Based on the sound of the name renewable, a person might think that using only “renewable” energy is ideal–something we should all strive to use exclusively. But there are lots of energy sources that might be called “renewable,” and lots applications for renewable energy. Clearly not all are equally good. Perhaps we should examine the “Renewables are our savior,” belief a little more closely.
1. Renewables that we have today won’t replace the quantity of today’s fossil fuels, in any reasonable timeframe.
Figure 1, above shows the distribution of fuels used since 1965.
Other renewables, which includes wind, solar, geothermal and other categories of new renewables, in total amounts to 1.6% of world energy supply in 2011, according to BP. The light blue line is not very visible on Figure 1. (The blue line that is visible at the top is “Nuclear.”)
Biofuels, which would include ethanol and other types of biofuels, such as palm oil, amounts to 0.5% of world energy supply. Its orange line is not very visible on the chart either.
Hydroelectric, shown in purple, has been around a long time–since 1880 in the United States. It amounts to 6.4% of world energy supply. Its quantity is not growing very much, because most of the good locations have already been dammed.
In total, the three categories amount to 8.5% of world energy supply. If growth continues at today’s rate, it will be a very long time before renewable energy supply can be expected to amount to more than 10% or 15% of world energy supply. We very clearly cannot operate all the equipment we have today on this quantity of energy. In fact, it is doubtful that we can even cover the basics (food, water, and heat to keep from freezing) for 7 billion people, with this quantity of energy. Continue reading