Progress on Pumped Storage Development – Hear from Developers
CLEAN CURRENTS 2026
Time: 3:45 PM - 4:45 PM
Day: 9/24/2026
Room Number: Water Power Intelligence Theater
New: Add Sessions to Your Calendar
Interested in this session? Click "Add to My Calendar" and save specific sessions so you don’t miss out. Available for Mobile and Desktop
Calendar Note: Selecting “Add to Calendar” may download a calendar file (.ics) to your device. On mobile, tap the downloaded file to open it in your calendar app. On desktop, open the downloaded file to add the event to your calendar.
This Intelligence Theater block features the following case studies:
Click a case study below to jump to its details:
How Big Pump Storage Hydro Gets done
Holistic Valuation for Proposed PSH at Craig-Hayden, Colorado
A mine repurposing success - update on Kidston Pumped Storage project
What Techno-Economic Values can Soldier Camp PSH bring to South West Oregon?
How Big Pump Storage Hydro Gets done
Oxford Global Projects
Pumped Storage Hydropower (PSH) is becoming increasingly important for enabling system flexibility and supporting large-scale renewable integration. However, PSH projects are often perceived as high-risk megaprojects, associated with significant cost and schedule uncertainty. This paper provides an evidence-based assessment of how PSH projects actually perform, drawing on Oxford Global Projects’ database of approximately 80 projects worldwide and benchmarking outcomes against broader megaproject performance.
The session is delivered by the consultancy behind Oxford Professor Bent Flyvbjerg’s best-selling book How Big Things Get Done, applying the same outside-view, data-driven approach to understand how pumped storage hydropower projects are delivered in practice.
The analysis identifies the key drivers of performance across cost, schedule, and delivery risk. Technical complexity associated with underground works, particularly cavern size, depth, and tunnelling scope, emerges as the dominant factor influencing outcomes, with geotechnical uncertainty representing the single most critical risk. Design choices that minimise underground volumes, avoid first-of-a-kind solutions, and optimise scale are shown to materially improve performance. Across the dataset, PSH projects exhibit average cost overruns of around 29 percent and schedule overruns of approximately 18 percent, with underground technical characteristics explaining a significant share of outcome variation.
To place these findings in context, the paper examines the “megaproject premium” using leading academic reference class evidence. Delivery risk increases significantly once projects exceed USD 1 billion, with both the likelihood and magnitude of overruns rising with scale. However, when compared with other infrastructure sectors, PSH performance is broadly in line with, and in some cases better than, typical megaproject outcomes, challenging common perceptions of the sector.
The paper also draws on extensive project research and case evidence to identify practical strategies to mitigate the megaproject risk premium and improve delivery success. These include strengthening front-end development before final investment decision, investing early in comprehensive geotechnical investigation, optimising design to reduce underground scope and complexity, avoiding unnecessary first-of-a-kind elements, and establishing strong governance, alignment, and independent assurance.
Together, the findings provide energy and infrastructure decision makers with an external benchmark and a set of evidence-based actions to support more realistic risk assessment, improved contingency setting, and greater certainty in the successful delivery of pumped storage hydropower projects.
Holistic Valuation for Proposed PSH at Craig-Hayden, Colorado
National Laboratory of the Rockies
Valuing pumped storage hydropower (PSH) continues to be a key challenge for justifying power offtake agreements and capital investment, with each proposed site having unique characteristics contributing to its overall value proposition. The PSH system proposed by rPlus Energies near the towns of Craig and Hayden, Colorado is no different, being planned in a dynamic region of the grid that is juggling load growth with planned plant retirements, inverter-based resource deployments, and varied proposals for new generation and transmission. To characterize the holistic value of Craig-Hayden PSH, a team of researchers from the U.S. Department of Energy (USDOE) National Laboratory of the Rockies (NLR) and Oak Ridge National Laboratory (ORNL) partnered directly with rPlus under a technical assistance project funded by the USDOE Water Power Technologies Office (now the Hydropower and Hydrokinetics Office). ORNL used the PSH Valuation Toolkit to assess a full range of value streams available to Craig-Hayden PSH (energy, capacity, ancillary services), providing a high-level assessment of overall project economics under a range of market scenarios. NLR then used hourly production-cost modeling of the western interconnect to evaluate energy and ancillary service contributions under alternative generation and transmission topologies, demonstrating possible PSH operating regimes and grid contributions. NLR also performed dynamic stability studies that show how Craig-Hayden PSH can contribute to system inertia, grid strength, and grid stability under alternative contingency events and operating conditions. This unique emphasis on multi-scenario dynamic stability analysis can serve as a template for other PSH proposals. Results can inform discussions of Craig-Hayden PSH economics and financing not only from the plant perspective but also its local and regional contributions to grid reliability and stability. More broadly, attendees will gain an understanding of key metrics and potential local and regional impacts that new PSH can have on grid cost, reliability, and stability. They will learn about the value of integrating high-level economic analysis with high-fidelity models to explore the full range of values and services PSH can provide. Finally, participants will leave with a practical framework for combining economic and grid stability analysis in PSH valuation assessments.
A mine repurposing success - update on Kidston Pumped Storage project
GHD Pty Ltd
The globally unique 250MW Kidston Pumped Hydro Energy Storage (PHES) project is expected to be commissioning the pump turbines by the time of Clean Currents 2026. As the only successful mine repurposing scheme in the world, it’s a great time to look back at the challenges peculiar to taking a decommissioned mine and transforming it into a 2GWh energy storage as part of a solar energy hub.
This paper presents details on:
• Overcoming the draining of the large extant volume of highly contaminated pit water for a location subject to tropical cyclones
• Gaining an adequate understanding of complex volcanic geology
• Mitigating the risks posed by hydrogeologically induced instability during pit drainage and tunnel construction
• Tailrace tunnel completion in a pit with no access from above due to instability above and on previously constructed mine ramps
• Hydro plant delivery, storage and erection on a remote site often isolated by floods
It is hoped that by examining lessons learned in overcoming the challenges that mine site uniquely present, the industry can further the development of the very large number of abandoned mine site into valuable long term energy storage, while at the same time reducing the legacy hazards that these sites present. Disturbed sites also reduce the environmental impact that results from greenfield or onstream site development, so mine site repurposing doubles up in environmental credentials!
GHD has undertaken over a dozen detailed assessments of sites, including several in North America. Its strengths in geological investigation and interpretation have combined with its capabilities in PHES development, but a wider understanding in the hydropower industry by engineers, geologists and financiers is needed for more sites to proceed to completion.
What Techno-Economic Values can Soldier Camp PSH bring to South West Oregon?
Argonne National Laboratory
Introducing significant quantities of offshore and onshore wind (2700 MW) in Southern Oregon could provide significant opportunities for Rye Development’s Soldier Camp pumped storage hydropower (PSH) project (FERC # P-15311). The classroom session will provide insights into the issues of putting significant quantities of variable renewable energy resources into Coos and Curry Counties while only two-230 kV lines connect to the rest of the Western grid. As part of the US DOE Water Power Technologies Office PSH Technical Assistance, three National Laboratories will present on 1) wind production and impacts of weather systems for six wind farms, 2) price influencer modeling of wind introduction with and without the PSH, 3) Requirements to mitigate transmission congestion and stability issues, and 4) and is the PSH facility financially feasible. Pacific Northwest National Laboratory will focus on determining the production potential along with the variability due to different weather regimes for six different wind farms: Brookings offshore wind, Coos Bay Offshore wind, and four onshore wind farms in Coos and Curry Counties. Argonne National Laboratory (ANL) will provide a discussion on the approach to implementing the wind production scenarios with PSH and the how issues were resolved in the modeling process. Five scenarios will be discussed with and without PSH: 1) the 2032 situation without the potential of wind, 2) Brookings offshore wind, 3) Coos Bay offshore wind, 4) Coos and Curry Counties onshore wind, and 5) Brookings and Coos Bay offshore wind farms plus the onshore wind farms. The results will be presented for improvements to system cost and revenues for an owner/operator. Idaho National Laboratory will discuss transmission congestion and stability issues in presence of six wind farms, and how Soldier Camp PSH can address those. The local grid in Coos and Curry Counties serves low loads over two – 230 kV transmission lines – risking transmission congestion to reaching new 500 kV lines in Lane County, lacks inertia and short circuit current support – risking frequency and voltage stability. Resolution of these will be demonstrated with the addition of Solider Camp PSH, on the Western Electricity Coordinating Council (WECC) system base case. Finally, ANL will provide a financial analysis and discuss the alternatives reviewed in determining whether the PSH facility would be feasible in any of the scenarios analyzed. He will evaluate under what circumstances might make the facility more favorable and those conditions that might make the facility less favorable.
.jpg)