The world’s energy sources and sinks

The first posting concluded with the observation that the global average per-capita energy consumption is about 20 times the food energy required by an average adult, and with the prediction that global energy consumption would continue to rise regardless of the developed countries’ desire to see energy usage curbed. Whoever doubts the prediction of continuing increases in demand for energy should put themselves in the bare feet of the Third World’s poor, especially the 1.5 billion who are not yet connected to an electricity grid: Why should they not develop their economies to the point where they can enjoy at least a small fraction of the luxuries rich countries takes for granted? On the ground in sub-Saharan Africa and south Asia, this feeling is too powerful to be stopped by scientists who complain about such things as the need to reduce CO2 emissions. A Catch-22 ensues: Developing countries probably feel that the climate change problem was created by rich countries and should therefore be solved by and at the expense of rich countries. Rich countries know that all their expensive efforts will be insufficient and probably completely ineffective without the co-operation of the developing countries in curbing the amount of carbon in circulation. Thus a way has to be found to allow economic growth (and the inevitable growth in the consumption of energy in the developing world) while also curbing the carbon in circulation.

In order to address this problem systematically, it is helpful to see what are the world’s energy sources and energy sinks, and what are the trends in their usage. Concerning energy sources, we have the following picture thanks to Wikipedia [1], the excellent energy research firm Enerdata [2], and the US government’s Energy Information Administration [3].

Fossil fuel combustion accounts for the overwhelming majority of the world’s energy budget. In 2004, the share was 86%, and that has declined only slightly since then. In 2005, oil accounted for 37%, coal 25%, and natural gas 23% of the energy supply. In 2009, the figures were 33%, 27%, and 21% respectively. If one adds biomass and biofuels to those figures, then the chemical-fuel-based share of the total energy budget is holding steady at around 90%. Nuclear energy sits at around 6% and hydro about 3%. Solar thermal, solar photovoltaic, wind, and geothermal sources together account for only about 1% of the energy sources. Enerdata’s yearbook [2] provides very nice graphical overviews of the situation.

These figures should be sufficient to make the point that the world cannot quickly rid itself of reliance on fossil fuels! Even if the whole world were collectively determined to put a serious dent in fossil fuel consumption (and it’s doubtful that it is), it would take decades to build the necessary alternative infrastructure. It isn’t even proven that satisfactory alternative technology exists. The global addiction to fossil fuels runs deep, but we can predict with relative confidence that the share of the global energy budget provided by oil and gas will decline, while that of coal will grow on the scale of the next century or so – whether we like it or not. To understand why this is so will be examined in coming postings. Among other things, we will look at the “Peak Oil” theory first proposed in 1956 by Dr. Marion King Hubbert, and will examine the workings of electricity grids.

For the moment, let’s have a peek at the flipside of the global energy supply, the energy uses or “sinks”. Here is how the global energy budget is consumed. Wikipedia [1], citing the EIA and industry sources, indicates that industry (including agriculture but apparently excluding the energy industry) consumes 37% of the energy, transportation (personal and commercial) consumes 20%, residential use (heating, lighting, and appliances) consumes 11%, and commercial use (lighting, heating, cooling, provisioning) consumes 5% of the total. The remaining 27% of the world’s energy is consumed in its recovery and distribution (called generation and transmission loss in the case of electricity).

Remember, combustion of fuels accounts for 90% of the energy market. As energy usage sectors or “sinks” go, heating and transportation tend to use combustion directly, and in many cases industry does too. However, many other applications, notably lighting and cooling, use energy after it has been transformed into electricity. Unfortunately the transformation of chemical potential energy from fossil fuels to electricity is particularly lossy. Generating electricity accounted for about 33% of the energy consumed in 2005, but the average efficiency of the process was only 40%, so the amount of electricity made available was only about 13% of the energy consumed, and electricity generation alone accounted for half of the 27% overall energy loss.[1]

The world needs to think about that going forward, so we will revisit the electricity market frequently in future postings. For example, if we were to remove all of the fossil fuel transportation equipment off the world’s roads and replaced them with zero emission electric vehicles, we would seemingly be cutting out 20% of the consumption of CO2-producing fuels, but in reality we would be worse off for it unless we also very drastically changed the world’s mix of electricity generation technologies. That is an extremely challenging undertaking, as we will also explore in coming posts.

[3], see e.g.

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