Hydroelectric power stations

There are two main types of hydroelectric power station:

In conventional hydroelectric stations, the water flows from the reservoir to the turbines through a high pressure conduit then it flows out, usuay into a river.

In pumped-storage hydroelectric stations, the water flows from the turbines to a second reservoir. Then it is pumped back up to the higher reservoir and stored for later. These stations are often built in areas where there isn't enough rain of river water to keep the upper reservoir full, so the water must be reused.

Wind farms

Wind farms use the kinetic energy of the wind to generate electricity. The wind turns the blades of a turbine, at the top of a tower. The blades are connected to a gearbox which increases the rotational speed of the generator.

Nuclear power stations

A nuclkear power stations is a thermal power station that uses a nuclear reactor to produce heat. The reactor uses radioactive material as fuel. The most commonly used materials are isotopes of uranium, such as U-238.

Thermal power stations that usu fossil fuels

Thermal power stations use fossil fuels to produce thermal energy. Them the thermal energy is converted to mechanical energy, in order to generate electricity.

Electrical energy

Electrical energy is a from of  energy that is transported by an electrical current.

Electric power stations
A power station or generating station is a place where energy from natural resources is transformed into energy that we can consume If the energy obtained is electricity, it is called an electric power station.

The trasportation and distribution of electricity

- Raising the voltage
- High voltages lines 
- Reducing the voltage
- Power is distributed 

Energy sources

Energy sources are natural resources that we can use to generate different forms of energy. They can trannsform that energy for various purposes.

Non-renewable energy sources 
Non-renewable energy sources come from natural resource that are limites and can be exhausted.At the moment, the most commonly used energy sources are non-renewable.  They include fossils fuels (oil,coal and natural gas) and nuclear energy, which uses radioactive materials, such as uranium.

Renewable energy sources
Renewable energy sources come from natural resources thet we cannot use up completely. These include hydroelectric, solar, marine, geothermal an biomass resources, as well as energy that we can produce from solid urban waste.

Energy transformations

Energy can be transformed, but it cannot be created or destroyed. This is the principle of energy conservation 

Types of energy:
- Chemical energy
- Electrical energy
- Luminous and thermal energy
- Mechanical energy
- Kinetic energy
- Nuclear energy

Power

Power is a measurement of how quickly work is done.

The power of a machines is the amount of work that it can do in a certain amount of time. We express this relationship as: P = W/t

In the previous equation, P is power, expressed in watts (W); Wis work, expressed in joules, and t is time, expressed in seconds (s)