Energy storage is an unglamorous pillar of an expected revolution to clean up the world's energy supply but will soon vie for investors attention with more alluring sources of energy like solar panels, manufacturers say.
"It's been in the background until now. It's not sexy. It's the enabler, not a source of energy," said Tim Hennessy, chief executive of Canadian battery makers VRB Power, speaking on the sidelines of a "CleanEquity" technologies conference in Monaco.
VRB will start mass production this year of a longer-lasting rival to the lead acid battery currently used to store energy, for example, produced by solar panel, Hennessy said.
Low carbon-emitting renewable energy is in vogue, driven by fears over climate change, spiraling oil prices and fears over energy supply and security.
While the supply of the wind and sun far exceeds humanity's needs it doesn't necessarily match the time when people need it: the sun may not be shining nor the wind blowing when we need to cook dinner or have a shower.
Soaring production of solar panels and wind turbines is now spurring a race to develop the winning energy storage technologies which will drive the electric cars and appliances of the future.
The race is heating up as manufacturers with entirely different solutions near the moment of commercial production.
For example, UK-based ITM Power sees the future of energy storage in the explosive gas hydrogen. The company is developing a piece of kit called an electrolyzer which uses solar or wind power to split water into hydrogen and oxygen.
The hydrogen is then stored in a pressurized container until it is needed, whether to drive a car, produce electricity or for cooking.
"With batteries you're taking enormous quantities of basic raw materials," said Chief Executive Jim Heathcote, referring to cadmium in nickel cadmium varieties. His company won an award for research at the Monaco conference, organized by corporate finance advisers Innovator Capital.
"Two things we're confident of is the supply of renewable energy and water," he said.
ITM Power aims to start production later this year of electrolyzers and next year of hydrogen fuel cells which generate electricity.
"The one problem everyone's had is how to store. The ability to take (surplus) renewable energy and make useful fuel out of it is almost priceless," Heathcote said.
The economic opportunities are highlighted by a third company, U.S.-based EnerDel, which aims to supply batteries for the "Th!nk City" electric vehicle, manufactured by Norway's Think Global.
In the case of electric cars, cheap, lightweight batteries are needed to power motors, and will eliminate carbon emissions if the batteries are charged using renewable power sources.
EnerDel has patented a lithium-ion battery which it says is lighter and cheaper than the nickel metal hydride batteries currently used in hybrid electric cars such as the Toyota Prius.
"I think energy storage is the next frontier," said Charles Gassenheimer, chairman of EnerDel's owners Ener1 Inc.
The "Th!nk" car could be the world's first mass production electric vehicle, starting in earnest in 2009. It will go from 0 to 60 miles an hour in about 8 seconds and have a range of up to 100 miles, said Gassenheimer.
Investors have given their thumbs up to Ener1, which now has a market capitalization of around $700 million, a ten-fold increase over two years ago.