Contemporary Science

The Stirling Heat engine was invented in 1816 by Robert Stirling. He was trying to create a better, more effective steam engine, which often exploded because of high steam pressure. In essence, the Stirling engine functions like other heat engines in that it converts heat energy into mechanical energy, but unlike other engines, the Stirling is closed cycle, meaning that it uses a fixed amount of air or whatever fluid it is using which never leaves the chamber, and it is heated from the outside. Because of this, the Stirling engine can run on any heat source: solar, wind, fossil fuel, chemical, etc. It can run on a very small difference in temperature, as low as 7 degrees Celsius, so it can even be powered by steam from a cup of coffee or body heat.

(How a Stirling Engine runs. Source: http://www.mpoweruk.com/images/sterling_engine.gif)

Peltier Devices run based on the Peltier Effect, discovered by Jean Peltier in 1834. The Peltier Effect is also sometimes called thermoelectric cooling, which occurs when an electric current goes through a thermocouple, a “junction of two dissimilar conductors” (Source B.). It was known that when this occurred, there was a heat current, Joule heating, but Peltier discovered in his experiments that his current was too hot to be just Joule heating. This process occurs when two conductors are in electric contact, causing electrons to flow from the more electron-bound conductor to the less electron-bound conductor. Then, the change in electrostatic potential caused by the moving of electrons causes a temperature gradient. The right materials have to be chosen, but a perfect Peltier device looks like the one pictured below:

(How a Peltier Device runs. Source: http://www.activecool.com/technotes/images/TEC_JC.jpg)

Both devices have serious modern benefits. Both are much quieter than their common alternatives, making them ideal for situations when silence is of the upmost importance. Peltier Devices are used in submarines, for example, when stealth is required for operations. Both devices are also more energy efficient and greener than others. The Peltier Device, unlike similar products, uses no CFCs, which are harmful to our atmosphere. The Stirling engine can run on solar power, the benefits of which have already been discussed in other posts on this blog. Both devices work to enhance naturally occurring scientific phenomena and create cleaner, safer, and more efficient energy and temperature changes.

Sources:

A. http://www.mpoweruk.com/stirling_engine.htm

B. http://www.activecool.com/technotes/thermoelectric.html

C. http://www.physics.rutgers.edu/ugrad/351/oldslides/Lecture11.pdf

The Tesla car is a potentially revolutionary vehicle in terms of environmental impact as well as cost of use. The Tesla company released their first car in 2008, and continues to release new models periodically while perfecting their mechanisms. Unlike most other cars, Tesla cars are mostly battery operated, and need to be charged in order to work. Unlike Priuses or other hybrids, the Tesla has no gasoline powered motors. Instead they have a large lithium-ion battery, the same kinds of batteries that are in MacBooks. Like a laptop, the Tesla batteries hold a charge for a certain amount of time until they need to be plugged in again, but unlike a laptop, these batteries are large enough to operate cars for hours. According to Tesla, their most powerful battery can run a car going 55 mph for 300 miles before it needs to recharge. The weight of a single Tesla battery is as much as 1000 lbs. These heavy, powerful batteries power motors that are more advanced than combustion motors; they get significantly more miles per charge than the other motors get per gallon.

Environmentally these cars are a dream, but they are still unaffordable for the majority of the masses. The starting price for the basic model is $101,500, and although gas costs less than electricity in most places and the cost of use is less than a combustion motor, the original purchase is much more than most can pay. The other hassle about the Tesla car is where to charge the car. The company suggests getting an electrician to install a high power charging port in one’s garage so that it can charge more quickly with more voltage than other outlets. Even with charging stations in garages, there are few charging stations in other areas, although there are more opening in different gas stations across California. Theoretically if these cars continue to grow in popularity then more charging ports will be installed publicly, solving the problem of sparse opportunities to repower. However the cost will still be out of reach for many. The positives of the Tesla car still seem to heavily outweigh the negative, especially considering the Tesla car releases just 15 tons of CO2 for every 160 tons that combustion engines release.

Sources:

http://www.teslamotors.com/about

http://mashable.com/2013/01/17/tesla-electric-car/#B1FPHQy5D5qT

http://visual.ly/how-electric-cars-and-tesla-model-s-work

There are three major sources of energy in the U.S. right now: nuclear energy, coal-based energy, and natural gas. All three operate in the same basic way, by converting water into steam which powers turbines that are connected to generators. However, the process of heating up water is very different in each case.

Nuclear Energy:

Nuclear power plants are to thank for about 20% of the U.S.’s energy today. In these plants, atoms of uranium are split through nuclear fission. Two different isotopes of uranium can be used in these plants: U-238, which is most common, and U-235. These isotopes are unstable, and when these atoms are split, the nuclei release neutrons, as well as heat energy. The neutrons that are released bump into other atoms, causing them to also release neutrons and heat energy, making a self-sustaining system. These uranium isotopes are contained in tubes that, when inserted into the system, are surrounded by water. When the heat energy is released, the heat goes into the water and converts it into steam.

(An image of a nuclear power plant as made famous on The Simpsons. Source: http://www.risefeed.com/wp-content/uploads/2015/08/Springfield_Nuclear_Power_Plant2.png)

Nuclear energy is not renewable, but it is sustainable, meaning that while there is not a limitless supply of uranium like there is sun or wind, there is enough to continue to power nuclear plants for roughly one hundred years. A very small amount of uranium can produce the same amount of energy as large amounts of coal and natural gas. There are no greenhouse gases that are emitted through nuclear fission since nothing is burned the way it is with other energy sources. What radioactive waste there is is kept contained until the radioactivity decreases enough that it can be released without harming the environment or people. Unfortunately, as nice as the pros here are, the con is that its safety is not foolproof. Chernobyl was once thought to be safe, and we all know now that that land is still unsafe to live on. More recently, the Fukushima disaster in 2011 encouraged some countries to phase out their nuclear power plants in case some similar emergency could occur there, but the U.S. continues to heavily rely on nuclear power with no intention to stop.

Coal:

Coal is burned, creating the heat that allows water to change into the steam that powers the generators. The coal is first ground into a fine powder, allowing it to burn more quickly and at a hotter temperature. The diagram below shows exactly how coal becomes electricity in the ways I have already described:

(How coal is burned to power generators. Source: http://www.worldcoal.org/media/jpg/585/174139cgart.jpg)

Coal has been the basis of the energy in this country for generations and is still used heavily, although recently companies have been working to make their systems more efficient so that the same amount of coal can produce more energy and fewer byproducts such as CO2 and other greenhouse gases. Newer systems are also planning on being fitted with CO2 capture systems which can help filter carbon dioxide and prevent it from entering the atmosphere. Although this energy system has been around for ages, today there is much work being put into modernizing it to help cut costs and pollution, two of the biggest concerns about relying on coal-powered energy.

Natural Gas:

Natural gas occurs from plants and animals that have died and decomposed thousands of years ago. The energy that they had gained from the sun is contained in the form of carbon in natural gas. This natural gas is a fossil fuel that is harvested through the process of fracking, something I have already explained in an earlier blog post. Once the natural gas is available for use, it is treated for impurities so it can be made more efficient, and then it can be converted into usable energy in two different ways. As in the case of coal, natural gas can be burned to produce steam from water and the steam powers turbines which in turn power generators. Another system in use is bypassing the water entirely and just burning natural gases in a combustion turbine which directly produce electricity. Recently it was discovered that it is possible to use these two systems at the same time, so that steam and gas vapors are both used to power turbines, resulting in the same amount of gas being used twice and producing twice the amount of energy.

(The path of natural gas form its source to the consumer of its produced energy. Source: https://www2.dteenergy.com/wps/wcm/connect/08d8250d-ff32-4b69-aee3-d3552d45f240/naturalGasIndustry.gif?MOD=AJPERES&CACHEID=08d8250d-ff32-4b69-aee3-d3552d45f240)

Burning natural gas does produce fossil fuels like NO and CO2, but it produces these in smaller quantities than the burning of coal does, for example. Methane can leak out in a few places during the process of harvesting, transporting, or burning as well. Minimal solid waste is produced from burning natural gas, but that should not suggest that this is a harmless energy source. Fracking can destroy agriculture, natural habitats, and communities, even when done correctly and carefully. Harvesting coal is much safer, as is mining uranium when done properly.

All sources have positive elements but troublingly they also all have seriously negative elements. It is important to remember that these three sources, while the biggest sources for energy in the U.S., are not the only available options. Solar energy and wind energy are just two of the increasingly popular renewable and clean energy sources we have available today, and neither of those are nearly as harmful as fracking has been in Appalachia or nuclear energy has been in Japan.

Sources:

http://www.nei.org/Knowledge-Center/How-Nuclear-Reactors-Work

http://www.worldcoal.org/coal/uses-of-coal/coal-electricity/

http://www.epa.gov/cleanenergy/energy-and-you/affect/natural-gas.html

Fracking is a method used to extract natural gas from deep into the earth. First, a well is drilled, and then a high-pressure mixture of water, sand, and various chemicals is expelled from a hose, causing gas and oil underneath shale to be released into the well where it can be gathered for consumption. Fracking, or hydraulic fracturing, allows us to access fossil fuels underneath our own soil, making the U.S. less dependent on other countries for energy sources. In fact, because of fracking, it has been estimated that the U.S. has enough oil and natural gas to be secure for just under one hundred years, something President Obama announced in his 2012 State of the Union.

Despite the optimism in the U.S. government and among big oil companies, fracking is not necessarily as bountiful and harmless as once believed. Recent data shows there may not be as much shale as once thought, meaning there are fewer places where fracking will successfully lead to harvesting natural gas and oil. Accurate data is difficult to gather, even in the U.S., where we have more shale gas wells providing data than any other country. Other countries are considering following the U.S.’s lead on natural gas, but data will be even more difficult for countries such as the U.K. and Poland where there is much less shale.

There are more problems than just inaccurate data about the amount of shale. The environmental concerns about fracking are vast and varied. Fracking causes small tremors in the earth, too small to be felt, usually, but they could potentially add up over time and contribute to unsafe land. Environmentalists also suggest that dependence on natural gas and oils found through fracking is distracting us from more environmentally friendly energy sources (solar, wind, etc). Lots of water is used in fracking; water that, for example, might have been used to help the citizens of California in the bad drought they’ve been experiencing recently. My biggest concern about fracking was brought to light when a high school teacher showed the film Gasland during class: fracking frequently pollutes the water supply in the surrounding area. One part of the film was devoted to people who lived near fracking sites, and in one scene, residents showed the camera crew that when they turned on the faucet and held a lighter near it, they were able to set the stream of water on fire. That cannot possible be safe drinking water. Animals in the area were having health problems as well as humans, forcing many people to move from the houses they had once been comfortable and safe living in. I cannot forget that film and the impact that fracking had on those lives. It is clear to me that the cons heavily outweigh the pros, but oil executives are much more concerned with the cheap cost of this gas than the health of the citizens of the country whose land they are ruining.

Sources:

http://www.bbc.com/news/uk-14432401

http://www.foodandwaterwatch.org/water/fracking/

http://www.nature.com/news/natural-gas-the-fracking-fallacy-1.16430

According to Barry K. Worthington, Executive Director of the United States Energy Association (USEA), and David Ropeik, Consultant in Risk Perception and Risk Communication at Ropeik and Associates, the energy grid is defined as the web of wires that connects people’s homes and offices to substations, which, through the grid, are also connected to sources of power. The black wires found at the tops of telephone poles are part of this grid; they connect to many different subsections, making it possible for power to be brought to people anywhere in the 9,000 square mile the grid covers. In an article from 2011 quoted at alternativeenergy.procon,org , Worthington and Ropeik take a moment to consider the larger picture of how this grid functions as a whole: “The wires are all interconnected. It is technically possible to light up a light bulb in Seattle with a watt that was generated in Tallahassee.” Although these wires are connected, the US Energy grid is divided into three parts: the Eastern Interconnection, which spans from the Rocky Mountains in the West to the Atlantic Ocean in the East; the Western Interconnection, which goes from the Rocky Mountains in the East to the Pacific Ocean in the West; and then the Texas Interconnection, which covers most of Texas.

(http://alternativeenergy.procon.org/files/usa_grid.gif)

This power grid looks, and is, complex. However it is not nearly so complex as most of the technology we have today; in fact there are many efforts to bring the technology involved in power grids up to date. The idea of modernizing the equipment to enable more transparency is referred to as the “smart grid,” which would include trackers and computer sensors, technology that could make it much easier for power companies to fix problems along the grid without having to search for the problem area first. These sensors would not only transmit data to the power companies; consumers would be able to monitor how much power they are using at any given time, something that is impossible to do now, when consumers only see the energy used in their end of the month statement. Users would also be able to see the price of power in real-time. Through a smart grid, it would also be possible to coordinate large-scale energy needs, for example if many people owned electric cars and needed to charge them at the same time. In addition to more informed consumers and more organized transfers of power, a smart grid would make it easier for people to use alternative energy on their homes, like solar or wind. So, not only are people more conscious of the power that they would take from the grid, but they might be inclined to use more clean energy. The pros seem endless, and the cons are few, but also large. The biggest obstacle in the way of a smart grid is cost, as it would cost a few hundred dollars to install just one smart grid, so giving every building a sensor would seriously add up. The other major thing preventing a complete smart grid is the attitude of power companies. Understandably, they are not thrilled that people would learn to consume less of their product with smart grids, so they are very hesitant to encourage their installation en masse. Hopefully soon enough their greed will peter out and the government will see the benefit of less power consumption and find money in their budget to install a complete and comprehensive smart grid across the whole country.

Sources:

http://alternativeenergy.procon.org/view.answers.php?questionID=001247

http://energy.gov/oe/services/technology-development/smart-grid

http://www.economist.com/node/13725843