Environmental Engineering Reference
In-Depth Information
It is comforting to know that, at present, energy received by the surface of the
earth in one hour is approximately equal to the total energy consumption of the entire
world in a year. In other worlds, the amount of energy the surface of the earth
received is approximately ten thousand times the energy consumed by human so-
ciety. It means that if we were clever enough, we can depend entirely on solar
energy. For example, if an inexpensive and practical photovoltaic cell, that con-
verts 10 % of solar energy to electricity becomes available, it will only take 1 %
of the planet's land area to generate enough electric energy to satisfy the energy needs
of the entire world. If the electrical energy generated by a photovoltaic cell could be
effectively stored or used to electrolyze water into hydrogen and oxygen—or to
even more directly dissociate water by using a combination of photovoltaic cells—it
is not inconceivable that countries with large land masses could become energy ex-
porting countries, nor that hydrogen gas might then become a major energy source
as we enter the age of the “hydrogen economy”. If we learn to develop biofuel
more efficiently, or to invent efficient “artificial leaf”, photosynthesis might provide
enough biomass on earth to satisfy the need for liquid fuel and other chemical feed
stocks now provided by petroleum.
To make it possible for the world to achieve sustainable development, we must
do the following things to reduce our dependence on fossil fuel.
1. Increase of our energy efficiency, and improve the recyclable usage of materials.
2. Develop efficient renewable energy sources, e.g. photovoltaic cells, wind power
generators, geothermal, ocean current and thermal energy conversion, and vari-
ous biofuels.
3. Develop a new generation of safe nuclear reactors and appropriate waste dis-
posal technology and fusion reactors.
4. Examine our population policies and the way of life. We need to learn to live
simpler and more frugal lives.
5. Protect our living environment and ecosystems, and maintain biodiversity.
Although our current scientific knowledge and technology enables us to get it start-
ed, there are many challenging scientific problems awaiting a solution. For exam-
ple, in photosynthetic processes, most of the solar energy is stored in the fiber plants
rather than carbohydrates. Although the production of alcohol from sugar cane or
corn has been effective and successful, the challenge lies in the effective production
of alcohol from fiber through hydrolysis and fermentation. For harvesting energy
from geothermal, ocean flow and thermal energy conversion, new engineering tech-
nologies need to be developed.
With concerted efforts, which include the development of various renewable en-
ergies, changes to our way of life and social structure, 40-50 years from now, we
could become largely free from the use of fossil fuels. We will be again like our
ancestors, directly reliant on the power of the sun; perhaps supplemented by new
generations of nuclear fission reactors or micro suns, in the form of fusion reactors.
But during the transition period of the next 30 years, especially before fusion
reactor becomes successful, while nuclear fission reactors still play a role, we
