Solar Energy-Fueling The Future Demand

EXECUTIVE SUMMARY

RESEARCH OBJECTIVE

The main focus of this study is to find out alternative ways to generate electricity (mainly from Solar Energy) at a smaller or medium level thus reducing dependence on the electricity supplied by the national grid. It is a work dedicated towards Sustainable Development of India which is a vital need for today’s degrading environment. Sustainable development can be achieved, starting with non-conventional methods for creating infrastructure to shifting dependence from fossil fuel(like coal) to renewable sources(like solar energy) to fulfil our ever increasing energy demand.
Renewable sources of energy, mainly Solar can play a major role in diminishing the demand-supply gap (12%, peak load deficit in India). Major advantages are:
‘ Environment friendly, they can help in protecting and hence sustaining environment and keeping the earth as green and clean as possible.
‘ Government Support is also immense towards this sector (e.g. Policies like Jawaharlal Nehru National Solar Mission (JNNSM).
‘ Fuel cost is zero and available abundantly w.r.t location of India on the globe.
The main focus of this report is to show that the solar energy is the better fuel than coal in future. And it will help in maintaining the environment and it helps in meeting the future demand.
In the attempt of making Solar Thermal plants (STPs) financially strong, concept of installing combined heat and power systems at STPs is discussed in this report and it is tried to prove that this concept is Feasible
‘ Financially,
‘ Economically,
‘ Ecologically,
‘ Operationally,
‘ Technically.
And also a brief introduction about the World’s Largest Solar Energy Project (5GW!) Planned for Gujarat, India.

INTRODUCTION

Energy is like an Engine to the whole world. It plays a pivotal role in our daily activities. The amount of utilization of energy by a country’s citizens measures the degree of development and civilization of a country. Demand of energy is increasing day by day due to rapid increase in population, urbanization and industrialization of world. The world’s fossil fuel supply i.e. coal, petroleum and natural gas are being depleted every day and in a few hundred years, these fossil fuel supply will be depleted completely. The rate of energy consumption is increasing; supply is depleting thus resulting in inflation and energy shortage. This is called energy crisis. Hence alternative sources of energy have to be developed to meet future energy requirement. Answer to this growing energy crisis is indeed RENEWABLE ENERGY.

1.2 ENERGY CLASSIFICATION:

Energy can be classified into several types:

1.2.1 Primary and Secondary Energy

Primary energy sources are those that are either found or stored in nature. Common primary energy sources are coal, oil, natural gas, and biomass (such as wood). Other primary energy sources available include nuclear energy from radioactive substances, thermal energy stored in earth’s interior, and potential energy due to earth’s gravity. The major primary and secondary energy sources are Coal, hydro power, natural gas, petroleum etc. Primary energy sources are mostly converted in industrial utilities into secondary energy sources, for example coal, oil or gas converted into steam and electricity. Primary energy can also be used directly. Some energy sources have non-energy uses, for example coal or natural gas can be used as a feedstock in fertilizer plants.

1.2.2 Commercial Energy and Non Commercial Energy

Those sources of energy that are available in the market for a definite price are known as commercial energy. The most important forms of commercial energy are electricity, coal and refined petroleum products. Commercial energy forms the basis of industrial, agricultural, transport and commercial development in the modern world. In the industrialized countries, commercialized fuels are predominant source not only for economic production, but also for many household tasks of general population. The sources of energy that are not available in the commercial market for a price are classified as non-commercial energy. Non-commercial energy sources include fuels such as firewood, cattle dung and agricultural wastes, which are traditionally gathered, and not bought at a price used especially in rural households. These are also called traditional fuels. Non-commercial energy is often ignored in energy accounting.

1.2.3 Renewable and Non- Renewable Energy

All forms of energy are stored in different ways, in the energy sources that we use every day. These sources are divided into two groups namely: Renewable (which can use over and over again) and Non-renewable (which cannot recreate in a short period of time).

FIGURE 1.1: RENEWABLE AND NON-RENEWABLE SOURCES OF ENERGY

Renewable and non-renewable energy sources can be used to produce secondary energy sources including electricity and hydrogen. Renewable energy sources include solar energy, which comes from the sun and can be turned into electricity and heat. Wind, geothermal energy from inside the earth, biomass from plants, and hydropower and ocean energy from water are also renewable energy sources. Today, most of our energy demands are satisfied by non-renewable energy sources, which include the fossil fuels – oil, natural gas, and coal. They’re called fossil fuels because they were formed over millions and millions of years by the action of heat from the Earth’s core and pressure from rock and soil on the remains (or “fossils”) of dead plants and animals. Nuclear energy is another non-renewable energy source in which the element uranium, whose atoms we split (through a process called nuclear fission) is used to create heat and ultimately electricity. We use all these energy sources to generate the electricity we need for our homes, businesses, schools, and factories. Electricity “energizes” our computers, lights, refrigerators, washing machines, and air conditioners, to name only a few uses. We use energy to run our cars and trucks. Both the petrol used in our cars, and the diesel fuel used in our trucks are made from oil.

1.3 The Sun & Energy

FIGURE1.2, THE SUN AND ENERGY

The sun is a star. It is the largest object in our solar system and one of the larger stars in our galaxy. The source of energy in the Sun is at its core where hydrogen is converted to helium in a thermonuclear reaction. This energy travels from the core to the surface of the Sun and is released into space primarily as light. The energy that comes to the Earth is in 2 main forms, heat and light.
Every hour, enough sunlight energy reaches the Earth to meet the world’s energy demand for a whole year.
— U.S. Department of Energy —
The amount of energy from the Sun that reaches the Earth annually is 4 x 1018 Joules.
4 x 1018 Joules/ Year ?? 365 Days/ Year = 1 x 1016 Joules/ Day
1 x 1016 Joules/ Day ?? 24 Hours/ Day = 4 x 1014 Joules/ Hour
The amount of energy consumed annually by the world’s population is about 3 x 1014 Joules.

Speed of Light Energy from the Sun to Earth.
The earth is the third planet from the sun at a distance of about 93,000,000 (93 million) miles. If you could pitch a fast baseball to the sun at 100 miles per hour (mph) it would take the ball over 100 years to get there. On the other hand, it only takes light energy 8?? minutes to reach the earth from the surface of the sun, traveling at the speed of light of course.
Pitching a Baseball at 100 mph to the Sun
93,000,000 miles ?? 100 miles/ hour = 930,000 hours to reach the Sun.
930,000 hours ?? 24 hours/ day = 38,750 days to reach the Sun;
38,750 days ?? 365 days per year = 106.16 years to reach the Sun.

Light Energy traveling to Earth
The speed of light is equal to about 11,000,000 (11 million) miles/ minute.
93,000,000 miles ?? 11,000,000 miles/ minute
= 8.45 minutes for light to travel from the Sun to Earth.
Calculations are rounded for simplicity.

1.4 SOLAR ENERGY
The word solar stems from the Roman word for the god of the sun, Sol. Therefore, the word solar refers to the Sun and ‘solar power’ is power from the Sun. When we say something is solar powered, we mean that the energy it uses for power came directly from solar energy or sunlight energy. The sun provides Earth with 2 major forms of energy, heat and light. Some solar powered systems utilize the heat energy for heating while others transform the light energy into electrical energy (electricity).

Fig. 1.4
There are many practical applications for solar power that are in use today. Passive solar home designs utilize heat energy. By slanting windows in a house and facing them to the south you can control the heat energy that enters the house. During the winter when the Sun is low in the sky it shines into the window to warm and illuminate the house. During the summer when the Sun is high in the sky the slant of the windows keeps the sunshine out so that the house stays cooler.
There are vehicles that run on solar power. Some have PV panels as a direct power source that converts light energy into electricity to power their motors. Since those cars will not run when the sun is not available it is more practical to have a car powered by batteries that can be recharged with solar energy. In countries and locations where traditional power sources are not available it is more economical to power a house with solar energy. To these a person, solar is not an alternative energy; it is their primary energy source.

1.5 Solar Energy- The Law of Conservation of Energy

The Law of Conservation of Energy:
‘ Energy can only change from one form to another.
‘ Energy cannot be created or destroyed.
Solar Energy is the energy from the Sun. The Sun is a big ball of heat and light resulting from nuclear fusion at its core. The nuclear reaction releases energy that travels outward to the surface of the Sun. Along the way to the surface the energy transforms so that by the time it is released it is primarily light energy. The two major types of solar energy that make it to Earth are heat and light.
Solar energy is often called ‘alternative energy’ to fossil fuel energy sources such as oil and coal.

Fig. 1.5
One example of our use of solar heat energy is for water heating systems. A solar panel is used to collect heat. The heat is transferred to pipes inside the solar panel and water is heated as it passes through the pipes. The hot water, heated by the Sun, can then be used for showers, cleaning, or heating your home.
We also use solar thermal energy through passive solar designs. Windows or skylights in your home can be designed to face the Sun so that they let heat into the house, keeping you warmer in the winter.
The light energy from the Sun can be transformed into electrical energy and used immediately or stored in batteries. Photovoltaic (PV) panels are the devices that convert light energy into electrical energy.
Energy changes from one Form to Another.

Fig. 1.6
Let’s look at a solar powered vehicle that runs on electricity directly from solar energy as a simple example in the transformation of energy from one form to another.
‘ Sunlight hits the PV panel and the panel transforms the light energy into electrical energy.
‘ The electrical energy (electricity) passes through the wire circuit to the motor.
‘ The motor transforms the electrical energy into mechanical energy to turn the drive shaft which turns the wheels.
‘ The wheels rotate on the ground to move the vehicle transforming mechanical energy into vehicle motion (kinetic energy).
Solar Vehicle Ideal Energy Chain:
Light Energy >> Electrical Energy >> Mechanical Energy >> Kinetic Energy

Energy transformation is not perfect…..
The above case is ideal because not all systems are perfect and in reality there will be losses of energy from our system.
In a simplified view of this case some losses will be from:
‘ Friction of electrons passing through the wires; this is released as heat energy.
‘ Friction of the drive shaft or wheels on the ground; this is released as either heat or sound energy.
Even with these losses the law of conservation of energy still holds. The amount of energy into a system will always equal the amount of energy out of a system.

1.6 Solar Energy in India

India is densely populated and has high solar insolation, an ideal combination for using solar power in India. India is already a leader in wind power generation. In the solar energy sector, some large projects have been proposed, and a 35,000 km2 area of the Thar Desert has been set aside for solar power projects, sufficient to generate 700 GW to 2,100 GW.
In July 2009, India unveiled a US$19 billion plan to produce 20 GW of solar power by 2020. Under the plan, the use of solar-powered equipment and applications would be made compulsory in all government buildings, as well as hospitals and hotels. On November 18, 2009, it was reported that India was ready to launch its National Solar Mission under the National Action Plan on Climate Change, with plans to generate 1,000 MW of power by 2013.

Current status
With about 300 clear, sunny days in a year, India’s theoretical solar power reception, on only its land area is about 5 Petawatt-hours per year (PWh/yr.) (i.e. 5 trillion kWh/yr. or about 600 TW). The daily average solar energy incident over India varies from 4 to 7 kWh/m2 with about 1500’2000 sunshine hours per year (depending upon location), which is far more than current total energy consumption. For example, assuming the efficiency of PV modules were as low as 10%, this would still be a thousand times greater than the domestic electricity demand projected for 2015.

Installed capacity
The amount of solar energy produced in India is less than 1% of the total energy demand. The grid-interactive solar power as of December 2010 was merely 10 MW. Government-funded solar energy in India only accounted for approximately 6.4 MW-yr of power as of 2005. However, as of October 2009, India is currently ranked number one along with the United States in terms of solar energy production per watt installed.

Fig Solar Resource Map of India

Table 1.1 India’s largest photovoltaic (PV) power plants
Name of Plant DC Peak Power
(MW) GW’h
/year[10]
Capacity
factor Notes
Adani Bitta Solar Plant, Gujarat[11]
40 To be Completed December 2011
Sivaganga Photovoltaic Plant[12]
5 Completed December 2010
Kolar Photovoltaic Plant[13]
3 Completed May 2010
Itnal Photovoltaic Plant, Belgaum[14]
3 Completed April 2010
Azure Power – Photovoltaic Plant[15]
2 2009
Chesdin Power – Biomass and Solar Photovoltaic Plants[16]
4.1 Completes December 2011
Jamuria Photovoltaic Plant[17]
2 2009
NDPC Photovoltaic Plant[18]
1 2010
Thyagaraj stadium Plant-Delhi[19]
1 April, 2010
Gandhinagar Solar Plant[20]
1 January 21, 2011
Tata – Mulshi, Maharashtra[21]
3 Commissioned April 2011
Azure Power – Sabarkantha, Gujarat[22]
10 Commissioned June 2011
Moser Baer – Patan, Gujarat[23]
30 To Be Commissioned July 2011
Tata – Mayiladuthurai, Tamil Nadu[24]
1 Commissioned July 2011
REHPL – Sadeipali, (Bolangir) Orissa [25]
1 Commissioned July 2011
Tata – Patapur, Orissa [26]
1 Commissioned August 2011
Tata – Osmanabad, Maharastra [27]
1 Commissioned 1st Aug 2011
Abengoa – Gwal Pahari, Haryana[28]
3 Commissioned September 2011
Chandraleela Power Energy – Narnaul, Haryana (EPC by Aryav Green Energy Solutions Pvt. Ltd.) [29]
0.8 To be Commissioned December 2011
Green Infra Solar Energy Limited – Rajkot, Gujarat [30]
10 Commissioned November 2011
Total 122.9

Still unaffordable

Solar power is currently prohibitive due to high initial costs of deployment. To spawn a thriving solar market, the technology needs to be competitively cheaper (i.e. attaining cost parity with fossil or nuclear energy). India is heavily dependent on coal and foreign oil, a phenomenon likely to continue until non-fossil/renewable energy technology becomes economically viable in the country. The cost of production ranges from 15 to 30 per unit compared to around 5 to 8 per unit for conventional thermal energy.

Solar engineering training

The Australian government has awarded UNSW A $5.2 million to train next-generation solar energy engineers from Asia-Pacific nations, specifically India and China, as part of the Asia-Pacific Partnership on Clean Development and Climate (APP). Certain programmes are designed to target for rural solar usage development. [35]

Future applications

Rural electrification

Lack of electricity infrastructure is one of the main hurdles in the development of rural India. India’s grid system is considerably under-developed, with major sections of its populace still surviving off-grid. As of 2004 there are about 80,000 unelectrified villages in the country. Of these villages, 18,000 could not be electrified through extension of the conventional grid. A target for electrifying 5,000 such villages was set for the Tenth National Five Year Plan (2002’2007). As of 2004, more than 2,700 villages and hamlets had been electrified, mainly using solar photovoltaic systems.[4] Developments in cheap solar technology are considered as a potential alternative that allows an electricity infrastructure consisting of a network of local-grid clusters with distributed electricity generation. It could allow bypassing (or at least relieving) the need to install expensive, loss, long-distance, centralised power delivery systems and yet bring cheap electricity to the masses.
Projects currently planned include 3000 villages of Orissa, which will be lighted with solar power by 2014.

Agricultural support

Solar PV water pumping systems are used for irrigation and drinking water. The majority of the pumps are fitted with a 200’3,000 watt motor that are powered with 1,800 Wp PV array which can deliver about 140,000 litres of water per day from a total head of 10 meters. By 30 September, 2006, a total of 7,068 solar PV water pumping systems had been installed. Solar driers are used to dry harvests before storage.

Solar water heaters

Bangalore has the largest deployment of rooftop solar water heaters in India. These heaters will generate an energy equivalent of 200 MW every day. Bangalore is also the first city in the country to put in place an incentive mechanism by providing a rebate (which has just been increased to50) on monthly electricity bills for residents using roof-top thermal systems. These systems are now mandatory for all new structures. Pune, another city in the western part of India, has also recently made installation of solar water heaters in new buildings mandatory.

Government support

The government of India is promoting the use of solar energy through various strategies. In the latest budget for 2010/11, the government has announced an allocation of 10 billion (US$202.8 million) towards the Jawaharlal Nehru National Solar Mission and the establishment of a clean energy fund. It is an increase of 3.8 billion (US$77.1 million) from the previous budget. This new budget has also encouraged private solar companies by reducing customs duty on solar panels by 5% and exempting excise duty on solar photovoltaic panels. This is expected to reduce the cost of a roof-top solar panel installation by 15’20%. The budget also proposed a coal tax of US$1 per metric ton on domestic and imported coal used for power generation. Additionally, the government has initiated a Renewable Energy Certificate (REC) scheme, which is designed to drive investment in low-carbon energy projects. The Ministry of New and Renewable Energy (MNRE) provides 70% subsidy on the installation cost of a solar photovoltaic power plant in North-East states and 30 percentage subsidy on other regions. The detailed outlay of the National Solar Mission highlights various targets set by the government to increase solar energy in the country’s energy portfolio.

Fig. 1.7

1.7 SOLAR POWER AS A SOLUTION TO THE INDIAN POWER SCENARIO:

Due to its proximity to the equator, India receives abundant sunlight throughout the year. Solar PV solution has the potential to transform the lives of 450 million people, who rely on highly subsidized kerosene oil and other fuels, primarily to light up their homes. Renewable energy source is a practical solution to address the persistent demand supply gap in the power industry. The following features of solar power make it the most viable renewable source of energy for India:

‘ Solar energy is available in abundance.
‘ Available across the country ‘ unlike other renewable sources, which have geographical limitations.
‘ Available throughout the year
‘ Decentralized / off-grid applications ‘ addressing rural electrification issues
‘ Modularity and scalability.

The PV approach is particularly suited for the geographical and socio-economic features of this country having highly skewed energy distribution between urban and rural areas.

1.8 SOLAR PV APPLICATIONS IN INDIA:

The range of applications for solar PV in India is very different from the global mix. Globally, grid connectivity accounts for nearly 75% of the installed capacity and off-grid lighting and consumer applications for the balance 25%.Currently, PV installations in India, almost entirely consist of off-grid connectivity and small capacity applications, used mostly for public lighting, such as street lighting, traffic lighting, and domestic power back up in urban areas and small electrification systems and solar lanterns in the rural areas. In recent years, it is also being used for powering water pumps for farming and small industrial areas. Government organizations like railways, telecom and other agencies are the major consumers of PV solar systems in India.

The installed base of solar PV systems in India as of December 2009 is given below:

PV Based Systems
Total Installations

Solar Street Lighting System 54,795
Home Lighting System 434,692
Solar Lanterns 697,419
Solar PV Pumps 7,148
Solar PV generation Plants 2.12 MWp

Table 1.2: Status of installed base of solar PV systems in India

1.9 WHY SOLAR ENERGY IS PREFERRED OVER OTHER SOURCES OF RENEWABLE ENERGY?
Various types of nonconventional energy sources are such as geothermal ocean tides, wind and sun. All nonconventional energy sources have geographical limitations. But Solar energy has less geographical limitation as compared to other nonconventional energy sources because solar energy is available over the entire globe, and only the size of the collector field needs to be increased to provide the same amount of heat or electricity. It is the primary task of the solar energy system designer to determine the amount, quality and timing of the solar energy available at the site selected for installing a solar energy conversion system so among all these solar energy seems to hold out the greatest promise for the mankind. It is free, inexhaustible, non-polluting and devoid of political control. Solar water heaters, space heaters and cookers are already on the market and seem to be economically viable. Solar photo voltaic cells, solar refrigerators and solar thermal power plants will be ‘technically and economically viable in a short time. It is optimistically estimated that 50% of the world power requirements in the middle of 21st century will come only from solar energy. Enough strides have been made during last two decades to develop the direct energy conversion systems to increase the plant efficiency 60% to 70% by avoiding the conversion of thermal energy into mechanical energy. Still this technology is on the threshold of the success and it is hoped that this will also play a vital role in power generation in coming future.

SOLAR PHOTOVOLTAIC TECHNOLOGY

Chapter 2

Introduction

Photovoltaic offer consumers the ability to generate electricity in a clean, quiet and reliable way. Photovoltaic systems are comprised of photovoltaic cells, devices that convert light energy directly into electricity. Because the source of light is usually the sun, they are often called solar cells. The word photovoltaic comes from ‘photo’ meaning light and ‘voltaic’ which refers to producing electricity. Therefore, the photovoltaic process is ‘producing electricity directly from sunlight. Photovoltaic are often referred to as PV.

2.1 BRIEF HISTORY:

In 1839 Edmond Becquerel accidentally discovered photovoltaic effect when he was working on solid-state physics. In 1878 Adam and Day presented a paper on photovoltaic effect. In 1883, Fxitz fabricated the first thin film solar cell. In 1941 Ohl fabricated silicon PV cell but that was very inefficient. In 1954 Bell labs Chopin, Fuller, Pearson fabricated PV cell with efficiency of 6%. In 1958 PV cell was used as a backup power source in satellite Vanguard-1. This extended the life of satellite for about 6 years.

2.2 PHOTOVOLTAIC CELL:

A Photovoltaic cell is a device that produces an electric reaction to light, producing electricity. PV cells do not use the sun’s heat to produce electricity. They produce electricity directly when sunlight interacts with semiconductor materials in the PV cells.

Fig. 2.1

‘A typical PV cell made of crystalline silicon is 12 centimetres in diameter and 0.25 millimetres thick. In full sunlight, it generates 4 amperes of direct current at 0.5 volts or 2 watts of electrical power’.

FIGURE 2.2: ROOF TOP SOLAR MODULES

2.3 SOLAR THERMAL POWER GENERATION TECHNOLOGIES:

Solar Thermal Power systems, also known as Concentrating Solar Power systems, use concentrated solar radiation as a high temperature energy source to produce electricity using thermal route. Since the average operating temperature of stationary non-concentrating collectors is low (max up to 1200C) as compared to the desirable input temperatures of heat engines (above 3000C), the concentrating collectors are used for such applications. These technologies are appropriate for applications where direct solar radiation is high. The mechanism of conversion of solar to electricity is fundamentally similar to the traditional thermal power plants except use of solar energy as source of heat.
In the basic process of conversion of solar into heat energy, an incident solar irradiance is collected and concentrated by concentrating solar collectors or mirrors, and generated heat is used to heat the thermic fluids such as heat transfer oils, air or water/steam, depending on the plant design, acts as heat carrier and/or as storage media. The hot thermic fluid is used to generated steam or hot gases, which are then used to operate a heat engine. In these systems, the efficiency of the collector reduces marginally as its operating temperature increases, whereas the efficiency of the heat engine increases with the increase in its operating temperature.

Concentrating solar collectors:
Solar collectors are used to produce heat from solar radiation. High temperature solar energy collectors are basically of three types;
a. Parabolic trough system: at the receiver can reach 400?? C and produce steam for generating electricity.
b. Power tower system: The reflected rays of the sun are always aimed at the receiver, where temperatures well above 1000?? C can be reached.
c. Parabolic dish systems: Parabolic dish systems can reach 1000?? C at the receiver, and achieve the highest efficiencies for converting solar energy to electricity.

a.) Parabolic trough collector system

Parabolic trough power plants are line-focusing STE (solar thermal electric) power plants. Trough systems use the mirrored surface of a linear parabolic concentrator to focus direct solar radiation on an absorber pipe running along the focal line of the parabola. The HTF (heat transfer fluid) inside the absorber pipe is heated and pumped to the steam generator, which, in turn, is connected to a steam turbine. A natural gas burner is normally used to produce steam at times of insufficient insolation. The collectors rotate about horizontal north’south axes, an arrangement which results in slightly less energy incident on them over the year but favors summertime operation when peak power is needed. The major components in the system are collectors, fluid transfer pumps, power generation system and the controls. This power generation system usually consists of a conventional Rankine cycle reheat turbine with feed water heaters deaerators, etc. and the condenser cooling water is cooled in forced draft cooling towers. These types of power plants can have energy storage system comprising these collectors usually have the energy storage facilities. Instead they are couple to natural gas fired back up systems. A typical configuration of such systems is shown in Figure 2.3

FIGURE 2.3 CONFIGURATION OF PTC SOLAR THERMAL POWER PLANT

These systems were commercialized in 1980’s in California in the United States. LUZ Company installed nine such plants between 1980’1989 totalling to 350 MWe capacity. These plants are commonly known as SEGS (solar electric generator systems). SEGS uses oil to take the heat away: the oil then passes through a heat exchanger, creating steam which runs a steam turbine.
Besides research and development in components and materials, two major technological developments are under way; 1.Integration of parabolic trough power plants in Combined Cycle plants and, 2. Direct steam generation in the collectors’ absorber tubes. Using direct solar steam generation the HTF and water heat exchanger will no longer be required resulting in improvement of the efficiency conditions can be achieved which increases overall efficiency of cycle

b.) Power tower system

In power tower systems, heliostats (A Heliostat is a device that tracks the movement of the sun which is used to orient a mirror of field of mirrors, throughout the day, to reflect sunlight onto a target-receiver) reflect and concentrate sunlight onto a central tower-mounted receiver where the energy is transferred to a HTF. This energy is then passed either to the storage or to power-conversion systems, which convert the thermal energy into electricity. Heliostat field, the heliostat controls, the receiver, the storage system, and the heat engine, which drives the generator, are the major components of the system.
For a large heliostat field a cylindrical receiver has advantages when used with Rankine cycle engines, particularly for radiation from heliostats at the far edges of the field. Cavity receivers with larger tower height to heliostat field area ratios are used for higher temperatures required for the operation of Brayton cycle turbines (Figure 2.4).

FIGURE 2.4 SCHEMATIC OF POWER TOWER SYSTEM

These plants are defined by the options chosen for a HTF, for the thermal storage medium and for the power-conversion cycle. HTF may be water/steam, molten nitrate salt, liquid metals or air and the thermal storage may be provided by PCM (phase change materials). Power tower systems usually achieves concentration ratios of 300’1500, can operate at temperatures up to 1500o C. To maintain constant steam parameters even at varying solar irradiation, two methods can be used:
‘ Integration of a fossil back-up burner; or
‘ Utilization of a thermal storage as a buffer
By the use of thermal storage, the heat can be stored for few hours to allow electricity production during periods of peak need, even if the solar radiation is not available. The modern R&D efforts have focused on polymer reflectors and stretched-membrane heliostats. A stretched-membrane heliostat consists of a metal ring, across which two thin metal membranes are stretched. A focus control system adjusts the curvature of the front membrane, which is laminated with a silvered-polymer reflector, usually by adjusting the pressure in the plenum between the two membranes.
Examples of heliostat based power plants were the 10 MWe Solar One and Solar Two demonstration projects in the Mojave Desert, which have now been decommissioned. The 15 MW Solar Tres Power Tower in Spain builds on these projects. In Spain the 11 MW PS10 Solar Power Tower was recently completed. In South Africa, a solar power plant is planned with 4000 to 5000 heliostat mirrors, each having an area of 140 m??.

c.) Parabolic dish system

The parabolic dish system uses a parabolic dish shaped mirror or a modular mirror system that approximates a parabola and incorporates two-axis tracking to focus the sunlight onto receivers located at the focal point of the dish, which absorbs the energy and converts it into thermal energy. This can be used directly as heat for thermal application or for power generation. The thermal energy can either be transported to a central generator for conversion, or it can be converted directly into electricity at a local generator coupled to the receiver (Figure 2.5).

FIGURE 2.5 SCHEMATIC OF PARABOLIC DISH SYSTEM

The mirror system typically is made from a number of mirror facets, either glass or polymer mirror, or can consist of a single stretched membrane using a polymer mirror of thin metal stretched membrane.
The PDCs (parabolic dish collector) track the sun on two axes, and thus they are the most efficient collector systems. Their concentration ratios usually range from 600 to 2000, and they can achieve temperatures in excess of 1500o C. Rankine-cycle engines, Brayton-cycle engines, and sodium-heat engines have been considered for systems using dish-mounted engines the greatest attention though was given to Stirling-engine systems.
The main challenge facing distributed-dish systems is developing a power-conversion unit, which would have low capital and maintenance costs, long life, high conversion efficiency, and the ability to operate automatically. Several different engines, such as gas turbines, reciprocating steam engines, and organic Rankine engines, have been explored, but in recent years, most attention has been focused on Stirling-cycle engines. These are externally heated piston engines in which heat is continuously added to a gas (normally hydrogen or helium at high pressure) that is contained in a closed system.
The Sterling Energy Systems (SES) and Science Applications International Corporation (SAIC) dishes at UNLV and the Big Dish in Canberra, Australia are representatives of this technology.

d.) Solar chimney

This is a fairly simple concept. As shown in figure 2.6 the solar chimney has a tall chimney at the center of the field, which is covered with glass. The solar heat generates hot air in the gap between the ground and the gall cover which is then passed through the central tower to its upper end due to density difference between relatively cooler air outside the upper end of the tower and hotter air inside tower. While traveling up this air drives wind turbines located inside the tower. These systems need relatively less components and were supposed to be cheaper. However, low operating efficiency, and need for a tall tower of height of the order of 1000m made this technology a challenging one. A pilot solar chimney project was installed in Spain to test the concept. This 50kW capacity plant was successfully operated from 1982 to 1989. Figure 2.6 shows the picture of this plant. Recently, EnviroMission Limited, an Australian company, has started work on setting up first of its five projects based on solar chimney concept in Australia.

Figure2.6 50 kW solar chimney pilot project, Manzanares, Spain

The Luz Company which developed parabolic trough collector based solar thermal power technology went out of business in 1990’s which was a major setback for the development of solar thermal power technology.

2.4 ELEMENTS INCLUDED IN A SYSTEM OF PHOTOVOLTAIC
CONVERSION:

The main elements that can be included in a system of photovoltaic conversion are: Batteries, Photovoltaic Modules, Loads DC and AC, Load Regulators, Invertors, Converters.

‘ Batteries: Normally they have been considered as a simple element of storage of electrical energy. Batteries are often sold with a PV system. The primary purpose is to store the electricity not immediately used, which could be used at some later time.
With net metering, the value of batteries is less because the utility grid basically acts as a storage facility. For a reliable generation system that can function independent of the utility grid, however, batteries may be a viable component to the total system. Back-up generators may be included in a system to provide power when the PV system is not operating, and are generally included when systems are not grid connected. Neither batteries nor generators are eligible for rebate money.

‘ Solar panel: The solar panel is the power source of all photovoltaic installation. It is the result of a set of photovoltaic cells in series and parallel. Solar panel gives power to battery or inverter through charge controller (Regulator).

‘ Regulator: It is the element to protect the battery against to risking situations as overloads and over discharges. The theoretical formulation of the model can be simple, although it is necessary to consider the peculiar discontinuities of the model and the inter performance with the rest of the analysed models.

‘ Inverter: The inverter allows transforming the DC current to AC. A photovoltaic installation that incorporates an inverter can belong to two different situations, based on the characteristics of the alternating network. In first an isolated system, where the inverter is the element of the network and has to feed the set of loads and in second situation the inverter is connected to the public network, to which it sends the energy generated by the system.

‘ Converter: The positioning of a converter between the panels and the batteries will improve the whole photovoltaic installation, allowing different controls from the system. Depending on the applied regulation, the panels will contribute to the maximum energy given to the system or the optimal energy for their operation, assuring an efficient charge of the battery.

‘ Load: It is the component responsible to absorb this energy and transform it into work

2.5 TYPES OF PHOTOVOLTAIC SYSTEM:

PV technology was first applied in space, by providing electricity to satellites. Today, PV systems can be used to power just about anything on Earth. On the basis working operation PV systems operate in four basic forms.

‘ Grid Connected PV Systems – These systems are connected to a broader electricity network. The PV system is connected to the utility grid using a high quality inverter, which converts DC power from the solar array into AC power that conforms to the grid’s electrical requirements. During the day, the solar electricity generated by the system is either used immediately or sold off to electricity supply companies. In the evening, when the system is unable to supply immediate power, electricity can be bought back from the network.

FIGURE 2.7: GRID CONNECTED PV SYSTEMS

‘ Standalone Systems: PV systems not connected to the electric utility grid are known as Off Grid PV Systems and also called ‘stand-alone systems.’ Direct systems use the PV power immediately as it is produced, while battery storage systems can store energy to be used at a later time, either at night or during cloudy weather. These systems are used in isolation of electricity grids, and may be used to power radio repeater stations, telephone booths and street lighting. PV systems also provide invaluable and affordable electricity in developing countries like India, where conventional electricity grids are unreliable or non-existent.

FIGURE 2.8: OFF GRID PV SYSTEMS

‘ Hybrid System: A hybrid system combines PV with other forms of power generation, usually a diesel generator. Biogas is also used. The other form of power generation is usually a type which is able to modulate power output as a function of demand. However more than one form of renewable energy may be used e.g. wind and solar. The photovoltaic power generation serves to reduce the consumption of non renewable fuel.

FIGURE 2.9: HYBRID SYSTEM

‘ Grid Tied with Battery Backup PV system: Solar energy stored in batteries can be used at night time. Using net metering, unused solar power can be sold back to the grid. With this system, you will have power even if your neighbourhood has lost power.

2.6 GRID CONNECTED PV SYSTEM IS PREFFERED:

Because as day by day the demand of electricity is increased and that much demand cannot be meeting up by the conventional power plants. And also these plants create pollution. So if we go for the renewable energy it will be better but throughout the year the generation of all renewable energy power plants. Grid tied PV system is more reliable than other PV system. No use of battery reduces its capital cost so we go for the grid connected topology. If generated solar energy is integrated to the conventional grid, it can supply the demand from morning to afternoon (total 6 hours mainly in sunny days) that is the particular time range when the SPV system can fed to grid. As no battery backup is there, that means the utility will continue supply to the rest of the time period. Grid-connected systems have demonstrated an advantage in natural disasters by providing emergency power capabilities when utility power was interrupted. Although PV power is generally more expensive than utility-provided power, the use of grid connected systems is increasing.

INTRODUCTION OF COAL

Chapter=3

3.1 INTRODUCTION

Coal is non-renewable energy source. Coal, together with oil and natural gas belongs to fossil fuels. Coal was formed about 300 million years ago. Coal is a combustible mostly black sedimentary rock composed mostly of carbon and hydrocarbons. Coal takes a million years to create and therefore it belongs to non-renewable energy sources. Coal mining uses two methods: surface or underground mining where surface mining is more dominant method because it is less expensive than the underground mining. Coal is mostly transported by train. Coal as the other fossil fuels as well isn’t ecologically acceptable because of CO2 and global warming. Coal is classified into four main types: lignite, subbituminous, bituminous, anthracite and the coal value is determined by the amount of the carbon it contains. Coal is mined in 27 US states. Coal is mainly used for generating electricity (more than 90 % of US coal). Coal has a long history of use, and its use started somewhere during the Bronze Age (3000’2000 BC). Fast developing economies like China and India owe their economic success to coal, mostly because coal is still the cheapest energy option, and is widely available in many countries across the globe. Coal is extracted from the ground by mining, either underground or in open pits. The total known coal deposits recoverable by current technologies should last for more than 100 years. On the other hand coal consumption is constantly increasing and some energy experts even believe that maximal coal production could be reached within the decades.

Currently, some 63% of the electricity generated in India is produced from coal. India’s iron and steel industry also depends on the use of coal – it is the principal form of reluctant in the metallurgical industries. The importance of other fossil fuels (oil and gas) and alternative energy sources (such as nuclear and renewable) cannot be ignored. Today, none of these alternatives offers a trouble-free, long-term economic source of energy. At current production levels, known coal reserves are forecast to last over 200 years – significantly longer than known reserves of oil or gas. However, all fossil fuel reserves are finite – they need to be used as efficiently as commercially possible in order to conserve valuable resources. Coal usually has a negative impact on environment, mining can damage ground and surface waters and when coal burns as the fuel it releases CO2 which is the main greenhouse gas that causes global warming.

3.2 Coal Reserves

China is currently the world’s largest coal producer, followed by United States and India. At the end of 2006 the recoverable coal reserves amounted to around 800 or 900 gigatons. If we were to look at the current rates of extraction and use this should last for around 132 years.
British Petroleum, in its 2007 report, estimated at 2006 end, there were 909,064 million tons of proven coal reserves worldwide, or 147 years reserves-to-production ratio. This number however only includes reserves classified as “proven”, and in many cases, companies are aware of coal deposits that have not been sufficiently drilled to qualify as “proven”.
According to the BP’s Statistical Review of World Energy in 2009 global proven coal reserves are at the highest levels of all time. Global reserves of coal were at 826,001 million tons at the end of 2009. This is 119 years of production at 2009 production levels and the United States has the largest share (28 per cent) of these coal reserves.
If we compare coal with other fossil fuels (oil and natural gas) we can see that coal has the most widely distributed reserves; coal is mined in over 100 countries, and on all continents except Antarctica. The largest reserves are found in the USA, Russia, Australia, China, India and South Africa.

3.3 Coal ‘ Environmental impact

Many environmentalists will agree that burning coal is the most polluting method for producing electricity, and is causing huge environmental damage. The worst thing that happens in this process is of course the production of greenhouse gases (mostly carbon dioxide emissions) by burning coal, but carbon emissions are not the only negative thing in this process as there are also many other harmful compounds released during coal burning. It also has to be said environmental problems connected with coal are not only limited to the burning process. The extraction of coal, its transportation, storage and disposal of all create additional environmental issues.
The total amount of pollution caused by burning coal depends on the type of technology that is used for burning. New coal-fired power plant technologies are emerging with the ability to reduce the amount of carbon emissions and other harmful compounds released during the burning process. Integrated gasification combined cycle (IGCC) combustion is the best example of this new technology and some experts say this significantly reduces harmful carbon emissions. Despite certain reductions in carbon emissions from the use of IGCC technology, coal fired power plants will still have very negative impact on environment. A typical (500 megawatt) coal plant burns 1.4 million tons of coal each year. If we look at the United States alone we can see that there are about 600 coal power plants in US.
Carbon emissions are one problem connected with coal burning and air pollution is another. Air pollution is a major cause of environmental degradation, and there are also sulfur dioxide and nitrous oxides being released into the atmosphere causing acid rain and lung problems in humans and animals. Together with these harmful particles there are also some amounts of mercury, arsenic and lead, all of which can have serious health impact on living organisms.
And there is also the problem with the waste. The waste created from the coal burning is also very harmful to our environment. The sludge from smoke stack scrubbers is toxic, containing a number of heavy metals that can potentially contaminate the environment. Large quantities of coal waste are stored on site at the power plant, and thus it can easily enter the water supply of the surrounding area, contaminating it. When we talked about the water then I should also point out that the water used to cool the coal power plants is often sourced from a local water body and then simply pumped back after it has been used. This hot water, often containing chlorine or other chemicals, can result algal blooms and some other environmental problems. The extraction and transportation of coal to a power plant is also connected with the number of different environmental issues. Since coal is predominantly mined from near the surface, this often causes damage to nearby ecosystems as many of the ecosystems above are degraded or sometimes even completely removed. Coal is usually transported by diesel trains over great distances, meaning that there’s an extra releasing of carbon dioxide and other harmful particles. And there is also coal dust that once produced contributes to particulate matter in the air (air pollution).

Burning coal is a leading cause of smog, acid rain, global warming, and air toxics. In an average year, a typical coal plant generates:

‘ 3,700,000 tons of carbon dioxide (CO2), the primary human cause of global warming–as much carbon dioxide as cutting down 161 million trees.
‘ 10,000 tons of sulphur dioxide (SO2), which causes acid rain that damages forests, lakes, and buildings, and forms small airborne particles that can penetrate deep into lungs.
‘ 500 tons of small airborne particles, which can cause chronic bronchitis, aggravated asthma, and premature death, as well as haze obstructing visibility.
‘ 10,200 tons of nitrogen oxide (NOx), as much as would be emitted by half a million late-model cars. NOx leads to formation of ozone (smog) which inflames the lungs, burning through lung tissue making people more susceptible to respiratory illness.
‘ 720 tons of carbon monoxide (CO), which causes headaches and place additional stress on people with heart disease.
‘ 220 tons of hydrocarbons, volatile organic compounds (VOC), which form ozone.
‘ 170 pounds of mercury, where just 1/70th of a teaspoon deposited on a 25-acre lake can make the fish unsafe to eat.
‘ 225 pounds of arsenic, which will cause cancer in one out of 100 people who drink water containing 50 parts per billion.
‘ 114 pounds of lead, 4 pounds of cadmium, other toxic heavy metals, and trace amounts of uranium.

REVIEW OF EARLIER WORKS

Chapter 4

4.1 INTRODUCTION:

It is important to state that the amount of literature on solar energy, the solar energy system and PV grid connected systems is enormous. So much study is needed to design a grid connected PV system without battery backup accurately from first principles. The author of this thesis has attended courses on the subject, read books, journals and papers. This chapter will cover just a little portion of that enormous amount of literature.

4.2 REVIEW OF EARLIER WORKS:

Several works are going on solar photovoltaic systems. Some of these are discussed below:

1. P.Sritakaew & A.Sangswang, ‘On the Reliability Improvement of Distribution Systems Using PV Grid-Connected Systems’. IEEE Asia Pacific Conference on Circuits and systems. pp.1354 – 1357, 2006.

Prakasit Sritakaew, Anawach Sangswang, and Krissanapong Kirtikara presented a paper about On the Reliability Improvement of Distribution Systems Using PV Grid-Connected Systems. The purpose of their paper was to examine issues related to the distribution system reliability improvement using photovoltaic (PV) grid-connected systems. The output characteristics of a PV system were experimentally measured. The measured data were used to investigate the effects of PV system installation to improve the distribution system’s reliability. The system constraints such as, recovered real power, and loading reduction of the tie line/switch after the installation of PV grid-connected systems are concentrated. Simulation results show that with the action of a tie switch, system losses and loading level of the tie switch can be reduced with proper installation location.
2. Allen M. Barnett, ‘Solar electrical power for a better tomorrow’. Photovoltaic Specialists IEEE Conference, Page(s): 1 ‘ 8, 1996.

Allen M. Barnett presented a paper about solar electrical power for a better tomorrow. The promise of solar electricity based on the photovoltaic (PV) effect is well known. Why don’t we see these systems all over the world? Consumers in the United States are well-known for their attraction to new technology. Why aren’t PV systems appearing on roof-tops in the U.S.?

The answer may be that grid-connected roof top systems are too difficult to acquire, too difficult to integrate with the grid, too difficult to measure the energy and too expensive .It is essential that we make PV systems user friendly, while reducing the component and system costs. Our elegant technology must be reduced to practical systems that can be used by the average person – everywhere.

3. N. Jenkins, ‘Photovoltaic systems for small-scale remote power supplies’, IET Journals. Volume: 9, Page(s): 89 ‘ 96, 1995.

N. Jenkins presented a paper about Photovoltaic systems for small-scale remote power supplies. In his article, he considers the technical aspects of using photovoltaic systems for small power supplies where a connection from a main electricity distribution network is not appropriate. The technology of the various components of a photovoltaic system is discussed and the overall system design considered. Typical applications of photovoltaic systems are described.

4. Souvik Ganguli and Sunanda Sinha, ‘A Study and Estimation of Grid Quality Solar
Photovoltaic Power Generation Potential in some districts of West Bengal’. National
Conference on Trends in Instrumentation & Control Engineering, Thapar University,
Patiala, Page(s): 522-528, 29-30th Oct., 2009.

Souvik Ganguli & Sunanda Sinha presented a paper about Estimation of Grid Quality Solar Photovoltaic Power Generation Potential and its Cost Analysis in Some Districts of West Bengal. The objective of their work was to estimate the potential of grid quality solar photovoltaic power in some districts of West Bengal (Birbhum, Burdwan, Hooghly, Howrah and Kolkata), study the solar radiation level and potential of the above mentioned districts and finally develop a system corresponding to the potential. Equipment specifications were provided based on the system developed and finally cost analysis was also carried out.

5. A paper about Effects of the Solar Module Installing Angles on the Output Power. In their paper they discussed that the output power increment of photovoltaic cells is mainly based on two factors. One is decreasing the cell modular temperature and the other is increasing the cells received solar illumination intensity. The former can be simply achieved by maintaining a proper radiating space between the modules and the ground. The later is more complicated. One needs to consider the installation of cell modules and then the maximum power output which can be derived. This paper was theoretically calculated the solar orbit and position at any time and any location. With the estimation of their model on the variation of solar illumination intensity, they can derive the output power of the solar modular cell at any tilt angle and orientation. The simulated results could be utilized in large scale photovoltaic power generation systems when considering placement for optimal installation. It also provides a useful evaluation for the output power of photovoltaic cells mounted on roofs and out walls of buildings.

6. D. Picault, B. Raison, and S. Bacha, ‘Guidelines for evaluating grid connected PV
System topologies’. IEEE International Conference on Industrial Technology.
Page(s): pp. 1-5, 2009.

Several grid connected photovoltaic system topologies are used in existing installations. D.Picault, B. Raison, and S. Bacha presented a paper about proposes evaluation criteria for comparing and choosing topologies compatible with the user’s demands. After presenting an overview of current architectures used in grid connected systems, five key points for comparison based on topology upgradeability, performance under shaded conditions, degraded mode operation, investment costs and ancillary service participation were discussed. The proposed method can be adapted to the user’s particular needs and expectations of the photovoltaic plant. These evaluation guidelines may assist grid-tied PV system users to choose the most convenient topology for their application by weighting the evaluation criteria.

7. A paper, written by anonymous writer, about performance of a grid ‘connected PV system with energy storage. One kilowatt amorphous photovoltaic system has been operated in a grid-connected mode with energy storage. The purpose of the system development and performance experiment is to investigate the additional value a grid connected system garners with dispatch able battery energy storage. These values are then weighed against the added cost of the system and inefficiencies incurred in the charging and discharging of the battery.

8. Grid-connected PV plants, aimed at delivering energy to the grid. However, the cost/kWh of PV energy is still quite high. An article was there which reported some of the most promising research approaches currently in progress on new PV materials and devices, focusing on the reduction of PV generation cost expected from the technological implementation of such research.

9. Hironobu Igarashi and Shoichi Suenaga, ‘Electromagnetic Noise from Solar Cells’.
Photovoltaic Specialists IEEE Conference, Page(s): 1820 ‘ 1822, 2005.

Hironobu lgarashi and Shoichi Suenaga [21] presented a paper about Electromagnetic Noise from Solar Cells. Recent advances in semiconductor technology have seen growing efforts to improve the efficiency and reduce the size/weight of power conditioners. The power conditioner is an indispensable component of a photovoltaic power generation system. On the other hand, power conditioners do have a serious problem: they generate electromagnetic noise. To make matters worse, the electromagnetic noise that is generated at power conversion is transmitted to the solar cells through electric wires, the solar cells serving as an antenna to radiate the electromagnetic noise. The radiated electromagnetic noise may cause operation and communication failures in other electronic equipment.

It is seen from various earlier works that application of renewable energy will be forecast more and more in near future due to presence of Global Warming and clean renewable energy will reduce unacceptable air pollution and mainly to meet up the heavy energy demand.

10. Jawaharlal Nehru National Solar Mission
The objective of the National Solar Mission is to establish India as a global leader in solar energy, by creating the policy conditions for its diffusion across the country as quickly as possible. Their target to create an enabling policy framework for the deployment of 20,000 MW of solar power by 2022.

11. World’s Largest Solar Energy Project (5GW!) Planned for Gujarat,
India
Project Would Be Significantly Larger Than Fossil Fuel Power Plants.
At about five times the capacity of a typical coal or nuclear plant, this project would certainly a big step in the right direction towards making solar power a greater part of India’s power mix. Recently Prime Minister Singh announced that solar power would be a key part of his plan to deal with climate change. Currently, the largest solar energy project in the world is a solar thermal plant in the Mojave Desert being developed by Bright Source, with an eventual capacity of up to 900 megawatts.

12. U.S.-India Partnership on Clean Energy, Energy Security, and Climate
Change

US President Barack Obama and Prime Minister Dr. Man Mohan Singh have announced the setting up of Joint Clean Energy Research and Development Centre. The proposed centre is part of the Partnership to Advance Clean Energy (PACE). And they decided to use renewable energy more and more to make the environment clean and safe. And to use the technology which are eco-friendly.

13. A different problem to be solved: Solar Power Technologies President and CEO Ray Burgess on SPT’s Clarity suite and power optimization for large PV plants

Ray Burgess joined the Solar Power Technologies team as President and CEO in July 2009. He has over 30 years of leadership experience in the technology industry, spanning semiconductors, software and micro-mechanical systems. Prior experience includes TeraVicta Technologies, Tao Group, Freescale Semiconductor, Motorola and Texas Instruments.
Solar Server: Let’s start with an overview of your Clarity suite of products, and what they specifically offer to your clients. What are the main barriers to system performance that your Clarity products address?
Ray Burgess: I will start by referring to something in Solar Server’s April 2011 piece on micro inverters and power optimizers . Where we came from two years ago when we started the company, our objective was to do an optimizer product for larger-scale systems. As we got into that and got down to development for prospective clients, it became clear that there was not a lot of credibility in the claims of energy harvest that would come in larger scale systems for an optimizer or micro inverter technology.
The headline claims of 20-25% gain just aren’t there. They are not there unless you’ve got badly compromised or shaded arrays or arrays that are misaligned, and that just doesn’t happen in larger-scale arrays. So we got into this believing that there is a different problem to be solved.
With Clarity, what we are trying to do is optimize harvest, maximize return, and minimize the risk for people that own, operate, finance and insure large-scale arrays. And that’s a very different type of topic. It ends up not being specifically a hardware problem; it ends up being as much a data management problem.
So we do need best-in-class hardware. We have an optimizer, a DC optimizer, and we also have a standalone panel monitoring device.

14. Lung disease caused by exposure to coal mine and silica dust.
Cohen RA, Patel A, Green FH.
Source
Department of Environmental and Occupational Health Sciences, University of Illinois School of Public Health, Chicago, USA. bobcohen@uic.edu
Abstract
Susceptible workers exposed to coal mine and silica dust may develop a variety of pulmonary diseases. The prime example is classical pneumoconiosis, a nodular interstitial lung disease that, in severe cases, may lead to progressive massive fibrosis (PMF). Exposure to silica and coal mine dusts may also result in pulmonary scarring in a pattern that mimics idiopathic pulmonary fibrosis, and in chronic obstructive pulmonary disease (COPD), including emphysema and chronic bronchitis that appears indistinguishable from obstructive lung disease caused by exposure to tobacco smoke. Coal mine and silica dust may therefore result in restrictive, obstructive, or mixed patterns of impairment on pulmonary function testing. Most physicians are aware of the nodular fibrosing pulmonary tissue reactions in response to retained dust, but they may not realize that these other reactions of the pulmonary parenchyma and airways to dust exist and can result in significant respiratory dysfunction in sensitive individuals. This article discusses current data on exposure to coal mine and silica dust in the United States, the epidemiology of the diseases caused by these exposures, and new concepts of causation and pathogenesis. We also review the patterns of pulmonary disease and impairment that may result.

15. Solar technology charges forward despite Washington’s backward march.
Mon, Aug 08 2011 at 3:12 AM EST
There was some good news last week. While Washington was busy holding the global markets hostage and placing billions in badly needed R&D funding on the chopping block, a new report from REN21 (the Renewable Energy Network for the 21st Century) showed that global investments in renewable energy jumped 32 percent to a record $211 billion, this despite a downturn in the economy and massive R&D cuts in clean energy.
It’s a little reassuring that progress marches forward, despite our nation’s best efforts to stop it. Solar in particular appears to be growing in leaps and bounds due in large part to a 60 percent drop in price per kW (kilowatt) production in just the past three years. In many regions solar power is getting competitive with coal power, and its price will continue to drop with the onset of a many new advancements in solar technology

COMPARISION BETWEEN SOLAR AND COAL

Chapter- 5

5.1 Solar energy is better than fuel in terms of Financially, Economically, Ecologically, Operationally, Technically, These have been discussed below:

1) FINANCIALLY:

i. As we know that the price of imported coal is increasing because the coal demand is also increasing. We are importing coal from Indonesia, Austria, and South Africa and from many other places recently, Indonesia has changed their policy and they are exporting coal in a high price. This is increasing a burden on us.
ii.

Solar energy
Demand
Imported coal

Price

As we can see in the above graph, that solar energy can be forecasted to be cheaper in upcoming year as we can show through the graph which shows the forecasted data of year(2012-2030), here the price is comparatively less in case of high demand situation, while that of imported coal is increasing with the increase in demand.

iii. If we see in terms of manufacturing, the cost of solar energy is higher than of coal, which can also be taken as most probably the only drawback in solar energy. These are initially expenses which may go lower when we understand well how to produce it. The coal manufacturing cost is also high but still lower than solar energy.
iv. Government is also promoting the solar energy by providing the high subsidy on solar energy to promote its use in consumer. Government provides subsidy of 10Rs on solar on its total cost of 15Rs. This is also a policy to keep the environment clean and free from harmful gases. Like (CO, CH3, CH4) etc., burnt out from coal.
Government is doing all this to promote solar energy, because this will be the best alternative to generate electricity and it is environmental friendly.
A 100 kW SPV power plant can easily replace a 250KVa DG set and help save an amount up to Rs.21, 41, 500 annually through diesel, transportation and Operation & Maintenance. This also includes costs of Engine Oil, Coolant and Operators’ Salary and other miscellaneous expenses.
Average consumption of diesel by a 250 KVa DG set: 48,000 litres per year.
(= Rs.19, 20,000 per year @ Rs.40 / liter)
Average maintenance cost: Rs.2,21,500 per year.
2. Whereas, the cost of the SPV Plant, inclusive of cost of replacing the batteries after 5-
6 years is Rs.3, 60, 00,000.

2.) ECONOMICALLY:
Solar energy is renewable source of energy for which no one need to pay anything. India is at location where energy part of nation gets proper sunlight. The money is invested only in utilizing this solar energy by putting solar energy plants to convert this energy into the manner we want. It is widely used in rural areas now a day at primary and secondary level like solar cooker to solar cell plant respectively.
Now, The project would be an ‘integrated Solar City’ with a capacity of 5 gigawatts. Yes, 5 gigawatts. The facility is expected to cost Rs 200-billion (approximately $475-million) and will produce all raw materials and manufacture all panels on site. Hence ‘integrated Solar City’. This is expected to reduce costs so that the power produced at the site will cost about Rs 4 ($0.10) per (unspecified) unit. It has not been disclosed whether the project would employ solar photovoltaic or solar thermal technology. The government of Gujarat is considering a Kutch or Banaskanta location’in the westernmost part of the state near the border with Pakistan for those people for whom Indian geography isn’t a strong point’for the project.
Project Would Be Significantly Larger Than Fossil Fuel Power Plants
At about five times the capacity of a typical coal or nuclear plant, this project would certainly a big step in the right direction towards making solar power a greater part of India’s power mix. Recently Prime Minister Singh announced that solar power would be a key part of his plan to deal with climate change. Currently, the largest solar energy project in the world is a solar thermal plant in the Mojave Desert being developed by Bright Source, with an eventual capacity of up to 900 megawatts.

3.) ECOLOGICALLY:
The plant will have no adverse environmental impact. If the plant replaces a 250 KVa DG set it will not only save nearly 48,000ltrs of diesel every year but also improve the status of environment by eliminating the harmful gases which the diesel station emits into the atmosphere. Emission of pollutants from the use of high speed diesel (based on per year consumption of 48,000 liters / year).

S.No. Gases Emission in tonnes / year

1 Carbon dioxide 126.06
2 Nitrous Oxide 2.76
3 Hydrocarbons 0.24
4 Sulfur Dioxide 0.14
5 Carbon Monoxide 3.90

TABLE 5.1: EMISSION OF HARMFUL GASES PER YEAR

Coal-burning plants are some of the worst industrial polluters, producing approximately
‘ One-third of our carbon dioxide (CO2, a major contributor to global warming),
‘ 40% of our mercury (Hg highly toxic if ingested or inhaled),
‘ One-quarter of our nitrogen oxides (NOx an ingredient found in smog) and
‘ two-thirds of our sulfur dioxides (SOx a component of acid rain).
The Environmental Protection Agency (EPA) contends that sulfur dioxide promotes heart disease and asthma, while nitrogen oxides destroy lung tissue.
Additional hazardous byproducts produced by coal-burning plants include, arsenic, chromium, cobalt, lead, manganese, zinc, radionuclides and particulate matter. Each type of coal produces different levels of these pollutants, all of which negatively impact both the environment and our health.
Mercury, a known carcinogen, is of particular concern as it poisons fish in bodies of water miles away. Greenpeace reports that even at minimum levels, this neurotoxin has been shown to cause reduced intelligence in hundreds of thousands of children born annually. Mercury emissions occur at rates of approximately 25 pounds per 100 megawatts at the average coal plant, making coal-fired plants the largest single contributor of mercury pollution in the United States.
Radionuclides are unstable atoms that, if leaked into the environment, cause radioactive contamination. When people or animals are exposed to the contamination, they can suffer the effects of radiation poisoning including genetic issues such as cancer and abnormal or failed births. A coal-fueled plant has been known to produce more radioactive material than a nuclear power plant within industry regulations.
The American Lung Association (ALA) released a report in March 2011 offering this startling statistic: ‘Particle pollution from power plants is estimated to kill approximately 13,000 people a year.’ The ALA report singled out coal-fired power plants as among the worst offenders.

And, if we say about solar than no harmful gases are coming out from its electricity generation. And it is helping in making environment clean and meeting the consumer demand.

4.) OPERATIONALLY:
We can operate solar easily, because the technology which we use in solar in not so high and it’s maintains is also easy we can wash it with water time to time. We don’t need to give so much of attention towards the training, and workers can do their work eassily

5.) TECHNICALLY:
India needs to be been toward R&D, as we are having obsolete technology which renders us to import advance technology from outside. If India itself makes these advancement then such increasing expenses may go low.
Indian energy system is generally best on coal energy and the advancement is mandatory while we switch to solar energy and if India develops technology then instead of import expense. It can make life long research and make this shift from coal to solar energy far easier.

‘ Social impacts

1. Enhance quality of life and improve living conditions of the people.
2. Create awareness about importance of RENEWABLE source of energy.
3. Positive impact on women and children.
4. Increased level of health and hygiene.

5.2 SOLAR ENERGY IS SUSTANABLE ENERGY

Sustainable development is a prototype of resource use that aims to meet human needs while preserving the environment so that these needs can be met not only in the present, but also for generations to come. Generally it is defined as development that “meets the needs of the present without compromising the ability of future generations to meet their own needs.”
Sustainable development ties together apprehension for the carrying capacity of natural systems with the social challenges facing humankind. As early as the 1970s “sustainability” was employed to describe an economy “in equilibrium with basic natural support systems”. Ecologists have pointed to The Limits to Growth, and offered the alternative of a “steady state economy” in order to address environmental concerns.
The field of sustainable development can be theoretically broken into three components: environmental sustainability, economic sustainability and sociopolitical sustainability.

‘ Scope and definitions

Sustainable development does not focus solely on environmental issues.
In 1987, the United Nations released the Brundtland Report, which defines sustainable development as ‘development which meets the needs of the present without compromising the ability of future generations to meet their own needs.
The United Nations 2005 World Summit Outcome Document refers to the “mutually supporting and mutually reinforcing pillars” of sustainable development as economic development, social development, and environmental protection.
Indigenous peoples have argued, through various international forums such as the United Nations Permanent Forum on Indigenous Issues and the Convention on Biological Diversity, that there are four pillars of sustainable development, the fourth being cultural.
The Universal Declaration on Cultural Diversity (UNESCO, 2001) further elaborates the idea by stating that “…cultural diversity is as necessary for humankind as biodiversity is for nature’; it becomes ‘one of the roots of development understood not simply in terms of economic growth, but also as a means to achieve a more satisfactory intellectual, emotional, moral and spiritual existence”. In this vision, cultural diversity is the fourth policy area of sustainable development.

‘ Economic Sustainability

Information, combination and participation are the key building blocks to help countries achieve development that recognises these mutually supporting pillars. It emphasises that in sustainable development everyone is a user and provider of information. It stresses the need to change from old sector-centred ways of doing business to new approaches that involve cross-sectoral management and the combination of environmental and social concerns into all development processes. The broad public participation in decision making is a essential requirement for achieving sustainable development.
According to Hasna Vancock, sustainability is a process which tells of a development of all aspects of human life affecting nourishment It means resolving the clash between the various challenging goals, and involves the synchronized pursuit of economic prosperity, environmental quality and social equity famously known as three dimensions with the resultant vector being technology, hence it is a repeatedly evolving process; the ‘journey’ (the process of achieving sustainability) is of course critically important, but only as a means of getting to the objective (the desired future state). However, the objective of sustainability is not a fixed place in the normal sense that we understand destination. Instead, it is a set of wishful description of a future system.

‘ Environmental sustainability

Environmental sustainability is the process of making sure current processes of interface with the environment are pursued with the thought of keeping the environment as perfect as naturally possible based on ideal-seeking behaviour.
An “unsustainable situation” occurs when natural capital (the sum total of nature’s resources) is used up faster than it can be replenished. Sustainability requires that human activity only uses nature’s wealth at a rate at which they can be replenished naturally. Naturally the concept of sustainable development is entangled with the concept of carrying capacity. Notionally the long-term result of environmental deprivation is the lack of ability to sustain human life. Such deprivation on a global scale could imply destruction for humankind.

‘ Capital in Sustainable Development

The sustainable development discussion is based on the hypothesis that societies need to manage three types of capital (economic, social, and natural), which may be non-substitutable and whose utilization might be irreversible. Daly (1991), for example, points to the fact that natural capital can not necessarily be substituted by economic capital. While it is likely that we can find traditions to substitute some natural resources, it is much more doubtful that they will ever be able to replace eco-system forces such as the protection provided by the ozone layer, or the climate stabilizing function of the Amazonian forest. In fact natural capital, social capital and economic capital are often complementarities. A further barrier to substitutability lies also in the multi-functionality of many natural resources. Forests, for example, not only provide the raw material for paper (which can be substituted quite easily), but they also maintain biodiversity, regulate water flow, and absorb CO2.
Another problem of natural and social capital wear and tear lies in their partial irreversibility. The loss in biodiversity, for example, is often specific. The same can be true for cultural diversity. For example with globalisation advancing quickly the number of native languages is dropping at alarming rates. Moreover, the lessening of natural and social capital may have non-linear penalties. Utilization of natural and social capital may have no visible impact until a certain threshold is reached. A lake can, for example, absorb nutrients for a long time while actually increasing its productivity. However, once a certain level of algae is reached lack of oxygen causes the lake’s ecosystem to break down suddenly.

FINDINGS AND RECOMMENDATIONS
Chapter-6

6.1 FINDINGS:

On the basis of studies, following findings are there:

‘ About 64.75% of the electricity consumed in India is generated by thermal power plant. India is facing challenges to meet its growing demand for energy. The rate of energy consumption is increasing; supply is depleting thus resulting in inflation and energy shortage. This is called energy crisis. Hence alternative sources of energy have to be developed to meet future energy requirement. Answer to this growing energy crisis is indeed RENEWABLE ENERGY.
‘ Solar photovoltaic electricity generation is a promising technology taking into consideration climate compatibility.
‘ Solar energy is available in abundance.
‘ Available across the country ‘ unlike other renewable sources, which have geographical limitations.
‘ Available throughout the year unkike other renewable sources which depend largely on climatic conditions.
‘ The PV approach is particularly suited for the geographical and socio-economic features of India as it’s having high energy distribution between urban and rural areas.
‘ Solar PV power plant is the best economical option as raw material cost i.e. Sun light is zero and O&M costs are also less as compared to other conventional sources power plants.
‘ Distributed Generation.
‘ Energy security.

Solar PV power plant does have some limitations too:
‘ They are capital intensive. The initial cost of setting up a SPV power plant is very large (around 3 crores INR).
‘ For a pilot project like discussed in the project, area requirements are not very large but if capacity is increased say up to a few MW then land requirements are high.
‘ In the above case, build in time will also increase.
‘ People are still less aware about the solar energy and its benefits. Also about the benefits that are provided by government.

6.2 RECOMMENDATIONS:
Coal energy has been around for centuries, and still less expensive to produce than solar or other alternative energy sources. Despite the fact that it polluting fuel that pollutes the air, water and land. In addition, it also creates a high amount of waste that must be disposed off. The good news is, however that with each new discovery & advancement in solar technology, we are growing closer to putting the use of coal behind us once for all. In 2007 alone over 50 new coal fired plant were cancelled or delayed because of growing concerns over global warming & transportation cost .Coal fuel currently provides over half of our electricity nationwide. If we slow production, what are the alternatives? Nuclear fuel is still quite controversial & natural gas is not reliable, so that leaves alternative power sources such as wind & solar power.

Following are the recommendations:

‘ SPVs to be implemented on a large scale all over the country.
‘ India has to create such an environment so that synergy of PPP is exploited. Have to attract private players due to capital intensity of the projects.
‘ Handsome Investment and Performance based incentives to be provided by government to attract attention of private players and general public.
‘ Proper and aggressive R&D- This will facilitate cost reductions of materials and system, which can bring down costs to make CST competitive with conventional sources of base load power.
‘ Improve the current grid & transmission system.
6.3: CONCLUSION:
It is expected that with present acceleration in the efforts on the part of manufacturers, designers, planners and utilities with adequate Governmental support, PV systems will within the next two decades occupy a place of pride in the country’s power sector, ensuring optimum utilization of the energy directly from the sun around the year. It is clear that the Grid Connected SPV system can provide some relief towards future energy demands.

‘ It is well understood that Solar Prototypes and commercial power plants exist.
‘ It has capabilities for both base load and peak-matching power generation.
‘ It is affordable in the locations with lots of sunlight. Costs are in the range 10-15Rs/kWh currently, with great potential for the future.
‘ It can be coupled with fossil fuel based backup systems for even better reliability at a low cost.
Despite obviously having very bad negative impact coal still remains the mostly used energy source in the world. This is because coal is the cheapest energy option for many countries in the world, and the economy still outweighs ecology when it comes to energy. Coal looks very likely to remain dominant energy source for at least next few decades, despite significantly contributing to climate change and air pollution. The only hope are clean coal technologies (especially carbon capture and storage technology) but these technologies despite looking promising still seem to be many years away before being implemented on global scale, and in the meantime coal production is in the constant rise, especially in the new fast developing economies such as China and India.
If climate change issue gets out of hand then coal could be easily regarded as the major culprit for this.
Solar PV is a technology that offers a solution for a number of problems associated with fossil fuels. It is clean decentralized, indigenous and does not need continuous import of a resource.
On top of that, India has among the highest solar radiation in the world which makes Solar PV all the more attractive for India. The state of Orissa and Andhra Pradesh also houses some of the best quality reserves of silica. India has a large number of cells and modules manufacturers. In spite of all above advantages Indian Photo Voltaic programme is still in the infancy stage. One of the reasons could be absence of simple, action oriented and aggressive PV policy of the country both in the state and central level. More quickly we do it with the professionals more we protect our future energy security
References

‘ http://www.makeitsolar.com/solar-energy-information
‘ http://www.nasa.gov/centers/dryden/news/FactSheets/FS-054-DFRC.html
‘ http://en.wikipedia.org/wiki/Solar_power_in_India
‘ http://www.nrel.gov/solar/
‘ http://www.treehugger.com/renewable-energy/worldatms-largest-solar-energy-project-5gw-planned-for-gujarat-india.html
‘ http://www.solarserver.com/solar-magazine/solar-interviews/solar-interviews/a-different-problem-to-be-solved-solar-power-technologies-president-and-ceo-ray-burgess-on-spts-clarity-suite-and-power-optimization-for-large-pv-plants.html
‘ http://theconversation.edu.au/solar-will-force-coal-and-nuclear-out-of-the-energy-business-2557
‘ http://theconversation.edu.au/pages/business
‘ http://nuclearfissionary.com/2010/04/02/comparing-energy-costs-of-nuclear-coal-gas-wind-and-solar/
‘ http://www.auroma.in/inttocoal.pdf
‘ http://interestingenergyfacts.blogspot.com/2010/08/coal-introduction-and-facts.html
‘ http://www.ucsusa.org/clean_energy/coalvswind/c02c.html
‘ http://www.quoteoil.com/oil-imports.html
‘ http://www.worldcoal.org/resources/coal-statistics/
‘ http://articles.economictimes.indiatimes.com/2011-11-11/news/30387201_1_coal-prices-global-coal-merchant-power
‘ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1745225/?log$=activity
‘ http://www.mnn.com/green-tech/research-innovations/blogs/5-breakthroughs-that-will-make-solar-power-cheaper-than-coal
‘ http://www.scientificamerican.com/article.cfm?id=can-geothermal-power-compete-with-coal-on-price

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