Hydro as water battery: A big splash in energy storage solutions

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  Quantumrun Foresight
• April 26, 2024

Insight summary

The natural landscape is being transformed into a giant "water battery" using pumped hydro energy storage to store solar energy and generate electricity to power thousands of homes. This approach, which leverages the difference in elevation between two reservoirs to store and release energy, addresses the inconsistencies of solar and wind power. As interest in such energy storage solutions grows, the implications for grid stability, job creation, and environmental sustainability highlight the potential for widespread adoption and innovation in renewable energy infrastructure.

Hydro as water battery context

In 2022, the San Diego County Water Authority launched a project that utilizes the natural landscape to store solar power like a battery but with water. This concept, known as pumped hydro energy storage, involves strategically using two reservoirs positioned at different elevations. During periods when solar energy is abundant, typically when the sun is at its most intense, excess electricity is used to pump water from a lower reservoir to a higher one. 

This process effectively stores the solar energy in the form of potential energy. Then, as the demand for electricity surges, especially after sunset when solar power is not directly available, the stored water is released back to the lower reservoir. This descent drives turbines, generating electricity in a clean, renewable way. The San Vicente Reservoir project exemplifies this approach, aiming to generate 500 megawatts of electricity for up to eight hours to power 130,000 typical homes.

Pumped hydro energy storage is not a novel concept; it has been a part of the US energy infrastructure for decades, with over 40 sites already operational. These facilities were initially developed to store excess electricity from nuclear power plants during off-peak hours. However, the rise of renewable energy sources like wind and solar, which generate power intermittently based on weather conditions rather than consumer demand, has renewed interest in this technology. The challenge of integrating renewable energy into the power grid becomes evident during extreme weather events, as seen in California during a heat wave. Despite generating surplus solar energy during the day, the grid struggled to meet demand in the evening, highlighting the critical need for energy storage solutions like pumped hydro to bridge the gap between production and consumption.

Disruptive impact

Pumped hydro storage projects are gaining momentum in the US, supported by legislation that extends tax credits to pumped hydro projects, enhancing their financial viability. This resurgence in interest is not without competition; other energy storage technologies, such as battery storage systems and compressed air energy storage, are also vying for adoption. Yet, pumped hydro storage offers distinct advantages, including the capacity to store large amounts of energy without relying on scarce materials like cobalt and lithium. Moreover, these systems can have life spans exceeding a century, providing a durable, scalable solution to energy storage. 

Other countries are also amplifying their investments in this field. For example, Switzerland constructed a large pumped storage power plant in 2022. The project, built into an underground cavern, showcases a capacity to store electricity at a scale equivalent to the batteries of 400,000 electric cars. With the ability to generate and store up to 900 megawatts (MW) of power, this plant is poised to supply electricity to as many as 900,000 homes, highlighting its potential impact on Switzerland and Europe's energy grids.

With these benefits, there may be renewed investments in water battery plant structures globally, opening opportunities for jobs in rural places where most large bodies of water are located. There may be increased demand for engineers and companies that provide infrastructure maintenance, including drone surveillance. For communities, having access to a potentially unlimited supply of energy can drive energy costs down and gain support for green projects.

Implications of hydro as water battery

Wider implications of hydro as water battery may include: 

• Enhanced grid stability and reliability, minimizing the impact of power outages on critical services like hospitals and emergency response units.
• Shifts in labor demand, with a decrease in jobs in traditional energy sectors and an increase in renewable energy and technology sectors.
• Governments implementing policies to incentivize the construction of water battery storage, shaping the landscape of national energy strategies.
• Potential environmental concerns over constructing new reservoirs, including impacts on local ecosystems and wildlife habitats.
• Increased energy independence for nations, reducing geopolitical tensions related to oil and gas supplies.
• Development of new business models in the energy sector, focusing on sustainability and long-term resilience rather than short-term profit.
• Demographic patterns shifting, as regions with access to renewable energy resources and water battery technology become more attractive for living and investment.

Questions to consider

• How do you see water battery storage systems shaping the future of renewable energy in your region or country?
• How could governments balance innovation like these with preserving the ecosystem around them?