As homes become increasingly electrified and utilities respond to higher demand with new and complex rate structures, solar + storage projects have to find more creative ways to improve homeowner ROI.

The two largest residential solar inverter manufacturers have been adding new components to their offerings for the past few years. SolarEdge released its Energy Bank residential battery in the United States in 2021, added bidirectional EV chargers to its fleet in late 2023, and acquired EV charging software startup Wevo in April 2024. Enphase has been building its portfolio too, releasing a new LFP battery in May 2023, an EV charger in October 2023 and new power control software in April 2024.

The primarily inverter manufacturers argue that the sophisticated level of system visibility and intelligence required to get the most value out of systems is only possible when using key ancillary components from the same maker.

Installers find other benefits to these exclusive pairings too.

New Mexico contractor Solar Works Energy used numerous brand pairings for the past six years but found it difficult to troubleshoot problems with multiple manufacturers.

“One might say, ‘Well, it might be a battery setting,’ and other ones say, ‘It might be an inverter setting,’” said Solar Works’ operations manager Chris Hilkert.

To solve that frustration, Solar Works has switched to SolarEdge for both inverters and batteries on most grid-connected systems.

“When we’re dealing with SolarEdge, and we have their whole ecosystem, it makes it really easy. There’s only one point if you need support,” Hilkert said.

Iowa installer ECG Solar experienced the same customer service struggle in the past when mixing and matching inverter and storage brands. The company liked the reliability and streamlined service available for Enphase products, so it now primarily installs those inverter and battery combinations as an Enphase Gold Installer.

“Having it be an ensemble, meaning specifically designed to work together with all the Enphase product line, one single interface — it’s just a one-call type situation,” said Jason Gideon, president of ECG Solar.

Sticking with one brand for these main components is also helpful to the installers and electricians putting in these systems. Instead of trying to learn the basics of a plethora of products, they can become experts in a single brand.

“Asking a crew and an electrician to be a master of everything — that’s a tough ask. I’ve talked to other installers who kind of do everything and they never really know how to do anything very well, to be honest,” Hilkert said.

Whole-home energy systems

Both SolarEdge and Enphase said this exclusivity trend is inevitable as systems evolve from standalone solar to “home energy management systems,” including solar and storage, along with ancillary products like EV chargers, load control panels and more.

“There are really strong technical reasons why you want them both to come from the same vendor,” said Chris Thompson, VP of product and technical marketing at SolarEdge.

SolarEdge and other manufacturers use AI and machine learning to create digital twins of systems, predicting the best times to charge and discharge batteries, charge EVs and turn energy loads on and off.

“If you just have a discrete battery, that battery doesn’t know enough to make those decisions. So we’re increasingly getting to systems where, if you have a common platform, it makes better decisions, it generates more money [and] generates more savings by leveraging the synergy,” Thompson said.

While perhaps the most important work of these systems happens in the background to save customers money, choosing one vendor for these key products also means more streamlined visibility and management for the homeowner. It’s the difference between having one app to view all the pieces and parts or multiple apps to try to understand a home’s solar and storage consumption.

“It could be really complicated in the cloud, but for the homeowner, it’s just going to be ‘set it and forget it,’ and it makes all the decisions for them,” Thompson said.

Adapting to a changing electric grid

California’s NEM 3.0 shook up the industry in many ways, setting forth a complex matrix to determine ratepayer compensation for energy exported to the grid at certain times based on demand. To get the most value out of new California solar systems, homeowners need solar + storage software and hardware that’s intelligent enough to follow each utility’s unique plan.

“We have a very complicated solution in the sense of the complexity of the engineering. We’re running all these prediction models,” Thompson said. “You need a Ph.D. in math to figure this out, partly because the utilities are still figuring it out themselves.”

California is one of the first states to shift rate structures based on dynamic market variables, but it’s not far-fetched to expect other states to follow its lead as solar penetration increases and strain on the electrical grid grows.

After about two decades of electric demand remaining flat in the United States, it has spiked due to the boom in data centers and EVs, according to The New York Times. A Q2 2024 report by the NC Clean Energy Technology Center found that after a recent lull in policy actions, four states have initiated formal studies to inform net-metering successor programs and calculate the value of solar. Customers with smart, grid-responsive renewable energy systems will be the ones to benefit most as rate structures change with the times.

“When you have complex hardware and software now driving this energy system, mixing and matching becomes really problematic, because now you want to build this energy system. And it has got to operate as designed for 25 years, it has to adapt itself over time, because energy needs change and the usage profiles change,” said Raghu Belur, co-founder and chief products officer at Enphase.

Deep visibility into the home energy system paired with intelligent software is the only way to ensure customers are receiving the savings promised in the initial proposal, according to Belur. This starts with top-down system design.

“We use massive amounts of data to build our training models. And we use that same engine in the design and simulation tool. Then when we actually operate it, the two match,” Belur said. “Solar, battery, EV charger, heat pump, utility rates, VPP grid services — everything is incorporated into the design simulation engine.”

Stand-alone residential solar systems are giving way to whole-home energy systems including batteries, electric cars, load controllers and other tools to help homeowners become active managers of their own energy instead of passive utility customers. Orchestrating the smartest system possible is the challenge manufacturers are trying to solve by expanding to sell all the products these systems need.