Read more about fossil fuels.
Fossil Fuels comprise the world’s primary energy sources, which are projected to continue to account for nearly 80% of the world’s energy consumption through 2040 (US EIA International Energy Outlook 2013). While fossil fuel formation is an ongoing process on Earth, new fossil fuel formation takes hundreds of millions of years. The rate at which fossil fuels are being extracted far exceeds the rate at which they are produced; hence they are classified as nonrenewable.
Nuclear power is the energy that comes from reactions which change the nucleus of an atom. Nuclear fission is an atomic reaction whereby one atom’s nucleus is split into two smaller nuclei, and energy is released. Nuclear fusion is an atomic reaction where two smaller nuclei fuse to form one larger one, energy is released in this reaction as well. The energy released is typically in the form of high energy radiation such as gamma rays and x-rays, which can be highly dangerous to living organisms when exposure is acute.
Nuclear Energy makes up about 8% of the world’s total energy. Nuclear energy is beneficial because there is an enormous amount of energy yielded from just a tiny amount of uranium- 235 in the initial reaction. Although nuclear energy is valuable due to its high yield, efficiency, and lack of greenhouse gas output, the technology required to produce safe nuclear energy is complex and controversial (Figure 11).
Learn how nuclear energy is generated from uranium.
The drawbacks to nuclear power production include the barium and krypton waste produced by the reaction (fission products) which is highly toxic to the environment as it continues to emit radiation. Of course, many things emit radiation, including rocks, soil, food, water, and air. However, not all types of radiation that we are exposed to are damaging.
Read more about electromagnetic waves from NASA's website.
Radiation can be classified by the Electromagnetic Spectrum (Figure 12), which defines different types of radiation according to its wavelength or energy. Wavelength is defined as the distance between successive crests of a wave. The longer the wavelength, the less energy is contained in the radiation. Thus, radio waves transmit very little energy, while gamma rays are powerfully energetic.
Visible radiation (or visible light, the solar radiation with wavelengths ranging between 400–800 nm on the electromagnetic spectrum) is the solar radiation absorbed by plants to stimulate photosynthesis. This radiation is typically not harmful to any life forms, including humans. Alternatively, gamma and X-rays, which are the most energetic, can be extremely harmful to the health of humans, plants, and animals. This type of radiation is harmful because it destroys the integrity of DNA molecules in living cells. Similarly, too much exposure to the sun’s ultra violet radiation can cause sunburn and skin cancer.
Because radioactive waste contains gamma and X-rays, it poses a problem both today and for future civilizations. Currently, most nuclear waste is disposed of in large cement containment vats at the facilities where it is created. Continuing to store this waste above ground poses security risks, such as damage from earthquakes, storms, or vandalism. It also requires future societies to maintain these storage facilities. Human error is also a concern when it comes to waste management of nuclear matter. An alternate option for the disposal of nuclear waste is to reuse the waste as fuel. This beneficial use of nuclear waste is currently being practiced with the use of breeder reactors in nations such as France, the United Kingdom, and Germany.
In the Energy and Ethics section you will explore the moral issue of energy availability to the poor and to future generations.
Another downside of nonrenewable energy sources is that they cause severe environmental problems, including climate change and air pollution, which pose a threat to humans, plants, microorganisms, and animals. Furthermore, nonrenewable energy sources are projected to be depleted in the foreseeable future (see Table 2). Therefore, for the protection of the environment and for ensuring the energy security and health of human societies, we must move away from our reliance on non-renewable energy sources and increase the use of renewable energy sources.