Energy Consumption-03 Dec 2007

Energy Consumption So, how much energy does humanity consume? In the following, this will be illustrated in a bottom-up way, starting with the most basic need for a single human to survive, then to a typical (urban Scottish) domestic household of two adults and two children, a national overview, and finally a global view of energy production and consumption.

A single person The most basic need of a human being is the food to survive. According to UK guidelines, the recommended daily amount of food is 2000kcal for women and 2500kcal for men, which is on the order of 10MJ Keeping in mind that these are UK government guidelines, the absolute minimum to prevent starvation is probably well below that figure, maybe a few MJ ...

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A Scottish household The figures listed here, were obtained from the annual fuel bills for a urban household of 2 adults and 2 children living in a 3-bedroom 19th-century flat (apartment) in a Scottish city (Ground plan of flat: around 12m by 10m, height of rooms: 4.5m, two outside sandstone walls, each of area 12m by 4.5m including 7 single-pane windows of around 2m2 each).

Their heating, cooking, and hot water is provided almost exclusively by natural gas, with one solid fuel fire place and one small electric heater. Electricity provides almost all of their remaining energy consumption. Lighting is largely by standard incandescent light bulbs with only a few energy-saving lights; they own a fridge/freezer, a washing machine, a dish washer, a TV and VHS recorder, several radios, a PC and a few other appliances. They own and operate a car but only drive about 3000 km per year (compared to a UK average just over 10,000km - so this household has a hidden energy use in the form of public transport ...) Annual energy consumption Fuel Solid Gas Electricity Diesel Total

Energy (GJ) 5 90 15 10 120

Cost (£) 50 450 250 150 900

Dividing this by four people, we arrive at a daily energy consumption of around 30GJ/person/year (or 60GJ if we only count adults). This is actually not too far off the UK average of about 50GJ for domestic energy. Dividing by 365 to get the daily consumption, we get around 100MJ/person/day. This is ten times as much as we need for our food and it does not take into account any energy expended on travelling by public transport, energy required at work, or in the production of any item or service bought or used by that household...

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The Energy consumed in the UK Final (delivered) energy consumption According to the UK government information produced by the Department of Trade and Industry (dti), the UK consumed in the year 2000 the following amount of energy for its different sectors: Transport Solid fuel (PJ) 0 Liquid fuel (PJ) 2280 Natural Gas (PJ) 0 Electricity (PJ) 32 Total (PJ) 2311 Total (%) 34

Industry 117 267 722 409 1515 23

Domestic 91 136 1332 403 1961 30

Services 16 101 456 341 915 13

Total 223 2783 2511 1184 6702

1. The 'Services' column includes public lighting and agriculture 2. The 'Electricity' row describes the electricity delivered to the customers, not the amount of energy used to generate this electricity With a population of about 60 million people, the total consumption per person per year is about 110GJ, of which about a third are used for transport and a little less than a third for domestic purposes. Primary Energy consumption As mentioned above, the electricity delivered did not take into account the energy required to generate that electricity. However, since thermal power generation (i.e. by burning a fuel and driving a steam or gas turbine) has a typical efficiency of only 30%, a substantial amount of energy not reaching the customer is hidden behind the figure of 1184PJ delivered in 2000. The exact figure obviously depends on the balance of types of generators, since hydroelectric generation has a typical efficiency in excess of 80%. With a typical proportion of fuels of about a third of coal, a third of natural gas, a little less than a third of nuclear energy, and a few % from hydropower and other Renewables, the actual energy input into the power generation was Fuel Coal Liquid (oil) Natural gas Nuclear Others Total

Energy (PJ) 1200 100 1160 850 80 3390

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This then gives a primary energy consumption (where nuclear, hydro, and others are all incorporated into 'Primary electricity': Fuel Coal Liquid (oil) Natural gas Primary electricity Total

Energy (PJ) 1697 3147 3972 891 9707

With a population of about 60 million people, the total primary energy consumption per person per year is then about 160GJ, of which about a quarter is used for transport, 20% in the domestic area, 16% by industry, 10% in the service industry, and 23% is lost in the power generation and distribution.

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The World-wide primary energy consumption The approximate global primary energy consumption in 2000 was Fuel Oil Natural gas Coal Nuclear electricity Large hydropower Traditional biomass New Renewables Total

Quantity 3500 million tonnes 2400 billion cubic metres 3100 million tonnes 2600 billion kWh 2700 billion kWh

Energy (EJ) 150 90 90 30 10 50 10 420

% 35 20 20 7 2.5 10 2

Numbers are rounded to give an impression of their magnitude, rather than their precise amount. As a result, the percentages do not add up to 100...

With a population of about 6 billion people, the total primary energy consumption per person per year is about 70GJ, which is less than half of the figure for the UK. The wealthiest countries (comprising of the USA, Canada, Western Europe, Australia, New Zealand, and Japan) account for 14% of the population, produced 35% of the primary energy, and consumed 48% of the primary energy. This can also be expressed that these countries consume over three times as much energy per person as the world average or over five times as much as the population in the rest of the world. This is reflected in a very similar Gross Domestic Product (GDP) distribution.

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