Definitions of renewable energy vary but generally comprise energy sources which will last indefinitely from a human perspective. (There are no sources of energy which can actually be renewed – that would violate basic laws of Physics – and the concept of "renewable energy" has been criticised for the way its use has affected the way energy policy is debated and conducted). Energy sources considered "renewable" include solar, wind, wave, tide, hydro, geothermal, and biomass. Wind, wave and biomass are derived from solar energy hitting the Earth and providing energy for plants to grow, evaporating water to create rain, and creating winds, which create waves. Geothermal energy comes partly from the decay of radioactive isotopes of Uranium, Thorium and Potassium in the Earths core, and partly from the heat remaining in the core from the time our whole planet was red hot. Tidal energy is derived from the kinetic energy of the Moon's orbiting of the Earth and the Earth's orbit of the Sun, and has the effect that very slowly the Moon is moving further away from the Earth.
There is some argument about whether nuclear fission energy using breeder reactors which create more fuel than they consume, and nuclear fusion reactors using effectively unlimited elements as fuel, should be considered renewable.
Not all renewable energy is carbon-free, environmentally friendly, small-scale, or safe, and the word is often used politically to mean any non-fossil fuel energy source except nuclear energy. A more useful term would be "sustainable energy" (the term chosen by the late David MacKay for his excellent book Sustainable Energy Without The Hot Air) – energy which we can continue to use as much of as we need, without harmful consequences such as climate change, air pollution, and other environmental degradation, for the forseeable future.
Various schemes have been proposed for powering regions, countries or even the entire world using only "renewables". Some of these restrict choices even further by excluding hydro or biomass. Most of these plans are the offerings of anti-nuclear "environmentalist" organisations; those that have been published in the peer-reviewed literature and assessed by the IPCC have not been found to be satisfactory, especially for more ambitions mitigation plans such as those attempting to hold global heating to 1.5°C.
There are a number of articles about renewable energy on this site, including:
- Types of renewable energy - Solar, Wind, Hydro, Biomass etc
A list of all articles on renewable energy can be found here
Footnotes and references
- The Laws of Thermodynamics, which are as well-proven as Gravity, tell us that we cannot get energy from nothing, and that valuable forms of energy (such as electricity) inevitably degenerate into less useful forms (such as low-grade heat) - see for example this explanation at The Khan Academy
"Abandoning the concept of renewable energy",
Atte Harjanne, Janne M. Korhonen,
29 Dec 2018
(The full article can be downloaded from this
coauthor download link)
Renewable energy is a widely used term that describes certain types of energy production. In politics, business and academia, renewable energy is often framed as the key solution to the global climate challenge. We, however, argue that the concept of renewable energy is problematic and should be abandoned in favor of more unambiguous conceptualization.
Building on the theoretical literature on framing and based on document analysis, case examples and statistical data, we discuss how renewable energy is framed and has come to be a central energy policy concept and analyze how its use has affected the way energy policy is debated and conducted. We demonstrate the key problems the concept of renewable energy has in terms of sustainability, incoherence, policy impacts, bait-and-switch tactics and generally misleading nature. After analyzing these issues, we discuss alternative conceptualizations and present our model of categorizing energy production according to carbon content and combustion.
The paper does not intend to criticize or promote any specific form of energy production, but instead discusses the role of institutional conceptualization in energy policy.
- See Wikipedia article Nuclear power proposed as renewable energy