Low-emission energy sources are exactly as their name suggests. They’re energy sources that generate lower emissions than their traditional counterparts. This includes the big five: solar, wind, water (hydropower), nuclear, and hydrogen.
In terms of emissions, they’re better for the environment because they release less carbon dioxide into the atmosphere. Remember — carbon dioxide is one of the main greenhouse gases currently driving global warming.
Of these big five low-emission energy sources, solar, wind, water, and some forms of hydrogen are all also known as ‘renewable resources’. This means that they are utilising and converting energy from a naturally occurring process which cannot be depleted or consumed like fossil fuels (Coal, LNG, Oil etc.).
Let’s dive into a refresher about what each of these low-emission energy sources involves.
Solar power converts sunlight into energy either through photovoltaic (PV) panels or through mirrors that concentrate solar radiation and heat up a receiver which generates steam to turn a turbine. This energy can then either be used as electricity or stored in batteries for future use.
Wind turbines use the aerodynamic force on propellor blades to turn a generator and create electricity. Fan turbines are currently the most common wind power generator, but there are prototypes being developed that use ‘airborne wind’ and look like giant kites. Traditional turbines are often found on high, open ground but can also be floated on top of the ocean to make use of strong offshore wind.
Humans have used hydropower for thousands of years, making it one of our oldest energy sources. Simply, hydropower uses the movement of water to generate electricity. As water flows or is pumped through a turbine, it converts that movement into power. Hydroelectricity can be generated almost immediately, meaning it can help support other power sources in low production times, especially when power generation requires damming a water reservoir. Much like wind power, some hydroelectric farms are being researched in the ocean, where the motion of waves or tidal currents is converted to electricity.
At the heart of nuclear power is the nuclear reactor. The reactor uses the natural radioactive decay uranium as fuel to produce heat through a process called fission. This heat is then used to generate steam which spins a turbine and produces electricity.
Fusion Power – Research and Development:
Both fission and fusion are nuclear processes, whereby the nucleus of an atom is changed due to nuclear forces. Fusion reactors produce the inert gas helium (chemically inactive), whilst also producing and consuming hydrogen isotopes like tritium and deuterium inside a closed circuit. This process generates electricity by using heat from the nuclear power reaction. Due to technology-readiness and scalability constraints, electricity generation and utilisation of fusion power is currently expected to ramp up in the second half of the century, contingent on funding and technical advancement.
As you know, hydrogen is the most common element in the universe. There are several ways it can be utilised to produce electricity or mechanical energy. There are a variety of methods used to extract hydrogen including through electrolysis and steam methane reforming. Once it’s extracted, it can be stored as a liquid, a gas, or an additive in other materials. Because of its diversity, it has potential to be stored for later use or exported overseas.
The energy sector accounts for a significant amount of the world’s emissions, making it one of the primary drivers of climate change. Because of this, renewable and low-emission energy sources have a role to play in meeting global climate change goals. It’s expected that these energy sources will take on a larger role over the next few years.
With this increased focus on low-emission sources comes important considerations around maintaining reliability, scale, and affordability.
The two biggest renewable sources, solar and wind, aren’t always ‘running’ – the sun doesn’t always shine, and the wind doesn’t always blow. To overcome this, great strides have taken place to improve the batteries needed to store solar and wind power. However, it’s highly likely we’ll always need to combine these sources with other generation methods to ensure there is sufficient and reliable electricity.
The low-emissions power industry has experienced a lot of growth, but there’s still considerable room for more. To help start your classroom discussion, ask this question — what do you think Australia’s energy production will look like by 2050? You can also follow this up with a project for a more in-depth look at low-emission energy.