Winning the Midwest: We look at how a new solar market is forming in the Midwest

Solar in the Midwest Map

You’ve probably heard, but more solar is being installed than ever before. As the cost of solar dropped the last decade, the economic case in areas of the country with high electricity prices was simple. This isn’t the case in the Midwest, where energy costs are lower, which keeps everyone mellower about the fossil fuels being mined and fracked in their backyards (we say this lovingly as Ohioans).

So, sure, most of the action is on the coasts, but even the Midwest is now starting to emerge from its cave, rub the soot from its eyes and see (and harness) the light.

Here’s what solar industry onlookers are buzzing about in the Heartland.

This article appears in the May/June issue of Solar Builder magazine. Subscribe here for FREE.

Midwest Means MW-scale

Cheaper electricity and a less demanding public means the case for solar in the Midwest mostly starts with policy incentives, and with little public demand for action, the balance of political influence over the shape of those incentives is tipped a bit more to utilities and any other interested stake holders (legacy fossil fuel companies?).

Utility-scale projects represent a little over half of the installations to date in those Midwestern states and about three quarters of the 2016 installations, according to data sent our way by GTM Research. The distributed generation markets in each state are all quite small still — sub 10 MW per state in each of the residential and non-residential markets for all of 2016.

The latest legislative triumphs in the region all seem to support this trend too with renewable energy portfolio standards (RPS) being raised in Illinois and Michigan and unfrozen in Ohio (for now). The Illinois bill in particular was two years in the making and has solar developers excited.

“It creates an adjustable block schedule similar to the successful California Solar Initiative model,” says Owen Goldstrom from Alta Energy, an analytics and procurement company that identifies and executes opportunities for renewable energy. “It’s an opportunity that we are closely tracking, and communicating to our customers with property in Illinois.”

Emerging Opportunities

chicago illinois solar

RPS standards don’t necessarily directly translate to DG solar projects unless there is a way for a smaller scale distributed system to benefit from the renewable energy credits (RECs), Goldstrom says. So, it is worth noting that these RPS bills did come with DG benefits too. The legislation in Michigan helped preserve net metering rules going forward, and GTM Research’s Allison Mond says they are classifying Illinois as an “emerging residential market.”

“The Future Energy Jobs Bill passed in the state mandates that a quarter of the 675 MW of DG required for the new RPS standard consists of sub-10-kW systems,” she says. “Though the market is still quite small, we expect residential installations in the state to double in 2017 over 2016 capacity and then continue to grow by between 100 and 200 percent each year through 2021.”

Illinois also allows for third-party ownership (leases or PPAs) of systems.

Implementation of Illinois’ RPS bill is the top issue of SEIA’s Midwest Committee, which has been working with the Illinois Power Authority to “get the regulatory language that allows the intent of the bill to move forward,” says Sean Gallagher, VP of state affairs for SEIA.

Perhaps the biggest exception to all of our Midwest generalizing so far is in Minnesota, where community solar has grown to become the third largest community solar market in the country after California and Massachusetts.

“It went from a cute idea to big business in two years, and now community solar is really picking up,” says Jake Rozmaryn, CEO of Eco Branding, the agency that represents the Midwest Solar Expo, now in its fifth year. “Large-scale development in Minnesota was over 300 MW in 2016 and is expected to be over a 1 GW in five years. Traction is there.”

midwest-solar-installations-chart

Lingering Problems

We start in Indiana, which is ground zero for problematic energy legislation right now. The much-discussed SB 309 would phase out net metering in tiers: Early adopters would be able to keep net metering for 30 years; those who install between July 1 and 2022 can keep it for 15 years. Anyone installing after that date would be under the new rules.

What are the proposed new rules? Essentially it would be a “buy all, sell all” arrangement where solar customers sell their power back to grid for the wholesale rate (~3 cents per kWh), and then buy it back at the retail rate (11 cents per kWh).

The carrot in the bill for the solar industry is that power purchase agreements (PPAs) would be made legal.

UPDATE: That bill is no longer proposed — the Governor signed it into law.

Gallagher also pointed to Iowa, which doesn’t have a huge rooftop market yet, but has an important DG proceeding happening that will set rate terms and compensation structure going forward “and perhaps set some precedent in the Midwest.”

“We’re also paying attention to a bill in Missouri that would be harmful to rooftop solar,” he says. “We’re just trying to keep those markets open. It’s not a giant market, but we don’t want to see bills that just squash it.”

Arguably worse than the specific inhibitory policies is the general uncertainty lingering over much of the region. For example, we chatted with a developer based in New York who has been eyeing Ohio as a next great opportunity. Well, with the state passing a bill to freeze its RPS, which the governor vetoed, only to have a new, even more limiting bill be passed — how can anyone get a feel for how to proceed over the long term?

Political Will of the Midwest

Getting to this point was definitely not easy, and maturing the market from here will require even more work. Relaxed Trump-era carbon regulations might defibrillate the fossil fuel industries. Longer-term environmental and social arguments in general seem to carry far less weight than short-term costs, politically. Plus, Midwestern utilities have had the benefit of seeing net metered residential systems deployed on a large scale on the coasts, and some are trying to nip it on the bud. For example, ComEd tried to get a demand charge put into that aforementioned bill in Illinois, even though the net meter market in the state at the time was around 800 total customers. The Public Utilities Commission in Ohio is also considering proposals by several utilities in the state to double fixed rates for all customers.

But despite it all, the momentum is real. SEIA and the Environmental Law and Policy Center (ELPC) formed a Midwest coalition about two years ago thinking there were opportunities on the horizon for new markets to develop. It was a baby step. SEIA took a larger step this year and formed a Midwest Solar Committee.

“We recognized that there’s been some activity toward the end of last year that’s starting to bring those potential new markets forward, which provides justification for SEIA and its members to devote more attention to those states,” Gallagher says.

“Utilities in the Midwest have a lot of political clout,” Goldstrom says. “However, solar companies and industry organization have demonstrated a significant capacity to drive change and work with legislators on policy relating to both utility scale and distributed scale generation. I have been pleasantly surprised by the success of a lot of these lobbying efforts.”

By the way, ComEd’s demand charge request didn’t make it into the final version of the bill.

“I think the biggest success solar has had in the Midwest is becoming a competitive form of generation, and as solar prices continue to come down, the cost for electricity in general continues to go up, even in the Midwest,” says TJ Kanczuzewski, president of Inovateus Solar, based in South Bend, Ind. “Even in places that have some cheaper electricity from coal or hydro or even nuclear, electricity prices continue to rise by an average of 5 percent annually while solar continues to become more cost competitive.”

Residential Solar IllustrationROOM FOR Residential

As we wrote about the lagging prospects of residential rooftop solar in the Midwest, Sunrun became the first large national residential rooftop solar company to expand into the Midwest, setting up shop in Wisconsin.

Customers in Wisconsin can either own their system outright with Sunrun BrightBuy or own and finance it with Sunrun BrightAdvantage, using a loan arranged by Sunrun.

“We see a demand for solar that has been underserved in the state and look forward to giving residents a choice to reduce their electric bills with solar, while providing value to the grid,” said Lynn Jurich, CEO of Sunrun.

This highlights Sunrun’s ability to enter new markets in a low fixed-cost way through collaborating with local partners in the state. Sunrun’s economic investment is adding job opportunities in Wisconsin, and it is currently hiring for several positions for its solar team in Southeast Wisconsin.

Chris Crowell is managing editor of Solar Builder.

— Solar Builder magazine

Clamps of Approval: Here’s what to look for when selecting PV clamps

AceClamp

Photo courtesy of AceClamp

The following advice was sent our way via Civic Solar. Check them out here.

Clamps, the racking component used to fasten and ground modules to rails, are an integral component of a racking system. Knowing what to look for in a clamp is a great place to start when vetting racking solutions. Ideally, solar module clamps should be versatile, high quality, aesthetically pleasing and ultimately save you time on the roof.

Versatile solar module clamps are important because they allow for streamlined purchasing and ensure that you always have the right materials in stock. With framed modules ranging from 30 to 50 mm in height, a clamp that can accommodate any height means that you only have to worry about stocking one part, regardless of the modules that you install. With module prices dropping, this simplicity allows you to opportunistically shift your module purchasing without having to worry about changing the racking you stock. Going one step further, the most versatile clamps will be both module height agnostic and double as a mid and end clamp. Having both of these features reduces SKU count and increases simplicity.

Does it meet standards?

Quality of the clamp needs to be considered because racking systems are responsible for the structural integrity of solar systems that will be around for more than 20 years. Some factors to consider are code compliance and certifications, the amount and quality of testing that has been done and the warranty provided by the manufacturer.

A clamp needs to be UL 2703 Listed, which means it passes electrical, mechanical and fire testing. Be sure the clamp is UL Listed rather than just UL Classified or UL Recognized. UL Classified means it has only passed a portion of the required testing, and UL Recognized means that only a component of the racking system has passed a portion of the testing.

Warranty is important because it shows the level of confidence a manufacturer has in its product. The industry standard for a racking product warranty is 20 years.

Is it a looker?

Aesthetics of a clamp should be considered because sleek looking systems will increase the adoption of residential solar.

For a clamp, more attractive means having multiple finish options and a hidden end clamp. Matching the color of the clamp to the color of the module frame will give the system a cleaner look. A hidden end clamp eliminates protruding rails, helping rail-based systems rival the aesthetics of rail-less while remaining more cost effective.

Does it save you time?

Purchasing a clamp that is pre-assembled with a low part count and integrated grounding can save you tons of time. Now, almost all of the top racking brands have integrating grounding, where modules are bonded directly to the rail through teeth on the clamps that bite into the module’s anodized coating. This eliminates components, reduces cost and results in significant labor savings. Also, choosing a clamp that is able to stand alone in the rail channel will increase ease-of-install and turn a two person job into a one person job. Some brands accomplish this through single pre-assembled pieces that have a robust enough end to stand alone while others use spring loaded clamps. Another consideration is whether the mid clamp has a t-bolt or square bolt end. Square bolts need to be run through the rail prior to installation, whereas t-bolts can be inserted into the rail at any point.

Looking for these key features will ultimately save you time and money and allow for a smoother installation process.

Marisa Borelli is product manager for racking at Civic Solar.


System Profiles: Clamps

SunModoSunModo’s Universal Bonding Mid Clamp Kit

These Pre-Assembled Universal Mid Clamps have a unique T-Bolt locking feature that ensure the T-Bolt remains vertical and in full contact with the rail to eliminate pull out. The spring-loaded top clamp and open collar nut accommodates module frames from 31 to 50 mm. The added Loctite easily engages the T-Bolt from the top of the collar nut. The shared rail adaptor converts standard rail to shared rail to allow landscape mounting of PV panels on E-W rails.

How does it save time and cost?

The SunModo self-grounding system that includes the pre-assembled universal bonding clamp eliminates separate module grounding hardware and saves installation cost.

  • Material: Aluminum
  • Certifications: UL 2703
  • Warranty: 20-year structural, 5-year finish

S-5!


The PV Kit from S-5!

The S-5-PV Kit is one of the first solar module mounting solutions to be listed to the new UL subject 2703 that covers both bonding and mounting. The S-5-PV Kit fits two grab components. The universal PV grab attaches adjacent panels, while the EdgeGrab cleanly resolves end condition requirements. S-5! clamps do not penetrate the roofing system or affect the roofer’s warranty. Fits the majority of metal roofs, including exposed fastened and corrugated.

How does it save time and cost?

With the new S-5-PV Kit, the module is simply anchored with the kit and automatically provides a ground path in the module frame. No lugs or wire required except to connect one string of modules to another and to ground the system. This connection detail represents installed electrical cost savings of $6-$12 per unit.

  • Material: Stainless steel
  • Certifications: UL and ASTM tested for use with extensive list of metal roofing manufacturers, profiles, materials and gauges.
  • Warranty: 25-year defect warranty (applies only when the S-5! product is properly installed, used and maintained).

AceClamp


AceClamp’s family of clamps

AceClamps are factory-assembled clamps with patented design features that allow strong connections to standing-seam roof panels without the use of set screws or any other loose parts that could damage the surface of the roof panel. Accessories include Solar Kits for securing PV solar panels; a Micro L-Foot to mount microinverters directly to the standing seam roof rib; and a custom designed L-Foot for attaching a racking system to the AceClamp when needed. AceClamp designs have been vibration tested during the development stage and incorporate special locking features to ensure that the bolts do not back out when subjected to vibratory loads from wind flutter and light seismic activity.

How does it save time and cost?

AceClamps and Solar-Kits are pre-assembled at the factory saving time at the jobsite. Four clamp styles fit the majority of the roof panels on the market, resulting in inventory cost savings. AceClamps install in less than half the time as most set-screw mounted clamps

  • Material: 6061-T6 aluminum and 303 stainless steel
  • Certifications: AceClamp ML and A2 UL Listed to 2703; AceClamp ML approved by Factory Mutual (4471) for wind uplift attachment. A2 and Solar-Kit tested to UL 467 Grounding.
  • Warranty: 20-year limited

EcoFasten


Ecofasten ASG-U Clamps

ASG-U clamps are efficient solar roof mount attachment options for any metal standing seam roof. Installation of the ASG-U clamps will not pierce the roofing material. ASG-U clamps are available in configurations for both vertical (double-lock) and horizontal (single lock) standing seams.

How does it save time and cost?

Two oval-point set screws are included as well as a hex-headed flange bolt for racking, making the ASG-U clamps not only fast and easy to install, but they will also maintain the integrity of your roof by not voiding roofing manufacturer’s warranties.

 This section appeared in our 2017 Mounting Guide. Not a subscriber? Sign up for a FREE subscription right here.

— Solar Builder magazine

Did Suniva just start a global trade war? A quick summary

solar trade petition suniva

It started with the Suniva bankruptcy earlier this month. Well, that’s not quite true because U.S.-based solar manufacturers have been crying foul regarding unfair competition from cell and module imports for awhile, but after filing for chapter 11, Suniva hit the button and filed a petition for global safeguards under Section 201-202 of the Trade Act of 1974 – the impact of which could reverberate far wider than just the solar industry.

But let’s stick with Suniva and solar for now.

Don’t we already have tariffs on imports?

Kind of. This module import influx was initially curtailed in 2013, when the U.S. Government, at the urging of SolarWorld (more on them later), instituted anti-dumping and countervailing duties against manufacturers in China and Taiwan. Since that time, according to GTM Research data, imports from China “have virtually disappeared in the past 2 years accounting for just 7% in the first two months of 2017” and Taiwan imports are all but gone. At the same time, U.S. manufacturing capacity has doubled.

However, market gaps were filled elsewhere. “Imports from Southeast Asia and Korea have skyrocketed, from 15% and 7% in Q1 2015 to 55% and 21% in Q4 2016 respectively,” GTM notes. As a result, despite the doubled capacity, U.S. share dropped below 15 percent overall while market prices fell drastically.

Suniva’s case

SunivaSuniva’s claim is U.S. solar manufacturers face serious injury from the ongoing and increasing influx of foreign imports, which continue to drive down domestic prices.

“The modern wave of solar technology was born from research in U.S. universities, industry and government, and U.S. manufacturers led the way in the commercialization of these technologies – and yet today, we stand fighting for the survival of jobs in an industry that the U.S. created,” said Matt Card, Suniva’s Executive Vice President of Commercial Operations. “Without today’s requested global safeguard, the U.S. solar manufacturing industry will die and we will not only lose solar manufacturing jobs today, but also those future jobs that will come from investing in the solar manufacturing industry of tomorrow.”

Suniva’s petition outlines these four requests:

1) An initial $0.40/W tariff on imported cells and a minimum price of $0.78/W for imported
Modules that incrementally steps down to $0.33/W on cells with a minimum price of $0.68/W on modules in four years.

2) “Equitable distribution” of AD/CVD duties based on production capacity as of March, which breaks down as:
• 25% distributed to U.S. c-Si cell manufacturers
• 25% distributed to U.S. c-Si module manufacturers
• 10% distributed to U.S. polysilicon, ingot and wafer manufacturers
• 20% to establish a fund, managed by U.S. Department of Commerce, for “re-initiation of manufacturing capacity idled between March 1, 2017 and date of imposition of safeguard measures.”

3) Creation of a “separate economic investment development program funded with any duties collected under a safeguard action” with the purpose of spurring new U.S. c-Si production capacity along the entire silicon to module supply chain.

4) Have the President initiate international trade negotiations to mitigate the underlying causes of increased imports to the U.S.

Implications

This Section 201 petition differs from the 2013 tariffs in significant ways that make a favorable ruling both more difficult to achieve but also (potentially) waaaaaay more impactful if achieved.

First off all, this thing will move quickly. The process starts with the International Trade Commission (ITC), which would decide on the “injury” within 120-150 days. A finding in favor of Suniva with recommended remedies could be sent to President Trump within 180 days. And then – that’s it. That’s the last step. It’s up to the Trump Administration, which hasn’t been shy about how it views global trade, to just accept, or even modify, the relief measures.

Um, uh oh?

solar trump agenda

There is no sense guessing how this plays out. Section 201 petitions are rare, and proving a “serious injury” to the ITC is a high standard.

But, let’s play out a potential scenario.

If a serious injury is found, the ITC could recommend a ton of remedies, including import tariffs, import volume limits, minimum prices and so on – and they could be aimed at any and all countries. And again, with such a decision then sent to President Trump as the final decider of implementation, this could just be the first domino in a series of politically driven trade petitions.

It is a cut off your nose to spite your face scenario. The unintended, wide-ranging, long-term consequences of such a move is enough that even SolarWorld showed hesitation in its statement on the petition filing. (bolded here for emphasis):

“The case of Suniva dramatically demonstrates that the U.S. solar manufacturing industry still suffers from unfair trade. In particular, highly subsidized Chinese companies as well as other producers are globally dumping their products, forcing competitors to take losses, lay off workers and exit the market. SolarWorld has fought decisively against this kind of unfair competition for many years. China now has managed to circumvent and violate existing trade defense measures in several ways and again incited a ruinous price race to the bottom, destroying U.S. manufacturing jobs. SolarWorld – as the largest U.S. crystalline-silicon solar manufacturer, with more than 40 years of U.S. manufacturing experience – will assess the case brought by Suniva but prefers that any action to be taken against unfair trade shall consider all parts of the U.S. solar value chain. We’re committed to helping to find a way that also considers the interests of other parties playing fair in the U.S. solar market.

— Solar Builder magazine

Ask an Expert: Inverter manufacturers give us their best troubleshooting advice

Christopher Barrett

Christopher Barrett

Wi-Fi Can Cause Communication Issues

Christopher Barrett, director of technical services, APsystems

We often see issues our installers are facing related to communication, often due to misplacement of the gateway or an unreliable internet connection. Following best practices recommended by the manufacturer will help installers reduce repeat site visits to fix communication problems. Some of these best practices include installing a gateway in the correct location, which is typically a direct connection to the service panel in which the PV array home-run is landed (often a dedicated PV sub-panel). We also recommend using a wired ethernet connection whenever possible to better ensure reliable communication and minimize returns to the jobsite.

Ryan LeBlanc

Ryan LeBlanc

Double-check those Airways, String Lengths

Ryan LeBlanc, senior applications engineer, SMA America

  1. Over-voltage, strings that are too long, are the fastest way to kill an electrical device.
  2. Blocking airways, installing inverters too close to walls or other inverters, and not inspecting inverters regularly for a blocked air intake are both common. This results in less production, but it’s hard to say if it kills them earlier.
Frank O’Young

Frank O’Young

Pro Tip: Try Different Cable Colors

Frank O’Young, associate VP, Darfon

Our tech team sees that often the polarities of the DC lines from a PV module or string are incorrectly connected to the inverter due to the fact that same color cables (mostly black) are used for the + and – of the module or string. This can be avoided by using different cable colors for different polarities or checking the polarities before inverter connection. Our tech team also sees of that the L1 and L2 lines of the AC circuit are incorrectly wired when tying the inverter to the grid. Caution should be taken when connecting the L1 and L2 and instructions from the inverter manual should be followed.

RELATED: 2017 Solar Inverter Buyer’s Guide 

Mark Cerasuolo

Mark Cerasuolo

Storage is Complex – Get Trained to do it Right

Mark Cerasuolo, director of training and marketing, OutBack Power

Since our products and systems typically either include or interact with batteries, some training beyond what most grid-tie installers have is really necessary to ensure a safe and reliable installation. Even then, we really encourage installers to use pre-wired systems to ensure that the system is complete and wired correctly.

Ed Heacox

Ed Heacox

Top 4 inverter installation issues from CPS

Ed Heacox, GM, CPS Americas

  • “Grid V Out of Limit.” This is when the customer forgot to check that AC switch is on, so the inverter thinks the AC grid voltage is out of limit.
  • String mis-match. An inconsistent number of panels per string on one MPPT.
  • Exceeding DC/AC ratio recommendations. This can lead to occasional intermittent faulting.
  • Installing the DC string from left to right when it would be more ideal to balance the load across two MPPTs. This can lead to one MPPT too far out of balance from other MPPTs (e.g. four strings in No. 1 and one string into No. 2).
Peter Mathews

Peter Mathews

Watch your Connections, System Design

Peter Mathews, North American general manager, SolarEdge

Two very common errors are the improper mating of the connectors or reverse polarity. Other items that relate to the connectors include leaving connectors open during the installation process, which can lead to water penetration, or not fully crimping the wires. Another area in which we see support issues arise is in system design. For example, SolarEdge enables the installation of longer strings, so installers who are used to standard design constraints may out of habit design short strings instead of the 11.25-kWp strings that are available with the SolarEdge solution.

Brian Lydic

Brian Lydic

Inverter Integrity Starts with a Correct Installation

Brian Lydic, senior standards and technology engineer, Fronius USA

The most common installation oversights we see are related to torqueing, inverter location and moisture management. The mounting bracket must be installed on a surface to ensure there is no bowing or warping of the bracket. The wiring compartment must be wired as per guidelines to ensure a flush mating of the inverter body to the mounting bracket chassis. If wire routing or conduit fittings are not considered, there may be a loss of integrity in this seal. Pay special attention to the DATCOM cover. Make sure it “clicks” or “snaps” in place before screws secure it. If the cover is simply screwed in, there may be bowing and slight gaps between the inverter body and DATCOM cover, allowing water ingress.

— Solar Builder magazine

Top 5 battery installation issues for solar installers

Battery Bank

With the right installation, battery banks can provide reliable power for years. In this article, you’ll discover how to avoid costly, hard-to-diagnose battery installation mistakes, and you’ll learn a holistic approach that prevents costly errors long before installation.

1. Not Starting with Efficiency

Each additional kWh of energy demand requires extra solar or wind generation, battery storage and backup generation. Thus, it’s cost-effective to start by increasing efficiency.

First steps include replacing inefficient electronics and appliances with Energy Star models, eliminating vampire loads using switchable power strips and adjusting thermostat settings seasonally.

Next, consider adding blown-in insulation to walls and attics. Since nearly half of household energy is used for space heating and air conditioning, this can drastically reduce heating and cooling demands.

Finally, whole-house fans and nighttime ventilation offer inexpensive comfort. And compressor-less Variable Refrigerant Flow HVAC reduces electricity usage by ~90 percent.

2. Improper Sizing

Oversized panels, turbines and batteries waste money, but undersized systems can make everyday living frustrating — and shorten battery life due to deep discharging. The solution? Calculate accurate electrical loads.

After taking steps to improve efficiency, check the past year’s utility bills to estimate power requirements. Affordable devices like Kill-A-Watt accurately monitor individual appliances’ energy usage and reveal vampire loads. From there, the basic calculation for a system’s power needs is: Watts = amps x volts

For instance, if 1,000 watt-hours (1 kWh) a day are needed, a 12-volt / 84 Ah battery bank (1,008-watt capacity) will not address power demands because the battery would be exposed to 100 percent depth of discharge every cycle.

Experts recommend sizing your system based on a maximum of 50 percent depth of discharge (DoD). In the example above, the battery bank would need to be sized to 12 V / 168 Ah — double the estimated Ah requirements.

Note that some battery manufacturers size systems based on 80 percent or 100 percent DoD. This assumption can provide inadequate reserve power for heavy loads during heat waves and frigid winters or for cloudy or foggy days with low solar production. Batteries discharged by more than 80 percent lack reserve capacity to power high-energy appliances or even keep the lights on.

3. Choosing the Wrong Batteries for the Application

There’s no one-size-fits-all battery. Instead, key factors include ambient temperature, technology, desired voltage, maintenance, sustainability/recyclability and cost.

Lead-acid batteries are the most common for renewable systems. Refined over 100-plus years, they’re longer lasting and 50 to 90 percent less expensive than other technologies. According to the EPA, lead-acid batteries are 99 percent recyclable — more recyclable than an aluminum can.

Options include flooded batteries, which offer the highest ROI but require periodic water adjustment and other preventive maintenance, sealed valve-regulated lead-acid (VRLA) batteries and zero-maintenance options that are more expensive.

RELATED: Is there a PV storage solution between lead-acid and lithium ion? 

Lithium-ion batteries don’t require maintenance and offer the highest power density (and thus, lightest weight). For lithium-ion batteries, battery management systems (BMS) are required to prevent overcharging and to reduce the risk of house fires and explosions caused by thermal runaway. Li-ion’s cost per Ah is the highest and they are zero to 60 percent recyclable.

BMS is not required for lead-acid and many other battery chemistries, but BMS is beneficial because features like temperature-based charging, total and per-cell voltage and DoD monitoring help increase capacity and minimize damage caused by temperature extremes.

Whatever technology you choose, only buy deep-cycle, renewable batteries designed specifically for heavy cycling.

4. Improper Wire Sizing

Wire size varies based on amps carried and how many feet electricity must travel. Often, undersized cables are the hard-to-diagnose cause of system failure.

Just as water needs enough pressure to travel through a garden hose, an electric current must have enough voltage to travel. And much like a garden hose, electrical current must exceed pressure (impedance or resistance) caused by wire shape, thickness, length and other variables.

When cables are too small, voltage drops and makes the load work harder. This can cause lights to flicker, heaters to underperform and motors to burn out early. Worse, undersized cables can generate heat and even start fires. A smaller AWG means a larger cable. To calculate ideal wire size, use a “wire gauge calculator” and specify no more than a 3 percent voltage drop.

5. Improper Storage

Batteries last longest at or around 77˚ F. Every 18° F temperature increase drops available cycles by 50 percent. The cold reduces available capacity exactly when solar production is lowest and energy demands are highest.

The only solution to this problem is protecting batteries, but common storage solutions such as insulated coolers and old refrigerators offer little buffer against the cold, and they trap so much summertime heat that battery temperatures often exceed 140° F.

A better solution is storing batteries in a well-insulated, enclosed structure, either inside the home or in a properly vented box in a garage or shed. To do this, arrange batteries to ensure 1/2-in. air gaps and allow for easy maintenance. Never install breakers, switches or spark-producing devices inside an enclosure — this could cause an explosion.

The best approach uses standalone systems such as EMPUS, an insulated structure that maintains ideal operating temperatures year-round, to maximize the lifespan of batteries and electronics.

John Connell is VP of Crown Battery’s SLI Products Group.

— Solar Builder magazine