How can solar energy be harnessed? Mention any two limitations in using solar energy. How are these limitations overcome?
Methods of harnessing solar energy:
Solar Cooker: Solar cooker is a simple device. It is composed of a rectangular box with a mirror at the top. The box has a glass cover. Mirror is kept in erect position so that reflected sunlight can go inside the box. Utensils are kept in the box. Glass cover on top prevents heat from escaping the box.
Solar Cell: A solar cell is also called photovoltaic cell. It converts solar energy into electrical energy. Electrical energy thus produced needs to be stored in inverters so that it can be used even during night.
Solar Furnace: Solar furnace is made of concave mirror. The heating device is kept at the focus of this furnace. Heat from sun is concentrated at the focus which helps in generating lot of heat.
Solar furnace can be used to heat water and steam generated by this process can be used to generate electricity.
Limitations of Solar Energy:
• Can be harnessed only at those places which get plenty of sunlight.
• Cannot be harnessed beyond certain latitudes.
• Cannot be harnessed during night.
• Current technologies are very costly.
Ways to overcome limitations: Batteries can be used to store electrical energy from photovoltaic cells. Cheaper technologies need to be discovered.
