just not a huge advantage in being larger,” says Mika Nuotio, CEO of Empower Micro Systems. “The system is collapsing. Hyper regionalized deployment is coming. The vast majority is from installers, sold through distribution.”

So, if smaller companies gravitating toward simple solutions is the operating assumption, Nuotio says SKU consolidation is one of the most important goals to shoot for — reducing inventory costs and inventory turns makes an installer’s job easier and more profitable.

“In particular in solar, if you sit on inventory for a month or two, you are eroding your profit margin and reselling that equipment. Fast inventory turns make things much easier,” Nuotio says. “Installers are in the service business. They need transactional efficiency. When we designed our technology, we looked at the whole value chain from manufacturers through distributors to homeowners. What’s the technology that streamlines everything?”

SKU consolidation

Installers like stocking products in a van or keeping confined stock at a distributor. Select the wrong size or put the wrong one in the van and another trip is needed.

Simplicity is far from a new concept, as pretty much all manufacturers are trying to simplify their products and an installer’s workflow, but Empower’s Genesys 8K modular technology platform is maybe the simplest out there, cutting the SKU count to two: just a PowerBridge and a PoweHub. With those two, Nuotio says you can build any system from 2.4 to 11.4 kW, which could cover about 99 percent of U.S. residential installs. Comparable module-level power electronic solutions will likely have eight to 15 different SKUs.

Introducing ‘fractal inversion’

Empower Genesys So, how is Empower able to say “just buy two components and then that’s it?” Nuotio explains it is part technology and part design. The Empower technology uses a combination of microinverters and DC optimizers, an architecture that Nuotio is calling fractal inversion.

Here’s how it was described to us: The PowerBridge is a microinverter, one installed per module; the input is DC, and the output is low voltage AC (operating between 0 and 40 volts). Multiple units are then connected in series to create an AC string and aggregated together to hit grid voltage.

The PoweHub is the smart energy combiner. It combines multiple output circuits into one circuit that goes into the service panel and can support up to three strings. Each string is 16 amps, and the aggregate output max is 48 amps. The power rating of the system scales with the number of PowerBridges.

“Because we are connecting the PowerBridges serially in the string, we have an all AC system that doesn’t need a proprietary trunk cable,” Nuotio says. “Installers we talk to say they don’t like trunk cables; they are complicated to deal with, you need three different versions in stock, slicing connectors, sealing caps. That whole thing goes away.”

Overall, the system concept reminds us of Enphase, except for the commitment to pared down SKUs and the move away from trunk cables. It is similar to SolarEdge in that the DC to AC ratios aren’t rigid, which is a trend you can expect to continue in residential solutions. It differs from SolarEdge by being all AC voltage, which means less thermal stretch compared to an oversized DC string.

“Thermal stretch on an individual PowerBridge actually goes down when you oversize in our system,” Nuotio says. “Each PowerBridge is operating at a lower power output, and the string current is limited to a max level of 16 amps. If you keep loading more and more DC power, the total power is max 3.8-kW AC, so each unit actually processes less power and therefore puts less thermal stretch on the electronics.”

Lastly, as solar + storage systems start to take off, Nuotio says the PowerBridge simply couples to a lithium ion battery pack in the way it would a PV module, to help keep those SKU counts low and install solar today but be ready with the infrastructure for storage down the road.

Limitations?

The rigid modularity of the system might not work for every single home on the market because a single string of at least 8 PV modules is needed to make the system and economics payoff. But that is a fairly small volume of projects.

“If you look at the cost of customer acquisition, permitting, installation and truck rolls to do anything, an eight-module system is just not economical. It is washed out by soft costs, so we don’t see that as a major limitation from an overall market perspective.”


Tigo with Amazon AlexaTigo Skill connects a PV system to Amazon’s Alexa

Tigo is now offering its customers the benefits of Amazon Alexa technology via the new Tigo Skill, available on Alexa-enabled products. Using the Tigo Skill, residential and commercial customers with monitored PV systems can request tailored information from Alexa, the cloud-based voice service by Amazon. For example, simply saying “Alexa, ask Tigo how much power my PV system generated today,” will report a day’s worth of power without the need to log in to Tigo’s SMART website.

“Within seconds, you can know how well your PV system is producing — without logging on to a computer or climbing on the roof,” says Maxym Makhota, Tigo’s VP of Software Development. “Tigo Skill is the first to bridge the gap between solar, artificial intelligence and the Smart Home mentality in which information is always available.”

— Solar Builder magazine

Advanced Cable Ties debuts new Nylon 12 tie for solar installations

Advanced Cable Ties NYLON 12

Advanced Cable Ties, Inc. announces another significant new product introduction, NYLON 12 Cable Ties, molecularly designed to withstand the harsh rays of the sun and corrosive outdoor elements. (PRNewsfoto/Advanced Cable Ties)

Advanced Cable Ties, Inc. announces another significant new product introduction, NYLON 12 Cable Ties, molecularly designed to withstand the harsh rays of the sun and corrosive outdoor elements.

The unique properties of Nylon 12 make it the choice for engineers designing for Solar and Wind Power Applications as well as other extreme climate environments. Nylon 12 Cable Ties resist temperature fluctuations, are chemical resistant, and insensitive to stress cracking. The smooth edges eliminate abrasion damage and won’t cut into panel cables. Low water absorption and high density maintains the stability of the cable tie providing ultra-long lasting performance for solar panel systems.

Advanced Cable Ties produces a complete range of sizes from 5″ up to a 14″ heavy duty in convenient contractor packaging of 100 per bag and 1,000 per case, proudly made in their Gardner, Massachusetts facility.

Established in 1994, Advanced Cable Ties, Inc. is a privately owned, leading, full-line manufacturer of cable ties and wiring accessories made in the U.S.A.

— Solar Builder magazine

SnapNrack debuts new universal wire clamp (compatible with Enphase Q Cables)

SnapNrack mounting

At Solar Power International, SnapNrack debuted its new Universal Wire Clamp, which will further enhance the company’s wire management solutions to reduce solar installation times and lower installations costs for customers.

The new SnapNrack Universal Wire Clamp is perfect for managing PV Wires and Enphase Q Cables on the roof. In fact, SnapNrack says this is the only wire clamp currently offered by any racking manufacturer for the Enphase Q Cables and PV Wires. The Universal Wire Clamp has the capability of securing four PV wires or two Enphase Q cables.

The Universal Wire Clamp is designed to organize and secure wires and cables with a lasting tight fit over the life of the system for any SnapNrack Series 100 Residential Roof Mount installation.

In addition to the Universal Wire Clamp, SnapNrack’s line of wire management solutions includes the Junction Box, Wire Retention Clips and Conduit Support Clamps. The full wire management line is made of materials which have been selected for their high UV exposure capability and ability to handle extreme rooftop conditions commonly seen under solar arrays.

SnapNrack customers can now purchase the entire wire management product line, including the Universal Wire Clamp, through their authorized SnapNrack Distributor.

The Ultimate SPI Showcase: Here’s what to see at Solar Power International 2017

— Solar Builder magazine

This non-traditional solar site drainage solution could save you thousands

HydroBlox

HydroBlox transports water from high head pressure to low head pressure, creating a path of least resistance.

Installing or building the perfect site requires planning beyond the system itself. In ground-mount applications, for example, field drainage is an underrated attribute.

Drainage Explained

Typically, the energy dissipation methods on a solar site are aggregate, fabric cloth and perforated pipe. This requires excavation and removal of excess soil as well as the logistics and expense of supplying the aggregate to a remote and often difficult-to-access location. The maintenance requirements are time intensive and expensive.

These traditional drainage systems have a lifespan of one to seven years with most failures occurring in year three. These systems fail because of the migration of fines and silt — small particles that are suspended in the water. Often, you have a pipe that is surrounded by aggregate and a geotextile. As the aggregate or gravel settles and compresses over time, movement of the surrounding soil and fines increases. When the soil and fines migrate, the geotextile and pipe fill with these fines and become impacted.

A Better Way

Instead of going that traditional route, HydroBlox, a drainage and filter product made from 100 percent recycled plastic, is the first geotextile that conveys fluid.

HydroBlox has a compressive strength of 40,000 lbs per ft and an irregular patterned composition with an internal void space of 50 percent, referred to as a permavoid. The pressure in this void space is naturally lower and will remain that way due to the non-compressive nature of the HydroBlox. During natural settling, the plank of HydroBlox will not compress and therefore does not become impacted and clogged.

Also, HydroBlox transports water from high head pressure to low head pressure, creating a path of least resistance. The water then moves through the irregular void path of the HydroBlox plank, with the surrounding soil acting like a filter. This way, water will continuously pass through. In fact, this method moves water over ten times faster than sand.

“This is called the Tergazhi effect. The water movement is based on Darcy’s principle,” says Ed Grieser, owner of HydroBlox. “The working example that seems to resonate with everyone is when standing at the ocean’s edge at the beach, recall how quickly the water travels back into the sand when the wave recedes.”

Lee Supply is the exclusive distributor of HydroBlox with stock at all of their locations.

Installation

The installation method is very straightforward. Simply trench 2 in. wide and 7 in. deep. The trench should be 18-ft to 24-ft down the slope from the drip line. This will allow for 2 in. of HydroBlox to remain above grade. The downhill side is backfilled by the trenched material.

Alongside the potential O&M savings, Fancher says HydroBlox installation costs approximately one-quarter of existing methods.

“The costs associated with traditional systems are approximately $26.50 per foot,” he said. “The perforated pipe which is often compared to the price of HydroBlox is the least expensive component of the standard system. In reality, the true cost is much greater than HydroBlox because of the labor and equipment required. The installation costs for HydroBlox is approximately $1 per foot.”

Each foot of installed HydroBlox could net a savings of $19.50. On a 25-acre solar field site, the costs of installation are reduced by $780,000.

Also, heavy equipment and large vehicles are not necessary for maintenance. This allows for the solar panels to be placed closer together than would otherwise be possible. The maintenance for HydroBlox is simply keeping the rocks and debris clear on the uphill side of HydroBlox and the drainage swale that carries the water to the retention pond clear.


Product to Watch: NRG Systems’ Soiling Measurement Kit

NRG Systems’ Soiling Measurement Kit Photovoltaic modules often collect more than sunlight after they are installed. Depending on the siting location, particles ranging from dust to snow can accumulate on a PV module’s surface, reducing its performance and ultimately leading to significant power losses. This buildup — commonly referred to as soiling — can be compounded by such weather parameters as wind speed, relative humidity and ambient temperature, as well as localized activities near or around the PV plant.

To address and ideally avoid power losses caused by soiling, the new IEC 61724-1:2017 standard for PV system performance monitoring suggests that operators of utility-scale and large PV projects measure soiling ratio, which is defined as the ratio of the actual power/current output of a PV array under given soiling conditions to the power/current that would be expected if the PV array were clean and free of soiling. By measuring soiling ratio, operators are armed with the vital information needed to make practical decisions, like scheduling solar panel cleanings, that can better optimize the performance of their PV plant.

NRG Systems recently introduced a Soiling Measurement Kit specially designed to help PV developers and operators obtain the information needed to quantify the site-specific impacts of soiling on prospective and current PV projects. The turnkey solution is offered as an accessory to the company’s Solar Resource Assessment System and comes with three PV modules (one for data logger power, one clean panel and one dirty panel), pre-installed back-of-module temperature sensors, flexible mounting hardware and an integrated soiling interface module.

The Soiling Measurement Kit connects with NRG Systems’ SymphoniePRO Data Logger and provides a wealth of raw soiling measurement data that can be used to determine soiling ratio.

Specifically, the kit measures short circuit current and back-of-module temperature with the user’s choice of statistical interval as well as optional 1 Hz sample data collection, providing flexible analysis options to meet data demands. Generally, solar module performance decreases with increasing temperature, so back-of-module temperature measurements provide the critical information needed to accurately predict a PV plant’s power output.

— Solar Builder magazine

Tigo Skill connects your PV system to Amazon’s Alexa (enter to win one)

Tigo is now offering its customers the benefits of Amazon Alexa technology via the new Tigo Skill, available on Alexa-enabled products. The Tigo Skill integration allows English- and German-speaking Tigo customers to use their voice to inquire about their PV production or other information collected by Tigo’s SMART website.

How does it work?

Using the Tigo Skill, residential and commercial customers with monitored PV systems can request tailored information from Alexa, the cloud-based voice service by Amazon. For example, simply saying “Alexa, ask Tigo how much power my PV system generated today,” will report a day’s worth of power without the need to log in to Tigo’s SMART website. Other voice commands include: Alexa, ask Tigo…

  • what is my [Daily/Monthly/Yearly] Production Summary?
  • what is my System Total Production Summary?
  • what is my [Average/Peak] Energy Production?
  • what is an optimizer?

“Within seconds, you can know how well your PV system is producing – without logging on to a computer or climbing on the roof,” says Maxym Makhota, Tigo’s VP of Software Development. “Tigo Skill is the first to bridge the gap between solar, artificial intelligence, and the Smart Home mentality in which information is always available.”

Tigo customers now have three options to monitor their PV system: use their voice with Tigo Skill via an Alexa-enabled device; log in to Tigo’s SMART mobile app; or log in to Tigo’s SMART website. Automated monitoring emails with production notifications and reports are still sent to customers using TS4 with monitoring capabilities. The Tigo Skill is available in North America and Europe on Alexa-enabled devices including Amazon’s Echo Dot, Echo, Tap, and via the voice remote on Fire TV. Users can acquire the Tigo Skill by simply searching for and enabling the Tigo Skill in the Amazon Alexa mobile app available on iOS, Android, and Fire tablets or by enabling the Tigo Skill directly from Amazon’s website.

Enter To Win Amazon Echo Dot Giveaway From Tigo

Tigo is giving away a limited number of Amazon Echo Dots to its customers with monitored solar arrays to experience the full benefits of Tigo Skill. This unique opportunity provides PV system owners the additional value of combining Smart Home technology with Smart PV energy. Owners of PV systems utilizing Tigo’s products activated between August 9, 2017 through September 30, 2017 are eligible to participate.

— Solar Builder magazine