Energy for a sustainable world - Environment and Development: A Global Commitment

THE concept of sustainability is a highly complex one, particularly where energy matters are concerned. We can only hope to approach anything like absolute sustainability by the use of renewable energy resources such as hydro-electricity; but even hydro-electricity involves problems such as the silting up of dams or the secondary environmental damage dams can cause, which makes it less than a hundred per cent sustainable.

On the other hand, some fossil fuels, such as coal, are quite abundant and evenat their present rate of consumption will last for several centuries, when other sources of energy might become available.

The Report of the World Commission on Environment and Development (1987) defined sustainable development as development that "meets the needs of the present without compromising the ability of future generations to meet their own needs". And this, perhaps, contains the hint that we need to introduce the notion of "depletion rates" into any discussion of sustainability. This opens the way to the establishment of compromises between what is desirable in principle and what is practical in terms of the realities of everyday life. Such compromises are unavoidable when a choice has to be made between preserving resources and the needs of survival and development.

If energy use were to be considered in conformity with the strict definition of sustainable development, this would mean that man should rely exclusively on renewable sources or energy. This was the case before the industrial revolution, when fuelwood, used in a renewable fashion, was basically the only source of energy.

With population growth and increased demand for energy, however, exhaustible fossil fuels came into use and became the predominant energy source. In the industrialized countries today, fuelwood represents less than one per cent of total energy consumption, the remaining demand being met basicaly by fossil fuels--coal,

This is clearly an unsustainable form of development, since the depletion of existing reserves of fossil fuels is proceeding at a fast pace and will certainly "compromise the ability of future generations to meet their own [energy] needs."

Depletion, and eventual exhaustion, of stocks of fossil fuels are not the only problems. Their use entails other problems which affect the sustainability of the system in which we live--the emission of carbon dioxide and other gases is the major cause of atmospheric pollution and global warming and thus poses a threat to the way of life of future generations.

In the less developed countries, fuelwood still represents an appreciable fraction of total energy consumption. If this resource were properly managed, by the systematic planting of trees to replace those cut down, it could become an inexhaustible energy source. This is far from being the case and wer are witnessing intensive deforestation which is consuming more than ten million hectares of forest--mainly tropical forest--every year. The problem is most acute in Africa, but is also very significant in south-east Asia and Latin America.

On a worldwide scale, only hydro-electricity can today be considered a sustainable energy resource--it cannot be depleted and it does not produce greenhouse gases. However, only ten per cent of the total energy used in the world comes from this source and, although the potential of existing untapped sites is considerable, they are unevenly distributed around the world.

Three approaches can be adopted to attain energy sustainability:

* extend the life of existing fossil fuels as much as possible by wise use;

* increase the use of other, little-used renewable energy sources such as wind power, solar thermal power, solar thermo-electric power, photovoltaics and biomass;

* increase the use of nuclear power.

Before the two oil crises of the 1970s, growth in energy consumption, based on the use of fossil fuels, seemed to be part of the way of life of developed countries and an example to be copied and a goal to be attained by all. The projection of future energy consumption reflected those expectations and predicted a sustained growth of at least three per cent a year, which meant that total energy consumed would quadruple in less than fifty years.

The two oil crises led to a re-examination of the situation and to moves to reduce what was seen as a dangerous over-reliance on oil. Two major energy studies were conducted during the 1970s--one by the Energy Research Group, Cambridge, England, for the World Energy Conference, the other by the International Institute for Applied Systems Analysis, Vienna. Both studies had one long-term objective in common--to shift from oil to more abundant energy resources such as natural gas, coal and nuclear energy while maintaining a significant growth in energy consumption.

Their approach was to estimate future energy demand on the basis of assumptions about future demographic and economic trends, to make historical correlations between such trends and energy demand, and to match this demand to a new mix of energy supplies. However, the scenarios they produced had the defect of projecting a perpetuation of the energy consumption imbalance between the developed and the developing world and thus of implying containment of the legitimate development expectations of the less developed countries.

In 1988, in his book Energy for a Sustainable World, the author of this article explored the possibilities of modern, energy-efficient technologies for meeting the energy needs of the world population in the year 2020. This study concluded that widespread use of new technologies could enable people in the developing world to attain a level of amenities comparable to that of the countries of Western Europe in the middle of the 1970s and the industrialized countries to reduce their per capita energy consumption by almost half. Taken all together he foresaw total energy consumption in the year 2020 remaining approximately the same as in 1980, but with a much higher level of comfort for the great majority of the world population.

Unfortunately, this projection did not really correspond to a sustainable situation because fossil fuels still represented the great majority of the energy needed and carbon dioxide emissions would continue to poison the atmosphere significantly. It did, however, demonstrate that it was possible to stabilize energy consumption at existing levels while extending considerably the life of fossil fuel resources.

A more recent study by R.H. Williams, of the Center for Energy and Environmental Studies, Princeton University, published in 1989, is more optimistic about the possibility of greater use of renewable fuels which evolving technologies seem to be making both feasible and economically viable.

More efficient methods of using fuelwood and of converting other biomass fuels (basically vegetation and crop residues) into electricity through gasification and the use of modern gas turbine generators, are rapidly being introduced. The conversion of sugar-cane into ethanol as an energy source for electricity generation is gaining ground and there are important new developments in wind, solar thermo-power and photovoltaics.

Re-examination of all these possibilities in the William study led to the conclusion that by the year 2025 renewable energy sources could account for more than half the energy used in developing countries.

NUCLEAR

OPTION

Finally, we have to consider the possible contribution of nuclear energy to the establishment of a sustainable world energy system. Nuclear energy does not emit carbon dioxide and with the development of breeder reactors sufficient nuclear fuel for the operation of thousands of nuclear power plants is guaranteed for centuries to come. Here theoretically is an ideal sustainable energy source.

The problem with nuclear energy lies elsewhere. Even with the use of the most advanced technology, accidents do happen, as the Chernobyl disaster so tragically demonstrated. In addition, there seems to be no solution to the problem of disposing of radio-active waste in a manner compatible with maintaining a "clean" environment. These problems, coupled with the danger of nuclear proliferation for military purposes, make the nuclear solution unacceptable to public opinion in many countries.

JOSE GOLDEMBERG, of Brazil, was formerly rector of the University of Sao Paulo, where he still holds a professorial chair, and is currently his country's Minister of Education. The author of many papers and books on nuclear physics and energy in general, in 1991 he was co-winner of the Mitchell Prize for Sustainable Development.

COPYRIGHT 1991 UNESCO
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