Except for photovoltaics, electricity is still generated using principles developed by Michael Faraday in the 1820s and 1830s. Copper wire wrapped around a shaft, or armature, is spun in a magnetic field. The motion of the magnetic field relative to the copper wire causes electrons to flow in the wire, creating electricity. Different technologies and fuels are used to power the machines that spin the wire.
● Coal-fired power stations produce 41% of the world’s electricity at present, with natural gas producing 21%, hydro 16%, nuclear 14% and oil-fired generation 5%.
● N on-hydro renewables like solar and wind power are our fastest-growing energy sources. They only account for around 3% of generation today, but their share is projected to rise spectacularly to
16% by 2035, mainly at the expense of coal, whose share drops to 32%.
It is possible to store electricity, but even the latest battery technology is not efficient enough to stock the power needed for all our daily consumption.
Once electricity is generated, it is transmitted at 300,000 km/sec. The network of lines used to do this is the grid, or high voltage transmission network.
High voltage current is too powerful to be used directly. A system of medium voltage and low voltage networks delivers electricity to utility companies for distribution to end users, or to large industrial clients who have their own installations for transforming it to usable levels. The overhead lines of the
distribution network are the most visible part of power supply systems. Medium voltage networks (usually 10 to 30 kV) supply urban and rural areas. Low voltage networks supply 220-230 V or 110 V electricity locally to households and small industries nearby.
