Today it’s somewhat controversial whether hydropower should be classified as a renewable source of energy. There are many schools of thought and qualification varies state-by-state. One argument against qualification is that most hydroelectric facilities were already built prior to adoption of renewable standards and policies by many states.[3] Another argument states that damming interrupts the flow of rivers and can harm local ecosystems and building large dams and reservoirs often involves displacing people and wildlife. However, unconventional hydropower using currents, waves, and tidal energy to produce electricity is less disruptive and qualifies as renewable.
U.S. Energy Consumption in 2011 by Energy Source is shown below.[4] As opposed to the previous figure, this chart breaks out the various energy sources that makeup renewable energy.
A closer look at the renewable energy component shows that solar, geothermal and wind are less than 2% of total energy mix of the U.S. (see following chart). Whether surprising or not, these renewables are not substantially reducing our thirst for fossil fuels.
Reasons for the lack of foothold of renewables include high cost to produce and use, location in remote areas, additional expenses to build power lines, lack of reliability to deliver power, 24/7, as and when needed (for e.g. nighttime and cloudy days reduce solar power and calm days reduce wind power, even droughts reduce the water available for hydropower).
To understand how these energy sources are used kindly refer to the following figure, which shows U.S.’s primary energy consumption by source and sector for 2010.[5] The electric power sector sits between source and sector because it holds a dual role of being both an energy consumer and an energy generator and by definition it is not a primary source of energy.
On the demand side, electric power generation is the major consumer of fuels (39.6%), followed by transportation (27.5%), industrial (23.3%), residential (11.8%) and commercial (8.7%) Electrical generation is primarily fueled by coal and natural gas and to a smaller degree by nuclear energy. Transportation is fueled almost exclusively by petroleum. Industry is a mixed bag of petroleum, coal and electricity. Here renewables are ranked fourth and only slightly below electrical consumption. Residential and commercial are somewhat similar in that they run by electricity and natural gas. From this it’s difficult to see a sector other than electrical generation that can truly benefit from and increase the usage of renewable energy. That is unless there is some paradigm shift in the way the U.S. consumes fuels.
