Actually, there are many uses for this. Your average home uses around 1000kw of power each month, but I imagine most everyone here uses way more power than that, that is just a national average used in the utiliity industry. Your friendly local power company, or not so friendly, has to keep plants warmed up and ready to generate power 24/7 to cover the maximum projected load during any 12-24 hour period. Not even a gas turbine can be turned on and generate power to the grid in less than 30 minutes from a cold start. Keeping standby generation hot and ready wastes a lot of energy, but is necessary so your lights go on when you flip a switch, your hvac works when you need it to, etc... If these were in large scale use, your utility company could idle some of their standby plants if these were charging overnight from unused capacity on the grid, and supply power during peak times on the grid, negating the need to keep so much spinning reserve hot and ready to generate power. Since virtually all spinning reserve is fossil, this is where the "green" comes in. For a small number of people and growing, this would be a huge improvement over lead acid storage, in efficiency, safety, maintenance, and undoubtedly cost in the long run. There are lots of people that actually generate enough power on average to run their own home. Small hydro, solar, wind. The problem is they don't generate 24/7 except for small hydro, and they do not generate consistently, again except for small hydro. A 1,500 watt gas generator running 24/7 produces enough electricity to run the utility average house at 1000kw/h per month, but obviously will not run your home at such a small output. With small scale generation (whether wind, solar or hydro) At times when the power consumption of your home is smaller than what you produce, you can charge storage for later use when you are using more power. People currently use lead acid storage for this, and the smart ones stay connected to the grid because during peak hours, like a hot summer day, your storage+production won't cut it with your peak power usage. But you can easily cut your electricity bill by 80% if you can produce just 1,500 watts of power per hour on a 24/7 basis. It really would not work well with small solar, you would need to generate significantly more than your homes peak usage of power while the sun is up so you have excess for charging and use during lower demand times. But their would still be an efficiency gain if your installation was big enough. Unfortunately, solar is very expensive, even with all the taxpayer money be thrown at it in subsidies. Initial costs of a solar set up require at least 10 years to recover cost in electricity savings, and that is best case like you live in the desert of Arizona or somewhere else with 95%+ days of sunlight. A friend of mine in Va has a small hydro setup that generally produces around 3,000 watts. He has net metering with the power company and some months he has a credit and some months he owes. According to him, counting maintenance, electric bills etc... he pays in the neighborhood of 500 dollars a year to be connected to the power company. I bet with a more efficient storage than his small lead acid setup, he could come out getting paid every year by the power company for the privilege of being connected to the grid.
