Definitions for Energy Tech Terms: Alternative, Renewable, Sustainable, and Green

In October, I posted a blog that asked the question, “Alternative, Renewable, Sustainable, and Green: What is the Difference?” I provided my thoughts on possible appropriate definitions, and I asked for reader feedback on what you think these terms actually mean.

In the interim, I asked the UNT Engineering Library staff to look up the formal definitions of these terms for the first lecture of my Alternative Energy Course at UNT. The following are my favorite results from this search.

According to the US Department of the Interior, “alternative energies are sources that are other than those derived from fossil fuels. Examples include: wind, solar, biomass, wave, and tidal energy.”

The US Department of the Interior also has a definition for renewable energy: “energy resources that are naturally replenishing but flow-limited. They are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time. Renewable energy resources include: biomass, hydro, geothermal, solar, wind, ocean thermal, wave action, and tidal action.”

The best definition we found for sustainable energy arises from the British: “energy that can be produced economically and safely for all time without impacting the environment and well-being of future generations.”

It was more difficult to find an official government-endorsed definition for green technology. Greentechnology.org says: “the field of ‘green technology’ encompasses a continuously evolving group of methods and materials, from techniques for generating energy to non-toxic cleaning products”. Unfortunately, this definition is not very satisfying.

It looks like I am not the only one that is confused. Even the US Department of the Interior concedes that renewable energy and sustainable energy are somehow different. However, it places wind, solar, biomass, wave energy, and tidal energy into both categories.

Therefore, I would like to propose that the designations I outlined for these terms in my post, “Alternative, Renewable, Sustainable, and Green: What is the Difference?” become the formal definitions for each of these energy technology words.