On April 30th, 2015 Tesla Motors announced the production of a new home battery that may usher in a new era in residential home energy and design. Today the vast majority of homes are served by an electrical grid provided by a public or private utility company. A small minority of houses have solar panels (photo-voltaics) that are either tied into the grid, in which case they can either pump energy back into the grid or pull energy from the grid in times of need, or they have a room dedicated to battery storage, making the house completely energy independent. Up until recently home batteries were expensive, took up a large amount of space and lasted just 5-10 years.
Now Tesla is deveping a lithium ion battery specifically for the home that is compact, quite affordable and comes with a 10 year warranty. The battery mounts to a wall and takes up just 52" x 34" x 7" of space and looks attractive to boot. It costs about as much as a tricked-out Mac computer, $3,500 for a 7kW battery - enough to power a relatively modest house. While it comes with a 10 year warranty, the battery is expected to last much longer then 10 years.
Tesla's Powerwall, as it's called, runs on DC current and receives it's energy from photo-voltaic panels mounted to the roof of the house. The panels need to bought separately as does the DC to AC adaptor. Those two components will add about $20-25K to the average house at current rates.
Prices continue to diminish for both solar panels and home batteries. There's a very good article written in Gizmodo that analizes the current state of the solar energy industry. The bottom line is that most US markets, especially in sun-blessed states, are becoming economically feasible moving from paying for energy from the utility grid versus relying on home-created solar energy. Hawaii, with extremely costly energy costs and abundant sunshine, is already primed for home solar energy production. While Texas has a lot of sunshine, we also have relatively inexpensive energy so it's not quite economically feasibly...but it's getting there.
The shift to prevalent home solar energy production could have subtle and maybe even dramatic effects on the way we live and design homes. First of all, we no longer need to add significant sqaure footage for battery storage. Second, we should consider designing all houses with roofs that face south, southwest in an optimal 4:12 pitch. Third, forget about running an overhead line from the city power pole to your house and having to pay for that connection, not to mention waiting for the utility company to get you in their queue. Power outages may also be a thing of the past.
The Tesla Powerwall battery would be replacing a home battery storage system similar to this 10kW system.
Local building supply retailer Treehouse will be offering the Tesla Powerwall later this summer. Treehouse CEO Jason Ballard says, "I think in the near future, having a battery in your home will be as normal as having a water heater or dishwasher".
We haven't heard any talk about how we will dispose of these batteries when their life expires. Lithium ion batteries can last a long time but they are made from chemicals that are very harsh to our environment. Where and how will we dispose of them? What if we don't properly dispose of them? While I'm optomistic about the possibilities I'm also cautious about potential side-effects.