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Demand for renewable energy sources has skyrocketed in 2023, with annual global investments reaching an all-new high at 1.7 Billion USD. As world-leading countries reconvene to develop public policies and regulations, renewable energy development will continue to flourish and innovate – in fact recently, Newfoundland and Labrador approved a $15 billion project alongside SK Group to develop green hydrogen via wind farms. Similar to other new technologies, green energy is experiencing a boom and is expected to continue its upward trend for quite a while.
WHAT IS RENEWABLE ENERGY?
Renewable energy is defined as energy derived from sources that can replenish themselves at a rate that lets humans meet their energy demands. Renewable energy isn’t always considered a sustainable energy source. Though we hear the term used interchangeably, there is a slight difference! Sustainable energy are sources that do not negatively affect the climate nor harm the needs of future generations.
TYPES OF RENEWABLE ENERGY
SOLAR
Solar energy captures solar radiation, commonly known as sunlight, and converts that to electricity. Two main forms of solar energy exist: photovoltaics (PV) and concentrating solar-thermal power (CSP).
Photovoltaics sound complicated but you’re probably familiar with them! They generally come in PV cells, also known as solar panels. Solar panels work by having the semiconductor material absorb photons from the sunlight and then release electrons, creating a current.
Solar panels are composed of a layer of glass, a positive and negative terminal and two semiconductor layers in between. Light interacts with the semiconductors, causing it to release electrons which creates a current.
Solar panels produce small amounts of energy (1 - 2 Watts), which is why you’ll see many of them assembled together in order to produce enough energy for our daily use.
Concentrating solar power (CSP) does not absorb sunlight like photovoltaics. Instead, it reflects sunlight onto a specified receiver which then converts it to heat. The heat can be used in different ways to generate energy, but typically it’s used to power steam generators.
WIND
Did you know that sail ships count as a form of wind energy, though we use wind a bit differently now. We use wind turbines to generate electricity to power our devices. The principle is similar – when the turbine receives wind, it’ll power a generator which then creates a current for the electrical grid to receive. Like how solar energy is only efficient in locations that receive a lot of sun, wind energy relies on being located in areas that receive a lot of wind. However, the speed of the wind matters too, as turbines are easily damaged when receiving high speed wind.
HYDROPOWER
The most common type of renewable energy source is hydropower and it is also one of the oldest types! Hydropower relies on the water cycle and on elevation differences to generate energy – the water flows through a pipe, spins a turbine, and then powers a generator. Though reliably used in history, recent droughts have weakened the reliability of hydropower which is why other renewable energy sources are being invested in.
GEOTHERMAL
Geothermal energy is when we harvest the heat that radiates from the Earth (known as the geothermal gradient) in order to meet our energy needs. To access this energy, we rely on harnessing the natural steam and heat emitted from vents, hot springs and mud pots. This is only a fraction of the geothermal energy that the Earth is able to release – to attain more requires us to drill into the Earth and install water pipes to be heated to create steam, which can then be used as a form of energy. Unlike the previous examples of energy, geothermal is much more consistent in its accessibility and reliability.
Image 4 shows the geothermal energy capture process. Two pipes are drilled into an underground water-system then siphoned up to a turbine generator to produce electricity. Once energy production is complete the water is then cooled down and piped back down to the water-system.
BIOENERGY
Plants and algae can be used as energy. That’s where bioenergy comes in! Bioenergy consists of four different areas of innovation: biofuels, biomass, biopower and bioproducts. Biomass is often derived from food, crop, and wood waste and from microalgaes which can then be converted into liquids known as biofuels. Biopower refers to the conversion of biofuels to electricity and heat. Bioproducts are the basic goods and materials derived from bioenergy, which can then be used in industries as alternatives to plastics.
Though renewable, biofuel is not always considered sustainable due to the fact that there can be negative consequences to the environment. Further development in bioenergy will innovate around the local people and the environment of future bioreactor sites.
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