Pumped‑Storage Hydropower in a Post‑Mining Landscapes: A Feasibility Study for Repurposing the Ptolemaida Lignite Basin in Western Macedonia, Greece

The contribution proposes a feasibility study for a pumped‑storage hydropower (PSH) scheme in the wider Ptolemaida lignite basin in Western Macedonia, Greece, aiming to repurpose post‑mining landscapes as multi‑functional water and energy infrastructures that support the rapid penetration of renewables into the national power system. The work is particularly relevant to the EGU community as it lies at the interface of fluvial and hydraulic engineering, energy transition, and post‑mining land and water management in a coal‑dependent region undergoing accelerated decarbonisation.

 

The study will develop and assess alternative PSH configurations using existing and planned mine pits and overburden areas as upper and lower reservoirs, constrained by local hydro‑geomorphological, geotechnical and hydrogeological conditions. A coupled hydrological–hydraulic framework will be applied to (i) quantify available storage volumes and head differences, (ii) evaluate seepage, slope stability and embankment safety under cyclic operation, and (iii) explore interactions with surface and groundwater systems at seasonal to multi‑annual time scales.

 

On the energy‑system side, the project will simulate PSH operation under different scenarios of wind and solar deployment in Western Macedonia and the wider Greek interconnected system, using high‑resolution time series of load and variable renewable generation. Key performance indicators will include round‑trip efficiency, contribution to peak‑shaving and intra‑day balancing, provision of frequency and reserve services, and impacts on curtailment of renewables during high‑production, low‑demand periods.

 

The economic feasibility assessment will combine capital and operational expenditure estimates for mine‑based PSH schemes with projected revenue streams from energy arbitrage and ancillary services, within evolving Greek and EU regulatory frameworks for storage and just transition financing. Special emphasis will be placed on uncertainty analysis with respect to future market prices, policy instruments, and potential support mechanisms for storage in former lignite regions, in line with ongoing decarbonisation and regional development strategies.

 

From an environmental and socio‑hydrological perspective, the study will investigate how PSH reservoirs can be integrated into long‑term mine‑closure and landscape‑rehabilitation plans, including water‑quality evolution, sediment management, and the creation of new aquatic and riparian habitats. The results are expected to demonstrate pathways by which PSH in Ptolemaida can simultaneously deliver grid‑scale flexibility, reduce environmental legacies of lignite mining, and support regional socio‑economic resilience, offering a transferable case study for coal regions in transition across Europe.