March 26, 2016 by locu5amoenu5
First, industrial society was only possible because our species briefly had access to an immense supply of cheap, highly concentrated fuel with a very high net energy—that is, the amount of energy needed to extract the fuel was only a very small fraction of the energy the fuel itself provided. Starting in the 18th century, fossil fuels—first coal, then coal and petroleum, then coal, petroleum and natural gas—gave us that energy source. All three of these fossil fuels represent millions of years of stored sunlight, captured by the everyday miracle of photosynthesis and concentrated within the earth by geological processes that took place long before our species evolved. They are nonrenewable over any time scale that matters to human beings, and we are using them up at astonishing rates.
Second, while it’s easy to suggest that we can simply replace fossil fuels with some other energy source and keep industrial civilization running along its present course, putting that comfortable notion into practice has turned out to be effectively impossible. No other energy source available to our species combines the high net energy, high concentration, and great abundance that a replacement for fossil fuel would need. Those energy sources that are abundant (for example, solar energy) are diffuse and yield little net energy, while those that are highly concentrated (for example, fissionable uranium) are not abundant, and also have serious problems with net energy. Abundant fossil fuels currently provide an “energy subsidy” to alternative energy sources that make them look more efficient than they are—there would be far fewer wind turbines, for example, if they had to be manufactured, installed, and maintained using wind energy. Furthermore, our entire energy infrastructure is geared to use fossil fuels and would have to be replaced, at a cost of countless trillions of dollars, in order to replace fossil fuels with something else.
Sourced through Scoop.it from: thearchdruidreport.blogspot.co.uk