The energy crisis of the 1970s led to an astronomical rise in the price of oil. This perceived threat to the economic security of the industrial and other nations acted as a catalyst in propelling nations towards energy conservation, search for new sources and long term solutions. With a partial stabilisation of this position in the 80s, energy moved out of the core of human concerns. This was but a short reprieve, and the entire international fossil-fuel based infrastructure is once again threatened by a new set of unpredictable circumstances, including an exponential rise in the costs of energy, the shifting of energy markets and serious environmental concerns. |
The present energy use pattern is structured on the paradigm of ‘Armament Protected Consumerism’ which has caused the intensification, concentration and centralisation of power production. Its ecological consequences are no longer a local or a regional matter, but arouse worldwide concern. It brings even the remotest of geographical areas and the smallest of nations into the mainstream of energy and environmental imperatives. |
This presentation highlights the following:
Some orders of magnitude about the projected availability of diverse energy resources and their ecological and other limitations in satisfying a wide variety of energy needs in global terms; Environmental consequences of using non-renewable fossil-fuels, and the need for technological innovations to enhance their ecological acceptability; The problems of substitution in terms of available time scale and missing technological links; The role of Sun-related sources of energy.
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Table 1 shows the worldwide availability of different categories of energy resources:
Non-Renewable:
Conventional fossil-fuels such as oil, gas and coal [Sec. A (a), (b) & (c)]. Non-conventional fossil-fuels such as tar-sands, shale-oil and gas processed from coal etc [Sec. B (a), (b) & (c)]. The cumulative fossil-fuel resources of mankind including both the conventional and non-conventional, are of the order of 115,000EJ (where E=109) which is equivalent to about 2500 billion (109) tonnes of oil.
Non-Renewable but technologically extendable resources:
Nuclear-fission with potential of almost indefinitely extending the life of the available uranium and thorium through new technologies for fast breeder reactors and others [Sec. C (a)]. Fusion-power with indefinite potential due to the availability of deuterium and tritium in large quantities from hydrogen [Sec. C (b)].
Renewable Resources:
Solar light and heat and other sun-based resources such as wind, water and biomass [Sec. D (a), (b), (c) & (d)] Geothermal and tides [Sec. D (e) & (f)]
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Top Energy requirements The estimated total worldwide energy requirement in the year 1989 was about 325 EJ and this is expected to increase to between 1100 EJ to 1400 EJ by the year 2030. |
The estimated total worldwide energy requirement in the year 1989 was about 325 EJ and this, on the basis of the present trend, is expected to increase to between 1100 EJ and 1400 EJ by the year 2030. In other words, these resources will at best be adequate for the next 100 years. Table 1, Sec. A (a, b & c) shows conventional fossil-fuel resources as 80,000 EJ, of which oil and gas together constitute only 15,000 EJ (and the remaining 65,000 EJ is that of coal). At the projected rate of consumption these resources will not be available, in economic terms, much beyond the middle of the twenty-first century. |
Top Ecological consequences of the energy use pattern ‘E’ for Energy was the keyword in the 1970s, ‘E’ for Environment was the ’ word in the 1980s and ‘E2’ for Energy and Environment have become the buzzwords at the beginning of this century. |
The environmentally and socially disruptive consequences of the accumulating carbon dioxide, other pollutants and the depletion of the ozone layer have caused widespread climatic and physical damage to our life support system. Carbon dioxide (CO2), though making up only 0.028 per cent of the atmosphere, traps enough of the escaping heat to warm the earth. It has increased by about 25 per cent in the last 200 yrs. |
The environmentally and socially disruptive consequences of the accumulating carbon dioxide, other pollutants and the depletion of the ozone layer have caused widespread climatic and physical damage to our life support system. The expanding energy needs and mounting ecological constraints are limiting the reliance on the available fossil-fuels. The high-energy demands require a shift towards nuclear power, which in turn would make it necessary to shift nuclear energy at birth from the military sector to peaceful power generation. This would call for a continuous effort to increase its safety factors by many orders of magnitude. Many current technologies may need to be replaced. In the case of nuclear fission, through the widely used technologies of light water reactor (LWR) or pressurised heavy water reactor (PHWR), serious problems of radioactive pollution and processing of waste will need to be addressed. |
The carbon dioxide (CO2), though making up only 0.028 per cent of the atmosphere, traps enough of the escaping heat to warm the earth. It has increased by about 25 per cent in the last 200 yrs, from 218 parts per million at the beginning of the industrial revolution to 315 parts per million 30 years ago and about 360 parts per million today. |
Top Contribution by Fossil-Fuels By the year 2060 the total cumulative consumption of fossil-fuels, conventional (31,500EJ) and non-conventional (18,500EJ), would have reached a total of 50,000EJ. |
Each EJ of conventional fossil-fuels (taking average combustion pattern) releases through combustion 19.7 million tonnes of carbon dioxide into the atmosphere. By the year 2060 the total cumulative consumption of fossil-fuels, conventional (31,500EJ) and non-conventional (18,500EJ), would have reached a total of 50,000EJ. Oil and gas release 19.75 and 13.8 million tonnes of carbon dioxide into the atmosphere respectively. Similar figures for non-conventional fuel including energy required for processing, further increase the carbon dioxide released to 38.6 million tonnes for synthetic oil, 40.7 for synthetic gas and 47.4 for shale oil. |
Many studies report that about 60 per cent of the carbon dioxide thus released is retained in the atmosphere. Working on this assumption, if all liquid and gas fossil-fuel resources were to be used, over 500 Giga (109) tonnes of carbon as carbon dioxide would be released into the atmosphere and about 300 Giga-tonnes be retained in it. This would raise the present level of carbon dioxide (of 335 PPM or 700 Giga tonnes) by about 40 per cent. |
If the coal resources with carbon dioxide release per EJ of over 23 million tonnes were also to be consumed, it would raise the level of carbon dioxide by over 1400 Giga tonnes to about 3 times the present level. |
It is also reported that the doubling of carbon dioxide is the threshold we dare not cross. But at this rate we would have reached that point by the middle of this century. So, the maximum level of fossil-fuel energy (conventional and non-conventional) available to mankind is 50,000 EJ and not 115,000 EJ, as shown to be available in Table 1. |
Planting 1.1 billion acres of new forest can neutralise all the 2.9 billion tonnes of carbon that gets added to the atmosphere each year. This would mean increasing the world forests by 16 per cent at a cost of US$ 500 billion. |
Hansen of NASA, USA, in 1988, proposed to the Congress a tax on carbon-rich fuel, such as coal, to curtail carbon dioxide emission by 20 per cent and estimated that it would cost the US economy US$ 800 billion to 2.36 trillion. Planting l.l billion acres of new forest can neutralise all the 2.9 billion tonnes of carbon that gets added to the atmosphere each year. This would mean increasing the world forests by 16 per cent at a cost of US$ 500 billion. This should be shared, through some fair apportioning methods, by the entire world. At least 20 per cent of the carbon dioxide being added to the earth's atmosphere is due to deforestation alone, thus highlighting the role of the trees. |
We are therefore, confronted with the problem of planning our energy strategies in a manner so as to avoid environmental excesses in order not to cross the magical, possibly irreversible doubling threshold. In other words the processes of substitution of fossil-fuels with other non-polluting sources of energy must start before such a situation arises. To begin this process a system of energy accounting must be more widely implemented |
Top Energy Accounting A nation claiming a high rate of growth in terms of the GNP may exhaust all its mineral resources, desecrate its own and others' forests and convert vast tracts of fertile land into a desert, erode soil, pollute all its aquatic resources, destroy its wild life, and all this devastation will appear nowhere in the accounting process while the country will continue to record a rising GNP. Adequate accounting would flash warning signals that the economy is on an unsustainable course. A negative interest deduction from development, as a consequence of the deterioration in the stock of natural resources, should be made compulsory. If a barrel of oil is sold for US$ 60 for instance, the cost of prospecting, pumping and transporting, drilling for a barrel of oil, or another equivalent source of energy, should be excluded from this income of US$ 60 on a viable rising scale so that the portion of GNP representing the income earned from oil may be accurately represented in the accounting system. Similarly, reforestation should also be accounted for in this process. Only by including all such negative factors in social accounting can a sustainable society be developed. Through recycling of waste material, (a negation of the throwaway culture) energy costs and pollution could be reduced substantially. |
The globalisation of the consumeristic paradigm is also about transferring an anti-social value structure to the elites of the developing societies. Neglect of public transport systems and the promotion of the automobile as a status symbol are rapidly committing developing nations to identical development processes, making rational energy use unpopular and further increasing environmental degradation. These should be reversed through social action and a scaled tax penalty. This would place the responsibility and cost of environmental protection where it belongs. |
The Nuclear option Nuclear Fission The total worldwide resources of uranium are about 3.5 million tonnes, which can largely be made available at a cost of between US$ 75–200 per Kg. Further quantities could be extracted from other unconventional sources, such as the ocean, at a much higher cost of between US$ 600–1000 per Kg. The economically extractable world thorium resources are in the order of 1.2–1.5 million tonnes. One gram of 233U containing 2.56 x 1021 atoms releases 82.4 GJ or 22,900 KW hours of heat, which is equivalent to combustion of 2 tonnes of oil. Generation of such large volumes of heat from small quantities of uranium was considered most promising but the genes of that technology at birth produced the Hiroshima Bomb, and to this day nuclear energy has not been able to or is not being allowed to live down this association. Nations desiring self-reliance in nuclear energy have no options other than to acquire an isotope enrichment facility. They must either enrich uranium or obtain it from reliable sources. |
Nations desiring self-reliance in nuclear energy have no options other than to acquire an isotope enrichment facility. They must either enrich uranium or obtain it from reliable sources and then employ LWR (light water reactor) or produce heavy water and use reactors burning natural uranium as fuel. In real terms it means that through this process highly concentrated weapon grade material can also be produced. This brings to the fore issues of nuclear proliferation, its use as an instrument of domination or superpower pressures and stringent controls. In LWRs for each fissioning of the uranium about 0.4 atoms of plutonium is produced. For PHWRs the rate of conversion is higher and may reach up to 0.8. It is also possible to design reactors with a conversion ratio greater than unity, i.e. they produce more fuel than they burn in maintaining the chain reaction. Such reactors, popularly known as breeder reactors, are thus a very attractive proposition for countries with small uranium reserves. While the cost for such reactors is low, they involve mandatory reprocessing and handling of large quantities of plutonium 233. With the potentially available uranium, the life of the nuclear fuels can thus be extended almost indefinitely. A modern LWR is designed for a burn out rate of about 30,000 MWD/ton. Breeder and gas-cooled reactors have achieved above 130,000 MWD/ton.Used fuel elements and the decayed fission products are intensely radioactive and generate large quantities of heat. Therefore, if we follow the ‘once through system’ for uranium use, the contribution of nuclear power to the energy scenario is at best limited to 80–100 years; hence the merit of choosing this option becomes doubtful. If, on the other hand, through technological solutions we can recycle uranium and thorium, we can extend the life of the available resources to provide energy equivalent to 200 x 106EJ which can sustain upto seven times the present energy consumption levels for over a hundred thousand years. Thorium is also emerging as a potential nuclear fuel. It has the potential to reduce the amount of plutonium generated per gigawatt year by a factor of five against uranium fuelled reactor. Thorium oxide is a highly stable compound, more so than uranium dioxide that is used as a conventional nuclear fuel. Thermal conductivity is 10–15 per cent higher than uranium dioxide allowing heat to flow more easily from the fuel rods to the reactors. The melting point of thorium oxide is 500°C higher than uranium dioxide and gives the reactor an additional safety margin if there is a temporary loss of coolant. Using the thorium fuel technology, plutonium can be disposed off three times as fast as MOX at a significantly lower cost. The Role of Small Units The process of making the peaceful use of nuclear power available to hundreds of thousands of communities, factories and workplaces can best be served by installing small units (from 50 to 100 Megawatts) of electric power. About three times that quantity of thermal energy generated in the process can be used for a wide variety of applications, such as extraction of oil from tar sands, water desalinisation, purifying and cracking of water. The reactor fuel matrix can be adjusted to provide the right output for each work process. The units can be connected in a series for larger applications and modular factories built and transported to destinations. These are placed in deep containment structures and assembled. The fuel rod core can be supplied to a factory or a fuel station every 8–12 years. A fast breeder reactor can irradiate thorium oxide which offers a very high safety margin. Large savings can be affected in the electric energy transmission and distribution cost. Fusion Power D-D fusion is an attractive long term solution and this time scale can be further extended by using tritium of which the raw material is lithium, and in D-T reaction can provide 9 million times the total energy needs of the world. |
The other significant option is fusion power. The basic raw material for this is deuterium which is available in nature, as one part in 6700 parts of hydrogen. Its extraction is feasible and one gram in complete D-D fusion provides 96,000KW hrs. of power. With the estimated deuterium content of the oceans at 23 million tonnes, it will yield 2.2 x 1024 or 8 x 1012EJ of energy. This is over 25 billion times the present world consumption of energy and could go even beyond the life of the solar system. On the face of it therefore, it would appear that D-D fusion is an attractive long term solution and the time scale can be further extended by using tritium of which the raw material is lithium, and which, in D-T reaction can provide 9 million times the total energy needs of the world, according to current estimations.Fusion as an energy source lies way beyond our planning horizons because the missing technological links are still many. The recent programme for international cooperation in research and development of thermo-nuclear power within ITER may make it technically feasible soon. Then of course, there is the important consideration of how we substitute fusion energy, for the bulk of our needs, with thermal heat and distribute it to the millions of communities where 60 per cent of the energy required is for cooking alone. This is of special significance for most developing countries including China and India. Top Role of Sun-Based energy sources Table 1, Section D (a) and (b), shows that amongst the sun-based renewable sources of energy, the most significant are solar, thermal and photovoltaic. |
The estimated solar energy available is 93,000EJs (E=1018), whereas wind is only 4,000EJ and hydel 90EJ. This would mean that while other sun-based sources of energy can play an important supportive role, their availability, both in terms of quality and quantity, can provide only a very small proportion of our total energy needs. We have thus to rely on solar, thermal or photovoltaic sources. For instance, if we were just to take the major hot deserts of the world, it is estimated that 93,000EJs of energy can be collected. This could supply upto 300 times the estimated future energy needs of all mankind—on an average about 1300EJ per year by the middle of this century. |
A few tens of thousands of kms of the earth's surface can provide the entire needs of mankind for low intensity heat even at the present time. |
Apart from photosynthesis to grow biomass, solar energy has to be converted to some secondary source of energy, such as heat, light, bio-chemical or electricity. A few tens of thousands of kms of the earth's surface can provide the entire needs of mankind for low intensity heat even at the present time, whether it is through a thermal gradient in large quantities of water in solar-ponds or by direct collection through collectors. The generation of electricity with mechanical devices for conversion at an efficiency of about 3 per cent, through high temperature applications using tracking mechanisms or other technologies, is already becoming an economically acceptable solution. However, for quite some time the real large scale applications of solar energy will harness solar thermal radiation for non-electrical applications, such as heat for cooking whether through recycling of waste, direct use of biomass or solar heat, or in water heating, crop drying or other thermal applications. Technologies already exist to exercise many of these options. |
Wind Power We cannot design a world energy system totally based on biomass if our present energy use pattern and consumeristic life styles are to be maintained. |
Of the total solar energy intercepted by the earth, only about 40,000EJ is dissipated close to the surface of the earth. How much of this can be harvested without upsetting the ecological balance is not known, but one thing is clear— removal of more than a certain percentage of this energy will effect the climatic conditions, temperature and rainfall pattern globally and has thus to be avoided. Even if upto 10 per cent of this is available for interception, it may be enough to meet a substantial proportion of the present world energy needs of about 320EJ. Many authorities have expressed their opinion on the subject and according to some of them even this potential has been scaled down to about 100EJ. Then of course, there is the question of unpredictability of wind both in terms of availability and manageable intensity. It would, therefore, be fair to presume that wind energy, though reasonably extensive, within environmentally safe and manageable limits can only play a regional, peripheral or balancing role in the future energy scenario, and that also, in conjunction with other non-renewable or renewable sources.Hydro Power Similarly, in the case of hydropower, theoretical potential available for practical exploitation worldwide is no more than 90EJ per year. We are exploiting less than 15 per cent of this energy at present. Because of their negative ecological and social consequences large dams and hydel projects have become a major source of social dissent. To effectively use this potential wherever available the emphasis should be on mini and micro hydel systems. Biomass Of the 4 x 104 EJs of the energy of the sun reaching the earth, only about 3150EJs are naturally converted to organic biomass through processes of photosynthesis. About 38 per cent of this is produced in the oceans leaving about 2000EJ of terrestrial organic matter synthesis to take place on land. How much of this can be harvested by us, is of course a different matter. Even if we were to get 40 per cent (800EJ equivalent), it would be necessary to cultivate the entire surface of the earth. A substantial part of this has to be set aside for food and industrial production, like paper, and those chemicals which are directly dependent upon biomass inputs. This alone, on an average, needs about 300EJ and the best that we can get from the balance will be no more than 200EJ, which is less than two-third of the present total world energy consumption. In other words, we cannot design a world energy system totally based on biomass if our present energy use pattern and consumeristic life styles are to be maintained. Particularly in the case of countries like India and China, the goal should be to use a larger proportion of the biomass for the satisfaction of their thermal energy needs i.e. if they can keep pace by producing more biomass than they consume every year. Ecologically, the use of biomass does not, to any extent, increase the atmospheric carbon dioxide because any carbon dioxide emitted in the combustion of biomass, originates from the atmosphere in the first place. Integrated Energy Systems If all the sun-based sources of energy could be integrated into a system there would be a synergetic effect on its performance. Not only does one source support the other but it can increase reliability by many orders of magnitude, reduce storage costs and provide energy in diverse forms, such as gas, as also electrical, mechanical and thermal. This could help meet the energy needs of rural communities for a wide variety of applications. There are many such successful installations operating in India and in other countries, both as total systems and as hybrid sub-systems. The most urgent need is for technological inputs in developing systems for meeting the diverse energy requirements of millions of rural communities for food, habitat, education, health and employment. The creation of such an infrastructure could open up vast markets for new sources of energy in the developing world alone, while at the same time reversing environmental decline. The developed world is already committed to an energy infrastructure, an energy use pattern and its environmental fall out. Integrated energy systems would allow for a process to contain the damage being done to the environment and reduce its impact. The replacement of one source of energy by another is not just an isolated event, it implies change in an entire way of life, production techniques, social organisation, in fact the total transformation of the society. |
The replacement of one source of energy by another is not just an isolated event, it implies change in an entire way of life, production techniques, social organisation, in fact the total transformation of society. In the context of policies, supported by media blitz, meant to further accelerate consumeristic development in the developed world, and to launch the developing world on a similar path, effective utilisation of sun-based sources of energy through decentralised systems goes against the dominant trend. Yet from the point of view of energy availability and of the environment, there are few other options. Our only hope is to accelerate this process in the developing world. It is only through millions of decentralised energy systems that the pollutant and carbon dioxide neutralisation/absorption capabilities of the atmosphere, the waterways and the oceans can be harnessed to support sustainable human life-styles.Energy Substitution For every growth rate there is a substitution rate. The higher the growth rate, the shorter the period of time available before we double our carbon dioxide emissions. This means that non fossil-fuel capacities must be created. As an example, for every EJ of fossil energy used, we have to install 17,000MW of nuclear power plants or create 500 sq. Kms of photovoltaic capacity. In order to implement the existing development paradigm, we will be called upon to build 50,000 MW plants per year to avoid reaching the dangerous environmental threshold. But substitution has its own limitations. Solar energy or other diffuse sources cannot economically replace large power generation facilities. However, these sources can play a crucial role in the development of decentralised rural communities where a vast proportion of the world's deprived people reside. Major countries like India and China have their own diverse energy needs so substitution will have its own limitations. Our substitution policies have to take into consideration the available time scale of 20–30 years before we reach the outer limits of our rapidly declining environmental capacity. Top Conclusions The total annual world energy demand at present is of the order of 350EJ. On the present development path this is expected to reach 1100 to 1400EJ by the year 2030. The known deposits of oil and gas, 8000EJ and 7000EJ respectively in economic terms, are not expected to last very much beyond this period. Coal, with a worldwide availability of about 65,000 EJ, will be available for a much longer period of time, but brings about more serious ecological consequences which may reach dangerous threshold levels by the middle of this century. Hence many new technologies will have to be adopted to contain the environmental hazards. |
Nuclear fission through the use of present technologies, of light water reactor (LWR) or pressurised heavy water reactors (PHWRS), can only be relied upon as long as the known uranium resources last, but their use can be extended almost indefinitely through new technologies, such as fast breeder reactors. The proliferation issues can be contained gradually by using fuels like thorium. This would considerably reduce the problems of proliferation and nuclear waste. |
The renewable sun-based sources of energy offer other options that may satisfy many of our thermal and electrical energy needs. They also have the potential to satisfy the energy needs for poverty alleviation in backward rural areas. |
Top Table | Table 1: Estimated worldwide energy resources and carbon dioxide generation by fossil fuels
| | | Bil. (109) Tonnes of oil equivalent Resource | E (1018) J* Energy Value | Carbon Dioxide/Billion tonnes of oil equivalent Mil (106) tonnes | Carbon Dioxide for the entire resource Billion Tonnes |
| | A. | Non Renewable Fossil-fuels: | 1 | 2 | 3 | 4 | | a) | Oil | 180 | 8000 | 870 | 156 | | b) | Gas | 170 | 7000 | 570 | 124 | | c) | Coal | 1450 | 65000 | 1060 | 690 | | | | | | 970 | | B. | Non-renewable Unconventional: | | a) | Shale oil | 425 | 19000 | 2018** | 900 | | b) | Synthetic Oil | 150 | 7000 | 1800** | 270 | | c) | Gas | 200 | 9000 | 1830** | 360 | | | | | | 1530 | | C. | Non Renewable But Technologically Extendable — Unlimited | | a) | Nuclear Fission | 6340 × 1015 Wyr 200 × 106 | | b) | Fusion Power | 63400x1015 Wyr 2000 × 106 | | D. | Renewable: | | a) | Solar | 2080/Yr. | 93000/Yr | | | | b) | Wind | 127x1012 Wyr | 4000/Yr | | | | c) | Hydro | 28x1012 Wyr | 90/Yr | | | | d) | Biomass | 4.7x109 Wyr. | 210/Yr | | | | e) | Geothermal | 2.2x109 Wyr | 100/Yr | | | | f) | Tides | 2.2x106 Wyr | 1/Yr | | |
| *I. Dostrovsky and others. | **Including energy required for processing | | Fossil Fuel—Conventional—970 (+) Unconventional-1530 = 2500 Billion tonnes of Carbon dioxide |
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