Energy: Nuclear Fusion, Hydroelectric, and Hydrogen Fuel Cells In today’s world, where everyone owns an electronic appliance, energy is an extremely valuable resource and in high demand. Though in the past this energy was provided by burning fossil fuels such as coal and natural gas, this way of providing energy can’t last much longer due to the dwindling amount of fossil fuels and the damage it causes to the environment. Therefore, scientists have been searching for new ways of providing energy. They hoped to find inexpensive and eco-friendly sources.
Some of those solutions include hydroelectric energy, hydrogen fuel cells, and nuclear fusion. Hydroelectric energy is a reliable and easy to obtain source of energy. In order to produce energy, all that is required is flowing water. Since much of the world is covered by rivers, oceans, lakes, and many other bodies of water, hydroelectric energy is a very plausible replacement for fossil fuels. Energy is obtained through the use of a dam on a river or pumped storage facilities. hoover Dam – located on the colorado river
A hydroelectric dam is used on decent sized rivers that have a drop in elevation; both of these conditions have to be met in order for a dam to be very productive. The reservoir behind the dam itself will hold an insurmountable amount of water and pressure that push on the dam. At the bottom of the dam is an intake opening that allows the pressurized water to flow through. The pressure of the water above will push water through this opening at a very quick pace. The flow of water will run through a turbine and spin it before flowing out on the other side of the dam.
The turbine is connected to a generator above by a generator shaft. As the turbine is spinning, it is providing the mechanical energy needed to run the generator, which, in turn, is transforming the mechanical energy into electricity through the use of magnets. Pumped storage facilities are based on the same principles, including the turbines and generators, as hydroelectric dams. It takes water from an elevated position and runs it through a turbine which then runs the generator creating the electricity. However, the pumped storage facility is not run by a river.
Instead, the facility is attached to either a lake or reservoir. The facility will pump water up to an elevated position and then, when needed, will allow it to flow back down in order to create the electricity needed. The hydroelectric dams can be run around the clock for twenty-four hours a day. They are able to do this because rivers never stop flowing. However, the pumped storage facilities are only able to run only for a limited time until the water storage runs out. Yet, this is not a bad thing. The main reason for a pumped storage facility is to be used for peak hours of the day when the most electricity is consumed.
Therefore, the storage areas are large enough to hold enough water to get through those hours. There are no waste products when using hydroelectric energy. The only element used is water and water is the only product. Plus, the water remains as part of the river and can supply towns and farms further down the river with nutrients in the water. However, the dams can also cause problems. The dams create reservoirs behind them as the river builds up over time. These reservoirs may prove to cause problems for lots of people and the surrounding area. Reservoirs may become too large and flood nearby towns.
The people of those towns have to be relocated and compensated for by the company that built the dam. The dam will also stop the natural flow of the river. It causes the water to become stagnant and the minerals and nutrients in the water will build up over time at the bottom of the dam. The farms down river will stop receiving the nutrients from the water and their products will suffer. Also, the stagnant water can become a disease infested place and cause small scale epidemics. These are some of the prices to pay for taping into the energy located in water.
Another price to pay is the actual cost for the dam to be built. Dams, since they are built to last and are meant to withstand the pressure of a pent up river, have to be built with the latest technologies and strongest material. This makes them very expensive, more expensive in short term than many other energy sources. Much of the money is spent on the design, materials, and construction of the dam. Designing the dam should be taken seriously, because a dam that is poorly built may break and lead to a flood occurring in towns downstream. However, they eventually pay off after many years of running.
It is very easy and cost efficient for a dam to be run, since the water is supplied by the river and only repairs and maintenance are required for them to be ran. Since they are eco-friendly, they also don’t receive many fines or have to redesign very often which saves them a lot of money. Hydrogen fuel cells are also proving to be very useful sources of energy on much smaller scales than the hydroelectric dams. Hydrogen fuel cells are essentially batteries. They contain a cathode, anode, and an electrolyte. However, a fuel cell contains different chemicals than a regular battery.
The two elements needed for a hydrogen fuel cell to work are hydrogen and oxygen. The hydrogen gas (H2) is passed through the anode where it is ionized and stripped of its electrons. The hydrogen ions, essentially just protons, pass through the electrolyte to the cathode. The electrolyte is a major part of the fuel cell. Electrolytes can be many different types including alkali, molten carbonate, phosphoric acid, proton exchange membrane (PEM) and solid oxide. No matter which material it is, the electrolyte only allows for the ionized hydrogen to pass through it.
This makes the stripped electrons flow down through the wire providing electricity to the needed appliance. Then the electrons will travel in a circuit to the cathode end of the battery. There, the electrons will combine with the hydrogen ions and oxygen, mixed in with the surrounding air, to form water. The water is then able to be expelled from the battery and is completely safe to the environment. Hydrogen fuel cells can be used at anytime so long as hydrogen and oxygen are present. Therefore, all that is needed primarily for a hydrogen fuel cell is hydrogen; since, there is oxygen in all the air around us.
They are mostly designed so they can power small appliances and cars. Today, there are several car designs that have been made to use the hydrogen fuel cell. The fuel cell was also used on the Apollo spacecraft to power the ship’s life support systems. It is very useful on small scales; however, it has trouble being used as a design idea for power plants. These hydrogen fuel cells are very beneficial to the environment. The only product created from running hydrogen fuel cells is water. The environment is in no other way affected. There is plenty of oxygen in the air for the hydrogen fuel cell to use without causing any major disturbance.
Also, the elements needed for a fuel cell to be run occur around us naturally. They are not located below the earth’s surface where miners have to dig for them or they need to be drilled for. This makes them very accessible. However, fuel cells are very expensive. The electrolyte and the tips on the anode and cathode can be made of expensive material. One hydrogen fuel cell was made using platinum tips for the cathode and anode and made the fuel cell very expensive. Though the initial cost is pricey, the fuel cell pays for itself afterwards. There is no charge for using the surrounding oxygen and, if need be, hydrogen is asily obtained for a small price. Whereas when gas and other fuels run out, you have to pay a great deal of money to get them refilled. A viable new source of energy is nuclear fusion. Nuclear fusion is able to provide energy through the combining of two nuclei of different isotopes of an element. Once the overall repulsion of the positive forces is overcome, the two “light” nuclei combine together to form a “heavy” nucleus and a displaced neutron. This process results in a massive amount of energy released. Nuclear fusion is done by combining the nuclei of two hydrogen isotopes, deuterium and tritium.
The isotopes are the same as hydrogen, as they both have one proton in the nucleus; however, deuterium has a single neutron and tritium has two neutrons in their nuclei. The isotopes are pushed together through the use of immense heat. The temperature needed to have nuclear fusion is about the same temperature of the sun, approximately 40 million degrees Fahrenheit. At this temperature, the hydrogen isotopes are contained in a plasma state. They are then able to fuse together to create a helium nucleus (He) that has two protons and two neutrons and a lone neutron.
Both the nucleus and neutron maintain a great amount of excess energy that can be harnessed and put to use. Other elements could be used to run nuclear fusion. However, the temperature needed to combine those elements’ nuclei would be even higher than that of hydrogen, due to a greater repulsive force of more protons pushing away from each other. It is also easy to obtain the hydrogen isotopes of deuterium and tritium. Deuterium is abundant in seawater and, since seawater covers almost 70 percent of the earth’s surface, is very easily obtained. Tritium can be formed from the element lithium.
Lithium is a main component of the earth’s crust and can be transformed into tritium quickly and efficiently. The materials needed for nuclear fusion are readily available; yet, the process either yields a low percent yield or can’t be completed. Even with today’s technology, it is hard to fuse the hydrogen isotopes together. This is due to the immense temperature needed for the nuclei to overcome the repulsive nature of the protons. There are two methods that have proven to be able to contain a nuclear fusion, the magnetic confinement and inertial confinement.
The temperature of the plasma is so great that no container on earth can contain it without melting away. Therefore, the magnetic confinement of the plasma is used to keep the plasma in a hovering magnetic field. Since, the plasma is not touching the container it can’t burn through it. This allows for the temperature to be increased steadily and for a long sustainable reaction. The Tokamak Fusion Test Reactor at Princeton uses magnetic confinement. It is a large circle that uses the magnets to propel the plasma in a circle while keeping it suspended using the magnetic field.
The Tokamak Fusion Test Reactor was able to produce a 65 percent yield input energy during a fusion reaction and is the closet to actually producing a nuclear fusion which will exceed the energy input. Inertial confinement is almost the exact opposite of magnetic confinement. It is meant to produce the nuclear fusion so rapidly that the nuclei do not have any time to move away from each other. Since the fusion is done so quickly, there is no need to contain the plasma state because it will last only a billionth of a second for it to be completed.
This is achievable because of lasers and their ability to deliver extreme amounts of energy in a short time frame. Two sets of lasers were built to maintain a nuclear fusion, the Shiva and Nova Laser Systems. The Nova Laser System was able to achieve Lawson criterion, but failed to reach the needed temperature to initiate fusion. Unlike its counterpart, nuclear fission, nuclear fusion is a very clean and eco-friendly source of energy. After fusion takes place, there is no radioactive material to dispose of or contain, but only the element helium that was created by the fusion.
Helium occurs naturally and is perfectly harmless to the environment. Nuclear fusion does not affect the environment in any other besides through the use of the reactants, deuterium and tritium obtained from seawater and lithium, and the product of helium. If nuclear fusion occurs for many hundreds to thousands of years, the amount of seawater and lithium used to supply the reaction may decrease and cause serious events. However, for the present time, nuclear fusion is completely safe to the environment.
This process can be used at anytime and anywhere, so long as you can create the temperatures needed and have the ability to contain the plasma and extract the energy. Therefore, nuclear fusion is only done in reactors and there are very few in the world that can even contain a fusion. However, a fusion that has produced a 100 percent yield of energy input has not occurred yet. This is the result of having to put too much energy into the process of reaching the fusion ignition temperature that the fusion itself is not large enough to even account for that energy.
The cost of nuclear fusion is tremendous. It is astronomical compared to other energy sources. However, it is kind of like the lottery, if you don’t pay a lot, don’t expect to win a lot. Though nuclear fusion is extremely expensive now, if able to be properly done, it will be able to supply the world with energy for many years, upwards of hundreds to even thousands with just the energy from fusion alone. Fusion may be expensive now, but could lead to a future with more energy and less money being paid for it.
