Here is a recent IEEE article about battery-based grid energy storage. It's not from the PES, but from the general interest IEEE magazine "Spectrum."
http://spectrum.ieee.org/energy/the-smarter-grid/a-battery-as-big-as-the-grid

There is debate about the reality of this particular installation, and its economics, but the point is that there is interest and activity in the area of grid storage, possibly in proportion to its value and applicability. As the penetration of renewables increases, one would expect that any appropriate compensating systems like this, or other technologies or financial incentives or whatever would also be deployed.