What is it?
Fossil fuels are responsible for driving one of the most important technological developments in human history - The Industrial Revolution. Ever since the shift to mechanization in the early 19th century, fossil fuels, namely, coal, petroleum (also referred to as crude oil or oil), and natural gas have been the primary source of energy that powers the world.
Today, around 84% of the world’s energy is derived from these fossil fuels which have been formed over millions of years and will not be restored on the human timescale. Hence, these are not renewable and will be exhausted in almost a century.
The main concern with fossil fuels is the greenhouse gases, especially carbon dioxide, emitted. These gases trap the sun’s heat and have raised the earth’s average temperature by over 1°C since the 1800s. We have just begun to witness the catastrophic consequences of global warming accompanied by climate change which includes sea-level rise, drought, and intrusion of saltwater that have forced people to relocate.
Hence, there is an urgent need for “renewable” sources of energy i.e., sources that are naturally restored on a human timescale. More importantly, most of these are also clean sources of energy that do not emit planet-warming greenhouse gases and thus help in mitigating climate change. They are integral in meeting the objectives of The Paris Agreement that intends to limit the average global temperature rise below 1.5°C or at the most 2°C from pre-industrial levels.
The renewable sources of energy are:
- Sun or solar energy obtained from radiation emitted by the Sun
- Wind energy obtained from the kinetic energy of air in motion
- Water - utilizing the kinetic energy of water in motion
- Hydropower from the flow of naturally moving water, usually of rivers
- Marine energy from tides, waves, and ocean currents
- Geothermal energy from heat below the earth’s surface
- Bioenergy obtained from biomass and biofuels
- Wood and wood waste
- Municipal solid waste
- Biogas and landfill gas (methane)
- Wood and wood waste
- Hydrogen Fuel cells that convert chemical energy of hydrogen (combined with oxygen) into electricity
Caution: Although burning wood biomass for energy is considered carbon-neutral, its use as a clean source of energy is hotly debated. It is justified on the basis that the CO2 released on burning will be sequestered as new trees grow. But burning wood releases CO2 instantly and the time lag between sequestration and emission is usually high that elevating the risk of not meeting the Paris Agreement Targets.
Nuclear Energy is another energy form that produces zero emission. But its classification as a renewable source of energy is disputed. The fuel that is mostly used (uranium-235) is often considered ‘non-renewable’ and the radioactive waste generated is a long-term threat to the environment. Hence, the qualification of nuclear energy as a clean or green source of energy is a topic of debate.
Disputed renewable energies should be discussed as a secondary point in your analysis, whilst remaining critical.