The short answer to this question is because we have to since fossil fuels are not going to last forever.

Currently, electricity is generated using the following methods:

  • Coal: This is the most popular method of generating electricity. What you do is burn coal which produces heat which is used to convert water to steam. The steam, in turn, spins a steam turbine which drives an electrical generator and produces electricity.
  • Hydro: Hydro power plants work by converting water’s potential into electrical energy. Hydro power plants work in conjunction with dams that hold back water, thus creating a large reservoir. When electricity has to be generated, water is released form the dam. It flows under the effect of gravity, which converts its potential energy into kinetic energy. The water then strikes a turbine and spins it, which drives an electrical generator and produces electricity.
  • Renewable: There are many sources of renewable energy and they generate electricity in different ways. The primary sources of renewable energy are: wind, small hydro projects, bagasse co-generation, solar, biomass power & gasification, and waste to power.
  • Natural gas:Natural gas power plants are similar to coal-fired thermal plants. However, the only difference is that instead of burning coal, natural gas is burnt for producing heat.
  • Nuclear:Nuclear power plants are similar power plants in that they heat water and convert it to steam, which in turn spins a steam turbine which drives an electrical generator and produces electricity. However, in the case of nuclear power plants, the heat required to convert water to steam is produced by the nuclear fission reaction. The fuel for nuclear plants is highly enriched uranium (U-235) which is one of the few elements that can undergo induced fission reaction when a neutron is fired into its nucleus. A pound of U-235 produces the same amount of energy that burning a million gallons of gasoline does.
  • Oil–Oil power plants are similar to coal-fired thermal plants. However, the only difference is that instead of burning coal, oil is burnt for producing heat. A diesel generator (popularly called DG) is a type of oil power plant and burns diesel to produce electricity. It is very popular because it is available in small capacities and is also portable. Wherever reliable power is required and the grid is unavailable or unreliable, DG is used as a reliable power source.

As of December 31st 2013, the various sources of electricity contributed to the total electricity generated in India as per the pie chart above. Some observations about the pie chart are as follows:

  • Coal is the most popular source of electricity contributing 59% of the total electricity generated.
  • Hydroelectricity comes contributing a healthy 17%.
  • Renewable energy contributes 12% of the total electricity generated. Wind energy contributes a large part of this electricity.
  • Nuclear power, despite all the promise that it holds and the talk that surrounds it, contributes a meagre 2%!




Coal Based Thermal Power Plants


Is available in India, but some of it has to be imported

Hydroelectric Power Plants


Plenty in some places but not enough or not at all in most other places

Natural Gas Based Thermal Power Plants

Natural Gas

Is available in India to some extent, but most of it has to be imported

Nuclear Power Plants

Enriched Uranium

Has to be imported

Diesel Based Power Plants


Is available in India to a small extent, but most of it has to be imported

The above table shows the availability status of fuel for each of the electricity generation methods. As can be seen, the situation is not great as of today, and is likely to get bleaker in the future.

India has plenty of coal reserves and the actual numbers are specified in the table below:



Total Reserves

276.81 billion tonnes

Proven Reserves

110 billion tonnes

Extractable Reserves

55 billion tonnes

Out of the extractable reserves, only 5 billion tonnes are good quality reserves. The remaining – 50 billion tonnes or 90% – are of not-so-good quality.

The yearly consumption of coal from 1990 to 2011 is shown in the table below.


Consumption (million tonnes)

Change (%)



































































The average compounding YoY growth in coal consumption is ~ 5.5%. Assuming that the consumption keeps growing at this same rate, India’s proven coal reserves will last for only 45 more years! And India’s extractable coal reserves will last for only 35 more years!However, it is widely accepted that the consumption will grow at a faster rate, which means that the coal reserves will last for fewer number of years. Therefore, some alternatives need to be found.

The above figure shows the electricity production in India from 1985 till 2012. As can be seen, India’s electricity production is five times what it was in 1985. The average compounding YoY growth is ~6%.This is consistent with the coal consumption figures, the increase in which has supported most of this growth; the remaining growth has been supported by growth in electricity generation from other sources.

However, it is quite clear that rate of growth in electricity generation capacity hasn’t been sufficient because there are 400 million people in India today without access to electricity; around 90,000 villages are not connected to the grid. In areas that are connected to the grid, there is regular load shedding since there is energy deficit as well as power deficit, which are to the tune of ~ 10% and 12% respectively.

Moreover, the demand for electricity is expected to grow at a faster rate – 8% to 10% – in the future as more and more parts of India get urbanized and per capita consumption of electricity increases which is a natural consequence of growth and affluence in developing countries. So India will have to add electricity generation capacity at that rate at 8% to 10% at the very least. If India wants to reduce the number of people without access to electricity, it will have to add electricity generation capacity at a faster rate. If India has to allow for the increase in the per capita consumption in electricity, it will have to add electricity generation capacity at an even higher rate.

How can it be done? That is the million dollar question.

Historically, Coal India Limited (CIL) had monopoly rights for extraction of coal. (Government of India tried to privatize coal production but it resulted in the coal scam, popularly called as Coalgate, in March 2012.) It has increased its production capacity over the years, but it has been able to satisfy the requirements. In 2011, CIL produced 550 million tonnes of coal whereas the requirement was 721 million tonnes. As a result, 170 million tonnes of coal had to be imported, some of it from as far as Australia! Importing from Australia to light up homes in India is preposterous to say the least.

There are two other problems:

  1. Coal based thermal power plants also require water. So even if CIL were to increase its production capacity to meet the entire requirements of India, electricity generation could still be limited due to unavailability of water, which is something that has happened many times in the past.
  2. Even if we assume that both and coal are available, India would need to build coal based thermal power plants, something that takes at least 3-4 years due to all the environmental clearances required. That is simply not good enough because a developing India needs power now! The same is true with other types of power plants as well, and nuclear power plants take even longer to commission!

So coal based thermal power plants cannot be the answer to meeting India’s increasing energy demands. Increasing hydroelectric power plants has its own severe limitations. India will have to import the fuel for all the other types of electricity generation methods, which is not a good idea at all. India, and any country for that matter, needs to be self-sufficient as far as energy situation is concerned.

Therefore, renewables is the only electricity generation method that has limitless potential. And among the renewables, solar holds the biggest promise because India is such a sun-rich country. That is why we need to go solar.

The advantages of solar energy are:

  • Solar energy (and heat) is free and unlimited! Just to put things in perspective, the total energy that is incident on the Earth’s surface in one hour is enough to power the entire world for one year!
  • Solar energy is non-polluting; it does not emit CO2 or any other gases, greenhouse or otherwise, that are harmful to the environment.
  • Solar energy based power plants require very little maintenance and last for many years.
  • Solar energy based power plants are scalable, i.e. they can be built from mW (milli Watt) to MW (mega Watt) scale. This is a feature that is unique to solar energy; no other power generation method can boast of doing it.
  • Solar energy based power plants can be built very quickly compared to other types of power plants; a 100 MW solar PV power plant can be designed, installed, tested, and commissioned in less than one year!

That being said, solar energy based power plants have some caveats as well:

  • There is huge capital expenditure involved. Although this has reduced considerably over the years, it is still quite high and the biggest impediment in the adoption of solar energy.
  • It requires a lot of space. This becomes an issue even in a country like India; it is a lot more severe in countries like Japan which have limited land space.
But even with the caveats, there is no doubt that solar energy alone has the potential to take care of our energy needs in the future. And the sooner we realize, the better off we will be.