Clean Energy 101: How Batteries Can Support Grid Reliability
Grid-scale battery storage can beat traditional technologies in keeping our electric grid running in the face of rising demand.
Our electric grid is the “beating heart” of our modern economy and society, so it is vital to ensure it operates smoothly. There are a lot of challenges confronting electric grid reliability today, including unprecedented extreme weather events and rising failures in thermal generation plants. At the same time, our electric load is rising dramatically due to new datacenter and manufacturing demands, requiring new resource additions and operational approaches to ensure that this new demand can be met reliably.
As energy demand increases across the United States, some grid planners are making the case that new fossil fuel resources such as gas power plants are essential to meeting these emerging reliability needs. In many of these cases, other grid resources that could also support reliability (such as battery energy storage systems) aren’t being considered, even though they can do so just as effectively, and in some cases, at a lower cost. Already, there are real-world examples of the improved economics of battery storage outshining and replacing the buildout of new gas-fired power plants. Nevertheless, utilities and regional transmission organizations are proposing new natural gas development, and keeping uneconomic coal plants online, in the name of reliability — placing corporate, state, and national climate goals at risk.
There are examples of battery energy storage providing essential reliability services in successful demonstrations around the world. Batteries are one of the most flexible grid resources because they can be charged and discharged to support real-time grid needs due to their extremely fast response times that are even faster than that of thermal plants. In addition, grid-scale batteries can have many software- and hardware-based features that provide reliability “services” to the grid such as black start, peaking capacity, operating reserves, and more. Just as our hearts support a healthy body, batteries can help support a “healthy” grid; here are just three ways they do this.
How batteries can support a healthy grid
Batteries can help integrate a growing number of renewable resources by helping balance increasingly variable electricity supply and demand. Just like how our heartbeat automatically speeds up or slows down in response to our physical activity level, batteries can increase or decrease output to align supply and demand in real time. This service becomes increasingly important as growing amounts of renewable energy resources like wind and solar connect to the grid, which are referred to as “variable” because their output varies according to local weather conditions. However, demand for electricity doesn’t always turn up or down just because the clouds come out. On occasions when demand is greater than the ability of variable renewable resources to serve it, this gap can be filled by batteries that have been charged ahead of time. Further, batteries can increase their power extremely fast (with high “ramping” rates), making them an ideal resource to call upon for this grid need. In the figure below, batteries in the California electric grid (CAISO) provided over 8 GW over the course of just 5 hours in December 2023, when batteries made up the majority of flexible ramping product procured.
Batteries can provide critical stability services, such as frequency, voltage, and reactive power regulation, which help the grid maintain its ability to stay within safe windows of tolerance during regular and emergency conditions. Stable power is essential, not only to ensure the safety and operability of our homes, businesses, and electronics, but also the very power grid that transmitted that electricity. Batteries can provide these stability services so that if they detect any disturbance to the state of the grid, they can respond in a manner that returns it to normal, stable levels — at rates even faster than thermal generation can. For example, batteries stepped in to provide stability support on September 9th 2023, when the Texas utility grid (ERCOT) entered into a level two Energy Emergency Alert due to system stability concerns (see figure below). In 2021, most batteries deployed in the United States were already providing multiple stability services, with new market products being created and provisioned in Texas as recently as last year.
Batteries can re-energize the grid after a blackout, which is called “black start.” This restoration service bolsters the resiliency of the grid, but not every resource is capable of doing this — it must have the requisite hardware and software programming and be controllable by the grid operator. Grid-scale batteries that are capable of this feat are commercially available, and have been in operation on transmission grids in California since 2021, Germany since 2016, and elsewhere.
These examples are just a glimpse into grid battery capabilities (the US Energy Information Agency tracks 11 distinct battery storage applications in its annual electric generator report); many more features such as virtual inertia are being innovated and built-in to batteries being plugged-in to power systems worldwide, so they can continue to proliferate and support grid reliability.
What utilities and grid operators can do
In order for utilities to best capture the benefits of battery energy storage to support grid reliability, there are opportunities for utilities and grid operators to:
- First, conduct analytical studies to identify which reliability services — and how much of them — might be needed under different future scenarios when seeking to enhance transmission reliability and resiliency. Then, open an all-source procurement to allow any resource, including batteries, to bid in an offer to provide the necessary energy, capacity, and reliability services identified. Compared to pre-supposing a solution that may not be cost-optimal, this competition-focused portfolio will enable the least-cost resources capable of serving those needs to win out. In the UK, National Grid ESO opened a stability investigation and then created specialized markets to procure specific stability services. Advanced batteries proved to offer the most cost-competitive bids to provide those services — in some cases beating traditional synchronous condenser technologies — while saving millions of dollars.
- Consider the full range of valuable customer, utility, and power transmission operator services that batteries can provide. State-of-the-art advanced grid batteries are continually improving and providing new combinations of services that can be leveraged in new ways, such as the battery fleets deployed in Hawaii, Texas, and Australia.
- Ensure up-to-date inverter software, which is essential for reliable battery performance. For example, after two battery energy system disturbances in 2022, generator owners implemented inverter software updates to make their batteries more robust to such events. Just in 2024 alone, battery deployment in the United States is expected to nearly double; deploying these with outdated software and hardware would be a mistake in terms of both consumer costs and emissions-free reliability.
Batteries offer a cleaner, more capable, and increasingly cost-effective alternative to fossil generation and traditional reliability technologies like synchronous condensers to provide the quantity and quality of all the reliability services essential for supporting the grid — a win-win for both human and grid health.