Water power –the mature Water power –the mature renewable sourcerenewable source

Exploring Hydropower

Water power has a long Water power has a long history. Until the early history. Until the early twentieth century, water twentieth century, water powered mills ground powered mills ground grain into flour, sawed grain into flour, sawed lumber and performed lumber and performed numerous other tasks. numerous other tasks. Such direct usage is now Such direct usage is now rare, and most water rare, and most water power is used to power is used to generate a convenient generate a convenient secondary energy secondary energy source, electricity.source, electricity.

Hydro powerHydro power is available by creating dams in stream is available by creating dams in stream and river flows. Hydro power generation is an and river flows. Hydro power generation is an established technology established technology which is widely considered the which is widely considered the most environmentally friendly and cost effective way of most environmentally friendly and cost effective way of producing clean energy.producing clean energy.

Water CycleWater Cycle

Gravitational EnergyGravitational Energy

Potential energy is the energy that all forms of solid or liquid matter have. You have potential and you also have potential energy. That energy isn’t necessarily because of what you can do but because of what something else can make you do.Kinetic energy is the energy that anything which is in motion (except some gases) have. That energy can be multiplied (or divided) base on the path and direction of that item. i.e. going downhill, it’s multiplied, uphill, divided.

Hydroelectric power (hydropower) Hydroelectric power (hydropower) systems convert the kinetic energy in systems convert the kinetic energy in flowing water into electric energy. flowing water into electric energy.

How a Hydroelectric Power System WorksHow a Hydroelectric Power System Works

Flowing water is Flowing water is directed at a turbine directed at a turbine (remember turbines (remember turbines are just advanced are just advanced waterwheels). The waterwheels). The flowing water causes flowing water causes the turbine to rotate, the turbine to rotate, converting the converting the water’s kinetic energy water’s kinetic energy into mechanical into mechanical energy.energy.

The mechanical energy produced by the turbine is converted The mechanical energy produced by the turbine is converted into into electric energyelectric energy using a turbine generator. Inside the using a turbine generator. Inside the generator, the shaft of the turbine spins a magnet inside coils generator, the shaft of the turbine spins a magnet inside coils of copper wire.of copper wire. It is a fact of nature that moving a magnet It is a fact of nature that moving a magnet near a conductor causes an electric current.near a conductor causes an electric current.

How a Hydroelectric Power System Works

Hydroelectric dam in cross section Hydroelectric dam in cross section

In electricity generation, an electrical generator is a device that converts mechanical energy to electrical energy, generally using electromagnetic induction. The source of mechanical energy may be a reciprocating or turbine steam engine, water falling through a turbine or waterwheel, an internal combustion engine, a wind turbine, a hand crank, compressed air or any other source of mechanical energy.

The amount of electricity that can be generated by a hydropower plant depends on two factors:• flow rate - the quantity of water flowing in a given time; and• head - the height from which the water falls.

The greater the flow and head, the more electricity produced.

How much electricity can be generated by a hydroelectric power plant?

Large Dams such as Hoover Dam Large Dams such as Hoover Dam are able to provide large amounts of are able to provide large amounts of hydroelectric power; it has a 2.07 hydroelectric power; it has a 2.07 gigawatt capability.gigawatt capability.

Hoover Dam is among the most Hoover Dam is among the most recognized and renowned structures recognized and renowned structures built by the Bureau of Reclamation. built by the Bureau of Reclamation.

The dam was authorized under the The dam was authorized under the Boulder Canyon Project.Boulder Canyon Project.

Coal vs. Hydro Kinetic Energy Coal vs. Hydro Kinetic Energy Conversion Conversion

35%35% 95%95%

AdvantagesAdvantages

The major advantage of The major advantage of hydroelectricity is elimination hydroelectricity is elimination of the cost of fuel. The cost of of the cost of fuel. The cost of operating a hydroelectric plant operating a hydroelectric plant is nearly immune to increases is nearly immune to increases in the cost of fossil fuels.in the cost of fossil fuels.

Where a dam serves multiple Where a dam serves multiple purposes, a hydroelectric plant purposes, a hydroelectric plant may be added with relatively may be added with relatively low construction cost, low construction cost, providing a useful revenue providing a useful revenue stream to offset the costs of stream to offset the costs of dam operation. dam operation.

Economics

Since hydroelectric dams Since hydroelectric dams do not burn fossil fuels, do not burn fossil fuels, they do not directly they do not directly produce carbon dioxide produce carbon dioxide ((a greenhouse gasa greenhouse gas). ). While some carbon While some carbon dioxide is produced dioxide is produced during manufacture and during manufacture and construction of the construction of the project, this is a tiny project, this is a tiny fraction of the operating fraction of the operating emissions of equivalent emissions of equivalent fossil-fuel electricity fossil-fuel electricity generation.generation.

Greenhouse gas emissions

Reservoirs created by Reservoirs created by hydroelectric schemes hydroelectric schemes often provide facilities for often provide facilities for water sports, and become water sports, and become tourist attractions in tourist attractions in themselves. In some themselves. In some countries, farming fish in countries, farming fish in the reservoirs is common. the reservoirs is common. Multi-use dams installed Multi-use dams installed for irrigation can support for irrigation can support the fish farm with the fish farm with relatively constant water relatively constant water supply. supply.

Related activities

DisadvantagesDisadvantages

Hydroelectric projects can be disruptive to surrounding Hydroelectric projects can be disruptive to surrounding aquatic ecosystems. For instance, studies have shown that aquatic ecosystems. For instance, studies have shown that dams along the Atlantic and Pacific coasts of North America dams along the Atlantic and Pacific coasts of North America have reduced salmon populations by preventing access to have reduced salmon populations by preventing access to spawning grounds upstream, even though most dams in spawning grounds upstream, even though most dams in salmon habitat have fish ladders installed. We are finding salmon habitat have fish ladders installed. We are finding more ways every year to lessen these effects.more ways every year to lessen these effects.

Environmental damage

Population relocationPopulation relocation Another disadvantage of Another disadvantage of

hydroelectric dams is the hydroelectric dams is the need to relocate people need to relocate people living where the reservoirs living where the reservoirs are planned. In most are planned. In most cases, the compensation is cases, the compensation is very generous to the very generous to the displaced population. displaced population. Overall, it is in the best Overall, it is in the best interest of all involved. The interest of all involved. The good of the many must be good of the many must be considered over the good considered over the good of the few. The areas are of the few. The areas are historically a bad choice to historically a bad choice to live in as well due to live in as well due to natural seasonal flooding.natural seasonal flooding.

Dam failuresDam failures Failures of large dams, Failures of large dams,

while rare, are potentially while rare, are potentially serious — the Banqiao serious — the Banqiao Dam failure in Southern Dam failure in Southern China resulted in the China resulted in the deaths of 171,000 people deaths of 171,000 people and left millions and left millions homeless. Dams may be homeless. Dams may be subject to enemy subject to enemy bombardment during bombardment during wartime, sabotage and wartime, sabotage and terrorism. Smaller dams terrorism. Smaller dams and micro hydro facilities and micro hydro facilities are less vulnerable to are less vulnerable to these threats.these threats.

The future of hydropower lies in technologies that are also

environmental friendly.