I do believe that most everyone is familiar with the term "Energy Crisis", or has at least heard about it. To the casual observer, the terms "energy crisis", "peak oil", etc. would seem to insinuate that we are "running out of energy". It is somewhat bothersome when I am asked "Are we running out of energy?" or someone tries to argue "We have enough oil sands/oil shale/coal/etc.to last centuries". Even more irritating are the proposals to build new condensing (meaning no recovery of the waste heat) power generating plants, or the belief that we could continue on business as usual simply by seamlessly switching everything over to run on renewable energy.
My views on these perspectives came to fruition upon realization of the importance of the Second Law ofThermodynamics. Most of the general public is familiar only with aspects of the First Law of Thermodynamics, which states that energy is neither created nor destroyed. The first law fails to identify the quality of energy, only the quantity of energy; a joule of electricity is treated the same as a joule of heat, the heat of combustion of municipal solid waste is treated the same as a the heat of combustion ofgasoline, despite the fact that we cannot easily run our cars on municipal solid waste. Even more important than quantity of energy is its quality.
The sun produces about 365 yottawatts (365 x 1024 joules/second) of power through thermonuclear fusion. The fraction of this power reaching Earth is around 174 petawatts (174 x 1015 joules/second). In terms of only the raw number of joules per day,this is about equivalent to all of the conventional oil reserves, past and present, known to mankind, every thirty hours. So with all of these barrels of oil constantly raining down on us, how in the world could there EVER be an energy crisis?
The answer is that there is no "energy" crisis. There is an exergy crisis. Exergy is a measure of the quality of energy. Think of it like being stranded ona boat in the middle of the ocean. Dehydration generally sets in fairly quickly, despite the fact that the passengers of the boat are surrounded by water. What good is water when you can not drink it? What good is energy when you can not really use it?
The average human body at rest produces about 100 watts of power in the form of body heat. Why, then, can we not use our body heat to power up a100-watt incandescent light bulb? 100 watts of dilute HEAT is completely different from 100 watts of electricity, just as 100 kilos of lead is completely different from 100 kilos of gold.
EXERGY CONTENT OF VARIOUS FUELS BASED ON TYPICAL ELECTRICITY CONVERSION EFFICIENCIES.
As previously stated Exergy refers to the quality of energy. Modern human society requires an extremely high level ofexergy, a level of exergy so high that the only form of energy capable of supplying it is electricity. Electricity, when controlled as is done by humans, has the highest level of exergy of any form of energy. It can even be argued that the "advancement" of a society can be measured by its exergy needs. Agrarian societies rely on the sun, direct burning of firewood and other biomass, and motive powerfrom animals. These energy sources are of a much lower level of exergy than say the electricity guzzled by an urban industrial culture. I am expanding the official definition of exergy in thermodynamics by including such factors as "convenience of use". An automatic coffee machine powered by electricity is more convenient that building a wood fire in a cast iron cook stove just to heat up a kettleto make coffee.
Throughout human history, we have continuously moved towards forms of energy with higher and higher levels of exergy. Before the days of controlled fire, the only energy available to us was the energy in the food we consumed. Even in these days, however, it was surely known that meat yielded a higher level of energy per unit consumed than plant-based foods, hence...