The combination of solar photovoltaics with energy storage for electricity customers has been receiving "tremendous" attention in the last few months. According to a report from GTM Research, the anticipation is from the potential for the first wave of growth in markets such as California and Hawaii.

The annual market for solar-plus-storage is expected to grow from $42 million in 2014 to more than $1 billion by 2018, according to the report. Barriers remain for solar plus storage to be a viable option, including cost reductions being in the early stages and business models that need "continued refinement."

California, New Jersey and New York do have upfront incentive programs for behind-the-meter solar and storage: "California’s Small Generation Incentive Program, in particular, has facilitated the deployment of several megawatts’ worth of solar-plus-storage to date. For a typical commercial end customer, solar-plus-storage systems can provide electricity bill savings of 20% to 30%, depending on system size. More than half of those savings typically stem from demand-charge reductions," the GTM Research report said.

GTM's report focuses on behind-the-meter segments of residential and non-residential, providing a comprehensive analysis of the nascent but accelerating solar-plus-storage market, including market drivers and barriers, end-customer economics, the evolving vendor ecosystem, and a market outlook.