Solar PV-Plus Batteries Become a Reality in Residential Markets

On April 21, 2021, Elon Musk tweeted that Tesla will no longer be selling standalone solar energy systems to residential clients. Instead, customers must buy an integrated solar and Powerwall product. Tesla’s decision reflects how the value of solar energy is changing. Initial setups to encourage residential solar deployments, like net metering and high feed-in tariffs, are being replaced by time-sensitive designs, like time-of-use residential feed-in tariffs that account for when electricity is generated throughout the day. 

I have previously written about why Tesla should focus its energy business on their Powerwall technology, even if that means cannibalizing profit margins on its solar installations. By leaving the standalone residential solar market and focusing on combining solar and storage, Tesla is refocusing its customers on a product that is closely associated with the brand.

Increased Focus on Integrated Systems

It’s not only Tesla that is moving toward these integrated systems. Sunrun, in its March 2021 investor presentation, announced its impending transformation from having a simple standalone solar offering to becoming a key provider of distributed energy resource clean energy by integrating solar, storage, and EVs into its virtual power plant. It reported last year that one-third of its California installations included storage.

The world of independent installers is not much different. EnergySage reported in its 2020 Solar Installer Survey (conducted in collaboration with the North American Board of Certified Energy Practitioners) that around 75% of solar installers offer energy storage to their clients and around 63% offer EV charging equipment. The same report also highlighted that almost half (46%) of the people who bought solar through EnergySage installers showed interest in storage systems and that 20% bought both solar and storage systems.

In Europe, Germany has had a successful residential storage incentive program that saw a surge in PV-plus battery systems, and in other countries—like France, Italy, Spain, and Switzerland—installers have seen increased interest in these hybrid installations.

Integrated Systems Offer More Benefits to Consumers and the Grid

Although most residential solar installations are still standalone systems, there is a clear trend toward integrated systems. This is good for consumers, who now receive additional services such as islanding from their solar systems. It is also good for the distribution grid, which will see less impact from solar energy systems. Differing investments and reducing operational costs could also enable further benefits for the grid.