⚡Reverse Hydro Pumping & Energy Markets
Reverse pumping, the impact of renewables on energy markets, long-term infrastructure challenges, and the urgent need to preserve Spain’s world-class expertise for future generations.
It’s time to dive into one of my favorite fields in the water industry—hydropower.
In this episode, we explore reverse pumping, the energy market, and the key typologies and components that make up this powerful infrastructure.
I’m incredibly humbled and excited to be joined by José Manuel, from SENER, who is not only one of the top experts in Spain but also a global reference in this space.
Honestly, we could easily host a multi-day in-person event with José Manuel—3 or 4 days straight, full of knowledge sharing, questions, inspiration, and non-stop learning.
But for now, a powerful 1 hour and 30-minute episode to help you get up to speed.
To make the conversation more accessible, we’ve included at the background of the talk, a few visual slides that really help illustrate the concepts.
This was the perfect timing to watch the episode—exactly 7 days after the power blackout in Spain. What an unbelievable experience. Read this Article from BBC, I quote a sentence from it: “The initial focus was on hydro-electric plants, in particular pumped-storage plants with reservoirs full at this time of year and able to produce electricity fast from a standing start.”
It’s a clear example of the feeling you get when you're ahead of the curve. The blackout hit at 12:33 actually, but luckily, my office was running on UPS. I found out on “X” that it was a national issue and thought, “Wait, what?” I even asked ChatGPT, what may be the reason for a national blackout?!
But in the end, I decided to write a post on LinkedIn, tagging our guest and asking: What happened? By 13:00, I already had his response—and he wasn’t wrong, actually.
This is the “power” (absolutely intended 😄) of being connected with passionate and knowledgeable water professionals, and a clear proof of the quality of our guest and his team at Sener.
It was incredibly difficult to pick just one highlight from such a dense and rich conversation—but here’s some takeaways:
I finally understood the "duck curve" in energy demand… though it might now look more like a goose neck 😉.
We also explored how the energy market has shaped the water sector, the rise of energy storage and battery challenges, and how all of this links back to the feasibility of pumped hydropower.
As always, the recurring theme is the need for a long-term vision and political will.
These remain major blockers to the kind of infrastructure development we truly need.
Designing and building hydropower plants / reverse pumping facilities takes time—a bunch of years—and sadly, permitting issues often slow things down further.
Many countries with similar environmental conditions don't face the same regulatory hurdles we do in Spain. That gap is frustrating—and one of the reasons why many investors hesitate.
Another topic we touched on was the growing talent gap in this sector.
More and more experienced professionals are retiring—and with them, decades of knowledge risk being lost.
I personally know a few amazing engineers who’ve left the industry, and it’s clear we need to act fast to preserve and pass on this expertise.
Spain has built world-class experience in hydropower over the years.
Now is the time to share that expertise internationally, especially with so many countries actively looking for sustainable energy solutions.
I hope it brings you valuable insight—and a bit of inspiration too.
What’s Reverse Pumping?
Reverse pumping, or pumped-storage hydropower, is a method of storing energy using water. It works like this:
During times of low electricity demand and cheaper prices (traditionally at night), water is pumped uphill from a lower reservoir to an upper one using excess electricity.
When energy demand is high (typically during the day), the water is released back down, passing through turbines to generate electricity—just like a regular hydropower plant.
This system helps balance the electricity grid, acting like a giant battery.
In the past, the typical pattern was:
Pump at night (cheap energy)
Turbine during the day (when prices were high)
But with the rise of solar power, this model has flipped. Solar generates abundant energy during the day, lowering daytime prices.
So now, in some cases:
The grid needs to pump during the day (when solar oversupplies the system)
And generate electricity in the evening when demand rises and solar drops off.
This shift is forcing a rethinking of how and when pumped-storage plants operate.
Spain is one of the European leaders in pumped-storage hydropower, with around 20 plants in operation.
The largest is the La Muela II plant, near Valencia, with a capacity of almost 1,000 MW—making it not only the biggest in Spain, but one of the biggest in Europe.
Main Components of a Reverse Pumping Project
Just a quick snapshot to keep in mind, all of them discussed and showed in our episode with Jose Manuel.
Upper Reservoir
Stores water at a higher elevation, acting as the “battery” that holds potential energy.
Lower Reservoir
Collects water after it has passed through the turbines; it's the source of water to be pumped back up.
Intake and Outlet Structures
These control the flow of water into and out of the system from the reservoirs, often including gates or valves.
Headrace Tunnel / Penstock
Large, pressurized pipes or tunnels that carry water from the upper reservoir to the turbines (during generation) or from turbines back to the upper reservoir (during pumping).
Surge Tank / Chimney
A vertical shaft that absorbs pressure surges and helps regulate water flow to protect the system from hydraulic shock.
Powerhouse / Hydro Station
Contains reversible pump-turbines and motor-generators. These machines switch roles depending on whether the plant is generating power or pumping water.
Transformer and Switchyard
Equipment to convert and transmit the generated electricity into the grid.
