Initial Situation and Problem

The Upper Styrian pioneer city of Leoben (25,000 inhabitants) faces a critical challenge in implementing its 2040 climate neutrality roadmap: Despite optimal utilization of all available roof and facade surfaces, 3.5 GWh/a of electricity demand remains uncovered – equivalent to the consumption of 1,200 households. Simultaneously, the decommissioned municipal waste landfill Seegraben (5.2 ha) generates annual operating costs of €85,000 without creating added value.

Across Austria, ˜21 km² of urban landfills exist with theoretical PV potential of 2.1 GWp, yet systematically validated feasibility frameworks for inner-city sites are missing. Complex interdisciplinary challenges include geotechnical instability, regulatory gray areas at the interface between waste and construction law, environmental interactions with landfill gas emissions, and socio-economic acceptance issues in urban contexts.

Objectives and Innovation Content

The project develops the first integrated multi-benefit approach for urban landfill PV through systematic integration of methane oxidation windows between PV table rows, participatory brownfield lab with gender- and generation-specific citizen participation, and biodiversity-PV synergy through vegetation strategy combining erosion protection, methane oxidation, and biodiversity enhancement.

The 15-month feasibility study aims for implementation-ready decision basis for a 3.5 MWp PV plant with 3.5 GWh/a yield. Innovative stop-or-go mechanisms ensure risk minimization: At <4 kN/m² load capacity or >2 cm/a residual settlement, cost-efficient project termination occurs.

Targeted Results and Insights

The feasibility study delivers a publicly accessible replication package for Austria-wide utilization: fully validated planning foundations for multi-MWp PV systems on challenging landfill substrates, regulatory template as approval pathway blueprint, and scientifically proven evidence for synergistic PV-biodiversity effects. Upon successful implementation, the 21 km² potential of urban landfills enables additional annual electricity production of ˜2 TWh (3% of Austrian electricity demand) and CO2 savings of 600,000 t/a.

The four-member consortium (Municipality Leoben, 4ward Energy Research, Environmental Consultants, BOKU) combines municipal governance competence, applied energy research, contaminated site expertise, and university basic research for maximum knowledge transfer and sustainable impact.

Project management

Stadtgemeinde Leoben

Project or cooperation partners

• 4ward Energy Research GmbH RM
• Umweltkonsulenten ZT GmbH
• Universität für Bodenkultur Wien