A Dynamic Energy Mix
The types and amounts of energy used in the United States have changed over time in response
to technological discoveries, energy resource discoveries, relative energy prices, economic
conditions and social pressures.
The only constant is that the amount of energy used has been steadily increasing over time.
In the 1700's wood was burned as a fuel. Animals were used as means of transportation and power.
Water and wind were used to power simple machines. These forms of energy were abundant, reliable
Wood became the dominant source of energy because it was easily obtained, portable and could be
consumed on demand. Its use in space heating and power generation grew steadily until the late
1800's when coal assumed its place as the dominant form of energy.
In the early 1800's some of the first commercial coal mines were operating in several parts
of the country. Coal provided more heat per pound than wood and occupied a smaller volume, making
it a much more portable fuel. Steadily coal consumption climbed and in the late 1800's the amount
of energy produced from coal exceeded the amount produced from wood.
Industrialization, the use of coal to power machinery, and the use of coal in electric power generation
supported a strong demand for coal.
Oil and Natural Gas
The use of oil and natural gas in the United States was growing rapidly in the early 1900's and unlike
coal was not significantly slowed during the Great Depression. In the mid-1900s they became widely
used in space heating, electric power generation and as transportation fuels.
Demand for oil and gas grew rapidly and they each surpassed coal in importance in the mid-1900's.
Oil and gas were cleaner fuels that were much easier to handle in many applications.
The oil and gas industry enjoyed steady growth in demand for over 50 years. Then, in the early 1970s,
economic downturns and price manipulation attempts by producing nations caused significant interruptions
in demand growth. Growth resumed in the late 1970s and continued, almost uninterrupted, until the
financial crisis of 2008.
The commercial production of nuclear power began in the 1950s and began to increase rapidly in the early
1970s when a number of nuclear power plants began coming online.
Although the amount of nuclear power produced
has grown steadily, events like the Three Mile Island accident (1979) and the Chernobyl accident (1986)
have generated significant social pressures and safety concerns that have throttled the nuclear power potential.
Problems related to the secure disposal of nuclear waste materials have also been a problem.
Renewable Energy Sources
Renewable energy currently accounts for about 8.20% of the United States energy consumption.
Most of that comes from biomass and hydroelectric sources. Since 1995 the amount of energy
produced by renewable sources has increased by 15.9%.
||Percent Growth 1995 - 2009
||Percent of US Energy Supply in 2009
|Data Source: Energy Information Administration
The most rapidly growing renewable energy source since 1995 has been wind power. The implementation
of wind power has exploded with an increase of over 2000%. Although this is spectacular growth, wind
contributes less than 3/4% of the nation's energy supply.
Solar has grown over 55% since 1995 and the rapid fall in the price of solar panel capacity should
support future growth. Geothermal has grown nearly 27%. New technologies and higher fossil fuel prices
now make geothermal space heating projects cost competitive with fossil fuel units.
Renewable Energy Future
The future of renewable energy is very bright. The cost per BTU has been falling. Methods of integrating
them smoothly into buildings, vehicles and primary energy sources are improving. Climate change fears are
motivating governments to support renewable energy projects with grants, tax relief and other incentives.
Renewable energy projects almost always help the United States to become more energy independent. This is
because renewable energy projects are usually located close to where the energy will be consumed. This
decreases their environmental impact, decreases costs and gives governments incentives to reduce foreign dependency.
Unconventional Oil and Natural Gas
The energy future of the United States will also likely be heavily influenced by new technologies
in the fields of unconventional oil and natural gas. Procedures such as horizontal drilling and
hydraulic fracturing have enabled production from low permeability reservoirs that were unproductive
to marginal as recently the late 1990's. The availability of abundant, inexpensive domestic natural
gas will be a welcome injection into the United States economy.
Contributor: Hobart King
|This graph illustrates the history of energy use in the United States between 1775 and 2009. It traces the quantity of energy consumed in the form of wood, coal, petroleum, natural gas, hydroelectric power and nuclear in quadrillions of BTU. This allows the energy sources to be compared on a constant basis. Chart by the United States Energy Information Administration.
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