Battery Waste?

Batteries have been useful but not the most efficient storage medium for energy. However with the introduction of lithium batteries this has improved. However lithium is hazardous waste. A rechargeable battery can go through a recharge cycle a few thousand times at best. If you do it every day, as in a home system, then you may get three to four years of use. Then you have a non-rechargeable toxic boat anchor. Where do you put it? Not as bad as nuclear waste but definitely not "green".

Along comes Tesla who announces a home battery (see the CSM):

All of the new batteries run on the same type of lithium-ion, software-equipped technology found in Tesla's cars, and can be mounted inside or outside of a building.

As Computer World notes:

Europeans have a dimmer view of landfilling lithium ion batteries. "There is always potential contamination to water because they contain metals," says Daniel Cheret, general manager at Belgium-based Umicore Recycling Solutions. The bigger issue is a moral one: the products have a recycling value, so throwing away 2 billion batteries a year is just plain wasteful - especially when so many American landfills are running out of space. "It’s a pity to landfill this material that you could recover," Charet says. He estimates that between 8,000 and 9,000 tons of cobalt is used in the manufacture of lithium ion batteries each year. Each battery contains 10 to 13% cobalt by weight. Umicore recyles all four metals used in lithium ion batteries. 

 As Waste Management World has noted, there is a recyclable option, albeit costly:

With lithium recycling in its infancy, there is currently no main recycling infrastructure in the world that treats only automotive Li-ion batteries. A few pilot plants, such as Umicore's Hoboken plant in Belgium that are at a demonstration stage exist. Lack of standardisation in battery chemistries and changing landscape with respect to different elements under research for battery production other than lithium have made evaluation of the recycled value of the components uncertain for the recyclers.

Overall one should look at the full life cycle here. The "green" puffery is just that unless the plan to recycle safely is in place. Otherwise we will have mountains of un-usable trash!