Major energy project developers and utility buyers are on the same page regarding utility scale renewable energy projects like wind and solar. The projects are good for diversification and, in the right circumstances, appear increasingly more economic than fossil fuel alternatives. In fact, they are sufficiently economic to support relatively expensive backup battery storage capability and still beat out other options. An example is the 700-MW wind/solar/battery project NextEra recently committed to build for the Western Farmers Electric Cooperative (WFEC). Since major developers are offering and sophisticated buyers are committing to purchase the output from projects with a significant storage component, does this mean the technology risks associated with larger scale battery energy storage have been resolved?
Batteries were invented in 1800, so we’ve had over 200 years to study and perfect basic battery attributes like cycle life, efficiency, life-cycle costs, and energy density as well as health and safety issues such as fire risk and outgassing of hazardous components. However, many of the battery technologies vying for grid storage applications today have been in use for about 20 years and at grid scale for a much shorter period. The most prominent battery classes in the bulk storage arena include solid state batteries and flow batteries. Lithium ion (Li-ion) and sodium sulfur (NaS) are commonly deployed solid-state batteries seeing service in grid scale applications. Redox flow batteries (RFB) represent the most common flow battery configuration and, according to the Energy Storage Association, are suitable for energy storage applications with power ratings from 10s of kilowatts to 10s of megawatts and storage durations of 2 to 10 hours.
The energy trade press reports every day that energy storage system (ESS) applications in the power sector are growing rapidly in residential, commercial, and industrial facilities. The growth in some sectors has reportedly been more rapid than the development of standards by officials tasked with ensuring safety, particularly where residences and public spaces like commercial establishments are involved. We’ve all heard about fires and even explosions caused by battery equipped hover boards and occasionally laptops, cell phones, and electric vehicles (EVs). However, when we start wiring battery systems in-mass into homes and businesses, and we plan to routinely connect and charge EVs in homes and public spaces, we want to ensure the problem is not an endemic one.