
Chapter 1
Why renewable energy?
At present, a growing population of over 7 billion people inhabits the planet. The
growth rate is expected to slow each year, however, a population of somewhere
between 7.5 and 10.5 billion people by 2050 is anticipated, according to the Popula-
tion Division of the Department of Economic and Social Affairs of the United Nations
Secretariat (2009). Natural gas, coal, and petroleum power plants are responsible for
over 65% of all electricity today. Many accept these conventional sources of energy,
also known as fossil fuels, as reliable long-term energy sources.
As the world’s population increases so does the world’ ...