What Are Sources of Electricity That Charge Your Life?

How Electric Energy Is Generated for That Beloved iPhone

Wind turbines stand behind a solar power park
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Chances are that if you have an iPhone or any electronic gadget, you have at some point wondered what are sources of electricity that keep your electronics charged and working. Aside from lighting our homes and keeping us digitally connected, electricity also saves lives in hospitals, powers industry and keeps the economy going round — so how exactly does electric energy work and how is it generated?

What You Should Know About Electric Energy

Electric energy is created by the flow of electrons, often called "current," through a conductor, such as a wire. The amount of electric energy created depends upon both the quantity of electrons flowing and the speed of flow. Energy can either be potential or kinetic. A lump of coal, for example, represents potential energy that becomes kinetic when it is burned.  

The six most common forms of electric energy are listed below. The electricity generated through these forms is measured in terawatt hours — which means that in 1 terawatt hour, 1012 watts of electricity is generated.

Chemical energy. This is stored, or “potential,” energy. Releasing chemical energy from in carbon-based fuels generally requires combustion – for example the burning of coal, oil, natural gas, or a biomass such as wood.

Thermal energy. Typical sources of thermal energy are heat from underground hot springs, combustion of fossil fuels and biomass (per above) or industrial processes.

Kinetic energy. Kinetic energy is movement, which occurs when water moves with tides or flows downstream, or when air moves wind turbines in the wind.

Nuclear energy. This is the energy stored in the bonds inside atoms and molecules. When nuclear energy is released, it can emit radioactivity and heat (thermal energy) as well.

Solar energy. Energy radiates from the sun and the light rays can be captured with photovoltaics and semiconductors. Mirrors can be used to concentrate the power, and the sun’s heat is also a thermal source.

Rotational energy. This is the energy of spinning, typically produced by mechanical devices such as flywheels.

Common Sources of Electricity

Electricity generation in the world has increased at an average rate of 3.6% per year since 1971, according to the Organisation for Economic Co-operation and Development (OECD) Factbook.

According to 2009 data from the OECD Factbook, the sources of electricity worldwide were as follows:

  • Fossil fuels 67% [coal (41%), oil (5.1%), natural gas (21%)]
  • Renewable energy 16% [mainly hydroelectric (92%), wind (6%), geothermal (1%), and solar (1%)]
  • Nuclear power 13%
  • Other sources 3% (i.e. biofuels, biomass, data here is difficult to obtain ]

Based on the statistics provided by the OECD, electricity production from fossil fuels has decreased by 8% since 1971. This can be attributed to the shift from using oil for electricity generation to nuclear power.

 However, the use of nuclear power has been falling since 1996 while the use of coal for electricity generation remained stable and the use of natural gas increased.

How Many Terawatt Hours Does Your iPhone Need?

Now that you know how electricity is generated, you may be wondering how much electric energy is required to keep your iPhone working. A paper written by Mark Mills, CEO of Digital Power Group, a tech investment advisory, states that 1,500 terawatt hours of energy are required per year, per iPhone. This energy not only powers your phone, but also powers "the cloud," as well as wireless networks.

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