Sunday, September 15, 2013 -
From Print Edition
There have been developments in the field of energy generation that promise to change the manner in which energy will be used in the future. One of these is the increasing use of shale gas and shale oil as sources of energy. Shale is a fine grained flaky sedimentary rock that can have oil or gas trapped within its crevices.
Shale gas only constituted about one percent of the total gas production in the US in the year 2000 but by 2010 this had increased to 20 percent and it is thought that by 2035, almost 50 percent of the total energy consumed in the US will be from shale gas. The world’s largest gas reserves are in China, while Pakistan too may be very rich in shale gas and shale oil. According to estimates published in June 2013 by US Energy Information Agency, shale gas reserves in Pakistan are a huge 586 trillion cubic feet (tcf) while the recoverable shale oil reserves are estimated at 9.1 billion barrels of oil. Pakistan should rapidly acquire technology to exploit these vast reserves.
While shale gas and oil is already becoming a major game-changer in the world energy scenario, the next major source of energy is going to be methane. The world’s reserves of methane are estimated to be greater than the total oil, gas and coal present on our planet. About three trillion tons of methane are trapped on sea beds in the form of ‘methane hydrates’ or within icy deposits in permafrost.
Methane hydrates exist as an ice in the form of methane gas molecules trapped in a cage of water molecules. Chinese and German scientists have discovered significant deposits under the sea off the coast of Taiwan, while Indian scientists have discovered methane deposits off the east coast of India (the Krishna-Godavari basin). Japan too has discovered deposits of 50 trillion cubic meters which could meet its energy needs for centuries; commercial production is expected to begin by 2016.
Korea is expected to begin commercial production of another field by 2015, which could meet its energy needs for another 30 years. In view of the Indian discovery, as well the presence of these deposits in the Gulf of Oman, it is likely that vast deposits may exist near Karachi and off the coast of Balochistan. These could meet the energy needs of Pakistan for the rest of this century and beyond. Indeed a survey carried out over a decade ago by the US indicated significant deposits of methane hydrates near Karachi but for some unknown reason this was not publicised.
Another area where rapid progress in the energy sector is being made is that of solar technologies. Our planet is bathed by the sun with a huge amount of energy (about 85,000 terawatts) each year. This is more than 5,000 times the energy that we consume from various sources each year. Clearly we should be relying on solar power instead of polluting our planet by burning fossil fuels.
Solar cells are, however, expensive to produce. Amorphous (‘nanocrystalline’) cells can be produced at a fifth of the cost of crystalline solar cells and they have achieved about half the efficiency of crystalline silicon-based cells. These efficiencies are increasing rapidly because of intensive research. A couple of years ago Sharp Corporation developed new types of compound solar cells with efficiencies of over 40 percent in the laboratory and of 35.8 percent in the field. This was achieved by using indium gallium arsenide. The Fraunhofer Institute of Solar Energy Systems in Germany claims to have achieved a world record in solar efficiency cells by attaining a solar cell efficiency of 41.1 percent.
One problem with solar cells is that they use only a part of the light spectrum, while the remaining part of the spectrum – which also produces heat – is wasted. Now Nick Melosh and co-workers at Stanford University have developed a new type of solar cell that also makes use of the heat produced by the sun light and converts it into electricity. The new technology (‘photon enhanced thermionic emission’, PETE) works at high temperatures, unlike currently available solar cells, and its utilisation of light and heat (produced by solar radiation) increases the efficiency of the new solar cells to above 50 percent, making them competitive to other forms of electricity production.
About half the total energy in the sun light lies in the infra-red region. Infra-red light is reflected by the earth’s surface even after the sun has set. This energy in the form of heat can, therefore, also be captured at night.
The most attractive form of solar energy involves the use of thousands of parabolic mirrors that can focus the energy from the sun on to boilers located on towers. The steam thus generated is used to drive turbines that generate electricity. About 300MW of power is being produced in this manner in the Mojave Desert near California for the last two decades. The world’s largest solar power plant, which will produce five giga watts (GW) of power ,has been installed at the edge of the Kalahari Desert in the Northern Cape Province of South Africa. The plant has the capacity now of 1GW of power which will be expanded to 5GW of power by 2020.
A power plant is being built in the south of France that represents one of the most exciting experiments ever undertaken by man in human history. The International Thermonuclear Experimental Reactor (ITER) aims to copy the way the sun and stars produce heat and light – through nuclear fusion ie lighter elements fusing to give heavier elements with the production of huge amounts of energy. The sun produces its heat and light in this manner and has warmed our planet for billions of years.
Can we do this artificially? We should know by the year 2025 if it works. The project involves fusion of two isotopes of hydrogen (deuterium and tritium) by heating them together at a temperature of 100 million Kelvin. If it works, we should get far more energy out than what we put into the system. The source of deuterium is sea water. It could represent the first ‘mini-sun on earth’ lighted by a material present in water.
The new government is now focusing on solving our energy crisis. A comprehensive plan has recently been prepared by the most eminent scientific body of our country, the Pakistan Academy of Sciences. This plan identifies the problems and presents viable short, medium and long term solutions for implementation.
It is time for action, and to rebuild our country. Those who have devastated our industries by establishing hugely expensive oil-based thermal power plants must be given exemplary punishments so that this never happens again.
The writer is the former chairman of the Higher Education Commission and currently president of Pakistan Academy of Sciences. Email: [email protected]