The ESS family is used here as an internally consistent analytical framework. Its levels are not direct physical dependency percentages, and cross-country interpretation should focus on direction, relative position and documented inputs.
ESS1: fossil-import exposure
ESS1_oil = Σ(TOI × TOC × TEC) / Σ(TOC × TEC × GDP)
ESS1_gas = Σ(TGI × TGC × TEC) / Σ(TGC × TEC × GDP)
ESS1_ensemble = (ESS1_oil + ESS1_gas) / 2
TOI and TGI are oil and gas import inputs; TOC and TGC are product-consumption inputs; TEC is total energy consumption; GDP is the economic scaling input. Lower ESS1 values are interpreted as lower modeled exposure.
ESS2 and ESS3
ESS2 = Σ(industrial energy consumption) / Σ(GDP)
ESS3 = Σ(domestic energy production) / Σ(total energy consumption)
ESS2 represents industrial energy intensity, where lower is the stronger direction. ESS3 represents domestic-production coverage, where higher is the stronger direction.
ESS4: raw average and directional index
ESS4_raw = (ESS1_ensemble + ESS2 + ESS3) / 3
ESS4_index = mean(ESS1_base / ESS1 × 100, ESS2_base / ESS2 × 100, ESS3 / ESS3_base × 100)
The project retains the raw arithmetic average but displays a 2015 = 100 direction-normalized index so improvements in lower-is-better and higher-is-better components point in the same direction. The index should be described as a trajectory, not a probability or physical share.
What the index does not claim
- It is not the official Eurostat import-dependency rate.
- It is not a probability of disruption or an investment recommendation.
- Scenario movements are not causal estimates of a policy or corridor.
- External features do not replace the Eurostat-derived production-history targets.
For data lineage, validation and scenario construction, continue to the full methodology.