Pumped storage facilities rely on gravity to produce energy. The system moves water between a lower reservoir and an upper reservoir. When renewable energy from wind and solar power is plentiful, this excess energy is used to pump water from the lower reservoir to the upper reservoir. Then, when demand for power is high, water is released from the upper reservoir and used to turn hydroelectric turbines to generate on-demand renewable electricity.

The system is filled with water once, and then re-uses that water, over and over. It repeats the cycle, continually storing and dispatching renewable energy.

No. Pumped storage hydro facilities have been in use for more than a century, and are a well-established form of energy storage around the world. According to the 2021 US Hydropower Market Report, there are more than 40 pumped storage projects currently operating in the U.S..

Pumped storage facilities are the most common form of energy storage in the US, representing the vast majority of all utility scale storage, according to the U.S. Department of Energy. Pumped storage is the world’s largest, most efficient utility-scale energy storage solution.

When solar or wind energy is used to pump water to the upper reservoir, the resulting on-demand power is carbon- and pollution-free.

To meet our regional and national goals for safe and reliable clean energy, we need new cost-effective solutions to store and access it, especially in periods of high demand.

For 40 years, the 2,250-megawatt Navajo Generating Station produced electricity 24 hours a day, seven days a week until 2019, when it was decommissioned.

Currently, our two biggest sources of renewable energy — wind and solar power — are intermittent, producing electricity only when the sun is shining or the wind is blowing. Pumped storage hydro is a proven technology that allows us to harness the energy generated from wind and solar resources, storing it for use when demand is highest.

As the impacts of fossil fuel use on climate change become more dire to our planet and threaten the health and safety of future generations, there is increasing urgency to shift to renewable energy and away from fossil fuels. As of April 21, 2023, 10 states, including Nevada, New Mexico and California, have passed legislation setting 100 percent renewable energy goals. Integrating a mix of renewable energy solutions, including solar, wind, and pumped storage hydro, is our fastest and most effective way to achieve our clean energy goals.

• Long-lasting, with facilities operational for 100+ years.
• Affordable, costing 20-30% less than installed lithium-ion batteries.
• Low maintenance and resistant to supply chain disruptions.
• Helps stabilize the energy grid in otherwise potentially unreliable periods by providing a flexible and responsive source of electricity that can quickly ramp up or down to meet changing demand.
• Enables more intermittent renewable resources to be added to the grid because there is a way to store excess energy during times of low demand.

Several conditions must be in place for pumped storage facilities to be built.

• Topography: Pumped storage facilities require a specific topography that includes two reservoirs at different elevations.
• Geography: The geological formations should be stable and suitable for the construction of reservoirs, tunnels, and other infrastructure.
• Water availability: A reliable source of water is necessary to fill and maintain the two reservoirs.
• Land availability: Constructing a pumped storage facility requires land compatible with other local uses.
• Transmission lines: Projects located within proximity to transmission lines make them more feasible than alternatives.

In 2023, Rye Development, at the invitation of the Navajo Nation, began completing feasibility studies for two pumped storage projects. In March 2024, Rye was issued a permit by the Navajo Nation to study the potential impacts of the projects. Rye has narrowed its scope to just one project located within the LeChee Chapter near the former Navajo Generating Station.

Obtaining a license to construct and operate a pumped storage facility involves a 4-to-5-year process, and this is the initial step in that journey. By completing feasibility studies, Rye Development will gather the necessary information to decide whether to proceed with the projects. Rye is also meeting with local chapter leaders and residents to share information, answer questions, and gather valuable input. In a related effort, Rye is meeting with local chapter leaders and residents to kick off the Community Benefits Plan process.

Rye Development is leading a new generation of pumped storage hydropower in the U.S. and helping create a more reliable energy grid. Rye develops projects from inception to operations through site identification, permitting, offtake and construction.

Rye works in partnership with utilities, policymakers, community leaders, tribal nations, and others to develop pumped storage hydropower projects in an environmentally responsible way. Visit their website to learn more about Rye Development’s pumped storage projects across the U.S.

In a closed-loop facility, once the lower reservoir is filled, water is recirculated between the lower and upper reservoirs via a pipe. During times of surplus electricity (peak sun hours or windy days), the plant uses surplus energy to pump water from the lower reservoir to the upper reservoir. Then, during peak demand hours, the water is returned by gravity to the lower reservoir passing through turbine generators that generate electricity. In comparison, open-loop pumped storage projects are continuously connected to a naturally-flowing water feature, such as a river, often-times creating aquatic and terrestrial impacts that closed-loop facilities do not create.

The Navajo Generating Station, along with the Kayenta Mine, offered good paying jobs and provided between $30 million to $50 million in annual revenue for the Navajo Nation.

Pumped storage facilities are large infrastructure projects that create thousands of family-wage jobs during the construction phase. It takes 4-5 years to design and build a pumped storage project, employing plumbers and pipefitters, electricians, heavy machinery operators, and more, while also offering apprenticeship opportunities. Dozens of long-term positions would be needed to operate the projects over the next 100+ years.

A new pumped storage facility could generate millions of dollars in annual tax revenue for the Navajo Nation.

Pumped storage can enable more clean energy projects to be built on the Navajo Nation, which is a priority of the April 2018 Navajo Nation comprehensive economic development plan. Additionally, the projects could put the Navajo Nation in the driver’s seat for renewable energy infrastructure across the broader Southwest region.

The project would:

• Store electricity for about 8 hours daily.
• Have a generating capacity of 500 megawatts
• Provide enough electricity to power 150,000 homes^*
• Preserve agricultural, municipal and commercial water uses

^*Based on average household energy consumption according to the U.S. Energy Information Administration.

To address the climate crisis, lawmakers and utility commissions across the Southwest have signaled that 100% of their states’ electricity will come from clean resources in the near future. As a result, all regional utilities are seeking additional renewable electricity and storage capacity as they transition to a carbon-free grid. Numerous grid emergencies have brought renewed attention to the need for backup power options to complement the intermittent nature of renewable sources.

Rye’s proposed pumped storage project on the Navajo Nation can provide significant storage capacity to help utilities meet their near and long-term generation and storage needs.

In 2023 at the invitation of the Navajo Nation, Rye Development began completing feasibility studies for two pumped storage projects known as Western Navajo 1 and Western Navajo 2. In March 2024, Rye was issued a permit by the Navajo Nation to study the potential impacts of the projects. Rye has narrowed its scope to just one project located near the former Navajo Generating Station. Obtaining a license to construct and operate a pumped storage facility involves a 4-to-5-year process, and this is the initial step in that journey.