Introduction

Introduction
Introduction

Updated January 2025.

Number prefixes and units used on this site are listed below.

Introduction
Table 1. Explanation of (a) Prefixes, and (b) Units. Note the prefix for thousand is lowercase k, not uppercase.

The remainder of this page explains this site’s energy statistics. Energy data used on this site is published by the Energy Institute (EI, formerly provided by BP)1, and the International Energy Agency (IEA)2.

A national energy system can be represented by figure 13 4 5. Measures of interest are –

  • Primary energy (labelled ‘Consumption’ by the Energy Institute and ‘Total Energy Supply’ (TES) by the IEA), and
  • Final energy (unavailable from the EI, and labelled ‘Total Final Consumption’ (TFC) by the IEA).
Figure 1. Schematic of a country’s energy system.

Primary energy accounts for energy supplied in its primary form, prior to any conversions such as coal to electricity.

Primary energy of non-combustibles (i.e. renewable and nuclear fuels) can’t be directly compared with that supplied by combustibles because non-combustibles have natural forms of primary energy (e.g. sun, wind etc). To overcome this, it is convention to calculate an equivalent quantity for each non-combustible using a method of ‘primary energy equivalence’. The method used by the EI1 is the ‘substitution method'6.

The substitution method, as shown in figure 2, calculates the primary energy for each non-combustible required to be input to a thermal power station in order to generate an equivalent amount of electricity or heat. Primary energy values for non-combustibles are therefore the equivalent quantity of thermal generation that non-combustibles have supplanted. For example, if the share of primary energy in an energy system is ‘4% solar’, then the quantity of energy from solar is equivalent to 4% of an energy system that is 100% fuelled by combustible fuels (i.e. thermal).

A shortcoming of primary energy is that it’s a measure of the quantity of fossil fuelled electricity generation required to replace non-fossil fuelled, which is retrospective. Furthermore, the total quantity of primary energy is excessive relative to that needed in a fully decarbonised energy system solely fuelled by non-combustibles, because the inefficiency of thermal generation wouldn’t exist.

Final energy accounts for energy consumed in its final form. For example, accounting for gas burned to produce heat separately from that burned to produce electricity. Final energy data is only available from the IEA, and so is at least two years old. Despite this, it’s arguably a more useful measure than primary energy.

Figure 2. Calculation of primary energy, showing the substitution method for non-combustible sources.
  1. https://www.energyinst.org/statistical-review/about[↩][↩]
  2. ((https://www.iea.org/data-and-statistics/data-tools/energy-statistics-data-browser?country=WORLD&fuel=Energy%20supply&indicator=TESbySource[↩]
  3. J.M.K.C. Donev et al. (2017). Energy Education – Total primary energy supply [Online]. Available: https://energyeducation.ca/encyclopedia/Total_primary_energy_supply [Accessed: February 20, 2019].[↩]
  4. The International Energy Agency (IEA) statistics overview, http://www.iea.org/media/training/presentations/statisticsmarch/balances_overview.pdf[↩]
  5. Macknick, Jordan. “Energy and CO2 emission data uncertainties.” Carbon Management 2, no. 2 (2011): 189-205. http://www.iiasa.ac.at/web/home/research/researchPrograms/TransitionstoNewTechnologies/macknick_ene_co2_uncertainties_CM_2011.pdf[↩]
  6. There are two other methods of primary energy equivalency: the ‘direct method’ and the ‘physical energy content method’. The direct method directly compares quantities of energy from combustible and non-combustible sources without any account for the efficiency of thermal generation. This is only useful for future energy scenarios where the supplies of non-combustible fuels are high. The physical energy content method is used by the IEA for their TES values, which enlarges the contribution of nuclear energy and diminishes that from other non-combustibles. This method applies the following weights to non-combustible energy supplies: Nuclear = 33%, Geothermal heat = 50%, Geothermal electricity = 10%, Solar thermal heat = 100%, Solar thermal electricity = 33%, Hydro, wind, marine and solarPV = 100%. For further information see section A.II.4, Krey V., O. Masera, G. Blanford, T. Bruckner, R. Cooke, K. Fisher-Vanden, H. Haberl, E. Hertwich, E. Kriegler, D. Mueller, S. Paltsev, L. Price, S. Schlömer, D. Ürge-Vorsatz, D. van Vuuren, and T. Zwickel, 2014: Annex II: Metrics & Methodology. In: Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Edenhofer, O., R. Pichs-Madruga, Y. Sokona, E. Farahani, S. Kadner, K. Seyboth, A. Adler, I. Baum, S. Brunner, P. Eickemeier, B. Kriemann, J. Savolainen, S. Schlömer, C. von Stechow, T. Zwickel and J.C. Minx (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_annex-ii.pdf[↩]