The fastest growing part of Tesla’s business is grid-tied storage. About 1/3 of all home grid storage units sold in the US are Tesla PowerWalls. There is a lot more to this than just “a battery at home”. In many areas you will be able to sell electricity back to the grid at high-demand times and make a profit.
Why does this work? The load on the electric grid varies significantly each day. Generally, the time of highest demand is in the early evening. Everyone gets home from work and turns on lights and equipment and prepares dinner. At this time available power from grid-tied solar is dropping because the sun is going down. In order to meet this demand utilities need to operate what are called peaker plants. A good example is a natural gas-fired plant. The cost of their operation is much higher than what utilities use to meet their base load.
What that means is that utilities are willing to pay a lot more per kilowatt hour of electricity at these times. Paying you, a homeowner, is cheaper than running a peaker plant. Thus, your system can make money helping the utility over a high-demand hump and it then can be recharged at a lower rate late at night.
For more information, check out The Electric Viking video.
