Janice Goodenough, the CEO of hydropower developer HYDROGRID, contends that this battery storage vs. hydropower debate is a false dichotomy. She emphasizes that comparing these two energy sources directly creates a distorted picture of their capabilities and roles in the grid. Instead, Goodenough highlights the importance of recognizing how these technologies complement each other, driven by three critical factors: deployability, response time, and storage duration.
In her analysis, Goodenough makes the case that hydropower’s storage durations are typically overcounted. Most stakeholders consider a 6 – 24 hour range as the minimum expectation for hydropower. She notes that unlike other energy storage technologies, many reservoirs are capable of storing energy for days, weeks, and even months and years. This significant disparity in storage power illustrates a very important issue. We need to know much more about how hydropower and battery technologies will truly work best together.
The Complementary Nature of Hydropower and Battery Storage
Goodenough’s breakdown of the various layers of reserves that grid operators buy gives further credence to the strengths of both technologies. Primary reserve has the fastest response times available (beyond zero seconds) and comes with inertia to boot. Such a secondary reserve, one which consists mostly of fast-responding resources, can be activated in only two to three minutes. In contrast, the tertiary reserve can respond within roughly fifteen minutes.
“The two technologies complement each other well,” Goodenough explains. But she points out that although batteries offer quick-response superpowers, their storage potential usually doesn’t measure up to hydropower. While batteries offer the benefit of quick response times, they are generally not high capacity storage. Hydropower is a whole different order of magnitude in both lifetime and long-duration storage capability,” she adds.
This interdependence highlights the need for a stacked system where short-duration storage is built on top of long-duration storage. Goodenough contends that it’s time to accept a unified strategy. This strategy is key to maximizing efficiency and resilience in our energy systems as they transition to increased dependence on renewable energy generation.
Risks of Imbalance in Energy Storage
Goodenough raises alarm on the industry’s future if it fails to create incentives for long-duration energy storage technologies. She cautions that without the right incentives, these solutions may dry up, which could result in a disaster of catastrophic proportions. “If the market doesn’t incentivise long-duration energy storage, it will eventually go away,” she warns. “And by the time it goes away, it will be too late to react.”
That’s an imbalance that can have deadly consequences. As Goodenough points out, the industry is in for a decade of curtailments—or worse, blackouts—while waiting for effective long-duration storage to be developed. She stresses the need to optimize the operational responsiveness—the ability to react—within a matter of minutes. If not, the grid may be unable to adapt and meet evolving energy needs.
Future Prospects for Hybrid Systems
Looking to the future, Goodenough sees Asia, and especially China, at the forefront of deploying large-scale hydro-battery hybrids. She thinks that coexistence between pumped storage hydropower and battery energy storage systems is important. This major step will ensure that we’ll have a resilient grid, one that can deliver super high levels of renewable energy.
In her plan for the future, she has called for a smart mix of energy sources. She recommends deploying 2GW of pumped storage paired with 500MW of stationary battery systems. This hybrid model would provide multiple benefits at scale by maximizing the benefits of both technologies by integrating them while more effectively balancing the grid in real-time.
She makes the case that the fundamental defect is in how we evaluate energy sources. A battery that can provide flexibility for two hours is equal in revenue to a hydro pump storage plant that can bring five months of flexibility. This misalignment in how energy sources are valued does nothing to help the cause of moving a middle-ground approach to energy storage forward.
