#GS-03 Science and Technology
- A solar cell is a semi-conducting device made of silicon and/or other materials, which, when exposed to sunlight, generates electricity.
- Unlike batteries or fuel cells, solar cells do not utilize chemical reactions or require fuel to produce electric power, and, unlike electric generators, they do not have any moving parts.
- It generates electricity by using sunlight to make electrons hop across the junction between the different flavors of silicon.
- India had committed to installing 1,75,000 MW of renewable energy by 2022 of which 1,00,000 MW 2was to be solar power.
- As of October 2022, 61,000 MW of solar power was installed, according to numbers presented in Parliament.
How Solar Cell works:
- A solar cell is made of two types of semiconductors, called p-type and n-type
- The p-type silicon is produced by adding atoms\that have one less electron in their outer energy level than does silicon such as boron or gallium.
- Because boron has one less electron than is required to form the bonds with the surrounding silicon atoms, an electron vacancy or “hole” is created.
- The n-type silicon is made by including atoms that have one more electron in their outer level than does silicon, such as phosphorus.
- Phosphorus has five electrons in its outer energy level, not four.
- It bonds with its silicon neighbor atoms, but one electron is not involved in bonding.
- Instead, it is free to move inside the silicon structure.
- When sunlight strikes a solar cell, electrons in the silicon are ejected, which results in the formation of “holes” (the vacancies left behind by the escaping electrons).
- If this happens in the electric field, the field will move electrons to the n-type layer and holes to the p-type layer.
- If you connect the n-type and p-type layers with a metallic wire, the electrons will travel from the n-type layer to the p-type layer by crossing the depletion zone and then go through the external wire back of the n-type layer, creating a flow of electricity.
Scheme for Development of Solar Parks and Ultra Mega Solar Power Projects
- Ministry: Ministry of New and Renewable Energy.
- Under the ‘Scheme for Development of Solar Parks and Ultra Mega Solar Power Projects’, a total of 57 solar parks of aggregate capacity of 39,285 MW were sanctioned until November-end.
- However, only solar power projects of 10,027 MW have been commissioned in these parks.
Reasons for Shortfall:
The key challenges in this scheme included;
- hurdles in acquisition of land with clear title;
- a “mismatch” in the time taken to set up a project and the infrastructure to route the power produced to the grid;
- “environmental issues” and
- the halt in economic activity due to COVID–
In recent years, the habitat of the Great Indian Bustard has been encroached upon by solar power projects, particularly by transmission lines that endanger the bird.