Solar MLPE hacks for the installer edge

APsystems-Fresno-roof1Time is money. We’ve all heard the age-old adage, but if you’re a solar installation company, it absolutely rings true: time is your worst enemy. Labor is expensive, so the longer a project takes, the more it costs an installer to put in a solar system, and it comes right out of their bottom line. Non-hardware costs such as installation labor, permitting fees and interconnection costs are referred to as “soft costs.” According to the U.S. Department of Energy, these soft or “plug-in” costs of solar account for as much as 64% of the total cost of a new solar system, and labor is one of the largest culprits. It’s no surprise that solar installers are looking for ways to reduce these costs, and any tool or trick they can employ to speed a project along may just give them the edge they need to not only survive in this highly competitive industry, but to thrive.

One challenge in this effort to reduce labor costs, is the growth in utilization of module-level power electronics (MLPEs) such as microinverters and DC optimizers. Unlike string inverters which, for residential applications, typically mean a single string inverter is serving all the PV modules on the roof, each MLPE is typically serving a single module. Although an MLPE solar system is often more expensive in initial capital costs and more labor-intensive to install compared with string inverters, it also has a better levelized cost of energy (LCOE) over string inverters as MLPE systems produce more energy over the life of system. It makes sense, then, why MLPE systems comprised 62% of the U.S. residential solar market in 2015, according to GTM Research, and the market isn’t done there as MLPE is predicted to be the fastest-growing product segment over the next five years.

Installers are feeling the time crunch and the challenge today is even greater to take a high-demand yet labor-intensive product and still perform a profitable installation. Let’s take a look at a few ways to streamline the MLPE installation process with some serious solar hacks.

 

APsystems-YC1000-4panels-side-sm-1030x928TIME-SAVING PRODUCTS
Microinverters which serve multiple modules exist today and with 2-to-1 and even 4-to-1 module to microinverter options available, homeowners can still get the benefits of an MLPE systems with independent MPPT per module, while installers cleverly reduce the amount of units they’re having to put on the roof by 50% to 75%.

 

MLPE ARCHITECTURE
Most MLPE systems utilize a trunk bus cable to which installers then attach every microinverter. Not only are trunk cables an expensive part of the system, but placing it on the roof and securing the cable to the racking takes time. Products, such as the APsystems YC500A, utilize a daisy-chain method of cabling and do away with the trunk cable. What’s more, the daisy chain is pre-integrated into the unit so it comes completely pre-cabled and ready to go.

 

APsystems demo-thumbFREE TRAINING
Most solar equipment manufacturers offer free training webinars and videos on their products anymore so absolutely take advantage of this. Don’t miss out on the time (and money) saving tips you can pick up in a short training course or online video series.

 

GATEWAY SET-UP
The gateway communication unit for microinverter installations can be a breeze if installers follow a few simple tips for commissioning the system. Connect the gateway to the internet via a standard Ethernet cable so it can download the most current firmware before you begin to commission the system. Ideally, you’ll want to do this after the inverter installation but before module installation so the unit can update while your team puts panels on the roof so you don’t lose time. Be sure to connect cables in the right order as some gateways may take longer if power is applied before the network cable (unless the system will be connected via Wi-Fi). Obtaining the homeowner’s Wi-Fi network information and password before hitting the jobsite will also save you time in connecting the gateway.

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TIME-SAVING APPS
There are some amazing apps out there for solar installers that can help installers streamline system setup. ArrayApp by APsystems, for example, allows installers to create the homeowner account for online monitoring, scan units directly without having to wait for up to 30 minutes for auto-detection of the inverters and create the array site map all from their mobile phone or tablet. Simply search for ArrayApp on your iPhone App Store or Google Play for Android devices.

Taking advantage of these time-saving measures can save an installer money but also help them get more installations completed in a single day. As the solar industry continues to lean heavily toward MLPE systems, finding ways to install faster and more effectively can mean the difference between a profitable operation and one that struggles to be competitive. Be sure to do your research, training, find out what other installers are doing and build your own list of valuable solar installation hacks.

5 Reasons a String Inverter Won’t Cut It.

Microinverters or string? PV system designers fall into two camps, some favoring big inverters and others moving toward the powerful little boxes that meet each module where the real action is: on the roof.

Knowing the limitations of string inverters may tell you just why the Module Level Power Electronics segment – microinverters – is on the rise.

 

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Not made in the shade:
A PV array only works as well as the lowest-performing module. That means intermittent shading from trees, flagpoles – even fallen leaves – can cripple a string of modules as even minor shadows pass across the array throughout the day.

By offering independent, module-level inversion, a microinverter installation can outperform a conventional string array by up 20 percent. You’ll get the most out of every module, every hour of the day.

 

Want to add modules? Too bad:
A string inverter that’s right-sized for an array today may be too small if you want to add more modules tomorrow. That means buying a bigger inverter, too. Ouch.

Microinverters are the forward-thinking choice, letting you add on to your array at any time, easily and cost effectively.

 

Better value in the long run:
Startup costs of a string system might be lower on a per-watt basis, but what you save up front, you’ll lose over time in lower performance.

The key metric of Levelized Cost of Energy – that is, system cost measured over its lifetime – favors microinverters. The microinverters start generating power at lower light levels than string inverters, so the power curve raises and peaks earlier in the day and extends further into the afternoon and evening.

Thanks to module-level inversion at these lower light levels, microinverters enjoy a superior output and higher rate of energy production.

 

Don’t forget safety:
Every module in a string adds more to the DC current flowing across the rooftop – quite a volt load by the time it reaches a inverter, up to 1,000 volts DC. Not very safe for installers or emergency responders who may have to cross the roof.

Microinverters take the jolts out of the volts. Module-level inversion means only low-voltage DC in each circuit, keeping you safe over the life of the system.

 

Module-level power is the future:
String inverters still have their niche, but module-level power inversion is tomorrow’s technology today. A leading analytics firm recently noted that sales of microinverters and related products should top 2 gigwatts by year’s end, and predicts the microinverters’ share of the larger MLPE market could triple by 2018.

That’s a product with a bright future.

Still not convinced? Hear what solar professionals have to say at our APsystems video channel on YouTube. Find out why installers choose APsystems microninverter technology over conventional string systems, and then put module-level power to work in your next PV project.

 

Module-inverter mismatch:
For best performance, the power rating of modules must be matched to that of the string inverter that serves them. Yet these inverters offer a narrow range of power ratings that may not correspond to the cumulative output of the array. You may be buying more inverter than you really need.

Module-level inversion lets you to match inverters to modules throughout the array. Pay for the inversion power you need to get the job done – and no more.

 

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University of Kansas (USA) architecture students take solar construction into the future

Powering old homes with solar is only half the renewable-energy equation.

Designing and building new homes that make the most of that renewable power – achieving ultra-efficient “Net Zero” construction, and beyond – is the next frontier for sustainable living.

American graduate students in the University of Kansas Department of Architecture, Design and Planning are pushing construction into the future through Studio 804, a nonprofit organization that tests their drafting-board skills against real-world challenges.

Where conventional construction ends, the Studio 804 program begins.

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“If a group full of students who have never worked construction or designed and built a project can accomplish these highly sustainable buildings, it shows what the industry as a whole should be capable of,” said Taylor Pickman, now in his fifth and final year in the colloquially known “M-Arch” program. “We like to think we’re setting an example in that sense.”

Their most recent success: the East Lawrence Passive House, an innovative solar home set among the tree-lined streets of a quintessential college town, a mix of modest historic homes, and even the mansions of nineteenth century industrial tycoons.

Outside, the home was designed to fit in with the scale and aesthetics of the neighborhood, while maximizing square footage on a prominent but narrow corner lot. Cut-cedar siding offers a look familiar to the neighborhood while carrying a low carbon footprint. Generous windows maximize passive solar potential.

Inside, the home boasts a laundry list of energy-saving features. A triple-thick blanket of insulation achieves dramatic “R” values, while an advanced air barrier wrap further reduces heat loss. A low-energy HVAC system and energy-recovery ventilator supplies fresh air without energy waste, while the plumbing includes an insulated hot-water recirculation system for more efficiency still.

The home meets the rigorous standards of the LEED Platinum, Net Zero and Passive House certification programs – a trifecta for sustainable construction.

Net Zero, for instance, requires that all heating, cooling and electrical needs must be met through energy-conserving design features and onsite renewable sources.

That’s where solar comes in. The East Lawrence home features a 6kW rooftop system powered by 20 Trina modules and 10 APsystems YC500 dual-module microinverters.

Studio 804 students approached APsystems for help with the project, and the Seattle-based solar technology company offered the microinverter units as a donation.

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“These students are really leading the way forward for energy-efficient design and construction,” said Thomas Nelson, APsystems vice president for sales, USA. “As a leader in innovative solar technology, we were glad to sign on to the project and be included in this showcase home.”

Pickman said microinverters represent “a huge innovation” in the solar field, helping students meet their project goals even without real experience as solar installers.

“I have to say that those microinverters were very simple to install, very simple to work with and very simple to use,” Pickman said. “We had more trouble getting the panels up onto the roof than we ever did working with the micro inverters.”

Bigger, more ambitious projects

KU’s Studio 804 program is committed to the research and development of sustainable, affordable, and inventive building solutions, from the standards of human comfort to the nature of urban spaces.

Two education tracks are offered: a three-year Master of Architecture program for students who already hold undergraduate degrees, or a five-year program that melds both undergraduate and graduate studies and also culminates in the master’s degree.

The final year is a rigorous practicum in which students tackle all aspects of design and construction: from site selection to negotiating building and zoning codes, to working with neighborhood associations and project engineers, to pouring concrete and pounding nails.

“A lot of our projects are speculative, so we are also in charge of making sure the project gets sold,” Pickman said.

To date the studio has completed seven LEED Platinum buildings and two with Passive House certification, meeting the most rigorous environmental standards for materials and construction.

Solar has become a regular feature of Studio 804 work, Pickman said, because it is one of the most effective means of achieving onsite energy production in the Midwest.

“Solar is relatively simple and it functions relatively well with different housing configurations,” he said. “And every year the technology gets better, so every year, we can demonstrate that technology as well.”

Studio 804 produces one building per year, and they keep getting more ambitious.

Twenty years ago, the first Studio 804 project put a simple metal roof over a historic farmhouse. Two years ago, students designed and built a lecture hall and auditorium addition to Marvin Hall, a treasured, 1908-vintage engineering building on the University of Kansas campus.

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Pickman said their next challenge may be achieving the WELL Building standard, which considers interior design and the ergonomics of the living spaces and fixtures – anything that will “reduce wear and tear on the human body.”

“Every year we set slightly different goals,” Pickman said, from building scale to advanced materials and construction and renewable energy techniques.

“And great architecture, or at least very good architecture,” he added. “There’s not a lot of it Kansas.”

East Lawrence Passive House
East Lawrence, Kansas, USA
Designer/installer: Studio 804, graduate students in the University of Kansas Department of Architecture, Design and Planning
System output: 6kW
No. of modules: 20
Module type: Trina TSM-290
Microinverters: APsystems YC500 dual-module
No. of microinverters: 10
croinverters: 10