The global off-grid energy storage market could surpass $13 billion by 2019, according to new analysis.

A report from research firm Technavio said the market is expected to grow at a CAGR of over 7% in the coming three years.

According to the report, lithium-ion (li-ion) batteries lead the field with revenues predicted to exceed $6 billion by 2019. A global increase in off-grid power production from renewables, especially solar and wind, has driven growth in this segment, as have the growing efficiency and falling prices of these batteries.

The market for lead-acid batteries, which is predicted to reach $4 billion by 2019, is next in line, with growth driven by these batteries’ low cost compared to other types of energy storage. Because they are relatively cheap, lead-acid batteries are much used in off-grid renewable power systems.  According to the report, most solar photovoltaic (PV) installations use sealed valve-regulated lead-acid (VRLA) or flooded lead-acid batteries, and this trend is predicted to continue.

Third on the list are sodium-based batteries, which are predicted to generate over $2 billion by 2019. Sodium-based batteries are vital to peak shaving and the power quality aspects of off-grid energy storage, the report said. Growth in this segment was found to correspond to these batteries’ low maintenance requirements, growing efficiency and higher storage capacity.

Technavio listed the top five off-grid energy storage firms as US-based Aquion Energy, Green Charge, NEC Energy Solutions and NRG Energy, and Korea’s LG Chem (storage system pictured).