Primary energy is natural energy that has not been altered by humans. Fossil fuels are the most used primary energy sources, but they have negative environmental impacts and are not renewable. Alternative energy sources, such as nuclear, solar, wind, hydroelectric, and biomass, are being explored. The return on energy investment (EROI) is a factor in determining the viability of primary energy sources.
Primary energy is any energy that exists naturally and has not been changed into another form by human beings. Examples of primary energy resources include both renewable resources, such as wind and solar energy, and non-renewable resources, such as fossil fuels. When primary energy resources are processed in a power plant or other facility, they are transformed into secondary energy “carriers” or sources. These include fuel and electricity. Primary energy is a relevant topic for the statistical analysis of energy consumption because it determines the energy supply available for human activities.
As of 2011, the most used primary energy sources worldwide were fossil fuels such as oil, coal and natural gas. Fossil fuels produce a large amount of energy proportional to their unit weight, making them currently the most efficient choice for energy production. Problems with fossil fuels include their environmental impact – burning these materials releases a large amount of carbon dioxide into the atmosphere, which cannot be easily absorbed – and the fact that they are not renewable. Substances such as coal and oil are produced over millions of years by the decomposition of biological organisms. Human society draws on fossil fuels at a much greater rate than they can be renewed, making shortages inevitable.
Alternative energy sources have been increasingly explored as options as the supply of fossil fuels dwindles. Nuclear reactors generate energy from uranium, a primary energy resource that occurs naturally in the earth. Although nuclear power plants can generate large amounts of energy from small amounts of uranium, nuclear power still accounts for only a small percentage of world energy production due to environmental and safety risks, as well as political factors. Uranium is also technically a non-renewable resource, as it is not replenished into the earth at a rate high enough to counteract human use.
Solar, wind and hydroelectric energy are examples of technologies that draw on renewable primary energy sources, sources of energy that are constantly replenished by natural processes. Biomass is another example. Solar energy is sequestered in plants through photosynthesis, the biochemical process by which plants convert sunlight into energy. When burned, plants release this energy. Biofuels, solid or liquid fuels refined from plants, are secondary energy products that make use of this principle.
As primary energy sources such as fossil fuels become harder to harvest due to dwindling supply, a ratio known as return on energy investment (EROI) comes into play. EROEI is the ratio of the amount of energy gained from a primary energy source to the amount of energy expended to obtain it. If more energy is required to obtain a resource than can be obtained from it, then it is no longer economically viable to pursue that resource, as energy will be lost in the process. While EROEI has been criticized for oversimplifying the complex energy harvesting process, it remains a factor for industries and governments in determining how to economize energy use and invest in various primary energy sources.
Protect your devices with Threat Protection by NordVPN
