i) It should have a high energy output per unit mass or volume.(High Calorific Value.)

ii) It should be easily available. iii) It should be easy to store and transport. iv) It should be economical.

HIGH CALORIFIC VALUE THE AMOUNT OF HEAT PRODUCED BY BURNING A UNIT

MASS OF FUEL COMPLETELY IS KNOWN AS CALORIFIC VALUE.

A SUBSTANCE WHICH HAS A HIGH CALORIFIC VALUE HAS A HIGH HEAT GENERATING CAPACITY.

A GOOD FUEL HAS HIGH CALORIFIC VALUE AND BURNS WITHOUT LEAVING MUCH ASH AFETR BURNING.

From the above table we conclude that hydrogen has the highest calorific value of 150 kilojoules per gram . Thus, because of it’s high calorific value , it is an extremely good fuel. Most fuels compound are compound of hydrogen and carbons called ‘hydrocarbons’ .Hydrogen doesn’t burns with smoke and it is also pollution-free. It also doesn’t leave behind any harmful substance.

EASY TO STORE AND TRANSPORT

A GOOD SSOURCE OF ENERGY SHOULD BE EASY TO HANDLE ,SAFE TO TRANSPORT, AND CONVENIENT TO STORE .

AN IDEAL FUEL MUST NOT CREATE ANY SAFETY RISKS DURING HANDLING ,DURING IT ’S TRANSPORTATION FROM ONE PLACE TO ANOTHER OR DURING IT ’S STORAGE .

FOR EXAMPLE :-

THE PICTURE ON THE RIGHT SIDE SHOWS THAT THE STORAGE OF LPG IS EASY AS WELL AS IT IS EASY TO HANDLE AND TRANSPOT ALSO.

There are two main sources of energy. They are conventional and non conventional sources of energy.

i ) Conventional sources of energy : - are wood, f lowing water and fossil fuels (coal, petroleum, natural gas).

i i ) Non conventional sources of energy : - are solar energy, wind energy, biomass energy, ocean energy (t idal energy, wave energy, ocean thermal energy), geothermal energy, nuclear energy etc.

Some sources of energy are renewable l ike sun, wind, f lowing water, ocean, wood, biomass etc.

Some sources of energy are non renewable l ike

coal, petroleum and natural gas .

2. 2. Conventional sources of energyConventional sources of energy :- :-a) Fossil fuels :- are fuels formed inside the earth from the remains of plants and animals after millions of years. The fossil fuels are coal, petroleum and natural gas. Fossil fuels are non renewable sources of energy so they should be conserved and used judiciously. Disadvantages of fossil fuels :- i) Burning of fossil fuels release gases and harmful particles which causes air pollution. ii) Burning of fossil fuels release acidic oxides of sulphur and nitrogen which causes acid rain which is harmful for living organisms, affects soil and water, causes damage to buildings, corrosion of metals etc. iii) Burning of fossil fuels release a large amount of carbon dioxide gas which increases the temperature of the atmosphere and causes global warming (green house effect).

1. Solar energy is free although there is a cost in the building of ‘collectors’ and other equipment required to convert solar energy into electricity or hot water.2. Solar energy does not cause pollution. However, solar collectors and other associated equipment / machines are manufactured in factories that in turn cause some pollution.3. Solar energy can be used in remote areas where it is too expensive to extend the electricity power grid.4. Many everyday items such as calculators and other low power consuming devices can be powered by solar energy effectively.5. It is estimated that the worlds oil reserves will last for 30 to 40 years. On the other hand, solar energy is infinite (forever).

1. Solar energy can only be harnessed when it is daytime and sunny.2. Solar collectors, panels and cells are relatively expensive to manufacture although prices are falling rapidly.3. Solar power stations can be built but they do not match the power output of similar sized conventional power stations. They are also very expensive.4. In countries such as the UK, the unreliable climate means that solar energy is also unreliable as a source of energy. Cloudy skies reduce its effectiveness.5. Solar power is used to charge batteries so that solar powered devices can be used at night. However, the batteries are large and heavy and need storage space. They also need replacing from time to time.  

SOLAR PANELS SOLAR LAMP

A solar lamp is a light fixture composed of an LED lamp, a photovoltaic solar panel, and a rechargeable battery.They have separately-mounted solar panels and are used for general illumination where centrally generated power is not conveniently or economically available. Solar-powered household lighting may displace light sources such as kerosene lamps, saving money for the user, and reducing fire and pollution hazards.Solar lamps recharge during the day. Automatic outdoor lamps turn on at dusk and remain illuminated overnight, depending on how much sunlight they receive during the day. Indoor solar lamps may or may not store power.

A solar lamp is a light fixture composed of an LED lamp, a photovoltaic solar panel, and a rechargeable battery.They have separately-mounted solar panels and are used for general illumination where centrally generated power is not conveniently or economically available. Solar-powered household lighting may displace light sources such as kerosene lamps, saving money for the user, and reducing fire and pollution hazards.Solar lamps recharge during the day. Automatic outdoor lamps turn on at dusk and remain illuminated overnight, depending on how much sunlight they receive during the day. Indoor solar lamps may or may not store power.