- RENEWABLE RESOURCES are those that are re-created as fast as we use them, so we can never run out of them.
Because we cannot run out of these resources, our use can be called sustainable, meaning that the use can go on and on forever.
- BIOLOGICAL RESOURCES:
Biological resources are based on living organisms that can reproduce and make more of themselves.
Living things are thus a renewable resouce, as long as we don't overuse them.
Plant foods are renewable (if sustainably farmed) because we can keep growing more of them. The same is true of Biofuels.
Forest products, including wood and paper, are renewable if sustainably managed.
Some animal foods can also be sustainably managed using current practices, but others cannot.
Overfishing, for example, depletes the fish stock of many fisheries around the world.
Common types of farming require far more plant food to feed animals for human consumption than if people ate plant foods instead.
Food energy and energy from biofuels is derived from solar energy that plants capture during photosynthesis.
- SOLAR ENERGY:
As long as the Sun keeps shining, solar energy is renewable and sustainable.
Solar energy can be used to generate electricity. Some of this energy can be stored in batteries.
Solar energy is already being used around the world to heat many homes and to supply them with electricity.
Many people hope that we can develop more solar energy because it is both sustainable and clean (non-polluting).
Energy storage is needed to supply energy during the night, when sunlight is not available.
Batteries will currently work on a small scale only; bigger batteries are being developed.
- WIND ENERGY and HYDROELECTRIC POWER:
Wind energy can be harvested by wind turbines or windmills. The energy can be used to generate electricity.
One problem is that the winds sometimes stop blowing, so batteries are needed to store the energy.
Winds are driven by the heating effects of the sun (see Topic 64) are are therefore renewable and sustainable.
Hydroelectric power can be generated by waterfalls on rivers turning the generators to generate electricity.
Many parts of Canada generate most of their electricity by hydroelectric power.
Hydroelectric power is driven by water flowing downstream. The water is renewed by rainfall or snowfall, and ultimately
by solar energy evaporating water into the atmosphere and forming clouds.
- TIDAL POWER:
Tidal energy can be used in certain coastal areas to generate electricity using turbines similar to those used in hydroelectric plants.
Several countries in Europe are already using tidal energy plants to generate electricity, and they are building even more.
Tidal energy is driven by the tides, which are driven by the revolution of the moon around the Earth.
- GEOTHERMAL ENERGY:
Geothermal energy is only available in a few places because it is related to present or past volcanic activity.
Very hot, underground magma can be used to heat water and drive turbines to generate electricity.
In places where geothermal energy is available, it is sustainable, dependable, and inexpensive to maintain once it is installed.
Geothermal energy is currently being used in Iceland, and in scattered locations elsewhere around the globe.
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