Electric energy consumption is the form of energy consumption that uses electric energy. Electric energy consumption is the actual energy demand made on existing electricity supply.
Consumption of electric energy is measured in watt-hours (written W·h, equal to watts x hours)
- 1 W·h = 3600 joule = 859.8 calorie.
Electric and electronic devices consume electric energy to generate desired output (i.e. light, heat, motion, etc.). During operation, some part of the energy – depending on the electrical efficiency – is consumed in unintended output, such as waste heat.
Electricity has been generated in power stations since 1882. The invention of the steam turbine in 1883 to drive the electric generator started a strong increase of world electricity consumption.
In 2008, the world total of electricity production was 20,279 terawatt-hours (TWh). This number corresponds to an average rate of around 2.3 terawatts continuously during the year. The total energy needed to produce this power is roughly a factor 2 to 3 higher because a power plants’ efficiency of generating electricity is roughly 30–50%. The generated power is thus in the order of 5 TW. This is approximately a third of the total energy consumption of 15 TW.
In 2005, the primary energy used to generate electricity was 41.60 Quadrillion BTU (Coal 21.01 quads, Natural Gas 6.69 quads, Petroleum 1.32 quads, Nuclear electric power 8.13 quads, Renewable energy 4.23 quads respectively). The gross generation of electricity in that year was 14.50 Quads; the difference, 27.10 Quads, was conversion losses. Among all electricity, 4.84 Quads was used in residential area, 4.32 Quads used in commercial, 3.47 Quads used in industrial and 0.03 Quads used in transportation. 1 Quad = 1.055 Exajoule.
16,816 TWh (83%) of electric energy was consumed by final users. The difference of 3,464 TWh (17%) was consumed in the process of generating power and lost in transmission to end users.
A sensitivity analysis on an adaptive neuro-fuzzy network model for electric demand estimation shows that employment is the most critical factor influencing electrical consumption. The study used 6 parameters as input data, employment, GDP, dwelling, population, HDD and CDD, with electricity demand as output variable.
World electricity consumption down in 2009
At the world level, energy consumption was cut down by 1.5% during 2009, for the first time since World War II. Except in Asia and Middle East, consumptions were reduced in all the world regions. In OECD countries, accounting for 53% of the total, electricity demand scaled down by more than 4.5% in both Europe and North America while it shrank by above 7% in Japan. Electricity demand also dropped by more than 4.5% in CIS countries, driven by a large cut in Russian consumption. Conversely, in China and India (22% of the world’s consumption), electricity consumption continued to rise at a strong pace (+6-7%) to meet energy demand related to high economic growth. In Middle East, growth rate was softened but remained high, just below 4%.
Electricity scenarios until 2040
In all scenarios, increasing efficiency will result in less electricity needed for a given demand of power and light. But demand will increase strongly on account of
- growing economy in developing countries and
- electrification of transport and heating. Combustion engines are replaced by electric drive and for heating less gas and oil, but more electricity is used, if possible with heat pumps.
As transport and heating become more climate-friendly, the environmental effect of energy consumption will be more determined by electricity. This is mainly supplied by burning fossil fuel which disturbs the natural carbon cycle. The scenarios arrive at very different results for the environment.
The International Energy Agency expects revision of subsidy for fossil fuel which amounted to 550 billion dollar in 2013, more than four times renewable energy subsidy. In this scenario almost half of the increase in 2040 of electricity consumption is covered by more than 80% growth of renewable energy. Many new nuclear plants will be constructed, mainly to replace old ones. The nuclear part of electricity generation will not increase much, from 11 to 12%. The renewable part goes up much, from 21 to 33%. That is not enough. The IEA warns that in order to restrict global warming to 2ºC, the carbon dioxide emission must not exceed 1000 gigaton (Gt) from 2014. This limit is reached in 2040 and emission will not drop to zero then.
The World Energy Council sees world electricity consumption increasing to more than 40,000 TWh/a in 2040. The fossil part of generation depends on energy policy. It can stay around 70% in the so-called Jazz scenario where countries rather independently “improvise” but it can also decrease to around 40% in the Symphony scenario if countries work “orchestrated” for more climate friendly policy. Carbon dioxide emission, 32 Gt/a in 2012, will increase to 46 Gt/a in Jazz but decrease to 26 Gt/a in Symphony. Accordingly, until 2040 the renewable part of generation will stay at about 20% in Jazz but increase to about 45% in Symphony.