November 4th, 2016
By Dr Jose Goldemberg
The following article is part of the SFG publication “Big Questions of Our time: The World Speaks”. To access the full publication please click here.
Renewable energy is obtained from resources that are naturally replenished on a human time-scale. In contrast, fossil fuels are exhaustible on the same time scale. All renewables originate in the Sun and will last as long as the Sun itself. Most of them, such as wind, waves, hydroelectric, solar thermal, and biomass result from the radiation incident in the Earth which is thousand times all our energy needs.
Furthermore, they are available in all continents in contrast to fossil fuels concentrated in a limited number of countries. However, the density of the solar radiation is very low and intermittent compared to fossil fuels. These are great challenges that are being solved.
Renewables represent today approximately 18 percent of all energy consumed in the world, half of which in the form of biomass which, in many developing countries, is the sole source of the heating and cooking needs of more than 2 billion people.
The other half (fuels and electricity) drive the devices that make our life comfortable such as automobiles, aeroplanes, motors and telecommunications.
Electricity production from solar photovoltaic systems as well as grid-connected wind turbines has been growing at an impressive rate. Between 1998 and 2008 wind electricity grew at an average rate of approximately 30%, while grid-connected photovoltaic energy grew by almost 40% “albeit” from a low base value.
Public policies can help the widespread use of renewables. Germany, for example, has a target of 50 percent renewables by 2050 and other countries, such as the United States and China, are moving in that direction.
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