US agency reaches 'holy grail' of battery storage sought by Elon Musk and Gates

Breakthrough in next generation of storage batteries could transform the US electrical grid within five to 10 years, says research agency, Arpa-E

A US government agency says it has attained the "holy grail" of energy - the next-generation system of battery storage, that has has been hotly pursued by the likes of Bill Gates and Elon Musk.

Advanced Research Projects Agency-Energy (Arpa-E) - a branch of the Department of Energy - says it achieved its breakthrough technology in seven years.