Tesla's Powerwall 2 can pay for itself in 6 years, then its electricity is free

"I am buying between six and nine years of solar power in advance - that's the way I look at it - and anything I get out of it after that is free power," he tells The Australian Financial Review.

The western Sydney computer store manager isn't alone in thinking Powerwall 2 is a fresh challenge to energy retailers like AGL Energy, Origin Energy and Energy Australia in a fast-moving market.

Energy expert Bruce Mountain says their "fabulous lunch" is coming to an end. Powerwall 2's "astounding" progress could enable a savvy rooftop solar customer to beat all discounted grid power offers, he estimate

This scotches the view that battery technology won't move as quickly as solar panels and brings closer the tipping point at which batteries penetrate the mass market as solar panels have done.

Read more: http://www.afr.com/technology/teslas-powerwall-2-can-pay-for-itself-in-6-years-then-its-electricity-is-free