Heatwave Crisis in Europe

Climate change is increasing the frequency, intensity, and duration of heatwaves across Europe. Heatwaves are defined as periods when the maximum temperature exceeds the 98th percentile of the 1961–1990 reference period and exceeds 28 °C for three or more consecutive days.

Recent Significant Events

  • 2019: Western European Heatwaves — record temperatures across France, Germany, and the Netherlands. ECMWF Analysis →
  • 2022: Extreme Heat Crisis — prolonged drought and heat across Southern and Western Europe. Copernicus Report →
  • 2023: July Heatwave Surge — Mediterranean temperatures exceeding 45 °C. ECMWF Blog →
  • 2024: Widespread heat events continuing the trend of increasing intensity and duration.

These events demonstrate the escalating frequency and severity of extreme heat across Europe, with significant impacts on health, agriculture, and critical infrastructure.

July 2019 European maximum temperatures

Triple Threat to Electricity Grids

Extreme heat events pose a compounding triple threat to power systems, simultaneously stressing demand, supply, and transmission:

  • ▲ Surging Demand: Cooling loads spike during heatwaves, pushing peak consumption to record levels.
  • ▼ Reduced Supply: Thermal and nuclear generators derate under high ambient temperatures; renewable output fluctuates with weather conditions.
  • ▼ Degraded Transmission: Overhead conductors heat up, increasing resistance and sag, which forces operators to reduce power flow to maintain safety clearances.

These heatwave-induced imbalances between demand and supply significantly increase the risk of power grid load shedding and blackouts.

Summer extremes threatening power grids

Methodology

The framework integrates climate projections, thermal engineering, and power system optimisation into a unified pipeline.

Modelling: Projected heatwave scenarios are generated via bias-corrected delta mapping from historical extremes onto CMIP6 projections. Weather-driven demand (BAIT model), renewable capacity factors (Atlite), and generator derating curves translate these scenarios into grid-level inputs. Conductor temperatures are resolved per line segment using the IEEE 738-2012 heat-balance equation.

Algorithm: The Temperature-Dependent ACOPF (TD-ACOPF) iteratively couples two sub-problems: (1) a full AC optimal power flow (Pyomo/IPOPT) that determines branch currents and dispatch, and (2) a heat-balance update that recomputes conductor temperatures and line resistance. The loop repeats until the resistance–temperature feedback converges, capturing the nonlinear coupling between electrical loading and thermal state that conventional OPF ignores.

HeatAnalysis Modelling Framework TD-ACOPF Algorithm Workflow

Demos

Explore demonstrations showcasing key components of our methodology and results.

Heatwave Generation

Bias-corrected delta mapping approach for projecting future heatwave scenarios from historical extreme events.

Demand Calibration

BAIT thermal-comfort demand model calibrated per country using SCEM optimisation against ENTSO-E data.

Conductor Thermal Model

IEEE 738-2012 heat-balance equation for computing steady-state conductor temperatures and dynamic line ratings.

TD-AC-OPF Solving

Iterative temperature-dependent ACOPF algorithm using Pyomo modelling with IPOPT non-linear solver.

IEEE Grid Analysis

Validation on the IEEE 30-bus test system with synthetic heatwave data to demonstrate the TD-ACOPF methodology.

European Grid Results

Our framework has been applied to multiple European countries to assess heatwave impacts on real transmission networks:

  • Load Shedding: Quantified involuntary load curtailment under projected heatwave scenarios across ES, FR, IT, GB, DE, PT, NL, and BE.
  • Branch Congestion: Identified thermally-constrained transmission corridors where conductor temperatures approach or exceed rated limits.
  • Conductor Temperatures: Spatially-resolved temperature maps showing localised hotspots along multi-segment transmission lines.
  • Cross-Border Flows: Analysed how heatwave-induced congestion affects interconnector utilisation and power exchanges between countries.
  • Sensitivity Analysis: Systematic sweeps across heatwave years, load-growth rates, battery storage ratios, and thermal limit assumptions.
European Grid Analysis Framework

Citation

If you find HEAT-Analysis helpful in your research, please consider citing our work:

@article{heatanalysis2025, title = {Heatwave Impact on European Electricity Grids: Temperature-Dependent Optimal Power Flow Framework}, year = {2025}, url = {https://github.com/emliang/HEAT-GRID} }