For thousands of years, people have been using hydropower from watermills. They used it for farming purposes and for moving machinery parts. The waterwheel can be traced back to the ancient Greeks and Chinese. Now hydropower is mainly used for generating electricity.
Hydropower depends on the water cycle. There are three parts to the water cycle. Solar energy heats up water from oceans, lakes, rivers, and other water sources. This causes the water to evaporate and turn into water vapour, which is a gas. The water vapour rises up into the sky and turns back into liquid water. This makes clouds. This is called condensation.
When the clouds are full of water, they will start to precipitate. This is when it will rain or snow. The rain or snow will go back into the water sources and the cycle begins again.
Hydroelectric power uses the force of fast-running water moving downstream to spin turbines. Rivers are dammed to control the amount and the flow of water. The water volume and its flow play a huge part in how much power can be made. When the dams release the stored water, gravity forces the water downwards and into the turbines. The turbines then move the generator and create power.
Hydroelectricity is made in 150 countries around the world. It is the most widely used kind of renewable energy. Although it is a clean and effective way of making energy, some critics say that the dams are ugly and interrupt the flow of rivers. It can also be dangerous for animals both upstream and downstream from the site. This system can cause population displacement. Some people and animals will have to move to make space for the dam system. Like many other hydropower systems, it can be expensive up-front to build.
There are micro hydro systems that can provide power to a single home or a small community. These systems make power at a smaller capacity. Instead of using rivers as their water source, many micro hydro systems use a small dammed pool. It can be an economical way to access power without using fossil fuels.
Wave power is a way of generating power from moving waves. Waves are a great source of energy because they are consistent and reliable. It doesn't depend on when it is windy or sunny. Wave power can always make energy.
Machines called wave energy converters capture the energy produced by the waves and use it to generate power. Wave energy is not commonly used around the world yet. One of the biggest concerns about wave power is that it can be very disruptive to marine animal life. The machines can be quite noisy and this noise could have negative impacts on marine animals that rely on sound to communicate and navigate.
Tidal power is often confused with wave power. The biggest difference is that wave power uses energy from waves in the open ocean, whereas tidal power uses energy from tides coming in and out near coasts. As tides go in and out every day, generators take advantage of the water movement.
Similar to hydroelectric and wave power, this movement of water powers the generators. Although tides, like waves, are easily predictable, they only occur at limited times during the day. This means that the time available for generating energy is short. There could also be an adverse impact on the animals living in the area. Often, fish mistakenly swim into the moving blades and get killed.
Despite the possible downsides, water power can be very useful for humans. With proper care and attention, we can use water power to generate a clean, efficient energy future!