A Paragraph to Ponder

From the current issue of American Scientist - The Rising Cost of Resources and Global Indicators of Change by Carey W. King:

"Just like the population, as we have slowed the expansion of our energy infrastructure, it has also become older.  I have calculated a dependency ratio for U.S. electric generation equal to the fraction of total capacity that is older than a certain age (for instance, 40 years) divided by the fraction of total capacity younger than that same age.  We have never had an older fleet of power generation assets than today.  Since the 1970s, we have relied more and more on older power plants."