by Stephen Lacey
July 07, 2017

Stephen Lacey: What happens when the most important market signal for energy storage gets stripped away virtually overnight? That's what happened in the U.S. this year when the regional transmission operator PJM put in place new rules for storage as a provider of frequency regulation. Between 2011 and 2015 hundreds of megawatts of storage were put in place to balance the grid in PJM territory. A strong market signal made it extremely easy to develop projects, and it caused an explosion of growth.

We are in a different world today. Those...