York Energy Storage
Reliable Renewable Electricity for PJM Interchange Customers from Hydro Pumped Storage
York County, PA
(Susquehanna River)
Project Description
At 858 MW, YES would rank among the largest long-duration energy storage projects in the eastern United States — with a single 10-hour cycle delivering 8,580 MWh, enough to supply over 715,000 homes simultaneously.
The York Energy Storage (YES) project is an 858 MW open-loop, long-duration pumped hydro storage facility planned in Chanceford Township, York County, Pennsylvania. It leverages Lake Clarke — an existing Susquehanna River reservoir — as its lower reservoir, paired with a newly constructed 580-acre upper reservoir at 680 feet of elevation holding 26,000 acre-feet of storage.
An underground powerhouse will house three reversible pump-turbine-generators (286 MW each), connected by a 44-foot diameter shaft and steel-lined supply tunnels. The facility will connect to the PJM grid via an above-ground 500 kV switchyard.
The project is expected to achieve 80% round-trip efficiency, generating 8,580 MWh over a standard 10-hour operating cycle — providing flexible, dispatchable clean power exactly when and where the grid needs it most.
The powerhouse, penstock, and major infrastructure are hidden underground, and the lower reservoir uses an existing body of water — minimizing surface disturbance and visual impact.
Grid & System Benefits
- Prime Location — Strategically positioned near the center of the PJM grid; independently cited as the best pumped storage site in the eastern United States.
- Proven Technology — Pumped hydro accounts for 94% of all long-duration grid-scale energy storage worldwide. A 100-year track record with a 50–100 year operating lifespan — far exceeding battery alternatives.
- Environmental Advantage — No emissions, no mining, and no solid or liquid waste. A genuinely green technology superior to batteries, gas turbines, or any currently known storage alternative.
- Grid Resiliency — Instantly dispatchable by the PJM Control Center, providing critical inertia and stability as fossil generation retires from the grid.
- Long-Duration Load Balancing — Unlike short-duration batteries, YES delivers sustained output over a full 10-hour cycle — managing voltage, frequency, power factor, black starts, and transmission congestion.
- Minimal Surface Footprint — Powerhouse and penstock are fully underground; lower reservoir uses existing Lake Clarke; upper reservoir on lightly developed land.
Community Benefits
- Economic Development — 300 to 500 construction jobs and 25 to 50 permanent positions, with billions of dollars in regional investment flowing into York County during construction.
- Lowest Life-Cycle Cost — Lower long-term cost than battery storage, gas turbine peakers, or any other currently available energy storage alternative.
- Clean & Green — Powered entirely by water. Produces zero air, liquid, or solid waste. Simply the power of gravity and water — the world's oldest and cleanest form of energy storage.
- Tax Contribution — $30 million in annual tax revenue to York County and the Commonwealth of Pennsylvania, with the potential to reduce local real estate and school taxes.
Regulatory Status
The YES project is currently in the Assessment Phase, focused on securing all required regulatory approvals from FERC and PJM.
YES filed for its FERC Preliminary Permit on February 14, 2023 and received approval on November 21, 2024 — granting site control and the first right to apply for a Construction License.
For PJM approval, YES must complete a grid analysis demonstrating project benefits to PJM customers and no adverse impact on downstream Susquehanna River hydro facilities.
Visuals
History of the Site
The YES site has a 50-year history of recognition as the premier pumped storage location in the eastern United States — studied and pursued by multiple entities across three separate development efforts before York Energy Storage, LLC acquired all prior work and moved forward.
Get in Touch
York Energy Storage, LLC welcomes inquiries from qualified development partners, investors, and interested parties. Contact us to learn more about the project, partnership opportunities, or our FERC licensing process.