1) the technology is improving rapidly, and we would hate to have buyer's remorse in a few years;
2) storage (i.e., battery) solutions haven't gotten to the point where we could be completely off the grid; one of our goals is to be independent of PG&E.
Energy storage is a problem faced by alternative energy systems. The wind doesn't always blow, the sun doesn't always shine, and both wind and solar
require extra, large-scale infrastructure to store the energy so that it is available on demand and not just when it’s windy or sunny.Ingenious energy storage solutions often involve gravity: water is pumped uphill using solar energy during the day, for example, then rotates turbines as it runs downhill during the night. But water is not always available or suitable.
|ARES: don't call it Sisyphus|
The rocks stand in for the water in a pumped-storage system. They are carried up- and downhill by a train that is thus the equivalent of the turbines.....The hill ARES has chosen has a gradient of about 8%. The track itself is just under 9km (about 5½ miles) long. The company estimates that its proposed system will be able to store 12.5 MWh of energy, and deliver it back to the grid at a rate of up to 50MW.Storage technology will undoubtedly improve, but probably not to the point where weights could be deposited on my roof during the day, then lowered during the evening. Besides, the neighbors will complain.