Integrating Geothermal Potential and Hydrogen Imports in PyPSA-Earth: Application to Japan’s 2050 Energy System
Abstract
Japan relies heavily on foreign energy imports while hosting immense untapped geothermal resources. Leveraging domestic deep geothermal energy could mitigate import dependencies, alleviate land-use constraints, and provide stable base-load clean power. This study introduces major open-source enhancements to the energy system modeling framework PyPSA-Earth by integrating spatially explicit Enhanced Geothermal Systems (EGS) potentials and maritime hydrogen import routes across ten aggregated regional nodes for Japan’s 2050 net-zero transition. Through a co-optimized capacity expansion and dispatch framework across the power, heating, transport, and hydrogen sectors, results demonstrate that EGS plays a pivotal structural role as a continuous base-load source. Deploying 35.0 GW_el of EGS (capturing 21.3% of total power generation) significantly reduces the required expansion of land-intensive variable renewables—avoiding 104 GW of utility PV and 26 GW of onshore wind—and cuts stationary battery storage discharge capacity needs by 70.4% (-45.3 GW). Although geographically concentrated EGS in Kyushu increases inter-regional AC transmission grid expansion costs, net annual system costs decline by 6.1% (yielding net annual savings of €4.29 billion/a). In urban district heating, direct geothermal heat achieves a dominant 67.3% share (3.5 TWh/a). Regarding clean hydrogen, maritime imports dominate at 80.4% under the baseline CIF target (€1.49/kg H2). However, an import price increase to €2.24/kg H2 triggers a sharp structural shift: imports collapse to 1.9 TWh/a, shifting supply to domestic SMR with carbon capture and co-located EGS-electrolysis. These quantitative insights highlight deep geothermal energy as a crucial, land-saving domestic anchor for island energy transitions.
