Battery storage, smart grid, and energy efficiency companies secured $2.8bn in venture capital funding last year, according to new research.

The study from clean energy research firm Mercom Capital Group found that battery storage companies raised $850m, smart grid firms $530m and energy efficiency businesses $1.5bn.

The $850m of battery storage funding – a 19 per cent increase on 2017 – was over 49 deals, with lithium-ion battery technology receiving the most, with $236m, followed by energy storage companies with $193m.

The top venture capital-funded companies in 2018 were QuantumScape with $100m, Stem ($80m0, sonnen ($71m), Sila Nanotechnologies ($70m) and Ionic Materials ($65m). Some 73 venture capital investors participated in battery storage deals in 2018 compared to 86 in 2017.

Smart grid companies raised $530m in venture capital funding in 29 deals in 2018, a 26 per cent increase on the $422m raised in 45 deals in 2017.

The top venture capital-funded companies were ChargePoint ($240m), Smart Wires ($55m), Volta Charging ($35m), AutoGrid ($32m) and Ample ($31m). The top investors included Energy Impact Partners, E.ON, Orsted, Shell Ventures and WindSail Capital Group. 

Smart charging of plug-in hybrid electric vehicle and vehicle-to-grid companies had the largest share of VC funding, with $348m in nine deals, followed by grid optimization firms with $59m in two deals.

Meanwhile, funding for energy efficiency companies jumped to $1.5bn in 23 deals in 2018 compared to the $384m in 38 deals in 2017.

The top funded companies were View ($1.1bn), UrbanVolt ($64m), ecobee ($61m and $36 million in two deals, and tado° brought in $50 million.

A total of 72 investors participated in funding deals in 2018 compared to 51 investors in 2017. Energy Impact Partners was the most active investor in 2018.