In a significant stride towards renewable energy integration, scientists from Argonne National Laboratory and the National Renewable Energy Laboratory (NREL) have revealed their findings from an exhaustive study identifying potential sites for pumped storage hydropower projects across Alaska.

The study – The Prospects for Pumped Storage Hydropower in Alaska – focused on mapping and geospatial analysis to pinpoint potential locations suitable for pumped storage hydropower development. Scientists identified about 1800 sites in the state.

Alaska, known for its rapid warming and environmental challenges, presents unique energy needs due to its vast size and isolated communities. Unlike many other states, Alaska lacks connection to large interstate energy grids, relying on more than 150 small, standalone systems. To address this, researchers explored the integration of pumped storage hydropower to store excess energy from intermittent renewable sources and provide a stable power supply during periods of scarce wind and solar availability.

"Pumped storage hydropower has the potential to integrate more wind and solar into the power grid by storing excess renewable energy to balance intermittent periods of weather," explained Vladimir Koritarov, director of the Center for Energy, Environmental, and Economic Systems Analysis at Argonne’s Energy Systems and Infrastructure Analysis division.

Apart from bolstering Alaska's efforts to combat climate change and reduce carbon emissions, the study has far-reaching implications for energy affordability in remote regions. The state's isolation and geographic challenges have resulted in high electricity costs, especially in rural areas where residents pay substantially more than urban dwellers due to the expense of transporting diesel fuel.

As part of the study, researchers from Argonne National Laboratory conducted a thorough evaluation of the potential for pumped storage hydropower in Alaska's integrated Railbelt system. The Railbelt system comprises five regulated public utilities that serve cities such as Fairbanks, Anchorage, and the Kenai Peninsula, with approximately 80% of its electricity currently coming from natural gas, which emits carbon dioxide.

Using the Argonne Low-Carbon Electricity Analysis Framework (A-LEAF), the scientists created detailed models for power system operations and planning, considering past and present energy transmission trends. They also analyzed the expected overall growth in electricity demand over the next 25 years and took into account the retirement of existing generators as they reach the end of their economic lifetimes.

A key finding from the A-LEAF modeling is that the Railbelt system will require both short- and long-duration energy storage in the future to balance the variability of wind and solar generation and ensure reliability and backup capacity during extended periods.

The study revealed that pumped storage hydropower can provide roughly 10 or more hours of energy storage, making it a promising option for meeting the region's energy needs. Additionally, the research showed that short-term energy storage, using lithium-ion batteries, could be feasible for four-hour durations in the Railbelt system.

Researchers from the National Renewable Energy Laboratory (NREL) also evaluated Alaska's remote areas, powered by small isolated electrical grids or "microgrids." Using the Hybrid Optimization Model for Electric Renewables (HOMER), they analyzed the viability of small-scale pumped storage projects in rural communities with at least 250 residents. The team identified 18 remote communities with potential for smaller pumped storage projects based on various criteria, including population size. However, for most cases, pumped storage hydropower may not be economically feasible due to the high investment cost of small-size projects. In these situations, lithium-ion battery storage might be a more economically beneficial option for lowering electricity costs, although it may not provide longer duration storage economically.

The study also included a sensitivity analysis of pumped storage hydropower capital costs and the price of diesel fuel, conducted by an NREL senior engineer, Rebecca Meadows. The goal was to determine the point at which distributed-scale pumped storage hydropower projects could become economically viable. For larger remote communities with higher diesel costs, results indicated that pumped storage hydropower could be a cost-effective option, depending on site-specific considerations such as renewable resources and constructability.

The findings of this study not only validate the potential of pumped storage hydropower as a viable technology for reducing carbon emissions but also provide valuable guidance for policymakers in developing clean energy policies, regulations, and investment decisions. Moreover, pumped storage hydropower projects hold the potential to boost the Alaskan economy, as developers have already expressed interest in pursuing such developments in the state.

Argonne National Laboratory played a pivotal role in spearheading a 2021 DOE-sponsored guidebook on valuing pumped storage hydropower projects, adding to the breadth of expertise brought to this research initiative.

The study was part of the DOE's HydroWIRES (Water Innovation for a Resilient Electricity System) initiative, which seeks to understand, enable, and improve hydropower and pumped storage hydropower's contributions to reliability, resilience, and integration in the rapidly evolving US electricity system.