Hydropower

Definition

• Hydropower, or hydroelectricity, is the conversion of energy from flowing water into electricity.
• It is a renewable energy source as the water cycle is continuously renewed by the sun.

History and Development

• Initially used for mechanical milling, such as grinding grains.
• Modern hydro plants use turbines and generators to produce electricity.

Mechanism

• Flowing water spins rotors on a turbine connected to an electromagnetic generator producing electricity.

Types of Hydroelectricity Production

1. Dams

   • Utilize potential energy from dammed water to produce electricity.
   • A dam raises water levels creating gravitational force to turn turbines.
   • Some dams have pumped storage, storing water in a lower reservoir to be pumped back up when electricity demand is high.

2. Run-of-River Hydro

   • Relies on natural water flow rates, diverting part of the water through turbines.
   • More intermittent due to natural water variability.

Sizes of Hydro Plants

• Large Hydro: > 30 megawatts
• Small Hydro: 100 kilowatts to 30 megawatts
• Micro Hydro: < 100 kilowatts

Example

• The Hoover Dam in the USA produces 2074 megawatts, enough to serve 1.3 million people.

Global Impact

• Hydropower holds the largest share of worldwide electricity production among renewable sources.

Benefits

• Cost-competitive form of electricity.
• Reliable compared to other renewable energy sources.
• Can serve as base load power.
• Dams can assist in flood control and provide reliable water supplies.

Concerns

• Environmental impact: changes wildlife habitats, blocks fish passage, displaces communities.
• Potential catastrophic failure if dams break.
• Not free of greenhouse gas emissions: CO2 emissions during construction and methane from decaying plant matter underwater.