What is it?
Fossil fuels are responsible for driving one of the most significant technological developments in human history - The Industrial Revolution. 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, including sea-level rise, drought, and saltwater intrusion 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 mitigate climate change. They are integral in meeting the Paris Agreement's objectives, which intend 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 power is obtained from radiation emitted by the Sun
- Wind energy is obtained from the kinetic energy of air in motion
- Water - utilizing the kinetic energy of water in motion
- Hydropower is from the flow of naturally moving water, usually from rivers
- Marine energy from tides, waves, and ocean currents
- Geothermal energy from the 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 the 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 energy source is hotly debated. It is justified 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, 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 mainly 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 energy source is a topic of debate.
Disputed renewable energies should be discussed as a secondary point in your analysis while remaining critical.