Only 12 percent of solar installers carry Tesla’s Powerwall, according to the latest findings in a report from EnergySage and the North American Board of Certified Energy Practitioners. 

The report, a nationwide survey of U.S. solar installers, noted that one in three customers are now expressing interest in energy storage solutions for their home. Of that subset, installers reported that 56 percent of consumers ask for the Powerwall. A much smaller portion are actually getting the product, according to the survey’s results.

“There were product availability issues for the Powerwall and the LG Chem Resu in 2018. Most of the installers and developers I talked to cited this as an issue,” said Brett Simon, a senior energy storage analyst at Wood Mackenzie Power & Renewables, an energy research and consulting group.

“One big reason," he added, is that "South Korea had attractive incentives that expired at the end of 2018, so manufacturers, especially local Korean companies like LG Chem, prioritized storage capacity to that market first.”

For Tesla, the problem has largely been prioritizing its vehicle manufacturing, with a push to meet production targets on its Model 3.

Source: EnergySage and the North American Board of Certified Energy Practitioners  

In the company’s second-quarter earnings call last year, CEO Elon Musk conceded that supply issues persist for the batteries. He said Tesla was “cell-starved for Powerwall” and had to “artificially limit” the number available because of those cell shortages.

Musk used the “cell-starved” line again in the most recent earnings call in Q4. But the company has also noted that, with a new manufacturing line opening at its first Gigafactory, it aims to bump overall global energy storage deployments to over 2 gigawatt-hours this year. 

In the U.S. residential storage segment, Tesla sells a significant portion of its products (it does not disclose how much) through third-party installers, which are also hungry for more supply, while some installers are still hoping for a chance to work with Tesla at all. The company is selective about certifying third-party providers that can offer Tesla products, a strategy seen as another way to manage its luxe brand image. 

Tesla’s internal distributed energy sales strategy evolved significantly in 2018, when it ended its partnership with Home Depot. The company has also ditched the door-to-door model used by many clean energy companies (including the now Tesla-fied SolarCity), and now focuses on selling solar and storage directly to customers via its website and retail stores.

In its Q3 2018 letter to shareholders, the company affirmed that it hopes Tesla vehicle ownership will act as a conduit to its other products. 

“At the end of Q3, there were almost 450,000 Tesla vehicle owners around the world,” the letter reads. “Ultimately, we believe this group will become the largest demand generator for our residential solar and Powerwall business.” 

So far, Tesla’s new sales strategy appears to be flagging for its residential solar business. Last year Sunrun overtook Tesla as the largest residential solar installer. Allison Mond, a senior solar analyst at WoodMac covering residential solar, called Tesla’s sales strategy “a pretty unproven way to sell residential solar.”

Simon at WoodMac also noted “a big gap” between customer interest in residential storage and actual sales, in part because of the price tag associated with the projects.

According to the EnergySage and North American Board of Certified Energy Practitioners survey, the portion of quotes including energy storage increased from 14 percent of projects to 20 percent last year. The number of installations that included energy storage rose from 7 percent in 2017 to 11 percent in 2018.

Other results from the EnergySage/NABCEP survey indicate that more installers are looking to add energy storage to their product lines in 2019. In the most recent survey, 9 percent of installers said they plan to add storage offerings in 2019 and 69 percent of installers said they offer energy storage today.