Introduction Part 4 – Energy Systems

Shane White, March 2019.

Reports describing the world’s energy system are readily available, but are compromised for a variety of reasons. For example, BP’s ‘Statistical Review of World Energy’ fails to fully account for bioenergy and groups together some sources of non-combustible energy, preventing separate analysis of them. The IEA does separately account for all energy sources but their analysis relies on a method that downplays hydro energy. This site overcomes these deficiencies using the methods described below.

A conventional representation of a country’s energy system, or that of the world, is shown in figure 1.1 2 3

Figure 1. Representation of an energy system.

Energy sources can be categorised as combustible or non-combustible, as shown above, and three methods have been devised to compare the quantities of their supply.4 These are known as methods of primary energy equivalency. The method used here is the substitution method, whereby the energy supplied by non-combustible sources is assumed to have supplanted or replaced traditional thermal generation, so it’s a measure of progress of the transition away from the supply of combustible energy, to the supply of non-combustible energy. This is the method endorsed by the German Advisory Council on Global Change.5 Therefore, the quantities shown for each non-combustible energy supply are those that would be demanded of thermal generation if it was to supply an equivalent quantity of energy. The substitution method is shown below –

Figure 2. Calculation of TPES using the substitution method for representing the supply of energy from non-combustible sources.

Note the quantities of electricity and heat generated by non-combustible sources are divided by average measures of efficiency for the respective forms of thermal generation,6 thereby calculating the quantity of energy that an alternative thermal generator would need to supply.

For validation of this website’s calculation methods, results for world energy supply (TPES) can be compared with those from the IPCC’s AR5. This provides statistics for year 2010 using IEA data, the same source of data as used by this site. The two sets of results are shown below and compare favourably. (They are not exactly the same because the IEA annually applies quality control methods to historical data, and the IPCC used 2012 IEA data whereas this site uses 2016 IEA data).

Chart 1. World energy system (TPES), year 2010, substitution method of primary energy equivalency, comparison of this website’s results with those from IPCC AR5 WG3, Annex 2 Metrics & Methodology.7

Large numbers used on this website are expressed using prefixes. Commonly used metric prefixes are listed in table 1 (a) below and units in 1(b) –

Table 1. Explanation of (a) Prefixes, and (b) Units.

The energy system of the world is profiled in World Energy Supply and World Energy Consumption, and profiles of selected countries are being progressively added.

  1. J.M.K.C. Donev et al. (2017). Energy Education – Total primary energy supply [Online]. Available: [Accessed: February 20, 2019].
  2. The International Energy Agency (IEA) statistics overview
  3. Macknick, Jordan. “Energy and CO2 emission data uncertainties.” Carbon Management 2, no. 2 (2011): 189-205.
  4. Section A.II.4, Primary Energy Accounting, WG3, AR5
  5. Future Bioenergy and Sustainable Land Use By Renate Schubert, German Advisory Council on Global Change
  6. Footnote of Table A.II.10, WG3, AR5
  7. table A.II.10, p. 1294, 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.