Renewable energy sources

Министерство образования и науки Российской Федерации

Государственное автономное образовательное учреждение высшего образования

«Санкт-Петербургский политехнический университет»

Гуманитарный институт

 

Кафедра «Лингводидактики и перевода»

КУРСОВАЯ РАБОТА

По дисциплине «English language»

На тему «Renewable energy sources»

 

 

 

Выполнила: студентка 33703/1 группы

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Красикова А.А.

Приняла: доц., к.п.н.

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Харламова О.Ю.

 

 

Санкт-Петербург

2015

                                                               Contents 
 
Introduction…………………………………………………………………………………… 3 
 
Renewable energy sources

Wind power………………………………………………………………… 4 
 
Hydropower………………………………………………………………… 5 
         
Solar energy………………………………………………………………… 6 
     Biomass…………………………………………………………………….. 8 
 
Nuclear power……………………………………………………………10 

The Advantages and Disadvantages of Renewable Energy……………………... 12 
 
Conclusion…………………………………………………………………….... 13 
 
Bibliography…………………………………………………………………….. 14 
 
 
 
 
 
 
 
                                                  

 

Introduction

Relevance. The subject of this work is very important since everyday humanity produces carbon dioxide (CO2). It is released to the Earth’s atmosphere and remains there for approximately one hundred years.

This increasing quantity of CO2 leads to the warming of our planet and becomes the main reason of the so-called Global Warming Effect. One of the ways to answer this challenge is to replace current technologies by alternative ones. They usually have comparable or better performance and at the same time they allow avoiding the usage of carbon dioxide. These sources are often called the Alternative energy.

Many experts state that the oil and natural gas reserves of our planet may be depleted within some 40-50 years. By the year 2050, one-third of the world energy mix will be formed by the energy from solar and wind power as well as from other renewable sources. The importance of renewables will grow due to such reasons as climate change, increasing of population and exhaustion of fossil fuels.

Alternative energy is based on energy sources that do not have undesired consequences of their usage. Compared to traditional energy sources, renewables have lower carbon emissions.

The aim of my work is to study various types of renewable energy sources and to identify both their advantages and disadvantages. In my research I shall point out wind power, hydropower, solar energy, biomass and nuclear power among the sources of renewable energy.

 

Renewable energy sources

Wind power

Wind power is the conversion of wind energy by wind turbines into a useful form –  such as electricity or mechanical energy. Wind farms of a large scale are usually connected to local power transmission network by small turbines used to provide electricity to isolated areas. Although the share of wind energy in the contemporary world energy mix is only about 1.5%, this index is growing rapidly. To be concrete, it has doubled within three years – from 2005 to 2008. Moreover, in some countries this index has achieved relatively high levels. For example, in 2008 in Denmark it formed approximately 19% of electricity production, in Spain and Portugal – 11%, in Germany and the Republic of Ireland – 7%. As of 2008, Europe played the leading role in the international development of offshore wind power due to the vast wind resources and shallow water of the North Sea and the Baltic Sea.

Technical potential of a wind energy in Russia is estimated more than 50 000 billion kWh per year. The economic potential is about 260 billion kWh per year, which is some 30% of total power generation in Russia.

Wind energy zones in Russia are located on the coast and islands of the Arctic Ocean. The largest wind farm in Russia (5.1 MW) is located in Kaliningrad region. 

Wind power as a source of energy: pro et contra

Advantages	Disadvantages
Clean	Unstable
Renewable	Safe for people
Economically effective	Expensive to install and maintain
Growing rapidly and with the vast potential	Suitable only for certain locations
Modern from the technological point of view	Threatening to wildlife

                                       

 

Hydropower

Hydroelectricity is a power generation from the sources of hydropower. I.e., the gravity of falling and flowing water is often used to produce power. Hydroelectricity is the most widely used form of renewable energy. Once a hydroelectric complex is constructed, the project produces no direct waste. Hydropower stations of a small scale (also called micro-hydro) are becoming increasingly popular generators of an alternative energy. This is especially relevant in remote areas where other power sources are not viable. Micro-hydropower stations could be built on a small rivers or even streams almost without discernible effect on environment and shall not lead to disruption in fish migrations. In most micro-hydropower stations the energy is produced by water wheels – not by the functioning of a dam or major water diversion.

Many hydropower projects are also designed to serve the needs of specific industries. As of 2006, hydropower production provided up to 88% of the world’s usage of renewables; this was some 20% of total energy production. The total output of all the hydropower stations was equal to 777 GW.

Iceland is the absolute leader in the development of hydropower. Though this kind of renewable has the highest shares in the national energy mixes of such countries as Norway, Canada and Sweden. Surprisingly, in Paraguay 100% of the energy produced is generated by hydropower stations. In the beginning of 2000’s China, for which hydropower is a major potential source of energy, was very active in building hydropower stations. In this country was built the largest hydropower station in the world called Three Gorges. It is situated on the Yangtze River.

 

Hydropower as a source of energy: pro et contra

Advantages	Disadvantages
Renewable	Methane emissions
Cheap source of electricity	Damaging ecosystems and harming the land
Reduced CO2 emissions	Siltation and flow shortages

Solar Energy

Solar energy could be converted directly into heat and electricity. The strength of a solar energy available at the certain point on Earth depends on the day of the year, the time of day and the latitude of this point. Solar energy is used for heating water for domestic use, heating spaces in various buildings, drying agricultural products and generating electrical power.

One of the first examples of using solar energy was the experience of a British astronomer John Herschel. He used a solar collector box to cook food during expedition into Africa in 1830’s. This is a sustainable solution: since, using the heat of the Sun to boil water, we reduce the amount of fossil fuels needed to be burnt to generate power.

We are also able to harness radiant or solar light energy. Radiant energy is produced on the Sun as a result of nuclear fusion reactions. This process is being used more and more widely. Relevant technologies are developed, and efficiency is increasing. These technologies are widely used in solar powered calculators and such other devices.

 

Solar Thermal Electricity Generation

Solar thermal power stations use the rays of the Sun to heat a fluid and thus to produce a high pressure, high temperature steam. During the technological process this steam is converted in a turbine into mechanical energy. There are currently three types of solar thermal power systems in use or under development: the solar dish, solar power tower and parabolic trough.

 

Solar photovoltaics

Some materials are sensitive to a solar radiant or light energy. And thus they react in such a way, that we can harness this reaction to generate power.

Solar light energy can be converted directly into electricity during a single process due to using photovoltaic cells (also known as PVs or solar cells). These cells are the thin plates of light and sensitive silicon material.

The silicon, being combined with one or more other materials, exhibits unique electrical properties under the influence of sunlight. Electrons, gravitated by the light, move through the silicon. This process is known as the photovoltaic effect and results in direct current electricity.

The photovoltaic cells were discovered in early 1950’s by the researchers examining the sensitivity of a silicon wafer to sunlight. In the late 1950’s, PVs were used to power U.S. space satellites. This success led to the launch of commercial applications for PV technology. The simplest PV systems power small calculators and wrist watches which are used every day. More complicated systems generate power needed to pump water, supply communications equipment and even provide our homes with electricity.

 

Solar power as a source of energy: pro et contra

Advantages	Disadvantages
No Pollution	High initial cost
Renewable	Inefficient
Low maintenance	Reliable
Easy to install	Suitable only for certain locations

 
 

 

Biomass

Biomass is a renewable energy source because it contains the energy which comes from the Sun. Biomass is basically an organic material made from plants and animals. Through the process of photosynthesis, chlorophyll present in plants absorbs the energy from the Sun by converting the CO2 from air and ground water in carbohydrates. The chemical energy of plants is passed onto the animals and people that eat them.

So, when these plants and animals are burned, they turn back into CO2 and water and release the solar energy they contain. In that way, biomass could be defined as a renewable source of energy: almost always we have the ability to produce more crops and plants hence waste will always exist. As long as biomass is produced, this source of renewable energy lasts forever. Examples of biomass include: plants, crops, trees and garbage.

Biomass itself contains chemical energy. So, when you burn wood – which is a biomass fuel – the chemical energy inside it releases as a heat. It could also be used to produce steam which, in turn, has the ability to generate power. Using biomass as an energy source can help shortening waste and reducing landfill.

So, crux of the subject of whether biomass energy is renewable or not is related with the aspects of releasing, recycling and reusing CO2. Definitely, biomass is environment-friendly since it does not contribute to global warming and could be produced over and over again.

In 2002 in the United States the capacity of power generated from biomass was equal to 9 733 MW. In 2003 4% of total amount of the US energy was produced from biomass. As of 2004, all of the world’s power stations working on biomass were capable of producing the total capacity of 35 000 MW.

Nowadays European countries are experimenting with growing specialized energy forests for biomass production.

On large plantations come up various fast-growing trees: poplar, acacia, eucalyptus and others. Hitherto some twenty species of plants have been tested.

In Russia, up to 300 million tons of dry organic waste is collected every year. This volume includes 250 million tons of agricultural production and 50 million tons in a form of households’ waste.

 
Biomass as a source of energy: pro et contra

Advantages	Disadvantages
Widely Available	Expensive
Renewable resource	Requires a lot of space
Carbon neutral	May lead to deforestation
Helps reducing waste	Not totally clean

 
 
 
 
 

 

Nuclear power

Nuclear energy is not-quite-renewable source of energy that has gained popularity in the last decades. Definition states that nuclear energy is released from the very nucleus of an atom. This happens as a result of its mass being converted to energy. Even though using nuclear power is safer than producing electricity from fossil fuels, there is still a hazard to our health and the environment.

Nuclear power is produced via two different processes: Nuclear Fission and Nuclear Fusion.

 

Nuclear Fission

Nuclear Fission is a process of releasing the atomic energy by splitting the nucleus and thus creating two products with approximately half of the original’s mass. A nuclear reactor splits the nuclei of uranium atoms, creating large amounts of energy. The side effects of this process are radioactive waste and radiation, which could contaminate the environment. Nuclear Fission is a physical process responsible for all types of power generation – including that used in nuclear weapons and nuclear power stations.

 

Nuclear Fusion

Nuclear Fusion is a very promising mean of generating power. This process provides the Sun and the stars with the energy to shine continuously for billions of years. During Nuclear Fusion multiple atomic particles assemble together to create a larger atom. Fusion reactors join hydrogen atoms together to form helium atoms, neutrons and other forms of energy. This is the same type of nuclear energy used in hydrogen bombs. Fusion has been used on Earth earlier to produce nuclear bombs, but has not yet been controlled so that we can obtain useful energy. Unlike in Nuclear Fission, there is no limit in the amount of the fusion that can occur.

The Future of Nuclear Power

Nuclear energy is a powerful force. Attempts have been made to find other constructive ways of harnessing it. Nuclear power is an important source of energy for many countries. 442 nuclear reactors are now operating worldwide with a total capacity of 300 000 MW. According to the data of the International Atomic Energy Agency – the bastion of the global nuclear community – the mentioned number will grow in 2,5 times by 2030 and in 4 times by 2050.

Relatively high prices of oil and natural gas make alternatives – such as nuclear power – more attractive. This, as expected, shall lead to a growth in nuclear generating capacity worldwide. Improvements in reactor design enhance safety, increasing efficiency and reducing costs – these are reasons that make nuclear generation an economically attractive way of generating power. Many countries, including the UK, have recently affirmed their intention to continue the use of nuclear energy for power generation. Although this decision has been condemned by anti-nuclear pressure groups, all the indicators show that nuclear power will continue to be an important source of energy for us in a long perspective.

Environmental concerns about the disposal of spent nuclear fuel persist, and countries are addressing those concerns in different ways. For instance, the US is developing a disposal facility on government property – though this solution may seem quite controversial.

 

Nuclear power as a source of energy: pro et contra

Advantages	Disadvantages
Low pollution	Environmental impact
Low operating costs	Radioactive waste disposal
Reliable	Nuclear accidents
More proficient than fossil fuels	Expensive