Mr BILLINGTON
Alternative Sources of Energy
Energy Storage & Generation - Generators and Batteries
Copyright © A.F.Billington 2022. All rights reserved.
Power is generated through a number of different methods in the UK and although renewable sources are increasingly being used the primary method is Fossil Fuels (Oil, Gas & Coal). With this method a fuel source is combusted producing heat energy which is used to boil purified water. The steam created then powers large turbines which drive a electricity generator to produce electricity.
A Dynamo is essentially a coil of wire and a magnet. When the coil of wire is rotated within the magnetic field electrons are moved along the copper wire via electromagnetic induction towards a positive source. This method produces Direct Current (DC)
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Most modern digital electronics use a DC power source however voltage is transferred as Alternating Current (AC) across the majority of the world through power lines. This is due to AC having a lower energy loss over large distances making it more energy efficient. Thomas Edison (lightbulb) championed DC due to his patents but lost out to AC for this reason.
An alternator is used in place of a dynamo generator to produce AC voltage on an industrial scale. A rotational magnetic field is used inside a conductive wound copper enclosure to induce an alternating current. By rotating the magnetic field the polarity constantly changes a set frequency producing AC power.
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Generated power is often at incredibly high voltages when conducted and a Transformer must be used to reduce this down. A transformer uses electromagnetic induction to transfer power across a magnetic core. Each side of the core are a number of windings of wire, one for the source and the other the output.
If there are less coils of wire at the output and more at the source it will Step Down the power and vice versa
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Once power has been generated it can be stored using batteries. There are a wide range of battery technologies used to store voltage for different purposes but they all work on the same principle. Two differing metals are contained within a casing surrounded by a acid/alkaline solution. The metals react with the solution in an ionic reaction and oxidisation from the anode (+) to the cathode (-) occurs, creating electron flow (current) when connected to a load. Altering the metals and chemicals used will change the current output and battery life (mAh) as well as function;
- Alkaline batteries have a longer battery life than similar alternatives, suitable for high current applications, long maintained voltage, higher capacity. They are however more expensive than other alternatives, cannot be recharged and can leak over time
- Zinc Carbon batteries are a cheaper alternative to Alkaline batteries and as a result have a lower capacity meaning they will not last as long. They are ideal for low current applications such as remote controls and clocks. The voltage level drops quickly during heavy use
- Nickel Cadmium (NiCad) batteries are available in the same sizes as the above but they are rechargeable. They can therefore be recharged many times making them cost effective despite the initial higher price. NiCad's have a 'memory' so will loose capacity over time if not allowed to reach the end of their charge cycle
- Button Cell batteries are the smallest battery available and are rated at 1.5V. They are used for low current applications where a constant voltage is required and in products where size is a restriction
- Lithium batteries ('coin cell') are available as small thin discs rated to 3V. They have a very long life when used with low current applications and hold their voltage accurately over their lifespan making them ideal for products such as calculators & watches
- Lithium Ion or Polymer batteries are fully rechargeable and found in nearly all modern portable electronic products. They have no 'memory' like NiCad and therefore hold their capacity for much longer periods of time and do not need to be fully discharged
- Lead acid batteries are typically found in the automotive industry due to their ability to produce high current surges required to ignite spark plugs in order to start an engine. Due to the use of lead they have a low energy-to-weight ratio & low energy-to-volume ratio
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Energizer provide further information and cross-sections of different portable battery technologies -