HR Europe Updated 2026-08-20

Croatia Geothermal Screening

Geothermal screening assessment identifies 23.8% prospective land reaching 185°C by 5.5 km depth in Croatia.

Key Geothermal Metrics

Land Reaching 185°C by 5.5 km Moderate
23.8%

Primary baseline screening criterion

Shallowest Depth to 200°C Deep Target
4.8 km

Minimum drill depth for high enthalpy

Peak Temperature at 5 km Depth Commercial EGS
213.8 °C

Maximum modeled temperature

Typical Geothermal Gradient Elevated
40.4 °C/km

Average to 5 km depth (15°C surface)

Grid Connectable Prospective Area High Accessibility
83.7%

Hot territory within 50 km transmission

Stored Heat In-Place (3–7 km) 1 ZJ = 10²¹ Joules
14.9 ZJ

Thermal volume in place (>80°C baseline)

Depth vs. Temperature Matrix (% Land Area)

Proportion of national territory exceeding target isotherm at specified depth

0.1° Inversion Grid
Isotherm 3.0 km 4.0 km 5.0 km 6.0 km 7.0 km 8.0 km
150°C 4.5% 9.4% 17.4% 22.1% 30.5% 36.2%
175°C 3.6% 8% 11.8% 16.2% 20.6% 26.2%
200°C 2.2% 5% 9.6% 13.8% 15.6% 17.5%
225°C 1.6% 3.7% 5.2% 8.1% 9.5% 13.1%
250°C 0.6% 1.4% 2.1% 3% 3.9% 4.2%

4-Stage Geothermal Resource & Infrastructure Funnel

Progressive screening from gross national territory down to grid-connected & populated prospective zones

1 Whole country
56 594 km² 100%
2 Reaches 185°C by 5.5 km
13 469 km² 23.8%
3 ...and within 50 km transmission
11 274 km² 19.9%
4 ...and within 100 km town
10 531 km² 18.2%

Geological Setting & Subsurface Parameters

Lithology, basement thickness, stress and thermal boundary constraints

Median Depth to 200°C Isotherm 6.8 km
Best 10th Percentile Depth to 200°C 5.4 km
Median Temperature at 5 km Depth 145.3 °C
Best 10th Percentile Temp at 5 km 195.5 °C
Median Sediment Thickness 0.9 km
Sediment / Hard-Rock Well Share 39.1%
Territory Under 1 km Sediment Cover 56.9%
Lithostatic Pressure at 5 km Depth 134.6 MPa
Moho Crustal Discontinuity Depth 33.3 km
Thermal Lithosphere Thickness 93.3 km
Curie Temperature Isotherm Depth 22.4 km
Model Temperature Spread Uncertainty (200°C) ±0.7 km

Transmission Grid & Demand Colocation

Infrastructure interconnectivity and urban power demand proximity

High-Voltage Transmission Network Length 4 805 km
Land Area Within 25 km of Grid 72.2%
Land Area Within 50 km of Grid 83.7%
Land Area Within 100 km of Grid 90.3%
Average Proximity to Nearest Substation / Line 13.5 km
Urban Centers (>10,000 Population) 46
Total Urban Population 3.6 M
Prospective Resource Colocated Near Demand (>1M Pop) 31%

Target Sensitivity & Deep EGS Upside

Sensitivity of prospective resource area to adjusted depth and temperature thresholds

150°C Baseline at 5.5 km 38.1% of national territory reaches 150°C at 5.5 km depth
185°C Baseline at 7.5 km 42.8% of national territory reaches 185°C at 7.5 km depth

Global Peer Benchmarking (vs. 278 Assessed Jurisdictions)

Relative ranking distribution of Croatia across 11 standardized geothermal indicators

Croatia Rank Global Peer Spread
Shallowest 200°C depth
4.8 km Lower 50%
P0 (Lowest) P50 (Median) P100 (Highest) • 46th percentile
Peak temp at 5 km
213.8 °C Lower 50%
P0 (Lowest) P50 (Median) P100 (Highest) • 46th percentile
Prospective land area (>185°C at 5.5 km)
23.8% Lower 50%
P0 (Lowest) P50 (Median) P100 (Highest) • 40th percentile
Stored heat in-place (3-7 km)
14.9 ZJ Lower 50%
P0 (Lowest) P50 (Median) P100 (Highest) • 37th percentile
Typical geothermal gradient
40.4 °C/km Middle 50%
P0 (Lowest) P50 (Median) P100 (Highest) • 58th percentile
Grid proximity (<50 km)
83.7% Top 25%
P0 (Lowest) P50 (Median) P100 (Highest) • 84th percentile
Thin sediment coverage (<1 km)
56.9% Middle 50%
P0 (Lowest) P50 (Median) P100 (Highest) • 57th percentile
Curie isotherm depth
22.4 km Middle 50%
P0 (Lowest) P50 (Median) P100 (Highest) • 51th percentile
Moho crustal thickness
33.3 km Lower 50%
P0 (Lowest) P50 (Median) P100 (Highest) • 40th percentile
Model temperature uncertainty spread
±1.4 km Middle 50%
P0 (Lowest) P50 (Median) P100 (Highest) • 62th percentile
Urban demand colocation
50.4% Top 25%
P0 (Lowest) P50 (Median) P100 (Highest) • 67th percentile
Asset-Level 3D Simulation Available

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Analytical Geothermal Assessment & Discussion: Croatia

Subsurface thermal interpretation, model uncertainty, infrastructure colocation, and resource quality analysis

Resource Overview

Geothermal assessment for Croatia indicates extensional_basin geological controls governing subsurface heat transport, yielding 23.8% of land area reaching the baseline target of 185°C at 5.5 km depth.

Uncertainty & Model Variance

Thermal inversion across Croatia shows consistent model convergence with constrained standard deviations across deep crustal layers.

Grid & Infrastructure Colocation

National electrical transmission coverage positions approximately 83.7% of prospective geothermal ground within 50 km of existing high-voltage corridors.

Geological & Basement Setting

Subsurface lithology is characterized by extensional basin dynamics with median sediment thickness of 0.9 km and crustal thickness of 33.3 km.

Stored Heat Volume

Accessible thermal energy in place between 3 km and 7 km depth above 80°C totals 14.9 Zettajoules (ZJ).

Peer Comparison

Benchmarked against 237 global assessment jurisdictions, Croatia demonstrates competitive positioning across heat flow, infrastructure, and basement competence indicators.

Target Sensitivity Analysis

Screening at 150°C baseline at 5.5 km increases prospective territory, demonstrating substantial deep EGS resource headroom.

Screening Methodology, Parameters & Limitations

This screening assessment for Croatia is generated from Geothermal Radar Data Pack 2026.1 utilizing global 0.1° hex-grid thermal inversion across 629 model cells (land area: 56 594 km²). Baseline prospective criterion is defined as reaching 185°C at or above 5.5 km depth with surface temperature normalized to 15°C.

  • Screening estimates represent regional-scale heat in place and do not replace localized 3D seismic or exploratory drilling.
  • Model uncertainties expand in regions with sparse deep boreholes and complex thrust fault kinematics.
  • Grid proximity indicators reflect line-of-sight distance to high-voltage transmission and do not account for local substation thermal capacity.
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