Hydroelectricity

Moving water can make power. This power comes from rivers. It makes the light in your home.

Some people build a big wall called a dam. The dam holds back a lot of water. This water can move to make power.

This power is very clean. It does not make much waste. It is a great way to get energy.

Many lands use this water power. Brazil and China use a lot. It is a very big job.

People have used water for a long time. They used it to grind flour. Now we use it for electricity.

Water can make electricity. This is called hydroelectricity. It is a very large source of power. In 2023, it supplied 15% of the world's electricity. This is more than all other renewable sources combined.

Most power comes from dams. A dam holds water in a large lake called a reservoir. Water flows from the lake through a large pipe. We call this pipe a penstock. The moving water turns a turbine. A turbine is a machine with blades that spin. This spin makes electricity in a generator.

There are different ways to use water. Some plants use a run-of-the-river method. These have very small reservoirs. Other plants use pumped-storage. This moves water between two lakes to save power for later. Some stations even use the tides in the ocean.

Hydro power helps many countries. Brazil and China use a lot of it. In 2022, China added a huge amount of new power. This helped them grow their capacity. Large dams can also help stop floods. However, building dams can change the land and the river. It can also move people from their homes.

Hydroelectricity is a way to make electricity using the power of moving water. It is a very important part of how the world gets energy. In 2023, hydropower supplied about 15% of the world's electricity. This was almost 4,210 TWh of energy. This amount is more than all other renewable sources put together. It is even more than nuclear power. Because it can provide energy on demand, it helps keep our power systems clean and steady.

Most electricity comes from a way of working that uses dams. A dam holds water in a large lake called a reservoir. This creates a difference in height between the top and bottom. This height difference is called the head. Water travels from the reservoir through a large pipe called a penstock. The moving water then hits a turbine to make it spin. This spinning turbine is connected to a generator that makes the electricity.

People have used water power for a very long time. In ancient times, it was used to grind flour. In the late 1700s, it helped start the Industrial Revolution. A French engineer named Bernard Forest de Bélidor wrote about water machines in the mid-1700s. Later, in 1878, William Armstrong built the first hydroelectric scheme in England. It was at a place called Cragside. He used it to power just one lamp in his art gallery.

There are many different ways to catch water power. Some stations use a run-of-the-river method with very small reservoirs. Other systems use pumped-storage to move water between two lakes. This helps save energy for times when people need it most. Some places even use the tides in the ocean to make power. There are also tiny systems called pico hydro that make less than 5 kW. These can help small, remote groups of people get light.

Large dams can change the world in many ways. They can help stop floods or help with farming. However, building them can also be a hard job for nature. It can cause people to move from their homes. It can also change the homes of animals in the river. In 2021, the world had almost 1,400 GW of this power capacity. China added 24 GW of new power in 2022 alone. This was nearly three-quarters of all new power added globally.

Hydroelectricity is the generation of electricity using hydropower. It is a vital part of the global energy supply. In 2023, hydropower supplied about 15% of the world's electricity. This equals almost 4,210 TWh of energy. This amount is larger than all other renewable sources combined. It is also greater than the electricity produced by nuclear power. Because it can provide electricity on demand, it helps create secure and clean energy systems.

Most hydroelectricity comes from conventional dams. These systems use the potential energy of water held in a reservoir. A dam creates a height difference between the source and the outflow. This height difference is known as the head. Water travels from the reservoir through a large pipe called a penstock. The flowing water then drives a water turbine. This spinning turbine is connected to a generator. The generator then produces electricity. The amount of power depends on the water volume and the head.

There are several other ways to generate power from water. Run-of-the-river stations have little to no reservoir capacity. They rely on the natural flow of water from upstream. Pumped-storage is a different method used for energy storage. It moves water between two reservoirs at different elevations. During low demand, excess energy pumps water to the higher reservoir. When demand rises, the water is released through a turbine. In 2021, pumped-storage provided almost 85% of the world's 190 GW of grid energy storage. Other methods include tidal power, which uses the predictable rise and fall of ocean tides. Conduit hydroelectricity uses existing water pipelines or canals to capture mechanical energy.

Hydroelectric facilities vary greatly in size and capacity. They are divided into large hydropower plants (LHP) and small hydropower plants (SHP). A plant is usually considered an LHP if it has a capacity of 50 MW or more. In some places, the limit is lower. For example, in Europe, SHP is below 10 MW. Small hydro can serve small communities or industrial plants. Micro hydro produces up to 100 kW. This can power isolated homes or small villages. Pico hydro is the smallest type, producing under 5 kW. These tiny systems can be very useful in remote areas.

Humans have used water power since ancient times. It was once used to grind flour. In the mid-1700s, Bernard Forest de Bélidor published work on hydraulic machines. By 1771, Richard Arkwright used water power to help develop the factory system. The late 19th century brought the electrical generator. This allowed hydraulics to be coupled with electricity. In 1878, William Armstrong created the first hydroelectric scheme. It was located at Cragside in England. It powered only one arc lamp. Later, the first Edison plant began operating in 1882 in Wisconsin.

As technology grew, hydroelectric projects became much larger. In the United States, the Federal Power Act was enacted in 1920. This helped regulate stations on federal lands. Large dams began serving many purposes. They provided flood control, irrigation, and navigation. The Hoover Dam was a major project completed in 1928. In 1936, the Hoover Dam's 1,345 MW station was the largest in the world. Later, the Grand Coulee Dam surpassed it in 1942. The Three Gorges Dam in China became the largest in 2008. It has a capacity of 22.5 GW.

While hydroelectricity is clean, it has environmental impacts. Building large complexes can cause the loss of arable land. It can also lead to population displacement. Dams can disrupt river ecology and affect animal habitats. They also change siltation and erosion patterns. In some lowland rainforest areas, flooding can release greenhouse gases. However, most plants emit much less greenhouse gas than fossil fuel plants. In 2021, global installed hydropower capacity reached almost 1,400 GW. This remains the highest capacity among all renewable technologies.