According to an article in my newspaper today, the California PUC is considering a regulation requiring all electrical utilities in the state to purchase more than 1.3 gigawatts of energy storage by the year 2020. This storage systems would store "green" energy for times when wind, solar and the like was not functioning due to the environment or other factors. The storage systems might consist of upper/lower water reservoir systems, flywheel systems, battery systems, or whatever else can be developed to store large amounts of energy over short periods of time. As an example, the article mentions PG&E's 4-megawatt Yerba Buena Battery Energy Storage System Pilot Project. This battery system cost $18 million and from the photo in the article looks to be about 20 feet high and 40 feet long. The system uses sodium-sulfer batteries made by NGK. They can store 4 MW of power up to about 6 hours. Naturally, the State's ratepayers will be picking up the tab and various battery storage companies, such as AES Energy Storage in Arlington, VA (which uses li-ion batteries) and other interested parties, are licking their chops over the program. Lets hope that some of the technology developed will trickle down to the transportation sector.