A few years ago, the country’s electricity production depended mainly on coal-fired super-thermal power plants where each group could generate up to 4,000 to 5,000 MW. The electricity produced would then be fed into the national grid for general distribution. There are several thermal power stations of this type across the country. In factories like these, coal is burned to produce heat, which then boils water, generating superheated steam. This steam would pass through a turbine, connected to a generator. Finally, the electricity produced would be routed to the switchyard for transmission to the electricity network. In some factories, petroleum or natural gas are exploited to replace coal. However, coal, oil and gas, all three, are dwindling.
The combustion of coal, oil and natural gas is accompanied by waste combustion gases, which are harmful to the environment because they contain toxic chemicals. In addition to polluting the environment, up to 60% of heat is released into the atmosphere, contributing to increased levels of global warming. About a ton of CO2 is emitted by MWh (Megawatt-hour) of energy. This means that a 2000MW super thermal power plant would generate 2000 tonnes of CO2 every hour or 48,000 tonnes of CO2 everyday. The thermal power plants have an installed capacity of 234 GW, of which 124 GW comes from coal-fired power plants. This can release up to 2,976 thousand tonnes of CO2 per day in the atmosphere.
Schematic diagram of a power plant based on solar photovoltaic energy – Totally pollution-free
There are several sources of renewable energy that nature provides in abundance. Several countries have already planned to take measures to limit the damage. Many countries have decided to go for large-scale solar and wind power plants and replace the old Super thermal plants.
At present, solar power generation in India is 40.09 GW. Contributions from Karnataka (7.1 GW), Telangana (5 GW), Rajasthan (4.4 GW), Andhra (3.47 GW), Gujarat (2.654 GW) and the rest of the other states are important. The renewable energy target by 2022 is 175 GW, of which 100 GW is for solar power, of which 40 GW is reserved for grid-connected solar power on the roof and off-grid. In addition to this, work is underway to set up several ultra-mega solar power plants on the PPA model in many states with private sector investment.
To cope with fluctuations in solar and wind power generation that vary with time and season, large-scale energy storage systems are installed with ultra-mega solar / wind farms for network stability.
The use of renewable energies not only replaces conventional energy, but also reduces it by up to 40%. This is because solar and electric systems are more efficient than conventional fuel-based systems.
The improvement in efficiency is of the order of 50% of traditional systems. The use of renewable electrical energy is 80% efficient compared to fuel-based combustion systems, which are only 40% efficient. No fuel can be used in crude form. It must be treated before use. Then it must be transported to the point of use. It takes a lot of effort and energy.
Converting to renewable energy can create several million more permanent full-time jobs than the jobs lost. Among renewable energy sources, the use by 2050, according to a study, should be around 30,000 TWh by solar energy, 9,100 TWh by wind and 800 by hydropower. The contribution of other forms such as waves, geothermal energy, tides, etc., would not be significant.
By: Challapalli Narayan Rao is a former scientist with Nuclear power Corp. ; former project engineer, NDDB; former NIC Senior Technical Director; former advisor, NGO ASA; currently acting as IT consultant, MP Pollution control board.