The La Muela pumped storage hydropower plant, one of the largest of its kind in Europe, is enabling large-scale integration of wind and solar into Spain’s grid.

The transition to net zero by 2050 will not be possible without significant investment in pumped storage hydropower as a back up for variable renewables like wind and solar.

Spain’s 1,500-megawatt La Muela project, completed in 2013 and operated by Iberdrola, has set an example by providing the urgent flexibility needed to accelerate the country’s emissions targets. But more needs to be done.

Roger Gill, President of the International Hydropower Association (IHA), visited the site at La Muela. He spoke with Enrique Sola, Head of Hydropower Generation at Iberdrola, to find out more about the project and the challenges that need to be overcome to build more like it.

“IHA believes that plants like La Muela are essential to get us to net zero by 2050,” says Roger Gill.

“In fact, the world has a looming crisis. There is not sufficient pumped storage being built to ensure that the massive investment in wind and solar can be firmed up for the world’s renewable energy needs in the future.”

IHA has recently launched a campaign focusing on the importance of hydropower to the clean energy transition, ‘We can with hydropower’. One of the main messages of the campaign is hydropower’s ability to support more renewables with its energy storage services.

Wind and solar require a backup

The La Muela pumped storage plant has been dubbed a “giga battery” due to its huge capacity to store energy. The facility has been vital in integrating wind and solar into Spain’s grid.

“As you know, these technologies cannot store energy,” says Enrique. “They produce when they have the source – the wind or the sun – but they require a backup. And pumped storage is the most efficient technology to store electricity.”

Pumped storage hydropower already accounts for more than 94 per cent of installed energy storage capacity worldwide, and is the only technology that can be developed at the scale needed to make net zero targets a reality.

Facilities like La Muela are beginning to feel the strain as more renewables come onto the grid, and intermittence increases.

“It used to be a weekly cycle, because the electricity system used to be very predictable,” says Enrique. “But now, with the integration and the participation of new renewables in the system, the cycle is changing.

“It depends on the wind, but sometimes we now have two or three cycles per week.”

As more wind and PV capacity is brought into the system, this strain will only become greater.

We need to start new pumped storage projects now

Pumped storage facilities at the scale of La Muela can take many years to build as a result of long lead-in and construction times.

“We require more or less around six years to build one of these plants, but you have to add on the permitting process, ”explains Enrique. “If you add another four years, we’re talking about ten years.

“So, if you want to have these kinds of facilities in the 2030s, the decisions should be made right now.”

Roger agrees: “I think it’s clear to IHA that this is a message that governments around the world need to listen to.”

More pumped storage is needed for firming capacity

As Enrique explains, the barriers to proceeding with new pumped storage facilities are complex.

“One important issue is the permitting, and the important civil works involved in that,” he says. “Another issue is the incomes and revenues of the plant. Right now, the electrical markets don’t pay for the services these plants are providing.”

Urgent action from policymakers and investors is needed to enable a pathway towards meeting emissions reduction targets.

“IHA absolutely believes that without pumped storage, the world will have a crisis in the 2030s,” says Roger. “Because there will not be enough firming capability to support wind and solar unless we start building more of these plants in many parts of the globe.”

Iberdrola is leading the shift to green energy

Projects like La Muela are leading the way in accelerating the growth of renewables and laying the foundations for coal to be phased out.

Iberdrola completed the closure of its own coal plants in 2020 as part of its commitment to shift towards green energy.

“I think Iberdrola is to be congratulated for having such a wonderful facility that’s going to stand the test of time for the 21st century,” says Roger.

“To help integrate solar and wind into the grid, pumped hydro is just what we need.”

Find out more about IHA’s new #WithHydropower campaign and how you and your organisation can help to support it and spread the word.