Comparing Nuclear Energy To Other Energies Sources Environmental Sciences Essay

Comparing Nuclear Energy To Other Energies Sources Environmental Sciences Essay This report contains information on five different types of energy sources. It is a literature study that compares two renewable (solar and wind) sources and two non-renewable (coal and natural gas) sources to nuclear energy. The comparison is based on factors such as usage, cost (both capital costs and running costs), safety and stability, storage of waste and the impact on the environment. The sources are individually compared to nuclear energy. In the comparisons only the factors relevant to the two energy sources being compared at any given time are considered factors are not repeated in the comparison. It also looks at whether the medias portrayal of the dangers of nuclear energy is accurate or whether it overestimates the dangers involved in producing nuclear power. The aim of the report was to determine the viability of nuclear energy as a source of power to support electricity needs of the population in the future. This is a literature study addressing the portrayal of nuclear energy by the media and its viability as an energy source in comparison to other methods of generating electricity. The report compares Nuclear energy to energy generated by coal, natural gases, wind and the sun (i.e. solar energy). The energy types are individually compared to Nuclear energy. Each section highlights specific problems and advantages associated with Nuclear energy as it relates to the energy to which it is being compared. Factors taken into consideration include the costs involved with the various types of energy, how much it is being used globally, impact on the environment, storage of waste, safety and stability. The report was written to meet the requirements laid down by JSQ216, a second year engineering subject at the University of Pretoria. The report was completed by allocating each of the four group members a specific energy to research and compare to nuclear energy. The research was then completed by using journal articles, books, internet sites and approaching two engineers about the problem. The information was processed, the reliability of the sources assessed and a short portion of the report was generated by each group member. All four parts were then put together for the final report. Figure 1: Break down of solar energy[2]The sun has been around since the beginning of time but only recently has it been used as a source of renewable energy. Approximately 120000 TW of solar energy is absorbed by the Earths surface which is equal to 10000 times the total global demand for energy. Only 0.1% of this energy would be required to satisfy the worlds present consumption of fuels.[1] There are three main ways to harness the suns energy. These include solar cells which convert sunlight directly into electricity. Solar water heating where heat from the sun is used to heat water inside panels on roof tops. And lastly solar furnaces that make use of mirrors to concentrate the suns energy into a small space to produce high temperatures. As illustrated by figure 1. There are close to 440 nuclear power plants in the world today which supply 16% of the worlds energy demand, however only 1% is useable energy with the rest being nuclear waste. If 1% of the area where there is recoverable energy utilised solar energy devices all the worlds energy needs could be met with solar energy alone. If 10% of the area were to be utilised then in two years the electricity produced would be equal to all known reserves of fossil fuels.[1] Cost problems with solar energy are the high capital costs involved in the installation of solar panels which can be very expensive. The need to store energy because of solar availability due to factors such as time of day and weather conditions is also costly. Countries at higher altitudes with daily cloud cover will have an economic disadvantage due to long distance transfer of energy. Maintenance of panels also has to be considered. Nuclear energy is presently cheaper than solar power however the construction of the facilities and the disposal of radioactive waste is costly and can affect the environment.[3] Solar power is relatively safe to use as long as you do not look directly into the suns rays or come into contact with hot solar panels. In the case of nuclear power it is also safe to use as the nuclear reactors are equipped with redundant systems to make sure there is no nuclear meltdown. This makes it a very stable energy source. Nuclear energy starts to get more dangerous in the form of spent fuel rods and radioactive waste. Even though nuclear energy is reliable and stable as a whole, when something does go wrong it can become very serious and very dangerous. Solar energy does not have any form of waste as replaced panels and components can be reused or recycled. Nuclear energy has two types of waste products, the spent fuel rods which if not stored properly in pools of water to cool down could become very unstable. The other form is radioactive gasses and other waste products that if released into the atmosphere can pose various risks. Solar energy produces no waste or pollution. Waste from nuclear power must be sealed and stored underground for long periods of time. This waste must be kept safe from external factors and from human contact in order to prevent a threat. Such a threat is currently under way at the Fukushima Daiichi power plant in Japan where a pool of spent fuel rods caught fire this year. Solar power is a renewable power source therefore it is environmentally friendly. It is silent and requires no fuel therefore there is no pollution. It even decreases the amount of harmful green house gasses. Although there are many advantages to solar energy there is still the fact that a large amount of panels is required to produce the needed electricity. This becomes very costly. It is reliable and has no risks that are associated with nuclear energy. Nuclear energy on the other hand is not a renewable source and if not handled in the correct way could impact the environment in a negative way. Even though it does not contribute to global warming like other fossil fuels, the waste gasses it does produce could potentially cause radioactive sicknesses and cancer in humans and other life forms. A summary of the advantages and disadvantages of solar and nuclear energy can be found in the tables below Table 1: Advantages of Solar and Nuclear Energy Solar Energy Nuclear Energy Renewable energy source Does not emit green house gasses Has no volatile waste Plenty of resources available Once panels are in place the energy is free Cheaper than solar power Table 2: Disadvantages of Solar and Nuclear Energy Solar Energy Nuclear Energy Does not work at night Radioactive waste Currently very expensive Long-term storage required for waste products Requires big fields in order to harvest a suitable amount of energy Some reactors produce plutonium which can be used to make nuclear weapons All around the world we require every energy source that we can get including nuclear. All energy sources have both pros and cons. Even though nuclear energy is portrayed as an unstable source of energy it is in fact one of the most reliable and stable types in the world today. The downside is in its waste that if treated incorrectly could land in the hands of terrorists. In the next 20 years there will be emerging economies throughout the globe that will require low cost, environmentally friendly alternative energy sources and Nuclear power is expected to satisfy this demand. Wind Energy Wind power is the generation of electricity through the use of wind to spin turbines, which in turn, convert the winds kinetic energy into electricity. [1] The process of using wind as a power source has been in use throughout history from around the 12th century where windmills were used to mill grain. [2] Wind power generation uses wind turbines to make electricity, wind mills for mechanical power and wind pumps for pumping water. [2] It is a renewable energy source that not many countries have attempted to develop. Wind Power Worldwide June 2010 [3] Country Capacity (MW) USA 36.3 China 33.8 Germany 26.4 Spain 19.5 India 12.1 Rest of the World 46.9 Total 175.00Table 3: Wind Power Worldwide June 2010 In June 2010, The World Wind Energy Association (WWEA) published that 5 countries alone accounted for approximately 73% of the worlds total wind energy production namely USA, China, Germany, Spain and India. [3] Figure 2: World Electricity Production 2008 On the other hand, nuclear energy production seems to be far more popular in a lot of countries with some countries such as the USA and France having no less than 104 and 59 nuclear reactors in operation respectively [4] in early 2010. A study done in 2008 to find the percentage of each type of energy that is globally produced showed that wind forms part of only 2.8% whereas nuclear energy accounts for 13.4% of the worlds total power. The main disadvantage of wind power is the unreliability of the wind itself. In most areas the winds strength is too low to spin a turbine. However, if wind energy were to be used in unison with solar and/or geothermal energy it could be developed into a stable and reliable source of power. The wind turbines themselves are quite safe with only a few reported cases worldwide of damaged blades caused by bad weather, none of which has resulted in any known injuries. [5] Nuclear reactor plants make use of radioactive materials to generate electricity. The idea that these materials could become unstable and get out of control is one of the main concerns (along with radiation poisoning) for countries producing nuclear energy. The Chernobyl nuclear disaster of 1986 lead to better, more efficient protocols being put into practice leaving most countries to believe that they are now better prepared to handle any destabilizing of the nuclear materials. [6] Nonetheless, wind energy remains theoretically a lot safer than nuclear plants even with all the safety precautions they take. The consequences are much higher for a nuclear disaster than for a wind turbine failure. Wind turbines do not emit any waste products as they do not burn any sort of fossil fuels or radioactive materials, so there is no concern over where to store or dispose of emissions safely- unlike nuclear energy. The radioactive materials (like Uranium and Plutonium) that are used up in nuclear power plants continue to produce dangerous radiation for thousands of years after they have been used up as a fuel for nuclear energy. The most effective way to store these depleted materials has not yet been found but for now they are being kept in underground storage pools where they will not be harmful to anybody. [7] The initial setups of both wind turbines and nuclear power plants are quite costly. But once built, wind turbines are cheaper to maintain than the power plants, but they are both relatively cheaper to maintain than their fossil fuel counterparts with the nuclear materials lasting a very long time and with wind being a free resource to be used. Environmental Impact: Both wind and nuclear energy as it is being produced, is friendly to the surrounding environment (except in the tragic case where radiation is leaked from the power plant). However, wind turbines do make more noise than the power plants which is disruptive to any locals staying near the turbines. [8] The amount of space that a wind turbine takes is less than that of an average nuclear power plant and the disruption to the environment during construction is worse for the power plants because they take so much longer to be built. [8] Coal Energy Coal, the most abundant and affordable of the fossil fuels (1), is a non-renewable energy source. It has been used as a source of energy for thousands of years and has numerous important uses such as in electricity generation, steel and cement manufacture, and industrial process heating. Coal often proves to be the only alternative when low-cost, cleaner energy sources are unable to meet the growing energy demand faced with today (1). Fossil fuels are formed from the organic remains of prehistoric plants and animals that have undergone changes due to heat and pressure over millions of years. The process is still taking place today but the rate of energy storage is small. The annual biomass production stored this way represents only around 0.001% of the current world energy use (2). Even though charcoal can be made artificially, it is not possible to produce it at the rate of consumption (3). Therefore, coal is regarded as a non-renewable energy source and is bound to get depleted. According to BPs (British Petroleum) Statistical Review of World Energy 2010, there is a estimated 826001 million tons of proven coal reserves worldwide, or 119 years reserves-to-production ratio(length of time that the remaining coal reserves would last if production were to continue at the previous years rate )(4). However, compared to other fossil fuels, coal reserves are the largest ones and are more evenly distributed worldwide. Nuclear energy is also a non-renewable source as it is reliant upon a finite source of fuel that can be exhausted. Although, the worlds known uranium resources increased by 15% in two years to 2007 owing to increased mineral exploration The uranium (and sometimes plutonium) used in nuclear power is a natural resource and is a common metal found in rocks all over the world. The World Nuclear Association suggested that there is approximately (13) 160 years of supply at todays rate of consumption. Coal is mainly used as a solid fuel to produce electricity and heat. The coal is usually pulverized and then combusted in a furnace with a boiler for the generation of electricity. The steam which results from the combustion is then used to spin turbines, which drives the generators thus creating electricity. When coal is heated at approximately 1000 degrees Celsius in an airless environment, Coke is produced. The Coke is then used is used to smelt iron ore for the production of steel. A by-product of this heating is Coal gas, which is a composition of methane and hydrogen, is produced. Coal gas was used for residential lighting and cooking in the 1940s; but it was very costly and so it was stopped. However, in recent times, these gasification processes are being developed to be more cost effective and so coal gas is often used as fuel for engines. Nuclear power plants create electricity through a process called fission in which subatomic particles called neutrons split uranium atoms, producing tremendous amounts of energy. The result of the fission of these large atoms is the creation of smaller atoms and radiation. The energy produced is then absorbed by water which heats it and so stream is produced. The steam is then used to spin turbines as in the case with coal power plants. According to the Key World Energy Statistics 2010 (5), 27% of the worldwide energy demand was fulfilled by coal in 2009.Coal was the second largest source of energy followed by Oil supplying 33.2%. China is a major producer with coal with coal always playing a dominant role in its primary energy consumption. China consumed a high 46,9% of the coal supplied and produced the most coal (45,6%) according to the BP Statistical World Energy Review 2010. World primary energy demand is expected to continue to grow steadily, as it has over the last two decades According to the International Energy Outlook 2010 (an assessment by the Energy Information Administration (EIA) of the outlook for international energy markets through 2035), world consumption of coal increases by 56% over the next two decades(6). Nuclear energy supplies the world 5.8% of the worlds consumption which is less than a quarter of what coal supplies. This is expected as there are only 442 operable nuclear power stations world-wide, the first one being created about 50 years ago which is relatively recent. The extraction of coal involves two types of mining: surface (strip) mining and underground mining. Surface mining involves the removal of coal deposits close to earths surface whereas underground mining is removing deposits found hundreds of meters below the earths surface. Underground mining accounts to approximately 60% of the worlds coal production (7) and requires the creation of shafts and tunnels that are dug in to the coal layers. There have been numerous tragic occurrences in the history of coal mining as it is a very risky business and devastating accidents occur in all countries that produce commercial quantities of this mineral. Most mining accidents occur as a result of cave-ins, methane explosions, mine wall failures, vehicle collisions or the flooding of the mine shafts. Also suffocation, gas poisoning, respiratory ailments (mainly Black Lung Disease) were common. Over 100,000 miners have dies over the past century in coal-mining accidents in the U.S (2nd largest producers of coal) only (8). However, most of these risks have been reduced in present-day mines owing to modern technology and health and safety acts setting stricter standards. Nevertheless, in lesser developed countries and some developing countries, continue to experience significant numbers of mining fatalities each year. The abundance of coal makes it easily accessible and the use of cheaper modes of transportation makes this resource an inexpensive form of energy when compared to energies such as solar, wind or hydro. It is also slightly cheaper than the costs involved in producing nuclear energy. When comparing the economics in producing energy from these two sources, it is important to consider several different types costs associated with both coal and nuclear energy. This includes costs associated with the fuel used in the production of energy which tend to be lower in a nuclear plant even though more intricate steps are involved in the production of the fuel assemblies used in the reactors. Transportation costs are, however, high for coal because a significantly large amount of coal is needed to generate the same energy as with the nuclear fuel. The capital costs are the costs associated with the initial construction of the plant and the modifications forms an important part when comparing the costs. For a nuclear plant, these costs are usually higher than for any other energy forms as the buildings used for containment or the safety-related equipment need to meet higher standards than those met by traditional coal plants. On the other hand, coal plants are required to include scrubbers to remove airborne pollutants as a result of the burning of the coal. Another consideration is the operation and maintenance costs involved. These are the costs involved in the day-to-day operation of the coal and nuclear plants. This includes labour costs, material costs, government fees and property taxes. It is found that the costs are very similar in both the plants. The costs associated with the by-product waste should also be taken into account. For a coal plants, this is the coal ash and for a nuclear plant, these costs include a charge levied by the government for ultimate storage of the high level waste. This charge is a flat fee based on energy use. The waste costs for nuclear energy is considerably higher than the costs for coal plants. Thus, the costs involved in producing coal and nuclear energy are roughly the same (9). The burning of coal is known to contribute to global warming, and is linked to environmental and health issues such as acid rain, smog and asthma owing to the particulate emissions that are emitted from power stations. According to the World Health Organisation, it is estimated that air pollution kills more than 2 million people annually (10). Coal is the largest contributor to the human-made increase of CO2, a greenhouse gas which causes global warming and climate change in the air (11). Strip mining causes large areas of land to be temporarily disturbed and this causes soil erosion and impacts on local biodiversity as after the land has been scraped and quarried for coal, it is usually abandoned. The waste after coal has been combusted is often disposed of in landfills or surface impoundments, which are lined with compacted clay soil and a plastic sheet. As rain filters through the toxic ash pits over years, the toxic metals are leached out into the local environment. Coal sludge i s the liquid coal waste generated by washing coal and is known to contain toxins, and so leaks or spills can pollute underground and surface waters. (12) Natural Gas Energy The Natural Gas used in power production is a colourless, odourless and tasteless gas made primarily of methane and other hydrocarbons (including ethane, propane, butanes and pentanes). It also contains carbon dioxide, helium, hydrogen sulphide and nitrogen, in smaller quantities. Natural gas is a molecular compound with Van Der Waal attraction between its molecules[1]. It has a boiling point of -161oC and is stable at a wide variety of temperatures and pressures[1]. Natural gas is transported in its liquid form as it taken up 600 times less space as a liquid than it does as a gas and weighs 55% less than the same volume of water. It is a result of the decomposition of plants and animals and is found in pockets beneath the earth and ocean. Natural gas is an important source of power in the modern world. According to Makogen (2010:49) if we were to use 17 to 20% of the worlds natural gas resources, we would be able to provide the world with energy for 200 years. Although it currently only accounts for 20% of the worlds energy, the demand is expected to increase substantially over the next 20 years. It is a cleaner fuel source than any other fossil fuel[2] emitting nearly no sulphur dioxide and far less carbon dioxide and NHx than either oil or coal. Natural gases can also be used in conjunction with other power generation methods, such as biomass[3], to produce energy which will change the amount of pollutants emitted. Nuclear stations do not produce the same pollutants as fossil fuels do but waste management remains the primary concern in nuclear technology. The waste products of a nuclear station are isotopes with extremely long half-lives. The storage of these waste products means creating a safe storage space that needs to last longer than all the human civilisations combined. There are three different levels of nuclear waste, high level, medium level and low level. Low level waste is not very dangerous and disposing of it is not a problem. The danger comes in with high level radioactive waste. The waste is encased in concrete drums and buried up to a kilometre and a half into the ground[5]. However, high level radioactive waste cannot be stored near any other high level radioactive waste as it will interact with the other waste. It is also important to find stable ground in which to store the waste, as concrete can crack and break in the event of an earthquake or tremor. South Africa is one of the safer places to store nuclear waste as it has a geologically stable countryside. Some areas, like the northern Karoo, have experienced about 30 000 years of stability. In between the removal of the waste from use and the final storage of the waste it needs to be left to soak in water for a period of time, to get rid of some of the residual radiation. In this time the fuel rods need to be safely guarded as the waste products are used in the creation of dirty bombs and nuclear bombs. A dirty bomb is a normal bomb containing high level radioactive waste and is detonated above a city, allowing the radioactive particles to contaminate the water supply in addition to other damage. [5]Plutonium, one of the waste products of a nuclear power station, is a primary component in atom bombs and the rods often have to be processed to remove all plutonium before they can be disposed. The use to which the waste products can be used also means that measures need to be taken in ensuring that any country with a nuclear power station does not use the waste in a nuclear weapons program. It also leaves a country more vulnerable to nuclear attack as should a dirty or atom bomb land near a nuclear station the products of the two would react with each other, compounding damage. The waste from a nuclear station can be greatly reduced by the correct management of the station but it still remains a serious threat. Cold fusion could theoretically produce energy without radioactive waste but experiments with cold fusion have produced very little energy, not even enough to power a light bulb. Cold fusion is also regarded as a scam by many scientists and has the same notoriety as perpetual motion and free energy in many scientific circles[9]. The level of efficiency of natural gas as a power source is, however, very much dependent on the technology used to produce the power. In a comparison of different technologies[4] it was found that Natural Gas combined cycle technology was the most efficient of the Natural Gas technologies. The technologies were compared based on efficiency, capital costs, maintenance costs, the service life and electricity costs (calculated based on the cost of the fuel, the maintenance costs, capital cost and service life). The capital costs of the combined cycle technology were just over à ¢Ã¢â‚¬Å¡Ã‚ ¬500 with an expected maintenance cost of less than à ¢Ã¢â‚¬Å¡Ã‚ ¬0.005 per kilo Watt hour and a service life of 20 years (i.e. the time the plant operates before equipment needs to be replaced.) A nuclear station has to replace its one third of its fuel rods annually[5] Comparatively, a nuclear stations capital costs are higher than any other fuel source[6] but they produce electricity at a very low cost which offsets the initial high cost. This can be seen in figure 2, below, which shows a comparison of the cost to generate energy for various technologies. The cost of power from a nuclear plant also tends to remain stable[7] even if the cost of uranium varies as up top 75% of the fuel cost in a nuclear plant is to cover the start-up cost. On the other hand, natural gas prices are very dependent on the supply and so prices tend to vary. Natural gas is also subject to carbon taxes in some countries because of its emissions, which reduces its cost efficiency. Figure 3: Cost of Energy Generation for Different Technologies Location also plays a very important role in determining whether or not natural gas or nuclear energy is the most efficient solution of a country. A country that is abundant in fossil fuels and does not pay carbon taxes would find that natural gas was a far more suitable technology. However, when it becomes necessary to import natural gases, the supply security of the plant becomes compromised and it Nuclear may be a more financially viable option. Both Nuclear and Natural Gas sources have the advantages of being able to supply on demand. Most renewable energy resources are offered on an as-available basis[8]. This means that you do not need to run a coal station alongside a nuclear station in case it does not produce enough energy to meet demand. Conclusion Media is incorrect in portrayal, too extreme but still not safe Waste disposal is dangerous, careful consideration as to storage facilities Safety, security Vulnerability to nuclear attack