The need of the hour is to reduce the dependence of thermal power plants on coal and natural gas by using green hydrogen. Electricity must be generated by renewable means, like solar energy, to break down water into its molecular constituents using electrolysis to produce hydrogen without any harmful by-products, explains ABHIMANYU JOON.
IN the last few days, 115 out of 135 thermal power plants in the country reported critically low levels of coal stock. According to the data with the power ministry, coal-based thermal power plants ideally should have coal stock for 21 days to ensure uninterrupted power generation. However, these plants have less than a week’s stock, which is rapidly shrinking.
A power crisis has the potential to jeopardise the struggling economy, which is trying to get back on track, supported by the rising volume of trade, as pointed out by the Union Commerce and Industry Minister Piyush Goyal.
Power generation and supply are vital for the social, economic and political stability of any nation. Apart from households, industrial units, agriculture and allied sectors, hospitals and nursing homes, educational institutes, and banks and stock exchanges are the key sectors dependent on electricity. Non- availability of power or disruption in supply can cripple a nation.
As pointed out by the union coal ministry, the low coal stock is owing to the delay in transportation from the coalfields caused by the heavy rainfall. But what about gas-based thermal power plants? Why are 31 out of 36 such plants on the brink of a shutdown and have turned into non-performing assets?
The root cause of the problem is the insufficient supply of coal and natural gas. Below-par domestic production and unaffordable imports from countries like Qatar, Australia, Indonesia and Russia have led to the drastic reduction in output from coal and gas-based thermal power plants.
If the situation persists, India could become hostage to a power crisis. But India faces a dilemma. If it decides to increase imports to replenish the depleting stocks of coal and natural gas, the per-unit cost of power generation will increase, creating cost-push inflation. While if the country decides to rely on domestic production, power outages would become a regular phenomenon, forcing industries to compromise their productivity and resulting in demand-pull inflation.
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Reduce dependence on coal and natural gas
The need of the hour is to reduce the dependence of thermal power plants on coal and natural gas. This can be achieved by taking a clue from the concept of green hydrogen, in which electricity generated by renewable means is used to break down water into its molecular constituents using electrolysis to produce hydrogen without any harmful by-products.
According to the performance audit report of the Comptroller and Auditor General of India tabled in Parliament in March 2018, a thermal power plant with 1,000 MW capacity requires an investment of Rs 5,000 crore. The chimney and the cooling tower, which condenses low temperature steam into water for recirculation, are among the costliest infrastructure besides the boiler and the turbine. If such a costly resource functions below capacity or stops functioning altogether, it would be an unbearable burden on the exchequer.
As per the US Department of Energy, 2.4 hectares is required to generate 1 MW of solar energy with horizontally laid out solar panels at ground level while vertically arranged panels, like on the walls of a skyscraper, would require only 1 hectare of exposed surface area to generate the same amount of energy. The cooling tower and the chimney, which are around 200 meters in height, provide an exposed surface area of 10 hectares and 2 hectares respectively.
There are, at least, three cooling towers and two chimneys in a thermal power plant. So, we are looking at the availability of 32 hectares of vertically exposed surface area per plant for mounting the solar panels.
Besides, the rooftops of the office building and the storage block within the complex of a thermal power plant can also be utilised to lay solar panels. Thus, approximately 19 MW of solar energy can be generated by utilising the available brick and mortar infrastructure of a thermal power plant.
A successful example of such a concept is India’s largest vertical solar power plant at DELL’s Bengaluru campus constructed by TATA Power Solar—120 KW of renewable electricity is being generated by solar panels mounted on one of the faces of the 11-storey 45 metre-high building.
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Electric suprerheated steam generator
There is an equipment utilised in the health care industry as well as in research labs known as electric suprerheated steam generator. This machinery utilises electricity to convert water into high-temperature steam, which can be used for sterilisation, experiments and power generation.
The idea is to involve the Institute of Plasma Research, Gandhinagar, to develop a customised electric superheated steam generator meant to be deployed at thermal power plants for generating the required quantity of high-temperature steam. This equipment will be installed in a parallel circuit bypassing the boiler-chimney arrangement and powered by a fraction of the solar energy generated in a thermal power plant as explained above.
Such a customised electric superheated steam generator would continue to work for 12 hours a day based on solar energy, keeping a thermal power plant functioning independently of coal. If the storage device, such as the battery, developed by TESLA—which stores solar energy during day time and puts it to use at night—is clubbed with solar panels and the electric superheated steam generator, the thermal power plant can function for almost 14 hours a day without any fossil fuel. At night, power can be generated in the conventional manner using coal or natural gas.
The immediate benefit of such an arrangement would be enhanced capacity of the thermal power plant as both solar energy as well as regular output of thermal power generation would be available.
Secondly, electricity generation will be uninterrupted along with reduction in air pollution. Third, the $22 billion spent yearly on import of coal, as mentioned in Economic Survey 2017-18, would be saved.
The reluctance of thermal power plants in investing in the above-mentioned arrangement citing lack of funds and expertise can be overcome by arranging financial help under the Green Climate Fund of World Bank or an investment made under International Solar Alliance. The manpower of Central and states’ nodal agencies responsible for renewable energy development can be put to use while technological partnerships with countries such as Germany and Japan, who have taken great strides in renewable energy generation and its optimisation, can be forged.
By adopting such a radical approach, we would be able to ensure energy security for the masses and set a model that could be adopted by other nations struggling with power crises.
(Abhimanyu Joon is a design engineer (mechanical – machine design) based in Vallabh Vidyanagar, Gujarat. He is associated with the Society of Automobile Engineers, Pune. The views expressed are personal.)