Energy storage--largely an emerging technology except for pumped storage--is expected to play a larger role in balancing supply and demand in a modernized grid. The hope and expectation is that it will largely fill in energy voids and excesses created by the ebb and flow of rising amounts of intermittent renewable supplies into the grid. PG&E has two types of storage projects in the pipeline: compressed air and battery storage demonstrations. The compressed air project seeks to store air in porous rocks in California during off peak hours and to release it at times of high energy demand. It is a $1.6 million, 300 MW project expected to be online at the end of this year. The other involves two sodium sulfur battery projects, up to 4 MW and 2 MW respectively. The larger pilot is for balancing on site power flows and the 2 MW project is to smooth out power flows from solar projects. This $50 million pilot is estimated to come on line in 2015. It received $25 million under the American Recovery & Reinvestment Act. Edison plans to pursue storage technologies under its grid plan, including a large 8 MW lithium ion battery system in the Tehachapi Wind Resource Area that can feed the grid for four hours. Edison also envisions testing smaller technologies located within its distribution area. The 8 MW system also is being funded by the federal stimulus funds.