Having a strong background in physics, this collection of words did not really resonate for me, so I pondered and researched this question extensively for the past several weeks.
Of course, we constantly see and hear this term bandied about without any thought for its accuracy or factual definition. The word "energy" is defined as a capacity, or ability, to do work, and is present in the forms of kinetic and potential energy. Plus, the word "renewable" is defined as something that can be renewed, or is capable of being renewed. So how does one rationalize any source of energy with the word renewable?
Well, the definition of renewable has adapted over time, partly from the lobbying of environmentalists and other interested parties, to include any energy source that is sustainable within a limited period of time. For this reason, many people accept that solar, wind, wave, geothermal, hydropower are all renewable, but nuclear, oil and coal are not. Perhaps the more exact term of "sustainable energy" should be enforced and "renewable energy" should be dropped.
Hydropower clearly meets the definition of renewable. With a process of water collecting in a reservoir due to precipitation, the controlled outflow driving turbines to generate electricity, and the eventual flow back to the oceans for evaporation to create rain clouds, clearly satisfies the definition of renewable. For solar or wind, it is harder to consider as renewable because once the photon packets or solar waves are intercepted and converted to electricity, they cannot be renewed. However, as the energy source is seemingly limitless, there is a justification to refer to these types as renewable.
Even accepting this creep in definition, there is an obvious case that nuclear should be among the list of sustainable energy sources. Depending on one's belief in the origins of certain fossil fuels, perhaps oil should be on the list as well -- yes, there are compelling thoeries why oil does not come from decaying dinasours.
The best approach to limitations of energy availability is to consume less. In the field of consumer electronics, designers and manufacturers strive to do more, or the same, while requiring less energy to power the product. My belief is that this approach is the fastest and more responsible way to conserve and prolong our energy supplies, whether they are "renewable", "sustainable", or otherwise.
My quest for a full answer is not complete, so I invite readers to post a reply or e-mail me at robert.newell@a4rec.com.
© 2009 Advocates for Responsible Energy Consumption
