AEP Sustainability - Energy Storage

Energy Storage

As we introduce more renewable generation into our energy mix, the need to invest in energy storage grows. Energy storage can help smooth the flow of power as generation from intermittent resources such as wind and solar varies.

The recent reduction in cost of commercially available energy storage technologies, particularly those leveraging Lithium-ion technology, has created an increased interest across our industry for proposed deployments of energy storage in the grid. AEP has seen a significant increase in project proposals from developers to pair renewable energy generation (solar or wind) with energy storage and connect to the AEP Transmission system.

We are also investigating and actively pursuing the application of Bulk Energy Storage Systems as transmission assets in situations where they can help to cost-effectively maintain or improve the reliability of the transmission system, compared to traditional options of building new transmission lines or stations. An example of this is the proposed installation of a 2 MW storage device adjacent to the Middle Creek station in Kentucky, to effectively take the place of a transmission line rebuild. Energy storage projects are being considered on the distribution system as well.

Storage technology supports local reliability and demand response for our customers, and it is integrated into our distribution and resource planning processes. For example, batteries are a relatively flexible solution that can be mobilized and relocated to meet changing demand in the system. We have pilot projects in AEP Ohio to help improve the reliability of sections of circuits. We are evaluating similar projects throughout most of our operating companies.

Applications of Distributed Energy Storage

  • Reliability improvements - AEP has more than a decade of experience with battery storage, which can provide back-up power in case of an outage. During that time we installed three 2-MW NaS (sodium sulfur) batteries in Appalachian Power, AEP Ohio and Indiana Michigan Power.
  • Frequency regulation - Batteries have the ability to rapidly respond to balance load and generation in real time on the grid. Regional transmission organizations (RTOs) are recognizing the need for greater amounts of frequency regulation to maintain system stability with the increased integration of variable generation resources.
  • Firming of renewables - Wind and solar often have points in time where they do not produce electricity. Deploying batteries to combine with wind and/or solar energy can allow for better use and management of variable renewable energy sources.
  • Peak shaving - Batteries can provide power during peak demand times to meet customer demand while alleviating strain on the power grid. APCo’s current RFPs for solar energy resources include a battery storage option.
  • Power quality - Batteries are capable of conditioning the flow of power to protect sensitive electronic equipment.

We make use of energy storage across our generation portfolio, such as in the Byllesby Hydroelectric Plant in Virginia, operated by Appalachian Power (APCo). The Byllesby facility is paired with 4 MW of battery storage, which enhances the flexibility of the 100-year-old plant so it can respond rapidly to changes in grid demand. The battery system also provides an additional revenue stream to AEP.

Another type of storage – pumped storage – has been serving customers of APCo since the mid-1960s. The Smith Mountain Pumped Storage Project can generate 585 MW of electricity for up to 11 hours or can be used for short periods to meet peak energy needs.

New energy storage projects may allow solar power to be delivered past sunset and into evening peak demand periods. We continue to explore opportunities to leverage the unique aspects of energy storage resources for expanded use in transmission, distribution and wholesale applications. Policymaking on these issues is extremely important to our ability to enable new technology and deploy it on the transmission and distribution grid.