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Renewable energies

Renewable energies come from sources that can be naturally replenished within a human’s life time.

The most common examples include wind, solar, geothermal, biomass and hydropower.

However, in this part we will only detail wind and photovoltaic renewable energies. 

Photovoltaic

It is possible to produce electrical energy from photovoltaic panels. Sunlight is transformed into electrical energy by silicon cells or other semiconductors placed in a sensor.

The energy thus produced can be stored in batteries or fuel cells (see part on energy storage).It can then be returned on demand.

An installation of 18 to 24 m² of photovoltaic panels can cover 3,000 kW/year. That’s to say the average electricity needs for a family of 4 people (including heating).

It is possible either to connect to the grid or to store energy in batteries.

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Wind energy

A wind turbine consists of a wind generator that converts mechanical energy into electrical energy.

Mechanical energy comes from the force of the wind that rotates the blades of the wind turbine through a direct current alternator.

The minimum wind speed for the wind turbine to produce energy is 4m/s.

There are small domestic wind turbines from 100 W to 30 kW. For instance 1 kW of power delivered for one hour gives 1kWh.

Similarly as photovoltaic panels, it is possible to connect it to the grid or to store in batteries.

In Portugal, an individual who wants to put wind energy into his house connected to the electricity grid, must submit a project to the energy distributor. If approved, the customer will be responsible for all expenses related to the equipment and the new meter that will record the energy input and output.

Wind energy

A wind turbine consists of a wind generator that converts mechanical energy into electrical energy.

Mechanical energy comes from the force of the wind that rotates the blades of the wind turbine through a direct current alternator.

The minimum wind speed for the wind turbine to produce energy is 4m/s.

There are small domestic wind turbines from 100 W to 30 kW. For instance 1 kW of power delivered for one hour gives 1kWh.

Similarly as photovoltaic panels, it is possible to connect it to the grid or to store in batteries.

In Portugal, an individual who wants to put wind energy into his house connected to the electricity grid, must submit a project to the energy distributor. If approved, the customer will be responsible for all expenses related to the equipment and the new meter that will record the energy input and output.