Batteries for homes and businesses is a good idea. Tesla has a new solution called Powerwall. The news reports say it has a 10-year guarantee. That is a very good guarantee. There are two things I like about the idea. First, you could distribute out energy load in a home or business such that you even out energy cost. Second, you simply have substantial backup power in the event the grid is down due to over utilization or outside damage. People on life support or whose life depends on continuous availability of energy would be well served with this technology. This is not the first product of its kind but it may be the first to see widespread adoption and that could mean a great compliment to the light bulb in terms of improving living conditions in society.