Solar Energy Show

People with rooftop solar systems almost always ask about using batteries to store their energy for nighttime use. Tesla recently announced an off-grid battery storage system, SolarCity announced a home backup power system, and a dozen other companies already have comparable products on the market. These announcements have re-energized (grin) the hype and excitement in this new product category. But are these systems practical and will they save you money? For the vast majority of homeowners, the answer is “no” to both questions. Only if you have a completely off-grid application -- such as a cabin in the woods -- can the new generation of lithium ion battery backup systems combined with solar be more practical and cost effective than traditional lead acid batteries. If you are currently on the grid, energy arbitrage makes no sense at all: with current electric rates it is simply not cost effective to generate your own energy with solar during the day and use it at night (or buy cheap electricity at night an