It’s Friday, and that means it’s time to kick back with some weekend reading — in this case, the latest grid energy storage white paper from the Electric Power Research Institute. EPRI’s new report (available for download here) goes deep into the nitty-gritty of different storage technologies, different energy and power applications, and different price points in terms of dollars per kilowatt-hour of storage. The take-away finding is that the U.S. energy storage market could grow to as much as 14 gigawatts of capacity, if energy storage systems can be installed for $700 to $750/kW-h and “the energy storage owners and operators could monetize the estimated benefits.” That last part is critical when it comes to bringing batteries into the mainstream for grid storage. Some energy storage projects can balance out at today’s high costs per kilowatt-hour, as VPs from lithium-ion battery company A123 and energy company AES noted at last week’s Green:Net conference. But building beyond these niche applications will require a whole host of technical, economic and policy issues to be aligned to allow batteries that can, for example, provide high-value grid-balancing services as well as longer-term load-shifting capabilities — and capture the revenue streams from both to make the projects pencil out.