Advantages and Need of Fusion
Potential advantages - Fusion has potential
advantages as a safe, sustainable and environmentally attractive source
of energy for electricity generation.
- The deuterium fuel extracted from water is an universally available and
essentially inexhaustible fuel supply. Tritium has to be manufactured from
lithium inside the reactor. Lithium is distributed in the earth's crust
and the known reserves would last for more than a thousand years if all
the world's electricity were to be generated by fusion. With the development
of advanced fusion reactors, operating at temperatures above 109
K, pure deuterium mixtures may be used in the future, and earth's fuel supply
would last for billions of years.
- No runaway reactions or large uncontrolled releases of energy are possible.
In the case of a malfunction the plasma strikes the walls of the reactor
and cools immediately.
- There is no chemical combustion products in a fusion reaction, and therefore
no contribution to atmospheric or water pollution.
- No long lived radioactive materials are produced. Radioactivity is produced
by neutrons interacting with the reactor structure, but decays rapidly with
the proper selection of low-activation materials.
- Fusion is appropriate for generating base-load electricity and producing
hydrogen in a sustainable, CO2-free energy mix.
The need for fusion - Energy supplies are
an essential requirement for economic growth and enhancement of life standards.
To sustain and increase the present rate of world energy use, according to expectations
for this century, there are only three large energy options available: solar
energy, fission with breeding, and fusion.
- Energy demand - In mid 2000 the world population reached
6.079x109 people (Total
Midyear Population for the World: 1950-2050) consuming energy at a total
rate of 13.345 TW (International Energy Annual
2001: Consumption - BTU), which corresponds to an average consumption
of 2.195 kW/person. The United States, with 4.63% of the world population,
consumed 24.90% of the total energy, at an average of 11.81 kW/person. By
comparison, Brazil, with 2.79% of the world population, consumed 2.26% of
the total energy, at an average of 1.779 kW/person. This gives just an example
of the large unbalance in the use of energy resources between the highly
industrialized and the developing countries, the situation being even worse
in the underdeveloped countries. It gives also a view of the dramatic demand
for energy in the near future, resulting both from the population growth
and the expected growth of the economy in the developing nations. The world
population in mid 2003 reached 6.302×109 people and should stabilize
at a little less than 10×109 people somewhat beyond 2050.
Assuming a relatively small increase in the average consumption, up to 3
kW/habitant (about one quarter of the USA consumption today), this gives
an asymptotic value of 30 TW.
- Energy supply - The world recoverable reserves of coal
are about 647 TWyear, of oil about 202 TWyear and of natural gas about 199
TWyear (January 2002 estimates: International
Energy Annual 2001: Reserves). Fossil fuels supply 85.5% of the world's
primary energy, hydroelectricity supplies 6.6%, nuclear energy supplies
6.5% and other sources (geothermal, solar, wind etc.) supply 1.4% (International Energy
Annual 2001: Overview). Maintaining this balance, even at the present
rate of energy consumption, the reserves will be depleted in less than 100
years. Taking into account the population growth and the expected growth
in the average energy consumption per capita, a considerable shortfall
in energy may occur in a few decades from now. Moreover, burning all
the fossil fuels in such a short period will cause serious damage to the
environment and possible shifts in the global climate.
- Long term energy options - Solar energy is irregular
and not uniformly distributed, requiring very large collecting areas and
major energy storage. Optimistic estimates indicate that solar energy could
provide somewhat less than 10 TW, about one third of the future energy requirements.
Installation of new nuclear fission with breeding power plants should
alleviate considerably the expected shortfall of energy, but this solution
would raise the problem of geological time-span nuclear waste disposal.
Fusion requires additional technical development to become an economically
acceptable energy source at the present time, which is true also for the
other two large energy options, but offers the best prospects as a long
term energy source. The fusion solution simplifies considerably the question
of energy availability, the waste disposal problem and the safety issues.
of the world energy use indicate that the demand for energy, by the
middle of the 21st Century, may significantly exceed the energy supplied
by conventional sources. The shortfall in energy becomes larger after
the depletion of fossil fuels, about 100 years in the future.
|Comment - The question of energy demand is highly
controversial. Maybe the world population will not grow at the expected
rate and we are persisting on Malthus viewpoint that the population demand
will always outrun the supply. Maybe a smaller, and controlled population,
could live in a pastoral society and in selected places using solar energy
during the lifetime of the Sun. However, it is quite certain that humanity
will not be able to conquer new frontiers and may stay imprisoned on Earth
if new, sustainable energy resources are not developed during the 21st
Technological spin-offs - Research in plasma
physics and nuclear fusion already resulted in technological advancements for
a variety of applications, notably in the areas of materials (processing, coatings,
new materials), industrial processes (waste disposal, welding) and new technologies
(plasma electronics, light sources, electric propulsion).
Plasma diagnostic instruments - Plasma and
fusion research has lead to many instruments and techniques, first developed
to diagnose plasma experiments but with a wide range of applications in other
areas. Magnets, lasers, tomographic and interferometric imaging, remote handling
and computerized control are presently used in biomedical applications among
others. Advances in numerical computation, modeling and computer networking
were in great part motivated by the need to solve the complex plasma problems
related to fusion experiments. In fact, the first large scale computer network
facility was established to study fusion plasma problems.