When is the solar-plus-storage era going to get here?

storing solar

You know how when you can see mountains in the distance, and it looks like they are maybe only a mile or two away but really they are 100 miles away? This is our perception of solar-plus-storage — the most visible topic towering over the industry for the last few years, and yet, where are all of the installs?

That was our starting point for this article. Is solar-plus-storage just great in theory and easy to hype, or is it close to catching on? As always, the answer is a firm maybe. Let’s dive into the factors that will get us from here to that proverbial solar-plus-storage mountain on the horizon.


This is the driver of the whole movement, but the available technology is already pretty great and not a barrier holding back wider adoption. There is now an abundance of system controllers with intelligent software that can handle solar-plus-storage as well as become the central hub for the oncoming smart home revolution, connecting with and distributing energy efficiently among home appliances.

But there’s always room for improvement. The next step could be connecting these decentralized brains. Sonnen’s already done this in Germany with its sonnenCommunity in which systems are networked together to act as a virtual power plant and energy trading community. The company is working on accomplishing the same in the U.S., opening its first net-zero community last year in partnership with Vermont utility Green Mountain Power.

“As discussions between renewable technology companies and local utilities begin, we can expect to see developments in the aggregation model, which allow it to be better integrated into the U.S. utility market,” says Michelle Mapel, director of marketing at sonnen.

Adara Power, as another example, just debuted its second-generation residential ESS Adara Pulse that uses its iC3 Smart Controls technology. Here, Adara has integrated the system controls with its cloud-based data network. This optimizes energy flows to and from the grid to automatically achieve the minimum cost profile. It also decouples the controller from the system so that it can work with an array of inverters and batteries as new technology becomes available while allowing Adara to remotely monitor for system performance, firmware updates, remote troubleshooting, etc.

Sales and Marketing

Storage is still in its early adopter stage, but becoming more mainstream is just a matter of stacking the right pieces together.

“People in the U.S. are much more savvy about the advantages of energy storage technology, especially as time-of-use rates change and evolve. They are very surprised to hear that solar alone won’t operate if the grid fails. That’s a clause buried at the bottom of every solar contract,” says Greg Maguire, co-founder and VP of sales and marketing of Adara Power. “In many cases, we find it’s the solar sales teams that need to understand the benefits of adding energy storage.”

To aid in that effort, Adara introduced a Partner Program for installers and developers in June 2016 that allows solar installers to make an easy transition into the energy storage industry, to better understand the benefits and make an effective sales pitch.

On the Scene: 11 cool things we saw at Intersolar 2017

But each installer can only do so much. Mapel points out that getting to the point where energy storage is part of a new home build requires utilities to play a key role in promoting energy storage to their massive customer base through growing partnerships.

“This will allow the innovative technology to be brought to neighborhoods and populations who may not be as green-conscious,” she says. “Education is key to increasing the implementation of energy storage across the country.”


In its published report “Installed Cost Benchmarks and Deployment Barriers for Residential Solar Photovoltaics with Energy Storage: Q1 2016,” Researchers from the U.S. Department of Energy (DOE) National Renewable Energy Laboratory (NREL) offered an expanded look at the component- and system-level cost modeling methodology for solar-plus-storage systems, to better understand the cost profile. This first effort showed that declining costs in customer-side energy storage products have opened the door for batteries to improve the value and flexibility of residential PV systems while falling costs in PV technologies have been driving the growing adoption of combined PV and storage solutions. However, gaps remain in developing an in-depth understanding of the costs of combined PV and battery systems and in effectively communicating their value proposition.

The authors separate installed system cost into 13 categories that range from direct hardware costs, such as the PV modules and batteries, to soft costs such as labor, permitting and net profits. The resulting cost for a DC-coupled system that integrates a 5.6-kW PV array and a 3-kW/6-kWh battery is $27,703, which is roughly half hardware costs and half soft costs. An AC-coupled system, which can be more effective in applications that tend to use the energy from the PV array at the time of generation, costs $1,865 more if the battery is installed at the same time as the array. In settings where the battery is retrofitted to an existing AC-coupled system, the cost increased to $32,786. The system design that provides for greater resiliency with a 5-kW/20-kWh battery costs $45,237 when DC-coupled and $47,171 when AC-coupled.

The cost of ESS equipment has come down as battery technology has evolved. Maguire has seen the total cost of ownership drop to less than half, or even one third, of the list price in the right market. Cost comparisons in storage systems can be complex because of the variety available. Some offer only batteries, some offer batteries with an inverter and others focus on one-stop, all-in-one systems.

All-in-one systems tend to have more premium pricing because they include all the needed components to effectively store and manage energy. Other systems on the market require some components to be purchased and installed separately, so while the initial price may look more affordable, once gathering all the other components, the prices are pretty comparable.

Sonnen, recommends comparing systems by the price that will be paid per kWh — multiplying the size of the system (10 kWh, for instance) by the number of cycles its warrantee guarantees, then dividing that value by the cost of the system.

“You should also consider the cost per warrantied battery cycle as this is a true indicator of the cost for using the battery instead of the cost of it just sitting in your home,” Mapel says, which you do by dividing the total cost by the warrantied number of cycles. So, in the case of sonnenBatterie systems, which are warrantied for 10 years or 10,000 cycles, the system usage cost is approximately $1 per cycle depending on system size.

“Price is an important part of the consideration set for end customers, however given the evolving business models for storage it’s important to consider price with a view of the long-term benefits of a system, not just the short-term cost,” Mapel says.

Rates and Incentives

The future of energy storage will be as impactful or as niche as utilities and policymakers allow it to be, either intentionally or unintentionally, just as has been the case in the solar industry.

Incentives certainly help, and there are more of these popping up. California’s SB 700, the Energy Storage Initiative, would create a rebate program for local, customer-sited energy storage. Much like the California Solar Initiative that transformed the solar PV market, this bill would create a declining rebate system to encourage businesses to bring down prices. Maryland is on track to become the first state to offer a tax credit to consumers with home energy storage systems. Massachusetts is investing $10 million to advance the storage segment of the state’s clean energy industry, and New York announced $15.5 million in funding for energy storage projects through 2020.

The Holistic Home: We peer into the future of home energy generation, usage

Incentives aren’t necessarily the path forward though. Ironically, some of the utility-driven energy policies that the solar industry is fighting against, like anti-net metering proposals, improve the case for solar-plus-storage. This has been borne out by examples set in Australia and Germany — two booming solar-plus-storage countries. If you won’t see a return sending your excess energy to the grid, then why not use it strategically to shave peak demand or shift time of use? Maguire believes that solar designers will look at reducing the amount of PV they are estimating for a job and offset it with a corresponding amount of energy storage. This will be the focus for the future for the solar industry in the United States.

“Payback periods and ROI calculations vary by the type of solution chosen, installation specifics and local utility rates and policies,” Maguire says. “System capabilities have significantly increased [e.g. 8.6 kWh to 20 kWh] with the cost per kWh decreasing even more as a customer goes up in energy size. So, we are at this point where it makes more economic sense to install larger energy storage systems, and we can use that premise to really build a solar-plus-storage system that probably requires less solar than a normal full net-metered solution would require. With rate structures changing to time of use rates, customers will definitely see a need to add storage to offset the higher energy costs later in the day.”


“There is opportunity for payback to households, but it will be unique to each individual utility partnership and may take longer to come to fruition under the U.S. system,” Mapel says. “However, once developed, these partnerships will have immense opportunities for end-users. As new business models arise and the market matures, storage adoption will increase, leading to a decrease in system costs and faster payback periods, but for now price and value are important factors in growing the storage market.”

This article appears in the Jul/August 2017 issue of Solar Builder. Get your FREE print or digital subscription here.

— Solar Builder magazine

On the Scene: 11 cool things we saw at Intersolar 2017

Another Intersolar has come and gone, but the product innovations, large and small, are here to stay. At least until next Intersolar. If you missed the event, or didn’t have time to see all three floors, here are some products that stood out to us in the exhibit hall.

1. This quick driveline disconnect

Array Technologies Duratrack

Array Technologies is the market leader in central drive solar trackers. Array tries to minimize parts count wherever it can (150 MW of PV only needing 150 components total), and we stopped by the booth to check out some of the handy new tweaks made to its DuraTrack HZ v3. In addition to a built-in above ground wiring component, we thought this quick disconnect driveline was a smart, simple improvement for those who have always wanted a streamlined way to move the driveline for maintenance activities.

2. This simple tile mounting system

Ecofasten simple tile

Ecofasten maybe wins our award for variety of new solutions packed into one booth at Intersolar. Many of these items aren’t fancy – like partnering with Unirac on an install kit (packs of 10) – but as most of the names suggest, they are simple, which is often even better. Like this new (so new it isn’t officially named) Rail-Based Tile System. The flashing itself replaces one complete tile, so no cutting, drilling or grinding there. After the stud and simple seal bushing are fastened to the tile base, place the flashing over, pound it with a hammer to form a hole over the stud and then install the L-foot with a bonded washer and nut.

3. An AC module power couple

LG enphase AC module

Details on this here.

4. The concept of ‘Microstorage’

JLM Energy

JLM Energy launched a new energy storage product category called MicroStorage — a battery pack that couples directly to a corresponding solar panel, as you see here. JLM says the advantage of its Phazr’s microstorage approach is that a single solar panel can concurrently charge a battery and deliver energy to the grid. The simultaneous nature of electron flow is unique to JLM’s patent-pending technology. The Phazr is designed for large scale solar plus storage applications, and is also perfectly suited for smaller residential and commercial installs.

5. A totally new approach to ground-mounts

Nuance Energy

This could be a gamechanger for ground-mount installations. Nuance Energy has a new solution, inspired by an old solution: anchoring. Nuance Energy wants to lessen the amount of steel needed on a site by not driving any into the ground at all. Using the pieces you see above, a hole is drilled, the anchor is driven down 40 inches into the soil and pulled by an uplift device. As the anchor turns and is pulled there is a natural ballasting that occurs using the earth itself. Utility poles are anchored using this strategy. This could drastically save on traditional installation, and even created a new “lift and shift” category, where a portable unit is fixed into place on a drilling or mining site and then removed once the project has ended.

6. This wall-mounted 100-kW inverter


The combo EV charger / inverter maybe received the most buzz on the floor, but we gravitated to its new wall-mounted 100 kW inverter. Yes, a wall-mounted 100 kW inverter. This prewired three box setup looks like (and installs like) three string inverters, but is commissioned as one inverter. Installing 1 MW in half a day is a possibility.

7. The wire management on this tracker

SF7 Soltec Bluxome party

Soltec made a splash at Intersolar this year as it tries to do more business here in the U.S. There is a lot to like about their product, like the amount of panels you can mount in one row (which makes for a more energy dense field), but it was the little things that stood out most. Specifically how the wire management of the system is housed inside the torque tube.

8. The potential of this smart home device for solar installers

smappee solar storage

I have no live photo of this (it was the afternoon of Day 3 and I forgot — give me a break, already.) but the Smappee is the coolest thing we saw the entire week. Attach it to the cable coming into the house, and the Smappee will listen to everything – what’s turning on and off, how much standby power there is, how much PV is being generated, and on and on. This gives homeowners much deeper (and easy to follow) insight into their home energy consumption and, at the same time, provides solar installers another touch point for customer follow ups and service. The low price point (under $400) makes it potentially an easy first foot in the door. Right off the bat, a homeowner is likely to save 12 percent on their utility bill, just through awareness and optimization tips from the app. From there savings could approach 45 percent.

9. This stepped-up decentralized tracker

solar flexrack tracker turnkey

Solar FlexRack launched its TDP Turnkey Tracker about this time last year. The update for this year is a newer, longer single row tracker (90 modules with 2 to 4 more posts), adjusted by a larger motor that will open up larger, utility-scale projects. The torque tube is offset to achieve better balance. The attention to detail is big for Solar FlexRack, which is why “turnkey” is built into this product’s name – its slew of engineers are involved in their installations to avoid adding their company name to the list of growing tracker system failures out in the field.

10. This tripod tile mount

Sun Modo tile

Sun Modo tripod

The last few years has seen a flood of great tile roof mount solutions enter the market. The TopTile Mount that SunModo debuted at Intersolar is an entirely above-the-tile system – no need to deconstruct the tile roof. The tripod mounting stanchion can be mounted on a tile ridge independent of rafter position. This could cut your install time in half, compared to a more conventional approach.

11. Smart surge software

Tabuchi Americas

Now with a two-battery system setup, Tabuchi Americas continues to improve upon its solar+storage system (now more than 20,000 installs worldwide). Thanks to an integrated transfer switch, everything needed to get a PV + storage system up and running is included in the package, which means at least $1,000 soft cost savings over an unbundled system. In fact, this is one of the first UL 9540 certified systems – the certification specifically for solar + storage systems. Updates to the system’s intelligence has also improved its defenses against power surges from things like water pumps.

— Solar Builder magazine

Delta debuts outdoor energy storage system cabinet at Intersolar

Delta Group launched its Outdoor Energy Storage System (ESS) Cabinet at Intersolar North America, expanding its extensive line of energy storage solutions.

Delta ESS Cabinet explained

Delta energy storage system

The Delta ESS Cabinet incorporates lithium-ion battery modules, a Battery Management System (BMS), and a built-in HVAC system for thermal management. Boasting a scalable system configuration, and IP55 rated for dust and water protection, the ESS Cabinet can easily meet a diverse array of field capacity requirements, making it the perfect solution for any environment.

Through high energy density and a long lifecycle, the ESS Cabinet helps commercial and industrial buildings optimize energy usage and save on operational costs by enabling demand charge management through peak shaving, time-of-use optimization via load shifting, power backup, renewables self-consumption optimization and ancillary power services. The ESS Cabinet has a scalable capacity up to 1.32 MWh, making it ideal for medium to large scale commercial and industrial deployments.

Delta’s Full PV and Energy Storage Solution

At booth 9021, Delta will also be showcasing a wide range of solutions that can be paired with the new ESS Cabinet or serve as add-ins for existing installations. Delta’s portfolio consists of a wide-range of solar inverter technologies, power conditioning technology and even control solutions.

Delta’s Power Conditioning System (PCS) is a bi-directional inverter with industry-leading power performance engineered for grid-tied energy storage systems. This technology pairs perfectly with the new Delta Outdoor ESS Cabinet or other mainstream branded battery systems. Delta’s PCS has minimal stand-by power loss, and provides real and reactive power compensation to improve power quality for a building.

Solar power inverters are a vital part of every solar installation. Delta has a wide-range of inverter options ranging from 3kw to 80kw. On display will be Delta’s M42U and industry-first M80U grid-tied, three-phase, transformerless inverters. The two inverters boast exceptional peak efficiencies of 98.6 percent and 98.8 percent, respectively. Through best-in-class engineering and quality manufacturing, Delta’s rugged inverters offer a combination of longevity and efficiency.

— Solar Builder magazine

Massachusetts sets high bar for 2020 energy storage target

massachusetts solar storage goals

Massachusetts has set a 200 megawatt hour (MWh) energy storage target to be achieved by Jan. 1, 2020. The target, set by the Department of Energy Resources (DOER), builds upon Governor Charlie Baker’s Energy Storage Initiative (ESI), a $10 million commitment to analyze opportunities to support Commonwealth storage companies and develop policy options to encourage energy storage deployment.

In order to continue supporting the development of energy storage in the Commonwealth, the Administration also announced up to $10 million in additional funding for energy storage demonstration projects that are consistent with the findings of the ESI’s State of Charge study and that DOER will examine the benefits of amending the Alternative Portfolio Standard (APS) to expand the eligibility of energy storage technologies able to participate.

“As the Commonwealth continues to make unparalleled investments in renewable energy, energy storage technologies have the potential to play an integral role in effectively deploying these new resources,” said Governor Charlie Baker. “This target, paired with our Energy Storage Initiative, will cause the state and industry to lead the way on exploring the most cost-effective deployment of energy storage for Massachusetts’ ratepayers.”

Energy storage potential

State of Charge, released by DOER in September 2016, identified hundreds of millions of dollars of potential ratepayer benefits from the deployment of energy storage in Massachusetts. Since its release, DOER has already implemented a number of the report’s recommendations to promote energy storage in the Commonwealth. They include, but are not limited to, becoming the first state in the nation to incentivize the pairing of energy storage with solar in the new proposed solar incentive program, SMART; authorizing the pairing of energy storage technologies with the largest procurement of clean and offshore wind energy generation in state history, 9,450,000MWh of clean energy generation and 1,600MW of offshore wind energy generation; continued energy storage grant opportunities through the Community Clean Energy Resiliency Initiative; and funding energy storage projects through the Peak Demand Reduction Grant Program.

“State of Charge showed that energy storage has the potential to be a game changer for Massachusetts, with hundreds of millions of dollars of ratepayer and system benefits,” said Secretary of Energy and Environmental Affairs Matthew Beaton. “The 200MWh target, developed with the feedback of a wide range of stakeholders, will build upon the Baker-Polito Administration’s commitment to growing the deployment of energy storage throughout the Commonwealth.”

The Holistic Home: We peer into the future of home energy generation, usage

In calculating the achievement of the target, DOER will consider procurement methods including, the refinement of existing clean energy procurement methods, participating in alternative compliance payment funded pilot programs in which the company is an awardee or in a partnership with an awardee, and through the use of energy efficiency funds. Additionally, the target sets a flexible goal for the electric distribution companies to identify the most cost-effective applications and the best locations for energy storage deployment, including both in front of the meter and behind the meter applications.

“Massachusetts should be congratulated for their holistic efforts to incorporate energy storage into multiple state programs focused on clean energy and grid reliability,” said Matt Roberts, Executive Director of the Energy Storage Association. “We look forward to working with the Baker-Polito Administration and leaders in the Legislature to build upon this initial target so that Massachusetts residents can reap the benefits of a more reliable, flexible, and affordable electric grid.”


— Solar Builder magazine

Inverter manufacturer Tabuchi invests in ground-mount developer Nuance Energy

Nuance Energy, the manufacturer of the Osprey PowerPlatform and a developer of distributed ground-mount solar projects, today announced it has received a $3 million investment from Tabuchi Electric Co. LTD.

The two companies already have a close working relationship. Nuance Energy, an early North American customer for Tabuchi, has installed the company’s commercial string inverters on several projects. Working together on these projects led Tabuchi Electric to discover the strategic advantages afforded by the Osprey PowerPlatform. The companies plan to continue working together to find synergies benefiting customers that use Nuance’s Osprey PowerPlatform and Tabuchi’s commercial products.

Tabuchi- Electric EIBSinverter crop

Tabuchi Electric made the investment in Nuance Energy to expand its learning and reach into the growing market segment of ground-mount distributed generation Solar+Storage. Tabuchi, already present in the residential Solar+Storage market with its EIBS, plans to expand its storage offerings to the commercial market and expects to gain valuable insights from the relationship with Nuance Energy to further drive innovation.

“As a leading provider of grid-friendly solar-plus-storage systems optimized for energy management and cost performance, we were early to recognize that Nuance Energy’s unique value proposition would give us a significant advantage in commercial applications,” said Harumi McClure, COO and pres-ident of Tabuchi Electric Company of America, LTD. “Together our companies will expand the available market for solar and open up more project opportunities for our mutual distributor and EPC contractor customers.”

Nuance Energy’s Osprey PowerPlatform is a modular ground-mount solar racking system that applies patent-pending technology to afford numerous advantages, including simplified engineering, adding modularity to the procurement process, and dramatically reducing construction costs and effort. The Osprey PowerPlatform employs a unique, minimal earth-penetrating anchor application process and a modular, scalable design that enables contractors, developers, integrators, and engineering, procurement and construction (EPC) firms to achieve peak profitability through the industry’s lowest labor and installation costs and fastest time-to-revenue for available ground mounted system solutions.

What you need to know about 1500-volt inverters

Unlike conventional ground mount systems that require a detailed geotechnical report, extensive engineering effort involving the use of ground screws and pier foundations, and costly construction techniques that require heavy onsite equipment, the Osprey PowerPlatform enables field crews to install the solar arrays using only handheld tools. The design also eliminates the need for special inspections by facilitating simple field load testing in real-time soil conditions to assure compliance with applicable codes and regulations. This ability to deploy solar arrays on varied terrain under any type of soil condition helps make solar energy more practical and affordable at any scale, and creates more opportunities for agricultural, commercial, industrial and small utility-scale projects.

— Solar Builder magazine