The indicator is the ratio between the Gross Inland Consumption of Energy and the Gross Domestic Product calculated for a calendar year. It measures the energy consumption of an economy and its overall energy efficiency. The Gross Inland Consumption of Energy is calculated as the sum of the Gross Inland Consumption of the five types of energy: coal, electricity, oil, natural gas and renewable energy sources. In addition, each of these figures is calculated as an aggregation of different data on production, storage, trade (imports/exports) and consumption/use of energy. The GDP figures are taken at chain-linked volumes, reference year 2005 (at 2005 exchange rates). The energy intensity ratio is the result of dividing the Gross Inland Consumption by the GDP. Since Gross Inland Consumption is measured in kgoe (kilogram of oil equivalent) and GDP in 1000 EUR, this ratio is measured in kgoe per 1000 EUR. All necessary data related to energy data is compiled through five annual Joint Questionnaires (one for each type of energy above-mentioned). These questionnaires are called « joint » because they are shared by Eurostat and the International Energy Agency (organisation that belongs to the OECD).
The indicator is a Sustainable Development Indicators, as it has been chosen for the assessment of the EU progress towards the targets of the Sustainable Development Strategy.