June 13, 2016

Demand-based rates could create a new market for combining rooftop solar with household battery energy storage to benefit customers and the energy grid, according to the Arizona Republic.

Reporter Ryan Randazzo writes that two companies, JLM Energy of California and Tabuchi Electric of Japan, have established a presence in Arizona to market their solar-battery storage combo systems. Both companies say that the technology can help customers lower peak usage (demand) charges and reduce strain on the grid.

They are among a number of companies, including Arizona-based Sun Valley Solar Solutions, American Solar and Roofing and Harmon Electric, that are researching new technologies that can make rooftop solar more beneficial to managing peak demand. Randazzo writes:

“That's because solar panels produce the most power at noon, but generate only about a quarter of their full capacity toward sunset and nothing after dark. Meanwhile, demand for electricity in the Phoenix area peaks around sunset, when businesses and homes are running air-conditioners the most. Despite the power rooftop solar panels generate when the sun is high, they don't do much to mitigate the late-afternoon demand.

“Batteries can change that. Rather than send excess power to the grid, the solar panels can fill up the batteries during the day and can be used to power appliances during the evening peak.”

The Arizona-based companies and JLM Energy are participating in the APS Solar Innovation Study. The collaboration includes outfitting 75 homes with technologies ranging from rooftop solar panels, battery storage and programmable thermostats to advanced load controllers and high-efficiency HVAC systems. Customers will also move to a demand-based rate plan as part of the study.

"The demand-rate structure will turn on a go light for all the cool technology customers have been waiting to use," said Marc Romito, Director of Customer Technology for APS.