Wind. Solar. Hydroelectric. Bioenergy. Countries all over the world are switching from fossil fuels to renewable energy sources like these to generate electricity.
But what is renewable energy? How does it work? And how will it impact our everyday lives? This is Decomplicated. Renewable energy, also known as renewables, There's energy that comes from a source that won't run out, because it's replenished faster than it's consumed.
Renewables use natural sources of power to generate electricity by harnessing the energy of the sun, wind or tides. This could also come from the burning of organic materials, such as plant matter or waste from animals or food. Renewables are self-replenishing, as their production only relies on Earth's weather patterns and natural ecosystem. rather than the intensive drilling or mining that's used to extract fossil fuels.
Fossil fuels like coal, oil and natural gas are non-renewable, as they're made from the fossilised buried remains of plants and animals that take millions of years to form. And, according to scientists, they're liable to run out this century if we keep consuming them at the current rate. How do renewable energy sources work?
The most common renewables globally are wind, solar, hydroelectric, bioenergy and geothermal. These generate electricity in different ways. Solar panels work by converting the light radiation from the sun to electricity through a reaction inside silicon layers within the solar panel. This reaction is called a photoelectric effect, where photons of light are absorbed and then electrons are released. The free electrons are captured, resulting in an electric current that can be used as electricity.
Wind power generates electricity via movement. On-and offshore wind farms use the wind to rotate a turbine's rotor blades. And the rotor connects to an electricity generator.
The larger the rotor, the more wind energy it can capture to be converted to electricity. As the wind is stronger offshore, wind turbines located at sea have proven to be more efficient as compared to the onshore turbines. But onshore wind turbines are easier to construct.
Hydropower is similar to wind power. Water released from a reservoir flows through a turbine, spinning it, which in turn activates a generator to produce electricity. The power extracted from the water depends on the volume and on the difference in height between the source and the water's outflow.
Bioenergy is a little different. Bioenergy refers to electricity and gas that's generated from organic matter, known as biomass. Examples of biomass can include plants, timber, agricultural and food waste, and even sewage. There are two types of biomass, dry and wet. Dry biomass, such as wood pellets, are burnt in boilers or furnaces.
And wet biomass, like food waste, are put into sealed tanks where they rot and produce methane gas, also called biogas. This gas can then be captured and burnt. The heat from burning either biogas or dry biomass boils water and creates steam. which drives a turbine to generate electricity.
Lastly, there's geothermal energy. Its method is to tap into underground reservoirs of steam and hot water. This means drilling underground wells of up to a mile deep and then harnessing the heat to drive turbines that are connected to generators to produce electricity. Why is renewable energy important?
Renewable energy is at the heart of the climate challenge. Fossil fuels have been the world's main energy source since the Industrial Revolution, and over 80% of the global energy system still uses them. When burned, fossil fuels produce large amounts of greenhouse gases, notably carbon dioxide and methane, which trap heat in the atmosphere. This is one of the main reasons why global temperatures have risen by approximately 1.1 degrees Celsius, compared with the Earth's average between 1850 and 1900. Rising temperatures have contributed to an increase in the frequency and intensity of extreme weather events, including heat waves, droughts and heavier rainfall.
Wildfires and floods have already seen millions of people lose their homes and animals lose their lives. It's predicted that in 2023, droughts could see UK farmers struggle to grow fruit and vegetables. Scientists say temperatures will continue to rise and these events will get even worse until we reach net zero. This is the point at which the amount of carbon emissions we're removing from the atmosphere is at least equal to what we're adding. To achieve net zero, experts say...
leaders must rapidly transfer to renewable energy which produces little to no emissions. Is renewable energy sustainable? Solar, wind and hydropower produce zero carbon emissions when generating electricity but they do produce emissions during the building of their infrastructure. And that's because all three energy sources use steel, which produces large amounts of carbon dioxide when it's made, which then contributes to global warming.
Bioenergy, which can come from plants, timber or food waste, also releases carbon emissions when burned to create electricity. But these materials do absorb as much carbon as they emit during their lifespans. Building solar farms often includes deforestation. This is of concern because trees play an important part in absorbing carbon dioxide from the atmosphere, which reduces global warming.
So, work still needs to be done to ensure renewables are 100% sustainable. But they're still much cleaner for the environment than fossil fuels. How will renewables impact the economy and consumers? The cost of renewables, particularly solar and wind power, are getting cheaper per year.
And it's expected to keep falling as investment in the sector continues. Energy providers have also stated that consumers could save on their electricity bills by installing certain infrastructure at home, such as solar panels and battery storage. And it's said that switching to renewables by 2050 could amount to saving as much as $12 trillion.
That's over £10 trillion worldwide. Countries face a race against time to slash carbon emissions and reduce global warming to limit the worst impacts of climate change. To do so, they must replace fossil fuels with renewable energy.
But there's still a long way to go. Between July and September 2022, almost 40% of the UK's electricity was generated by renewable energy sources. To meet these emission reduction targets, governments will need to invest even more heavily in renewables to ensure a cleaner, and more sustainable future for our planet.