Energy storage

The challenge of efficient energy storage

At Iberdrola, we are committed to energy storage as one of the great challenges to achieve the decarbonisation of the energy system.

At Iberdrola, we promote efficient energy storage as one of the key levers for decarbonisation and the energy transition. To this end, we use large-scale storage, through our pumped-storage hydropower plants, and small-scale storage, through lithium-ion batteries attached to renewable energy generation points. Our 2026 Strategic Plan foresees €1.5 billion of investment in this area. Our 2030 target: to reach more than 120 GWh of cumulative installed storage capacity. 

Energy storage for the energy transition

At Iberdrola, we are convinced that investment in storage is one of the fundamental pillars for accelerating the electrification of our energy systems, along with clean generation infrastructures and smart grids.  

But what is energy storage? Energy storage is the process of capturing and retaining energy for later release and use, which can be carried out using different technologies. This provision of energy enables the integration of intermittent electricity sources into the grid, such as solar and wind, expanding renewable energy’s supply and reducing dependence on fossil fuels. This in turn improves energy supply reliability and efficiency, as well as facilitates flexibility within the electricity market. 

At Iberdrola, we are leaders in energy storage through hydroelectric and pumped-storage generation – the cleanest and most efficient storage method to date, with 4 GW of installed capacity. Furthermore, we continue to add to our portfolio of assets various battery energy storage systems (BESS) around the world. A growing, versatile, efficient and customer-focused solution. 

Pumped-storage hydropower system (PSHS)

Pumped-storage hydropower plants are like giant "natural batteries in a riverbed", storing energy at times of low demand by pumping water from a lower reservoir to an upper reservoir. When the need for electricity increases, that water is released downstream, activating the power-generating turbines. This system, which uses gravity and the water cycle, is renewable, efficient, and clean.  

Depending on the upper and lower reservoirs’ size, the height of the waterfall and the turbines’ power, these systems offer a wide range of power outputs – from several megawatt-hours (MWh) to several gigawatt-hours (GWh) of energy. It is an iconic example of how engineering can join nature in a respectful way to foster a more autonomous and sustainable energy future. 

Battery energy storage system (BESS)

Battery energy storage systems (BESS) work by converting electricity into chemical energy whilecharging in rechargeable batteries during times of low demand, and releasing it when we need it; for instance, during peak consumption.  

There are several types of batteries for energy storage. Lithium-ion batteries are currently the most widely used due to their high energy density, long life cycle ,and relatively low maintenance requirements. 

Ignacio Galán

"We need to invest in electricity distribution networks and storage – not only in short-term storage such as batteries, but long-term storage such as pumped-storage hydropower – as well as promote interconnections between countries"

Ignacio S. Galán

Executive Chairman of Iberdrola

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