Solar Energy
 

We've used the Sun for drying clothes and food for thousands of years, but only recently have we been able to use it for generating power.
The Sun is 150 million kilometres away, and amazingly powerful.
Just the tiny fraction of the Sun's energy that hits the Earth (around a hundredth of a millionth of a percent) is enough to meet all our power needs many times over.
In fact, every minute, enough energy arrives at the Earth to meet our demands for a whole year - if only we could harness it properly.

How it works

There are three main ways that we use the Sun's energy:-

Solar water heating , where heat from the Sun is used to heat water in glass panels on your roof.This means you don't need to use so much gas or electricity to heat your water at home.
Water is pumped through pipes in the panel. The pipes are painted black, so they get hot when the Sun shines on them. This helps out your central heating system, and cuts your fuel bills.
Solar heating is worthwhile in places, where you get lots of sunshine.

Solar Furnaces, use a huge array of mirrors to concentrate the Sun's energy into a small space and produce very high temperatures.
Solar Cells (really called "photovoltaic" or "photoelectric" cells) that convert light directly into electricity.
In a sunny climate, you can get enough power to run a 100W light bulb from just one square metre of solar panel.
This was originally developed in order to provide electricity for satellites, but these days many of us own calculators powered by solar cells.

Solar cells provide the energy to run satellites that oribt the Earth. These give us satellite TV, telephones, navigation, weather forecasting, the internet and all manner of other facilities.

Advantages

  • Solar energy is free - it needs no fuel and produces no waste or pollution.
  • In sunny countries, solar power can be used where there is no easy way to get electricity to a remote place.
  • Handy for low-power uses such as solar powered garden lights and battery chargers

Disadvantages

  • Doesn't work at night.
  • Very expensive to build solar power stations. Solar cells cost a great deal compared to the amount of electricity they'll produce in their lifetime.
  • Can be unreliable unless you're in a very sunny climate. In the United Kingdom, solar power isn't much use except for low-power applications, as you need a very large area of solar panels to get a decent amount of power.

Highlights

There are about 300 clear sunny days in a year in most parts of India. This is equal to over 5,000 trillion kWh/year, which is far more than the total energy consumption of the country in a year.
  • The daily average solar energy incident over India varies from 4-7 kWh/m2, depending upon location
  • SPV systems have found applications in households, agriculture, telecommunications, defence, and railways among others. In the last two decades, the cost of PV has gone down significantly, increasing affordability for dispersed rural applications
  • Costs are expected to reduce further thus creating more demand
  • About 66 MW aggregate capacity (about 10,80,000 individual PV systems and power plants) have been installed for various applications. In addition, PV products of 55 MW aggregate capacity have been exported
  • Under MNES's PV programme, around 8.20 lakh systems have been installed - aggregating to about 29 MW. This includes 5,09,894 solar lanterns, 2,56,673 home lighting systems, 47,969 street lighting systems, and 5,000 water pumping systems. About 3.97 MWp of aggregate capacity of stand-alone and grid-interactive PV power plants have been installed as on March 31, 2003. These include State's own programmes also.
  • MNES is implementing two major schemes for the deployment of stand-alone PV systems in the country:
  • Lighting systems, stand-alone power plants and other specialised systems, implemented mainly through SNAs/departments/corporations, 'Aditya' solar shops operated by Manufacturers' Associations and NGOs
  • Water-pumping systems for agriculture and related uses, implemented through IREDA and SNAs
  • West Bengal, Rajasthan, Uttaranchal, Chattisgarh, Ladakh, Lakshadweep Islands, Andaman and Nicobar Islands and the North-eastern states are prominent regions where SPV solar home systems and power plants are in demand
  • About 3600 remote villages and hamlets have been electrified with SPV systems and power plants. Out of these 915 remote villages have been electrified during 2001-02 and 2002-03

Aims and Targets

An all India SPV programme to develop cost-effective PV technology and its applications for large-scale diffusion in different sectors, especially in rural and remote areas is under implementation by MNES. Major components of PV programme include:

  • R&D
  • Demonstration and utilisation
  • Testing and standardisation
  • Industrial and promotional activities

   Courtesy:  MNCS(Ministry of Non-conventional Energy Sources)  http://mnes.nic.in