Hybrid projects |
Hybrid storage, not either/or
HYDROGRID CEO Janice Goodenough argues that battery storage and pumped storage hydropower are not competing technologies but interdependent pillars of a resilient, high- renewables grid. In this interview, she explains how current market trends undermine the value of long-duration storage, how market design shapes both technologies’ futures, and what a genuinely hybrid storage landscape might look like by 2035
JANICE GOODENOUGH DOES NOT hesitate when asked about the future relationship between pumped storage hydropower (PSH) and battery energy storage systems (BESS). For her, the idea that the two technologies are competing for the same role, or even comparable, is not only misguided, but it also risks undermining the stability of the future power system. “The two technologies complement each other well,” she says. “Batteries provide super-fast response, but they don’t typically have a lot of storage capacity. Hydropower is a completely different order of magnitude in both lifetime and long-duration storage potential.”
Goodenough is the CEO of HYDROGRID, a company delivering digital production planning and optimisation software for hydropower plants in 15 countries across four continents. Her perspective is shaped by both the physical realities of these assets and the rapidly shifting operational environment they must navigate. On one side of the storage spectrum sits pumped storage hydropower, capable of storing vast amounts of energy for days, weeks or even months. On the other sit batteries, engineered for sub-second response, intra-day balancing and participation in increasingly granular reserve markets. She argues that the pitfall of comparing the
two directly – GW to GW – creates a distorted picture, in which battery capacity could soon “catch up” with hydropower. But that picture changes quickly when comparing storage volume, i.e., GWh to GWh, where hydropower will continue to “dwarve” batteries for decades to come. However, the grid needs both fast response and deep endurance: “What we need is a stacked system,” she says. “Short- duration storage layered on top of long- duration storage.” In that layered model, each technology strengthens the other and aligns with the current grid cost mechanisms. While this hybrid configuration fits well into
current power market dynamics, Goodenough sees a widening gap between what the energy system requires and what current markets reward. Policy frameworks overwhelmingly favour technologies that operate on short timescales. Long-duration storage, which
Janice Goodenough, CEO of HYDROGRID
ensures resilience during multi-day renewable droughts, receives almost no differentiated value. “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.” She refers to the inherent lifecycle of hydro investment, in which today’s decisions will bring consequences in 2035 and beyond.
What follows is a detailed journey through that warning. Goodenough explains why duration matters, how hybrid operation works in practice, why digitalisation is essential, and what must change for storage to support the next phase of the renewable transition.
Complementary by design: why hydro and batteries serve
The second factor is response time. Batteries
different roles When asked how the hydropower sector should think about battery storage, Goodenough identifies three factors driving complementarity. The first is deployability. Hydropower remains largely centralised because it requires specific geography. Batteries, on the other hand, “can be deployed decentralised,” enabling flexibility where hydropower cannot physically exist.
14 | December 2025 |
www.waterpowermagazine.com
can react in milliseconds, offering ultra-fast balancing. Hydropower responds more slowly, but “modern pumped storage plants can get from standstill to full capacity in probably the order of magnitude of 90 seconds,” which is already extremely fast for most grid needs. The third and most critical factor is storage duration. Lithium-ion batteries typically offer three to six hours of storage. Hydropower storage durations of 6-24 hours are considered minimal; most reservoirs hold days, weeks, months or even years of energy. Because of this difference, Goodenough stresses that comparing capacity alone “cannot draw any meaningful conclusions.” She notes that unused hydropower storage volume alone is likely comparable to the entire volume now being built in batteries globally. In short, response speed is not a substitute for endurance, and endurance is what supports entire systems through prolonged renewable droughts.
The value of hybrid configurations There is growing industry interest in co-locating
batteries with hydropower plants. According to Goodenough, this makes sense primarily
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