Utilities Take Different Approach to Grid Reliability and Peak Demand
By Jim Vess
Traditionally when demand for power rises, to maintain system reliability utilities respond by adding generation capacity from so-called “peakers” – typically gas-fired units – which can be brought online relatively quickly. That is relatively quickly when compared to the time required to bring additional baseload generation online. Now some utilities are looking break from tradition by employing battery-based energy storage systems designed to enhance reliability and increase stability on the electric power grid.
Duke Energy operates a 36-MW energy storage unit at its Notrees Windpower Project in Texas. The system, one of the nation’s largest battery-based energy storage and power management systems, was completed in 2012 in partnership with the U.S. Department of Energy.
Duke Energy has also recently teamed up with LG Chem and Greensmith to build a 2-MW battery-based energy storage system at the utility’s retired W.C. Beckjord coal-fired power plant in New Richmond, Ohio, that is expected to be operational by late 2015. With the addition of this new project, Duke Energy will operate a total of 4 MW of energy storage at Beckjord, site where a separate 2-MW storage system already exists.
“Fast-responding energy storage is recognized for the tremendous benefits it provides to grid operations, because it can instantaneously absorb excess energy from the grid or release energy. Delivering that power in seconds, as opposed to a power plant that could take 10 minutes or more to ramp up, is the unique value the battery system provides to grid operators. This accurate and rapid response will help improve the overall reliability and economic efficiency of the grid. It also demonstrates the capabilities of new technologies and the potential for future applications, such as large-scale integration of renewable energy onto the grid,” Phil Grigsby, Duke Energy’s vice president of commercial transmission said in a company press release.
While Duke Energy has chosen a centralized energy storage strategy, the Glasgow Electric Plant Board is taking different approach to their energy storage needs. The municipally-owned utility in southern Kentucky is installing Sunverge Energy’s smart energy storage devices. The Sunverge system, to be installed in 165 homes, provides utility-grade storage at individual homes along with cloud-based software to manage that storage. The devices will store power from the electric grid at night or times of low demand. During times of high demand, the stored energy in the batteries will released to the power grid, reducing the need to supply additional power from traditional generating plants. The installations also have the potential to provide a reliable source of backup power to customers should power from the electric grid be disrupted.
“Glasgow is our first customer to use distributed storage without solar to create significant network value,” said Ken Munson, co-founder and CEO of Sunverge Energy in a press release. “While many of our installations are in tandem with the use of solar panels, our technology offers the same reliability, cost savings and emissions reductions regardless of the source of the power. Glasgow is a pioneer and should serve as a model for other utilities that serve rural or isolated communities, where intelligent storage can play an important role when generation options are limited and where there are frequent weather-related power disruptions.”
Whether using centralized energy storage like Duke Energy or a distributed storage model such that being used by Glasgow Electric Plant Board, utilities are starting to see the benefits of adding energy storage into the mix. Benefits such as enhanced reliability and stability of the electric power grid, and reduced peaking generation costs.