Five common sources of alternative or renewable energy.

1. Energy that comes from natural resources
that are naturally replenished.
 Sunlight
 Wind
 Rain
 Tides
 Geothermal Heat

2. Derived from: The force or energy of falling water.
Uses: Irrigation, operation of mechanical devices:
watermills, sawmills, textile mills, dock cranes,
domestic lifts.
Image Source: http://www.fastcompany.com/1597414/hydropower-flush-cash-us-government

3. Derived from: Radiant light and heat from the sun
Uses: Solar heating, solar photovoltaics, solar
thermal electricity, solar architecture
Image source: http://auziontech.com/

4. Image source: http://awakeatthewheel.net/2011/08/26/propel-partners-with-pcf-to-expand-renewable-fuel-access-across-western-u-s/

5. Derived from: Biological material from living, or recently living.
Uses: Can be used directly or converted in to other energy
products i.e. biofuel.
Used directly: Plant matter used to generate electricity with
steam turbines and gasifiers or produce heat usually by direct
combustion.
Examples: forest resides (dead trees, branches tree stumps),
yard clippings, wood chips, green waste.
Used indirectly: plant of animal matter than can be converted in
to fibres or other industrial chemicals (including biofuels).
Examples: miscanthus, switchgrass, hemp, corn, poplar, willow,
sorghum, sugarcane, eucalyptus, palm oil.

6. Derived from: Thermal energy generated and stored in the Earth.
Uses: Approximately 70 countries made direct use of geothermal
heating in 2004. More than half went for space heating, and
another third for heated pools. The remainder supported
industrial and agricultural applications.
Image source: http://pixiegas.com/forms-of-energy-pixie-gas-supports/geothermal-tech/

7. Derived from: The conversion of wind energy into a
useful form of energy.
Uses: Wind turbines to make electricity, windmills for
mechanical power, windpumps for water pumping or
drainage or sails to propel ships.
Image source: http://thelincolnite.co.uk/2013/01/lincolnshire-people-against-wind-farms-council-survey-shows/