Tech-entrepreneur Elon Musk made a big splash last night in California. His company, Tesla, introduced the Powerwall, a big battery for your home. There’s a lot of hype around the battery, but is it practical for the average person?

The Powerwall will work by storing energy that comes from solar panels on your roof. This will allow for 24-hour energy, rather than only when the sun is out. In theory, this should save you money — but a few factors may stand in the way.

Analyst Brian Warshay says even with an aggressively priced Tesla battery, it doesn’t make sense today, for the home.

“The residential market will be limited, one because most people don’t have solar power. Two, most people that do have solar power are already saving money on their electricity bill without any storage. And in the U.S., for the most part, the power grid is quite reliable and quite cheap. So it does make sense for people to remain grid connected.”

Marketplace’s Scott Tong believes that a more likely scenario is for homeowners to partially defect from the grid with solar panels, battery, and a small utility bill. However, total grid defection could be in the future.

“This could be the big original cellphone that took two hands to hold. Technology costs have absolutely come down,” says Tong.

And a fun fact – the power grid that this battery will defect from evolved largely because of technology developed more than a century ago by a man named Nikola Tesla.