Solar, wind power and other types of electricity generation
Solar, wind power and other types of electricity generation
Ever wondered where your electricity comes from? Generating electricity is something you might not have given a lot of thought before. Electrical power is such a normal part of our everyday lives that it’s easy to take for granted – but as our electricity system transitions to more renewable energy sources, it’s worth knowing where the power for your home or business actually comes from.
There are many ways to generate electricity, generally categorised into two broad types of generation sources:
- Renewable energy sources
- Non-renewable energy sources (also known as ‘traditional’ energy sources)
Renewable energy sources are replenished faster than they are used. These include wind power, solar thermal and wave power.
‘Non-renewable’ means that there’s a limited supply of this source, which is either mined or extracted from the earth. Natural gas, oil and coal are examples of non-renewable energy sources.\
At the moment, types of electricity generation in WA include a mix of traditional and renewable sources. Here’s our guide to the different types of electricity generation.
Non-renewable energy sources
Coal is type of sedimentary rock extracted through the process of coal mining. Here’s how it works in generating electricity:
- Coal is crushed into powder form and burned in a furnace. This occurs at a coal-fired power station.
- The heat from the burning coal heats water in a boiler which gives off steam, which then passes through high pressure turbines which are connected to electricity generators.
- As the steam turbines spin, an electrical current is generated which is then sent out through the electricity network into the electricity grid.
Coal has long been used as a generally cheap and reliable source for generating electricity. Coal is a fossil fuel which contributes to climate change due to carbon dioxide created through the coal-burning process.
In WA, our energy infrastructure was originally designed around coal-fired power stations, but with the rapid installation of rooftop solar and challenges such as low load impacting our grid, these are now being phased out as part of the State and Federal Government’s move towards a low carbon future.
Over millions of years, the remains of ancient plants and animals have decomposed deep underground. The resulting natural gas (including methane) which becomes trapped in rock formations can be extracted and used in generating electricity. Here’s how:
- Natural gas-fired power stations burn natural gas to produce electricity.
- A common method is known as open-cycle production where natural gas is burned to become pressurised gas, which powers a turbine which is connected to electricity generation technology.
- Another method is known as combined-cycle production which combines a gas and steam turbine, recycling its fuel to make the most of its electricity production.
About natural gas
Natural gas is abundant and has generally been a reliable source of electricity in WA, in part thanks to our state’s domestic gas policy.
It’s also a non-renewable energy source which is highly flammable. The nature of gas means it needs to be carefully contained to avoid leaks, so the pipelines and infrastructure can be costly to build.
Generating electricity through nuclear fission involves harnessing the energy released when the nucleus of an atom is split into two or more parts. Here’s how it works:
- Uranium or other materials are used to produce heat through nuclear fission. This occurs inside nuclear power plants, nuclear reactors and specialised equipment to contain and control the reactions involved.
- The heat from the reaction will produce steam which is used to spin turbines which generate electricity.
Renewable energy sources
Here in WA, we receive plenty of sunshine throughout most of the year. Here’s how that sunshine gets used to generate electricity at grid scale:
- Solar photovoltaic cells inside solar panels are mounted on large areas of land (known as solar farms).
- As the sun hits those solar photovoltaic cells, electrons flow in a low voltage known as direct current (or DC) electricity.
- This DC electricity flows to a solar inverter, which turns it into alternating current (AC) to power homes and businesses.
About solar energy
Solar is a completely renewable energy source with no carbon emissions involved in generating electricity, however, the processes of producing and installing solar PV systems are likely to involve some carbon emissions. Most solar PV systems require very little maintenance due to there being no moving parts.
As the name suggests, solar PV systems can only generate electricity when the sun is shining, and so require battery storage in order to store excess solar energy for use at other times.
Wind turbines are constructed in areas which receive consistent wind, often near the coast. These wind turbines use blades to harness the wind’s energy. Here’s how they work in generating electricity:
- When the wind reaches speeds of around 10 to 15km/h, the wind turbine rotors will start to spin.
- These rotor blades turn a main shaft which isn’t fast enough to generate electricity on its own. Instead, it creates kinetic energy which builds by passing through a series of built-in gears.
- This kinetic energy moves through the generator to a transformer, which moves the electricity into the grid.
To learn more, explore how a wind farm works.
About wind power
Wind power is, in some cases, even more efficient than solar power and one of the cheapest forms of renewable electricity generation with lower operating costs compared to other sources.
Of course, the amount of electricity generated depends on the wind and weather conditions. Wind farms need a dedicated space in a location with enough consistent wind, so there are only limited areas where they can be constructed. Large expanses of land may also be required; a single wind turbine may not generate all that much electricity, but in large numbers, wind turbines can generate substantial amounts electricity.
Hydroelectricity involves harnessing the energy from moving water. Here’s how it works:
- Hydropower plants often store water in a dam. The movement of this water is controlled by a gate or valve.
- The water gains what is known as potential energy just before it flows over the dam. This is then converted into kinetic energy which turns a turbine.
- As the turbine moves, it generates electricity that is exported into the grid.
- The higher the dam, the more energy is likely to be generated.
About hydro power
While solar and wind generation depend on weather conditions, the flow of water can be controlled to meet supply and demand as required.
Of course, large volumes of water are required for this type of electricity generation and so can only be constructed in certain areas. The dams themselves can be expensive to build.
Hydro power is a renewable source of electricity which is reliable and can be very efficient, compared with other types of electricity generation.
Other types of electricity generation around the world
There are some less common types of energy generation technologies being used around the world including concentrated solar, tidal and geothermal, with new technologies being developed all the time. Here’s more about those types of electricity generation.
This is a type of solar power generation which uses mirrors or lenses to concentrate sunlight into a receiver. That concentrated light is then turned into heat, driving an electricity generator or thermochemical reaction. Concentrated solar usually connects to an energy storage system.
This is a type of electricity used to balance the load across an energy system. It stores the potential energy of water as it is pumped from a lower area to a higher area.
When demand for electricity is high, the stored water can be released to generate electricity. Pumped storage is one of the largest-capacity form of grid storage available.
As tides rise and fall, their kinetic energy can be harnessed and converted into electricity.
In order to take advantage of tidal energy potential, the high tide must be at least five meters higher than low tide.
Hydrogen is one of Earth’s most common elements. A common source of hydrogen is in water and once hydrogen and oxygen molecules are separated (a process known as electrolysis), the hydrogen can be stored and used as fuel for generating electricity.
You might have heard of different types of hydrogen – such as green or grey hydrogen. These colours refer to the energy source used to electrolyse the hydrogen, not the actual colour. For example:
- Green hydrogen is made using renewable energy sources to electrolyse water.
- Grey hydrogen is made using natural gas or methane – and is currently the most common form.
Hydrogen can be produced sustainably but the processes involved can be expensive. At the moment, there’s not much infrastructure support for this type of electricity generation.
The Earth’s core is full of heat – and geothermal energy taps into this as a source of energy. High temperatures from hot rocks produce steam, which can then be captured and used to move steam turbines to power electricity generators.
Geothermal energy plants can have low emissions by pumping steam and water back into their plant’s water supply. One disadvantage of geothermal electricity generation is that it is location-specific, and must be located close to sites where the energy is easily accessible; they are often located near volcanoes.
The State Government has invested $3.8 billion in renewable energy infrastructure for WA. Discover how Synergy is helping to lead the state’s energy transformation.
Image note: Greenough River Solar Farm is a Bright Energy Investment (BEI) asset which is joint venture between Synergy, CBUS and DIF.