Source of Energy (ME-107 : Energy)

There are many different sources of energy. We have seen varieties of energy forms in previous post. Now we will discuss about their source. Actually all sources of energy are grouped into two major categories.

• Renewable / income / non-dependable energy.
• Capital / conventional energy .

Renewable energy is such an energy which comes to earth from outer space. According to Twidell and Weir, "Renewable energy is the energy obtained from the continuous or repetitive currents of energy recurring in the natural environment." Sorensen says, "Renewable energy is the energy flows which are replenished at the same rate as they are used." The United Kingdom Renewable Energy Advisory Group (REAG) says, "It is those energy flows that occur naturally and can be harnessed for human benefit."
Example: Light energy from the sun (Solar energy).

Capital energy is the energy which already exists on or within the earth.
Example: Gas, coal, oil etc.

Source of Renewable energy:

(1) The Solar Energy:


Most Renewable energy are derived from the sun and it is called Solar energy. Solar energy has two types.

• Direct Solar energy: Solar energy reaching the earth in the form of electromagnetic radiation is called the direct solar energy. It can be directly used for heating and electricity generation.
• Indirect Solar energy: Direct solar energy generates a number of indirect renewable source of energy. These are:

1. Wind and ocean currents: The direct solar heating, combined with earth's rotation, produces large convection currents in the form of wind in the atmosphere and ocean current in the sea. Using wind or water turbine, we can produce electricity.
2.  Ocean thermal gradient: Absorption of solar energy by the sea water generates a significant thermal gradient in the ocean. OTEC (Ocean Thermal Energy Conversion) can utilize the ocean thermal energy gradient to produce power.
3. Rain: Solar energy evaporates surface water and forms clouds. This falls in the form of rain at higher attitude. This can be used to produce hydroelectric or water power.
4. Biomass: All the living materials like trees, animals, plants, organic wastes produced as a result of photosynthesis process. Some of these materials like wood are used directly as fuel. Some can be used to produce other fuels, such as charcoals, alcohols, methane and other fuel gasses.

(2) The Lunar Energy:

The other major source of income or renewable energy is the Lunar energy which the gravitational force from the moon. The gravitational energy produces tidal flows that range from few inches to 25 to 30 feet. By constructing a numbers of dams at the entrances to the tidal basin and using a number of reversible water turbines, electricity can be produced as the water flows back and forth the turbines.

Source of Capital energy:

1.  Fossil fuel: These are produced from fossilization of carbohydrate compounds. Example: Coal, Oils, Natural gasses.
2. Geothermal energy: Thermal energy trapped beneath and within the solid crust of the earth. This energy exists in the form of steam, hot water, hot and melted rock (magma). This energy is released naturally as geysers, hot springs and volcanic eruptions. Geothermal energy is of two kinds. Hydrothermal- associated with steam and hot water. Petrothermal- associated with hot rock.
3. Nuclear fuels: Ores within the earth. Example: Uranium, Plutonium.