Approximately 70% of the total energy used in the United States is for the generation of electrical power. Electricity is the most versatile form of power and can be used for lighting, heating, communication, powering electronics, and running electrical motors. It is also the most versatile in terms of origin and can be generated by burning all forms of fossil fuels, burning biomass or garbage, capturing solar, wind, waves, or geothermal energy, or capturing waste heat from other processes.
Although man has been aware of the phenomenon of electricity for thousands of years, dating back to interactions with electric fish and static electricity, modern day electrical power can be traced back to the invention of the steam turbine in 1884. Approximately 80% of the electric power in the world is generated from a steam turbine using a variety of heat sources. The next key invention was that of the transformer in the late nineteenth century which allowed the efficient transmission of electrical power at high voltages. At high voltages electricity could be generated at a centralized power station and then be transmitted relatively long distances to where it was needed.
The rise in use electrical power can be directly correlated to the rise in prosperity and standard of living across the world. However, this has not come without problems and challenges. In the United States today xxx% of the electrical power generated comes from the burning of fossil fuels, which are non-renewable energy sources and thus have a finite supply. In addition, the burning of fossil fuels leads to air emissions with a wide range of negative impacts. Historically, concern over air emissions has focused on public health. In particular, burning coal can result in sulfur dioxide (SOX) emissions which cause smog and acid rain, nitrous oxide (NOX) emissions which cause acid rain and which is a potent greenhouse gas, particulates which cause breathing issues and asthma, and heavy metals which have a wide range of health and environmental impacts. Over the last 20+ years since the passage of the Clean Air Act in 1990, such air emissions have been dramatically reduced, primarily by adding emission control equipment on coal burning power plants.
More recently, the focus has been on carbon dioxide emissions, which are now known to be the largest contributor to global warming and climate change. Burning of all fossil fuels results in carbon dioxide emissions; however, coal emits approximately twice as much carbon dioxide as natural gas for the same heating value. At this time there is no economic way to reduce carbon dioxide emissions caused by burning fossil fuels. Nevertheless, carbon dioxide emissions due to power generation have reduced dramatically in the past few years, primarily due to replacement of coal with natural gas as a fuel source.
The United States and other countries around the world are in the early stages of a transition from generating electrical power primarily by burning fossil fuels to one of renewable energy sources such as solar and wind power. Although solar and wind power still account for a relatively small fraction of total energy generation, the amount has been growing rapidly. In 2014 the amount of power generated by wind increased 6% and solar erssentially doubled from the prior year. This trend is expected to continue and even accelerate as the cost of electricity from these sources continues to rapidly decrease with new technology and pressure continues to grow for more environmentally friendly sources of power due to concerns over global warming.