Keeping the lights on - a quick guide to electricity

Keeping the lights on - a quick guide to electricity

What is Electricity?

Electricity is everywhere; it is a fundamental form of energy. But what exactly is it? The answer to this is not so straightforward; but in the most simplistic sense, it is the flow of electrons.

Electrons are one of the components within atoms, which are found in all matter – these contain a central nucleus consisting of protons (positively charged) and neutrons (uncharged), surrounded by electrons (negatively charged). Largely, the number of protons and electrons in atoms remain the same. However, if a significant change in balance occurs, then the atom can lose or gain electrons – the flow of these electrons between atoms carries charge, which accordingly induces an electrical current. This current flows through materials that can conduct electricity (e.g. copper wires) – and this movement is essentially the basis of electricity.

Components

There are three key components to electricity:

Voltage refers to the pressure of the system - if it is higher, then there is a greater push, which essentially is required for the electrons to move, and thus generates a significant electric charge. It is seen as the potential difference between two points. This is measured in Volts.

Current measures the flow of the electrical charge, and is measured in Amperes or Amps.

Resistance refers to the material through which the electrons flow, and is measured in Ohms. If a material has high resistance, it is an insulator (e.g. plastic) – here the electrons are tightly bound to the atoms. If resistance is low in a material however, then it is a conductor – meaning that flow of electrons is much easier (e.g. copper).

Combining the three:

Voltage = current x resistance (known as Ohm’s law).

The electricity consumed (i.e. the total power) is measured using Watts (W) and kilowatts (kW) (1000W=1kW), which is based upon the voltage and current:

Power = voltage x current

So, a stronger voltage and current will lead to more power available.
To work out the specific amount of electrical energy transferred to something (such as an appliance for instance), this power component would then be multiplied by time; i.e.:

Electrical energy transferred (kWh) = Power (kW) x hours (h)

This, in a nutshell, shows how much electricity is being used!

How does it work?

There are three steps involved in the overall processing of electricity –

The generation process principally involves the introduction of magnetic forces which subsequently allow electrons to flow – this converts mechanical energy to electrical energy. The source of the energy varies, as outlined in the next section. The current and voltage thus play a key role in this process. Burning fossil fuels for example, produces heat; the energy produced from this is then converted into mechanical energy in the turbines of a plant; this is subsequently placed into a generator utilising electromagnetic fields to finally convert this to electrical energy.

This is then transformed in order to increase the voltage, so that the electricity can then be powerful enough to be transmitted via power lines across long distances– the second step of the overarching process. In the UK, this is done via the National Grid, who own the transporting pipes and wires in the networks across the country.

When this electricity is ready to be distributed amongst buildings in a certain area, it passes through another transformer to reduce the voltage back down, so that it can safely be transferred in this way. This aspect is controlled in a more regional sense, where various distributors overlook activity of specific regions within the country.

Where does electricity come from?

Electricity comes from a variety of sources, primarily by converting certain forms of energy. To date, fossil fuels have been one of the most prominent sources of electricity production – this includes coal, oil, and gas. There has of course been a recent shift of focus away from the environmentally detrimental process of burning fossil fuels.

The alternatives include nuclear energy, and then the renewable sources – including wind, solar, hydro, and geothermal. There has been a great increase in the number of wind and solar facilities in the country recently. There is also much further scope and potential for the growth of hydroelectric power in the UK which is a growing arena.

Why the shift?

Firstly, the use of fossil fuels is harmful to the environment due to the emissions that are associated with it – including carbon monoxide, carbon dioxide, and methane. This leads to a variety of problems – relating to health impacts, water and air pollution – which is just not worth the harm. Not only this, but even the process of mining for coal, or drilling for oil, is hazardous and harmful.

Renewable sources on the other hand, don’t emit such harmful pollutants. Unlike fossil fuels, the supply is also inexhaustible – relying simply on the wind, sun, water, etc! In order to protect the world and its resources, and continue to make it a safe space for our future generations, renewables are certainly the way forward.

The UK has a commitment to produce 30% of electricity from renewable sources by 2020 – it was already three quarters of the way there in 2015. Internationally, there is a target to limit global average temperatures by 2oC, which if surpassed, will lead to dangerous effects. One of the key steps to accomplish this involves reduction of fossil fuel use.

The chart below shows official government figures of the electricity supply mix – which clearly shows the significant changes that have taken place recently, and the increased focus on renewables.

Coal-powered electricity generation accounted for just 9% of the total in 2016, and an increasing number of coal plants are being closed. In fact, there was one day in April 2017 where the UK was actually coal free for 24 hours – a huge positive step for our future.

Another post will be up soon about electricity at the level of the consumer… watch this space!

Topic: Nidhee Venkatesh

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