With the recent debate over coal divestment on Brown’s campus, there has been a renewed interest in looking at where our energy comes from. More specifically, how do coal, sunlight, and wind turn into the electricity used to turn on the lights?
First, we have to look at a very basic component of electricity and magnetism: flux. The concept is simple: When you move a magnet through a wire coil, or even spin magnets in a magnet coil, it generates an electrical current in the coils. Flux’s amazing application is transforming mechanical energy (moving the magnets) into electrical energy (the current created in the coil). This concept is the basis for almost all types of electrical power plants, with the only variation being how the power plant manages to spin the magnets.
However, not all power plants are created equal. Some power plants are more expensive, others use valuable resources, some are polluting, and some are not very reliable. Reliability is one of the most crucial aspects of electricity generation in considering the national energy grid. The grid has to be constantly running. It can’t start up and stop like a light switch because there is too much resistance when power lines stretch from one state to another. Think of the grid system like a train: A train can run at high speeds relatively smoothly, but it takes some time for it to get started again once it stops. This is why this year’s Super Bowl power outage and the 2003 blackout in the Northeast lasted so long.
It is important to keep these factors in mind when evaluating power sources.
Coal power plants are based on traditional steam power. Coal is burned, which in turn boils water, creating steam. The steam is then used to turn a turbine, which spins magnets around metal c
oils. Coal is the largest energy source in the world, and according to the U.S. Energy Information Administration, it accounts for 42.3 percent of the U.S.’s total electricity consumption.
In general, coal is one of the dirtiest forms of energy production. According to the European Union’s ExternE project, coal has the second highest fatality per kilowatt-hour. It is also a non-renewable resource that will eventually run out. So why is coal so widely used?
Coal is reliable, cheap, abundant, domestic, and easy to transport. Coal power plants always have a steady supply of coal being fed into them, allowing constant electricity to be provided to the energy grid, which keeps the metaphorical train running without having to stop. Coal is also extremely cheap, and it is easy to transport via freight rail. Coal is also abundant: The world has enough proven reserves to last another 112 years. Furthermore, the U.S. has such a large supply of coal that it actually exports some of its coal, meaning the country does not rely on other nations for coal-powered energy.
Natural gas power plants work in much the same way as coal, only natural gas is burned instead of coal. Natural gas accounts for 24.7 percent of the U.S.’s total energy consumption, a share that has been on the rise in recent years due to falling costs.
Natural gas has the advantage of being much cleaner than coal energy and in many cases less costly. Natural gas is reliable and can be burned constantly, ensuring no sudden stops in production. Natural gas is abundant in the U.S., and almost all natural gas used in the U.S. is produced in the U.S.
However, natural gas does have some distinct disadvantages. It is still a fossil fuel and is not as abundant as coal, meaning it will also eventually run out. Natural gas still produces greenhouse gases and is not 100 percent environmentally friendly. Logistically, natural gas requires large pipelines to transport, making transportation difficult.
Nuclear energy also uses steam to move turbines, but instead of burning a fuel, it uses heat created by nuclear fission. The lack of fossil fuels makes nuclear energy emission-free and not reliant on a limited resource. Nuclear plants are also able to run at all times, and they are capable of producing enough electricity to power a nation; for example, France uses nuclear energy for 77.1 percent of its energy needs. In the U.S., nuclear energy accounts for 19.3 percent of all electricity.
Nuclear energy does have some downsides, though. Nuclear waste never goes away; environmental groups have long opposed the use of nuclear power for this reason. Many countries have also shied away from nuclear energy after such incidents as the Three Mile Island accident and the Fukushima disaster, despite the fact that nuclear energy is one of the safest forms of energy, according to the E.U.’s ExternE report.
Hydropower is a renewable energy source that uses not steam but rather the running water of a river to manually turn its turbines. This means that hydropower is clean, renewable, and reliable. Hydropower can also generate a significant amount of electricity. Take the state of Washington, for example, where dams provide nearly 76 percent of the state’s electricity.
Hydropower does has significant geographical limitations, however, as some areas simply do not enough rivers to meet their energy needs. Furthermore, dams can often has negative ecological impacts. Therefore, not every river is suitable for hydropower plants.
Wind energy uses the force of the wind to turn a windmill’s large blades, which then turn the turbine, creating electricity. Wind energy is renewable and creates zero emissions.
The problems with wind energy though, are numerous. First and foremost, it is not a reliable source of energy, because if there is no wind, then there will be no electricity. This causes our metaphorical train to stop, and that is never a good thing.
Wind energy is also inefficient. Each windmill produces so little energy that it takes thousands of windmills to generate the power produced by just one conventional power plant. Despite the U.S.’s status as the second largest producer of wind energy in the world, wind energy only accounts for 2.9 percent of U.S. electricity consumption.
For another perspective, consider Texas. Texas is the leading state in wind production, so much so, that if Texas were its own country, it would be the sixth largest producer in wind energy. Even still, wind only accounted for 9.8 percent of the state’s electricity consumption.
Besides its abysmal production, wind energy also has a negative environmental impact because the vast stretches of windmills all but ruin the aesthetics of the countryside.
Solar power is unique among the major sources of electricity in that it does not convert mechanical energy into electrical energy. Instead, it uses photovoltaics to convert light energy into electrical energy.
Solar panels have an almost infinite source of energy (the Sun), and they don’t produce harmful greenhouse gases. However, they have been slow to catch on in the U.S. Why?
Solar panels need rare earth metals, which, as the name suggests, are rare. This drives up the cost of production and makes the technology not entirely renewable. Furthermore, almost 90 percent of the world’s rare earth metals come from China, so it still puts America’s energy needs in the hands of a foreign nation.
Solar panels also aren’t reliable as a constant source of energy, since the night happens every — well — night. This means that large capacitors are needed to store energy for nighttime use. Furthermore, in many northern climates, the sun isn’t very strong, so solar energy becomes even less reliable. Perhaps the final nail in the solar coffin is that solar panels aren’t very efficient. The roof of the Nelson Fitness Center is nearly covered in solar panels, yet they only cover 10 percent of the electricity demand for the facility alone. With such weak returns, solar energy simply cannot handle the lion’s share of the electricity demand.
Who knows what energy will look like in the future? Countries and private industry are all looking for energy alternatives, and the future could be very bright for emerging industries like solar power. However, it’s important that everyone —especially those vocal protesters — understand how it works now.