Tom Blum, a prominent clean-energy investor who's directly backed around 30 companies, agrees that energy storage is bound to explode, but his advice for investors looking at battery technology is clear: "Run away," he said. Blum says it's easy to get seduced by new battery technologies, but he knows of few examples of investors who have scored big returns.
You have to consider several specs, he said, such as energy density — the amount of energy stored within a specified area — in addition to cost, how long the battery lasts, and how safely it performs under extreme conditions. "Just because you invented the best battery doesn't mean anything until you've spent hundreds of millions and actually have a commercial plant," Blum said. "Even then, you still might not be making money." 'The simple advice is: Run away', largely thanks to a glut of lithium-ion batteries entering the market, it hasn't translated to high returns, he says.
He mentioned one company called Highview Power that uses extremely cold temperatures to turn air into a liquid, which is then stored in insulated vessels. When the air warms, it expands by 700 times, according to the company website, and it can then drive a turbine to generate electricity.