Rapid Shutdown and Beyond: Inside NEC 2017 and the effort to streamline PV design

collaboration illustration

New codes and regulations are notorious for raising prices and halting innovation in industries, but the new rapid shutdown requirements facing the solar industry are having the opposite effect. Thanks to a coalition of manufacturers and interested parties across solar, the solutions being developed to meet NEC 2017 Module Level Rapid Shutdown requirements will achieve something solar technology has long needed: common language.

“The intent is to create an open protocol for any manufacturer to apply,” says Michael Mendik, head of solution management, Solar Energy Division at Fronius USA. He has been an active member of the SunSpec Alliance, the group that has developed these standards. “Inverter manufacturers can build and design their own transmitters and then the rapid shutdown boxes will also be tuned to that language and can receive the signal. There is no proprietary stuff.”

“The current systems were designed to meet the previous rapid shutdown requirements using mostly proprietary communication systems,” says Mario Thomas, product manager at ABB. “Future system design will be vendor independent, allowing a better choice for the customer and the installer.”

“The solar industry is experiencing significant growth with new requirements, so we welcome the vendor coordination efforts and the wide adoption by many vendors working to improve the safety of clean energy production,” says Danny Eizips, VP of engineering at Tigo. “This is a great opportunity for multivendor support.”

This standard protocol has ramifications beyond the context of rapid shutdown, but let’s start there.

NEC 2017 changes

The 2017 edition of the National Electrical Code (NEC 2017) includes an update to section 690.12 Rapid Shutdown of PV Systems on Buildings. The update pushes the requirement to “module-level” rapid shutdown instead of the “array level” that was listed in NEC 2014. Effective Jan. 1, 2019, this requires conductors inside the array boundary to be discharged to 80 volts or less within 30 seconds of initiating a rapid shutdown event. This requirement comes in addition to the outside the array boundary voltage being limited to 30 volts or less.

At first glance, the changes didn’t require such a collaborative effort. Module-level electronics could have done the trick and piecemeal proprietary products and one-off collaborations from various manufacturers could have continued as usual. Luckily, that wasn’t the case.

The SunSpec solution

Formed in 2009, the SunSpec Alliance is a trade alliance of more than 100 solar and storage distributed energy industry participants, together pursuing information standards to enable plug-and-play system interoperability.

After nearly two years of intense technical collaboration, the Communication Signal for Rapid Shutdown Interoperability Specification was published in September 2017 as a method to comply with NEC 2017. This spec defines a communication protocol that uses the cabling of the solar array to transmit messages over the DC power lines between the PV modules and a master control device located near the inverter.

In addition, PV module manufacturers can implement the protocol on intelligent devices embedded in the junction box of each PV module. A master control device associated with the inverter communicates with the PV modules. Altogether, the specification enables plug-and-play interoperability and any-to-any rapid shutdown solutions.

“This open standard delivers multiple benefits to the distributed energy industry, most notably lower integration costs and the freedom to choose from an array of interoperable products,” saysTom Tansy, chairman of the SunSpec Alliance.

What’s this mean for me right now?

  1. If you are a big fan of installing microinverters, you’re already meeting these rapid shutdown requirements.
  2. As mentioned earlier, the implementation date for NEC 2017 is Jan. 1, 2019. Depending on the Authority Having Jurisdiction where you do business, you may not even be held to the NEC 2014 requirement right now, let alone NEC 2017 when it arrives. The Northeast portion of the country will be the earliest adopters, followed by California.
  3. If you are going to be held to NEC 2017 — or just generally would like to comply on your own — sit back and wait for these SunSpec-certified products to hit the market and design systems the way you always have.

“The complexity here is not on the installer end,” Mendik says. Manufacturers had to develop a transmitter that’s hooked to the DC line and puts in the signal.

Some of these solutions are already available, like the Fronius Symo. Other companies announcing immediate plans to incorporate the technology into their product lines include ABB, Maxim Integrated, Omron, Outback, SMA and Tigo. You can expect to see most of these around Q2 this year. There is no UL testing protocol yet to certify these products, but UL is part of the SunSpec Alliance, and you can expect this to happen soon.

Why else is this a big deal?

Not to be flippant about the importance of safety, but this protocol opens the door for way more impactful product developments. There’s an opportunity here to make your life even easier and bring the costs of a system down even more.

1. Proprietary boundaries will come down.

For starters, the array-to-rapid-shutdown-box-to-inverter architecture is more flexible. Prior to any updates, you had to procure the rapid shutdown box and the inverter from the same manufacturer. No more.

“The installer can install the systems as before and doesn’t have to worry about matching inverters of rapid shutdown boxes,” Mendik says.
So, that’s cool, but that flexibility goes way beyond the rapid shutdown, inverter pairing. “There’s no specific [module-level electronics] on the roof,” Mendik continues. “If there are different panels, they will be working with different rapid shutdown boxes. If one type of inverter in a system breaks, it can be replaced with another, and it will still work. A distributor can have different inverter types in stock for replacement, and everything will still be in line with the protocol.”

2. System designs will be streamlined.

Today, that rapid shutdown box is just an added expense, even now, after the protocol. This is why many installers prefer module-level electronics like microinverters, which meet rapid shutdown module-level requirements while also adding optimization, monitoring and design flexibility.

In the not-too-distant future though, this rapid shutdown box will be gone completely, even in a string inverter design. Soon, using this common language, module manufacturers will be including supped up junction boxes or chips from a company like Maxim instead of diodes. These will meet NEC 2017 and provide MLE performance with a string inverter design. This will keep costs and industry part counts down.

“An integrated module in the future, where the installer doesn’t have to buy and wire a specific rapid shutdown box … it’ll be like going back in time to when he didn’t have to worry about that,” Mendik says. “This also means you won’t have complex electronics on the roof. The standard forces you into more complexity for rapid shutdown, but the solution we’re looking at is simple electronics, not power electronics and doesn’t convert power from DC to AC.”

Thomas sums it up: “The customer in the end has a choice. I think that’s a big benefit. Customers don’t want to get stuck with one vendor and want the right to choose between different manufacturers. Having this choice and competition will reduce costs in the end.”

— Solar Builder magazine

Ask a Distributor: We ask distributors for their purchasing advice, products to watch in 2018

solar distributors

Solar is now the No. 1 new source of capacity being added to the grid, according to the U.S. Energy Information Administration, and solar installer is the fastest growing job in the country according to the Bureau of Labor Statistics. And what’s the reason for the rise of this new era? The impending doom of the ice caps melting? Hardly. The advancements in technology? Getting warmer.

Really, things just got cheaper.

This is to say that purchasing plays a large, perhaps outsized, role in the value proposition of the industry and your business. Given that reality, we wanted to kick off the year by polling a handful of solar distributors for their purchasing advice.

You’ll be hearing from:

purchasing

Here’s the No. 1 way to avoid purchasing problems

What are the common problems distributors see when it comes to purchasing systems to install? There are a few quick, solvable issues — stuff like reviewing the details of an order before signing off on it or avoiding last minute purchases.

“Plan ahead and inspect shipments to avoid/mitigate mix ups and ensure fast and timely solutions when needed,” McShea says. “Waiting three weeks until install to say something is missing and you need it now is not effective.”

But all of that feeds into the advice that resonated with us the most: Seeing the distributor relationship as a two-way street that adds value to your business. According to the distributors we talked to, the more often you communicate, the more the distributor knows about your business, the easier it is for them to help.

“Valuing price over loyalty and the quality of the relationship with a distributor, I think, is a mistake,” Schoder from Civic notes.

A simple step up in communication will not only solve a bunch of issues but could create additional value for your business.

“Good communication and transparency are always the best remedies for doing good business and mitigating potential errors,” Dufrenne says. “Everyone is busy and going to make mistakes, including distributors and shipping companies. When all parties pay attention to detail and plan accordingly, deliveries and installations seem to go more smoothly.”

And it’s not just an exercise in mistake avoidance. Keeping everyone on the same page, forecast-wise, can only make the ordering process smoother for everyone.

“At least one call a week to plan upcoming jobs would help avoid supply chain issues,” Kyler says. This ensures all orders and forecasting align with expectations.

There’s also the training aspect. “Manufacturers are constantly offering training, quite often through their distributors,” Bailey notes. “Yet we still see many installers deal with headaches for hours which they could have learned to avoid by going through some quick training on the product features and installation.”

Think about kits

Ordering from multiple suppliers for a given residential job can leave more room for error, such as damage during shipping, incorrect parts arriving or a delayed delivery, all of which lengthens install time and increases costs.

“The best solution I’ve seen yet for lowering soft costs is to have one to two standardized kits which the sales team and installation crew are both very familiar with,” says Leone with Civic. “This mitigates both sales and labor costs. We recommend having multiple kits to protect against upstream challenges such as availability.”

“Ordering from one supplier and having the experts kit the equipment per job before shipping to the jobsite or warehouse can reduce most mistakes that cause delays and additional labor/mobilization costs,” Dufrenne says.

Sticking with brands also avoids the hassle of resubmitting permits with different equipment types or brands.

4 soft cost reduction tips

Schoder: “Utilizing online software programs like Helioscope and Energy Toolbase to drastically reduce the amount of time and effort that goes into a respectable customer proposal.”

Bailey: “Smaller installers like to use microinverters for [lowering soft costs]. In many cases they don’t have the in-house expertise to properly design a string inverter system which can maximize production. Microinverters are flexible, and the installers can design in the field by adding modules as they see fit.”

Dufrenne: “Good operations management [from lead generation to final completion]. Use software, like ENACT.”

Kyler: “Installers should keep at least one administrator dedicated to handling all incoming and outgoing paperwork such as permits, SREC registrations and contracts. This would help reduce soft costs and avoid any confusion or dilemmas later on.”

Truck these rolls

For starters, it helps to have a mini-inventory of small accessories (L-feet, clamps, wire), but stocking extra parts for the rest of the system is always a good idea.

“A common purchasing mistake I see installers make is purchasing just enough for their project instead of calculating for inevitable adjustments when they get on the roof,” Kyler says. “Mostly when it comes to racking, I recommend keeping spare parts in each truck.”
Dufrenne laid it out like this: “Not ordering extra parts for racking and attachments ends up costing much more than you’d think, once you have to roll another truck and pay for overnight shipping charges for parts that are usually less than $10.”

When it comes to the inverter (and we will get into this more on page 28) MLPE or string inverters could each offer a route to reduced truck rolls, if handled correctly. But for now, we just note what Kyler recommends: “Select products that allow remote updates or choose manufacturers that provide service programs.”

“Carry spare parts and get your system up and communicating with your gateway and online account before leaving the site,” Bailey says. “Installers who use gateways can track performance as soon as the system lights up. They can coordinate with technical support and determine within a few minutes that all modules and inverters are performing to spec.”

Head to page 2 for advice on system purchasing

— Solar Builder magazine

Sponsored: Top 5 ways to become 24 hours of sun on the new Fronius website

fronius

Fronius USA redesigns their web presence to help connect people with 24 hours of sun, a vision of the future where 100% of our energy is made by renewable energy. Here are the top 5 new features of Fronius.com:

  1. Easy navigation: same bankable company, all new modern sleek design
  2. All new services and solutions: Solar inverters are not the only thing Fronius offers! Our new website helps us communicate the evolution of our training, services and O&M catalog.
  3. “Get involved” and contact pages allow you to narrow your search from homeowner information, to distributors in your area, etc. Now everyone can get involved with #24hoursofsun
  4. Easy event registration: from webinars to technical trainings; filter your searches in your calendar and get connected faster!
  5. Transparent technical product information: stay green and download datasheet information in our one stop shop product page.

Fronius is #24hoursofsun with their new sustainable website.

— Solar Builder magazine

SB Buzz Podcast: Fronius’ Dan Fortson on the future of inverters, how he’d fix energy policy

solar builder buzz podcast

Dan Fortson, applications engineer for Fronius USA, is a lifer in the solar energy – starting back in the wild west days of the ‘80s, learning from the early off-grid PV pioneers to now working for one of the top inverter brands in the industry. He has seen a lot over the years, and he’s not opposed to giving a few hot takes about solar and its place in the world. So, he made for a fascinating podcast guest. Our chat ranges from the technology most exciting him today to what he would do if he could change the energy industry right now. Click to listen, download and/or SUBSCRIBE below.

1 min. We start by discussing Dan’s start in solar — which dates back to his interest learning about energy in junior high science classes: “There’s something dreadfully wrong here.” I say “kind of” too many times.

2:30: What his first PV installation looked like and who is early mentors in the solar industry were.

4:20: Hilarious coincidence about what Dan alludes at this minute-mark.

6:00: What’s been most surprising to him about what’s possible today compared to the systems he was building in the early days – from racking fabrication to inverter technology to batteries — and how batteries can be like animals.

9:00: The effect the SunSpec Alliance standards are going to have on PV technology and system architecture going forward. Hot take #1: Why we might be a little too concerned with safety.

13:30: I struggle to come up with the words to explain the new testing for arc faults, which I wrote about in this article here.

15:30: Hot take #2: How utilities are overstating the issue of grid power quality.

18:10: How Dan would change the energy industry for the better. “Every form of energy is subsidized … We don’t fight wars over sunshine; we fight wars over oil.”

21:30: We get into some of the inverter tech support headaches that Dan sees in the field, and then he offers some advice for avoiding some of the most common installation errors he sees.

24:30: We end discussing some of the new initiatives and products that you can expect to see from Fronius heading into 2018. Be sure to take a look at their brand new website and check out this vision they have for the solar industry by 2020.

— Solar Builder magazine

All Fronius Primo, Symo inverters are now Rule 21 compliant

Fronius summer promotionFronius USA received UL certification for the Fronius Primo 10-15 kW and Fronius Symo 208-V inverters to comply with California’s Rule 21 inverter requirements. With that, all Fronius Primo and Symo inverters are now Rule 21 compliant.

What this means

Rule 21 refers to the generator interconnection requirements of each California Investor-Owned Utility (IOU). A years-long process has been underway to update Rule 21 with “smart inverter” requirements. Rule 21 requires inverters to have new grid support functions and a new certification under UL 1741 SA. Each new inverter also gets a new nameplate label that identifies it as a “Grid Support Utility Interactive Inverter.”

How California’s Rule 21 inverter requirements expand grid capacity, limit energy (revenue) generation

New smart functions, such as voltage and frequency ride-through or soft start ramp rate, will pave the way for further solar penetration into the California grid and help to better manage the fluctuations caused by distributed energy resources (DER). These new functions have a stabilizing effect on the grid as more DER is added to it. Fronius has always been a driving force when it comes to inverters’ Grid Support Functions and has years of experience from highly solar-penetrated markets such as Germany or Italy.

Fronius is currently shipping Rule 21 compliant residential inverters (the Fronius Primo 3.8-8.2 kW) and commercial inverters (the Fronius Symo 10.0 – 24.0 480V). Beginning November 6, 2017, the Fronius Primo 10-15 kW and the Fronius Symo 208V models will also ship with Rule 21 compliance. For more information on ordering your Rule 21 compliant smart inverter, please contact your local Fronius distributor.

— Solar Builder magazine