Once again, while wandering on another social media site, I ran across a question that needed answering. This time, someone wanted to know why hydrogen was never mentioned as a renewable energy source. As I wrote a response to this individual, I realized that there is significant potential for confusion and incorrect thinking around all of these terms that are thrown around today for various energy sources.
Baseload Power – Power that is generated pretty much continuously. Electrical use goes through peaks and valleys over time periods, baseload is that minimum power level that is pretty much always demanded. Most utilities will define different baseload levels for summer and winter. This seems to be a concept our FERC chairman, Mr. Wellinghoff, does not grasp. Baseload power is usually generated by the least expensive source available to the utility, but supply must be highly reliable. The three sources most commonly used for baseload power today are coal, nuclear, and hydro. Some regions use oil.
Low Carbon (Carbon free) Energy – Those sources of energy that emit little or no carbon dioxide (CO2) in the generation of energy. There is significant disagreement over how to tally the carbon impact of each energy source. Usually, it depends on the agenda of the author of any given study. Most agree that all hydrocarbon sources are NOT low carbon energy sources. All others can be considered low/no carbon sources. This includes geo-thermal, hydro, nuclear, solar, and wind. There are several more under development that may be added to this list.
Reliable Energy – Energy sources that can be relied on for consistent power generation over long periods of time. These sources are frequently considered for baseload supply. This term is not used as frequently because in the developed world, energy reliability is inherently assumed. However, as we consider new energy sources, reliability becomes important. For this article, I will assume reliable energy must be available > 75% of the time. Reliable energy sources today are coal, nuclear, hydro, oil, natural gas, wood.
Renewable Energy – These are those sources of energy that are either easily regrown, or are constantly available. Renewable forms of energy include, ethanol, solar, wind, hydro, geo-thermal, wood pellets. Renewable energy is perhaps the most misunderstood phrase in the energy pantheon. Many people believe that renewable implies ecologically sound, sustainable energy. This is not the case. Ethanol and wood pellets both are sources of atmospheric carbon, both are also not sustainable in the long term. Ethanol is currently made using corn. This places food and energy production in direct competition for land and resources.
Sustainable Energy – Those sources of energy that can be used long term with minimal total impact on the environment and without depleting the fuel source. Most consider this the intersection of renewable and low carbon sources. Typically, solar, wind, and geo-thermal are considered sustainable energy sources. Arguments for nuclear, hydrogen, and hydro are also quite compelling.
I hope that by spending a few minutes reading these definitions, I have provided some clarity to these discussions.