Update 2015-05-03: clarification that Tesla did not invent the first battery packs for households.
Yesterday, Elon Musk presented Tesla Energie, Tesla Powerwall, and Tesla Powerpacks. You should watch the keynote. Not because Elon is a great speaker. As a matter of fact, I would trust myself to have done this presentation way better than he did without overestimating my presentation capabilities. However, what Elon did present could be a huge thing for humanity. And this is not exaggerated at all.
Tesla Energy is shipping wall-mounted batteries (named Powerwall) for houses within the next months. Next year, when Tesla Gigafactory 1 is up and running, the production capacity of batteries will be much higher. Then, there will be enough Powerwall sets available to meet high demand.
A Powerwall is able to hold 7 kWh (US$3000) or 10 kWh (US$3500), with a continuous power delivery of 2 kW and peak power of 3.3 kW. It comes with a great ten year warranty and can be paired with solar power panels. They even have an appealing design and do only need little space on your wall. Up to nine Powerwalls can be stacked so that you can scale up to 90 kWh for households.
If you need more energy, there is Tesla Powerpacks which are able to scale with industry-grade requirements and much more.
The best part is, that Tesla is giving away the patents for Gigafactory and much more for free!
To be clear: Tesla is not the first company shipping battery packs for households or enterprise-grade application. There are many companies out there with many successful products. This new products just add a new dimension to this market in terms of numbers and in terms of public awareness.
In my opinion, Elon Musk is doing a great job for a better future for humankind. He is still able to make much money with his company. Further more, Tesla's patents and technology can help us to shift to renewable energy sources.
I am not sure how much the production and recycling of those batteries will harm the environment. However, there is a good chance that we can find solutions for that as well.
In a couple of years, I will buy myself solar panels as well. I also like the idea of having a battery pack (Powerwall?) as well. This way, I can get the most out of my panels while being more independent from the grid (more frequent power outages, rising costs, ...).