I find it useful in the event of a power outage. Other than that, the article mentions "to eliminate their home electric bill", which doesn't make much sense si

I find it useful in the event of a power outage. Other than that, the article mentions "to eliminate their home electric bill", which doesn't make much sense since the battery needs to be charged from time to time anyway... Unless of course, the battery could be used to store the energy from a renewable resource, like solar or wind power, in which case it would be really interesting. From an economic viewpoint, though, the savings should surpass in a reasonable time, the costs of buying and installing the battery, and the source of power (i.e. solar cells), and depending on the country, taxes on that.