The Substitution Approach: Alternative Energy
The burning of fossil fuels is an extremely efficient and economical
method of producing energy. The sun’s heat and the weight of Earth’s
crust have combined over hundreds of millions of years to concentrate a
tremendous amount of energy into every barrel of oil, bucket of coal, or
cubic metre of natural gas. As a result, the burning of these fossil fuels is a
very efficient way to produce energy. In addition, the costs (not including
the negative externalities) of extracting and refining these fossil fuels are
relatively low. The combination of these two factors results in a large
economic advantage for fossil-fuel-based energy (sometimes called
carbon-based energy) relative to non-carbon alternatives. It is therefore
no wonder that roughly 80 percent of the world’s energy is produced by
burning fossil fuels.
The substitution approach to reducing GHG emissions is difficult because
it requires making a substitution away from a low-cost and efficient
energy source on an immense scale. In order to reduce the world’s annual
GHG emissions by 90 percent (even if we assumed that total energy
consumption was held constant), it would be necessary to expand by
many times the amount of energy currently being produced by
hydroelectric dams, nuclear reactors, and renewable power sources such
as solar and wind. These alternative sources of energy have their own
limitations, however, and in most cases it is unlikely that large-scale
expansion can be readily achieved.