Bio-energy

Improvements in technology for using convectional sources of energy:-

BIO-MASS:-

If we can ensure that enough trees are planted, a continuous supply of fire-wood can be assured. You must also be familiar with the use of cow-dung cakes as a fuel.

Given the large live-stock population in India, this can also assure us a steady source of fuel. Since these fuels are plant and animal products, the source of these fuels is said to be bio-mass.

These fuels, however, do not produce much heat on burning and a lot of smoke is given out when they are burnt. Therefore, technological inputs to improve the efficiency of these fuels are necessary.

When wood is burnt in a limited supply of oxygen, water and volatile materials present in it get removed and charcoal is left behind as the residue. Charcoal burns without flames, is comparatively smokeless and has a higher heat generation efficiency.

Similarly, cow-dung, various plant materials like the residue after harvesting the crops, vegetable waste and sewage are decomposed in the absence of oxygen to give bio-gas. Since the starting material is mainly cow-dung, it is popularly known as ‘gobar-gas’.

BIOGAS is prepared in a plant with the help of micro organisms by the process of decomposition.

Bio-gas is an excellent fuel as it contains up to 75% methane. It burns without smoke, leaves no residue like ash in wood, charcoal and coal burning.

Its heating capacity is high. Bio-gas is also used for lighting. The slurry left behind is removed periodically and used as excellent manure,

WIND ENERGY.

-The kinetic energy from the wind was harnessed by windmills in the past to extract water from the wells.

-Now-days windmills are used to generate electricity

-A windmill essentially consists of a structure similar to a large electric fan that is erected at some height on a rigid support

-To generate electricity, the rotatory motion of the windmill is used to turn the turbine of the electric generator.

-The output of a single windmill is quite small and cannot be used for commercial purposes.

-Therefore, a number of windmills are erected over a large area, which is known as wind energy farm.

-The energy output of each windmill in a farm is coupled together to get electricity on a commercial scale.

Advantages:

-Wind energy is an environment-friendly and efficient source of renewable energy.

-It requires no recurring expenses for the production of electricity

limitations:

-wind energy farms can be established only at those places where wind blows for the greater part of a year.

-The wind speed should also be higher than 15 km/h to maintain the required speed of the turbine.

-Furthermore, there should be some back-up facilities (like storage cells) to take care of the energy needs during a period when there is no wind.

-Establishment of wind energy farms requires large area of land. For a 1 MW generator, the farm needs about 2 hectares of land.

-The initial cost of establishment of the farm is quite high. Moreover, since the tower and blades are exposed to the vagaries of nature like rain, Sun, storm and cyclone, they need a high level of maintenance.