FAQ

Pumped storage hydropower is essentially a giant, water-based battery. It involves two water reservoirs located at different elevations. When electricity is abundant and cheap (e.g., during peak solar generation hours), the facility uses the excess grid power to pump water from the lower reservoir to the upper reservoir. When electricity demand is high, the water is released back down through a turbine to generate electricity, flowing back into the lower reservoir.

Modern PSH plants operate with a round-trip efficiency of roughly 70% to 80%. This means for every 10 MWh of electricity used to pump water up, the plant will generate 7 to 8 MWh when the water is released. While the initial capital expenditure is high, the civil works (dams, tunnels) can last over 100 years, and the electromechanical equipment (pump-turbines) typically lasts 40 to 50 years before requiring major refurbishment.

PSH is the only commercially proven technology for massive, long-duration energy storage. While lithium-ion batteries are excellent for short bursts (2-4 hours), utility-scale PSH plants are typically designed to provide hundreds of megawatts of power—often in the 300 MW to 400 MW range or larger—for 8 to 12 hours or more, effectively serving as bulk baseload replacement when needed.

Intermittent renewables like solar generate power when the sun shines, which doesn’t always align with peak energy demand (often in the evening). A PSH facility can absorb the excess generation from large solar parks—preventing curtailment—and dispatch that stored energy later. This firming of renewable output is critical for stabilizing regional grids that are integrating hundreds of megawatts of new solar and wind capacity.

Kosovo currently relies on the aging Kosovo A and B lignite power plants for the vast majority of its electricity. These plants are major sources of air pollution, causing severe respiratory health issues in Pristina and surrounding areas. By acting as a massive battery, PSH makes it possible to reliably integrate hundreds of megawatts of solar and wind power into the grid, directly enabling the phased decommissioning of these polluting coal plants and significantly improving national public health.

PSH is highly valued by transmission system operators because of its heavy, spinning turbines. It provides critical ancillary services that battery storage struggles to replicate at scale, including:

• Inertia: Physical resistance to changes in grid frequency.
• Voltage Support: Absorbing or injecting reactive power to maintain grid stability.
• Black Start Capability: The ability to restart the grid independently following a total blackout.

Revenues are typically generated through a combination of mechanisms:

• Capacity Markets: Getting paid for being available to generate power during peak demand periods.
• Ancillary Services: Contracts with grid operators for frequency regulation and spinning reserves
• Power Purchase Agreements (PPAs): Structuring long-term off-take agreements, sometimes paired directly with a large renewable energy asset.
• Energy Arbitrage: Buying electricity when prices are low and selling when they are high.

Under Kosovo law and international environmental standards, developers must conduct a comprehensive Environmental and Social Impact Assessment (ESIA). A vital part of this process is public consultation. Local residents, NGOs, and municipal leaders have the right to attend public hearings, review the project plans, voice their concerns, and demand specific mitigation measures before environmental permits are granted. Developers are also required to establish a clear, accessible grievance mechanism for the community.