Energy balance - new methodology
What is an energy balance?
The energy balance is the most complete statistical accounting of energy products and their flow in the economy. The energy balance allows users to see the total amount of energy extracted from the environment, traded, transformed and used by end-users. It also allows seeing the relative contribution of each energy carrier (fuel, product). The energy balance allows studying the overall domestic energy market and monitoring impacts of energy policies. The energy balance offers a complete view on the energy situation of a country in a compact format, such as on energy consumption of the whole economy and of individual sectors.
The energy balance presents all statistically significant energy products (fuels) of a country and their production, transformation and consumption by different types of economic actors (industry, transport, etc.). Therefore, an energy balance is the natural starting point to study the energy sector. The energy balance is a multi-purpose tool to:
- Provide comprehensive information on the energy supply and demand in order to understand the energy security situation, the effective functioning of energy markets and other relevant policy goals, as well as to formulate energy policies;
- Provide the essential basis for calculating various indicators, including indicators monitoring progress towards Energy Union and Europe 2020 targets (energy efficiency indicators, share of renewable energy, energy dependency, etc.);
- Ensure comparability of statistical information between different reference periods and between different countries/regions;
- Provide data for the calculation of greenhouse gas emissions from fuel combustion;
- Serve as a quality tool to ensure completeness, consistency and comparability of energy statistics;
- Provide an input for modelling and forecasting.
The concept of an energy balance is an accounting framework for the compilation, reconciliation and understanding of data on all energy products entering, exiting and used within a country (territory).
The use of energy balances
In 1976 the United Nations Statistical Commission agreed on the use of energy balances as the key instrument to coordinate work on energy statistics and to provide data in a suitable form to understand and analyse the role of energy in the economy. Energy balance is the starting point for constructing several indicators, such as import dependency. Certain aggregates of the energy balance contribute to cross-domain indicators, such as energy intensity (energy input per unit of output (GDP)). More generally, a number of questions can be answered by looking at the data in the energy balance (such as the evolution of energy consumption by sector or efficiency of electricity generation from combustible fuels). In addition, the energy balance can be used as a high-level check on the data quality: the coherence and accuracy of energy statistics reported for individual energy products. Substantial statistical differences in energy units, apparent energy gains, significant losses in transformation processes, unexplained variations in indicators may point towards underlying data problems. Overall, the energy balance is an extremely useful and powerful tool, which is complemented by additional indicators calculated and disseminated by Eurostat. Such indicators include:
- Detailed data on origin and destinations of international trade (import/export data);
- Technical data: generation and production capacities, data on fuel stockholding, various product or flow specific indicators;
- Additional disaggregation of individual statistics into specific subcategories.
Energy balances in European policy decision making
The European Energy Strategy and Energy Union needs to be underpinned by statistical evidence for sound decision making. To this end, energy balances are a key input for the Commission's impact assessments in the area of energy policies. As energy is vital to many sectors of the economy, energy data are used for other purposes too, notably transport and climate change. The European Union's energy policy targets include the need for secure energy supplies, sustainable energy consumption and lower fossil fuel dependence. Energy balances help in assessing progress in these areas. They are also an essential input for monitoring the energy efficiency target of the Europe 2020 strategy. Directive 2012/27/EU on energy efficiency and its implementation measures refer to the aggregates of energy balances published by Eurostat. In the context of Eurostat's work on sustainable development indicators, energy balances provide a central contribution to SDG 7 Affordable and clean energy.
Constructing energy balances
When constructing energy balances, one has to bear in mind the first law of thermodynamics. The law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another but can be neither created nor destroyed. The first law is often formulated by stating that the change in the internal energy of a closed system is equal to the amount of heat supplied to the system, minus the amount of work done by the system on its surroundings. Consequently, energy gains are not possible and if present, they are results of either statistical discrepancy (data of low accuracy) or not fully considering all input products in the scope of energy statistics.
Constructing energy balances in 3 steps
- The first step is to construct commodity balances for each energy carrier in natural measurement units of the energy carrier – either physical unit (tonnes and cubic meters) or energy units (GWh for electricity and TJ for heat).
- The second step is to convert the commodity balance in various units into a common energy unit, by multiplying all the data by the appropriate conversion factor (calorific values for energy carriers in physical units and unit conversion factor for energy carriers measured in energy units).
- The third step refers to organising the columns and rows of the energy balance to avoid double counting of energy. For example, the production of secondary products is shown in the production row in commodity balances and it is reported as a transformation output in the energy balance.
The choice of the primary energy form
The choice of the primary energy form defines the boundaries of energy statistics. The general principle of Eurostat’s approach is that the primary energy form should be the first energy form in the production process for which various energy uses are in reality practised. Eurostat’s methodology is based on the physical energy content method. For directly combustible energy products (for example coal, crude oil, natural gas, biofuels, waste) it is their actual energy content measured by their gross and net calorific values. For products that are not directly combustible, the application of this principle leads to the choice of heat as the primary energy form for nuclear, geothermal and solar thermal; and to the choice of electricity as the primary energy form for solar photovoltaic, wind, hydro, tide, wave, ocean. The measurement of the primary energy form for the not directly combustible fuels is done as gross electricity production for those where electricity is the primary energy form and as gross heat production for those where heat is the primary energy form. According to obligations in Regulation (EC) No 1099/2008 on energy statistics the reporting is covering geothermal and solar thermal inputs needed for electricity and/or heat production from these sources. In a similar way, the heat generated by nuclear reactors has to be declared according to the reporting obligations on annual nuclear statistics. If countries do not have information on energy inputs available, but only the amount of electricity and/or heat produced is known, the reporting countries are advised to use the following efficiencies to estimate inputs:
- For electricity from geothermal sources: 10 %
- For derived heat from geothermal sources: 50 %
- For electricity from concentrating solar: 33 %
- For derived heat from solar thermal energy: 100 %
- For electricity and derived heat from nuclear sources: 33 %
The choice of units in the energy balance
The data for the different products need to be expressed in a common energy unit. The unit chosen can be any energy unit: terajoule (TJ), gigawatt-hour (GWh), thousands of tons of oil equivalent (ktoe), million tons of oil equivalent (Mtoe), etc. The unit adopted by Eurostat is the joule.
The choice of a heating value
The energy balance can be expressed in the “net” or “gross” energy content, where net/gross refers to the calorific values used for conversion. The quantity known as gross calorific value (GCV) (or higher heating value or gross energy or upper heating value or higher calorific value) is determined by bringing all the products of combustion back to the original pre-combustion temperature, and in particular, condensing any water vapour produced. This is the same as the thermodynamic heat of combustion since the enthalpy change for the reaction assumes a common temperature of the compounds before and after combustion, in which case the water produced by combustion is condensed to a liquid, hence yielding its latent heat of vaporization. The quantity known as net calorific value (NCV) (or lower heating value or lower calorific value) is determined by subtracting the heat of vaporization of the water vapour from the higher heating value. This treats any H2O formed as a vapour. The energy required to vaporize the water, therefore, is not released as heat. As the net calorific value represents the amount of energy that can be actually used, Eurostat adopted the methodology of using the net calorific values for its energy balances. This applies to the conversion of all energy carriers (products, fuels) of energy balance for all flows of energy balance.
Creating the matrix
The energy balance is presented as a matrix: a two-dimensional table with rows and columns. This matrix can be created in different energy units, for different geographical regions and also for different time periods. While the choice for unit, country and time period, is intuitive and has user-specific needs, the choice of rows and columns needs to be harmonised within one methodology approach. The actual link between the matrix and source data for every individual position of energy balance is available within Eurostat's energy balance builder tool. In the tool, every cell of the energy balance matrix is created with a link to the source data cell (mostly one data item, but for several data cells it is a sum, difference or other formula) with a combination of a conversion factor to TJ (calorific values). For many cells of the energy balance, this link is direct one to one relationship between the cell in the balance matrix and the source data. Consequently, the actually applied calculation methodology is described in the most exhaustive level of details in the actual MS Excel file representing the Eurostat's energy balance builder tool.
More details and additional information on construction of energy balances is available in the Eurostat's energy balance guide.
Technical specificity of Eurostat's energy balance
- The energy balance is a table matrix represented by columns and rows. Columns of the energy balance represent energy products (fuels). Rows represent flows of the balance (production – transformation – consumption sectors).
- The energy balance is constructed for each calendar year. Currently energy balances for all EU Member States are available starting in year 1990. Eurostat data also cover several non-EU countries and for most of them data are also available starting in 1990.
- The energy balance covers the national territory of a given country. The trade of energy commodities between countries is covered in the imports and exports.
- The energy balance calculated by Eurostat is available in thousands of tons of oil equivalent (ktoe), in terajoules (TJ) and in gigawatt-hours (GWh)
Products (columns of the energy balance)
This chapter presents the basic relationships between energy products (fuels). For the full set of relationships between products, please refer to the Energy balance guide. For the definition of individual fuels, please refer to the Regulation (EC) No 1099/2008 on energy statistics.
Total = Solid fossil fuels + Manufactured gases + Peat and peat products + Oil shale and oil sands + Oil and petroleum products (excluding biofuel portion) + Natural gas + Renewables and biofuels + Non-renewable waste + Nuclear heat + Heat + Electricity
Fossil fuels = Solid fossil fuels + Manufactured gases + Peat and peat products + Oil shale and oil sands + Oil and petroleum products (excluding biofuel portion) + Natural gas + Non-renewable waste
Solid fossil fuels = Anthracite + Coking coal + Other bituminous coal + Sub-bituminous coal + Lignite + Patent fuels + Coke oven coke + Gas coke + Coal tar + Brown coal briquettes
Manufactured gases = Gas works gas + Coke oven gas + Blast furnace gas and Other recovered gases
Peat and peat products = Peat + Peat products
Oil and petroleum products = Crude oil + Natural gas liquids + Refinery feedstocks + Additives and oxygenates (excluding biofuel portion) + Other hydrocarbons + Refinery gas + Ethane + Liquefied petroleum gas + Motor gasoline (excluding biofuel portion) + Aviation gasoline + Gasoline-type jet fuel + Kerosene-type jet fuel (excluding biofuel portion) + Other kerosene + Naphtha + Gas oil and diesel oil (excluding biofuel portion) + Fuel oil + White spirit and special boiling point industrial spirits + Lubricants + Bitumen + Petroleum coke + Paraffin waxes + Other oil products not elsewhere specified
Renewables and biofuels = Hydro power + Tide + wave and ocean + Wind power + Solar photovoltaic + Solar thermal + Geothermal + Primary solid biofuels + Charcoal + Biogases + Renewable municipal waste + Pure biogasoline + Blended biogasoline + Pure biodiesels + Blended biodiesels + Pure bio jet kerosene + Blended bio jet kerosene + Other liquid biofuels + Ambient heat (heat pumps) Non-renewable waste = Industrial waste (non-renewable) + Non-renewable municipal waste
Flows (rows of the energy balance)
Eurostat's energy balance has 3 blocks:
- Top block: Supply
- Medium block: Transformation input, Transformation output, Consumption of the energy branch and Distribution losses
- Bottom block: Final non-energy consumption and Final energy consumption (disaggregated into subsectors of the industry, transport and other sectors)
In the medium block, the Transformation input and Transformation output include real energy product transformations as well as virtual product transformations. These virtual transformations cover the following aspects:
- blending of various products into each other
- methodological transformations of electricity produced from non-combustible fuels such as nuclear heat, hydro, wind, geothermal, solar thermal and photovoltaic
- interproduct transfers, backflows and exchanges between petroleum refineries and petrochemical industries
The difference between transformation input and transformation output constitutes the transformation losses. This chapter presents only the relationships between the elements used in this publication. For the full set of relationships as well as a more detailed definition of each category, please refer to the Energy balance guide.
Gross available energy = Primary production + Recovered & Recycled products + Imports – Export + Stock changes
Total energy supply = Gross available energy – International maritime bunkers – International aviation
Transformation input = Electricity & heat generation + Coke ovens + Blast furnaces + Gas works + Refineries & petrochemical industry + Patent fuel plants + BKB & PB plants + Coal liquefaction plants + For blended natural gas + Liquid biofuels blended + Charcoal production plants + Gas-to-liquids plants + Not elsewhere specified
Transformation output = Electricity & Heat generation + Coke ovens + Blast furnaces + Gas works + Refineries & Petrochemical industry + Patent fuel plants + BKB & PB plants + Coal liquefaction plants + Blended in Natural gas + Liquid biofuels blended + Charcoal production plants + Gas-to-liquids plants + Not elsewhere specified
Energy sector = Own use in electricity & heat generation + Coal mines + Oil & natural gas extraction plants + Patent fuel plants + Coke ovens + BKB & PB plants + Gas works + Blast furnaces + Petroleum refineries (oil refineries) + Nuclear industry + Coal liquefaction plants + Liquefaction & regasification plants (LNG) + Gasification plants for biogas + Gas-to-liquids (GTL) plants + Charcoal production plants + Not elsewhere specified (energy)
Energy available for final consumption = Total energy supply – Transformation input + Transformation output – Energy sector – Distribution losses
Final energy consumption = Industry sector + Transport sector + Other sectors
Industry sector = Iron & steel + Chemical & petrochemical + Non-ferrous metals + Non-metallic minerals + Transport equipment + Machinery + Mining & quarrying + Food, beverages & tobacco + Paper, pulp & printing + Wood & wood products + Construction + Textile & leather + Not elsewhere specified (industry)
Transport sector = Rail + Road + Domestic aviation + Domestic navigation + Pipeline transport + Not elsewhere specified (transport)
Other sectors = Commercial & public services + Households + Agriculture & forestry + Fishing + Not elsewhere specified (other)
Statistical differences = Energy available for final consumption – Final non-energy consumption – Final energy consumption
Interpretations of zeros
The statistical data collection system for energy statistics cannot distinguish between the following cases:
- Energy quantity is a real zero (real no consumption)
- Consumption is negligible (quantity is less than half of the respective lowest reporting unit)
- Data are not available to the reporting authority
- Data are confidential and not shown
All these cases are shown as “zero”.
Specific flags used
Symbol Z means data are not applicable. This is either due to a methodologically impossible combination in the energy balance matrix or due to the non-existence of combination at the data collection phase. By the way of example, the following elements are not feasible: consumption of solid fossil fuel in aviation, use of hydro power in households and renewables as transformation output of blast furnaces.
Symbol : means data are not available. This is when countries did not make transmissions for the reference period concerned. It only relates to periods in past. If a country made data transmission, any eventual not available data might be shown as zero.
Additional information and more details
More details and additional information on construction of energy balances is available in the Eurostat's energy balance guide.
- Energy balance guide (direct link to the pdf file)
- Energy balance builder tool (direct link to the xlsm file)
- Data in database format (free for commercial and non-commercial use): complete energy balances and simplified energy balances
- Energy balances in the MS Excel file format (direct link to the zip file)
- Relationships between products and flows of energy balances (direct link to the xlsx file)
- Energy (t_nrg) , see:
- Energy (t_nrg)
- Energy statistics - main indicators (t_nrg_indic)
- Sustainable Development indicators Goal 7 - Affordable and clean energy (t_nrg_sdg_07)
- Energy (nrg), see:
- Energy statistics - quantities (nrg_quant)
- Energy statistics - quantities, annual data (nrg_quanta)
- Energy balances (nrg_bal)
- Supply, transformation and consumption - commodity balances (nrg_cb)
- Energy indicators (nrg_ind)
- Energy infrastructure and capacities (nrg_inf)
- Stocks (nrg_stk)
- Trade by partner country (nrg_t)
- Energy statistics - quantities, annual data (nrg_quanta)
The Eurostat Sankey diagrams tool published on the Eurostat website allows the visualisation of energy balances. Sankey diagrams allow the user to get an overview of the main energy flows and how they contribute to the global energy balance.