Renewable Energy
Written by Ariel Seong
Renewable Energy(Solar, Wind, Hydro)
Global electricity production still heavily depends on non- renewable energy sources(fossil fuels). Because such fossil fuels are not only limited but take millions of years to form. Moreover, they produce harmful greenhouse gas emissions(i.e. carbon dioxide) when they are burned to release energy.
Renewable energy, however, is energy acquired from sources that are constantly replenished. In other words, these sources of energy are unlimited. The most distinguished and common renewable energy sources are solar energy, wind energy, and hydropower.
Solar Energy
Solar energy is the most plentiful of all energy sources. Energy from the sun is harnessed and converted to thermal/ electrical energy, then is used for domestic, commercial, and/or industrial use. However, solar energy isn’t reliable 24/7. Without a storage device to store energy collected during the day, solar energy cannot be used at night. It also requires many energy sites to collect the sun's energy at a rate that can be useful to people.
Step by Step: How Solar Energy Works
Sunlight activates photovoltaic cells(solar cells) arranged inside panels. Sun’s energy is collected during daylight hours.
When energy from the sun strikes a photovoltaic cell, the cell is energized and electrons inside the cell are set into motion. This motion creates an electrical current called “direct current electricity”.
This direct current(DC) electricity is then converted into alternating current(AC) electricity via a device called an inverter.
Once direct current(DC) electricity is converted to alternating current(AC) electricity, it can run through electrical panels then be distributed for use.
Wind Energy
Wind energy utilizes large wind turbines(onshore/ offshore) to harness the kinetic energy of wind(moving air). Although wind energy is a popular source of energy, average wind speeds vary greatly depending on location, ample potential exists in most areas around the world for plentiful energy production.
Step by Step: How Wind Energy Works
Wind blows past turbines, causing the turbines(blades) to rotate.
The kinetic energy of the wind is transferred into mechanical energy. The amount of energy produced depends on the speed of wind(i.e. strong winds at 50- 60km/h generate energy at full capacity).
The gearbox forces a large amount of kinetic energy into a small rotor that spins an electromagnet inside the generator. Electricity is generated as mechanical energy is converted into electrical energy.
Electricity flows through cables and into a transformer. The transformer amplifies the voltage in order to enable a distribution at a larger scale.
Hydropower
Today, hydropower is the largest source of renewable energy in the electricity sector. It is heavily reliant on rainfall, since it depends on the energy of water moving from higher to lower elevations. During droughts or changes to ecosystems, rainfall patterns may be negatively affected, resulting in an inability to generate electricity. Although hydropower remains a popular option, hydropower dams aren’t the most environmentally friendly. There is a high risk of damage to river ecosystems and floods.
Step by Step: How Hydropower Works
The dam raises the height of the river, creating controllable falling water. This acts as a reservoir for stored energy.
The force in which water pushes against the turbines(inside/ under the dam) causes it to turn at a high speed. The kinetic energy of falling water is converted into mechanical energy.
The generator then converts mechanical energy into electrical energy.
Transmission lines carry electricity to be put into use.
