Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
SNIST (JNTUH) – B.TECH (MECH)
POWER PLANT ECONOMICS AND
ENVIRONMENTAL CONSIDERATIONS
Dr. S. VIJAYA BHASKAR
Professor in Me...
POWER PLANT ECONOMY
 The main purpose of design and operation of the
plant is to bring the cost of energy produced to
min...
COST ANALYSIS
 Capital Cost /
OPERATIONAL COST
FIXED COST / CAPITAL COST
 The cost analysis of power plant includes fixed cost
and running cost.
1. Fixed cost:
(i) Land...
(ii) Interest:
 All the enterprises need investment of money and
this money may be obtained as loan, through bonds
and sh...
(iii) Depreciation cost:
 Depreciation accounts for the deterioration of the
equipment and decrease in its value due to
c...
Let P = Initial cost of plant
S = Salvage value at the end of the plant life,
n = Plant life in years,
r = Annual rate of ...
(b) Sinking Fund Method:
 In this method, the amount set aside per year consists
of annual installations and the interest...
(iv) Insurance:
The costly equipment and the buildings must
be insured for the fire risks, riots etc. A fixed sum is
set a...
 In a thermal station fuel is the heaviest item of operating
cost. The selection of the fuel and the maximum
economy in i...
 For plant operation labour cost is another item
of operating cost. Maximum labour is needed
in a thermal power plant usi...
COST OF MAINTENANCE AND REPAIRS
 In order to avoid plant breakdowns maintenance
is necessary. Maintenance includes period...
COST OF STORES
 The items of consumable stores other than fuel include such
articles as lubricating oil and greases, cott...
TAXES
 The taxes under operating head includes the
following:
(i) Income tax
(ii) Sales tax
(iii) Social security and emp...
Types of Loads
(i) Residential load: This type of load includes domestic lights, power
needed for domestic appliances such...
 The load on power plants will always be changing with
time and will not be constant because consumer of
electric power w...
LOAD CURVES
 The combined daily load curve for all types of
consumers is shown in figure (a) and the
approximated curve f...
TERMS AND FACTORS
Connected load: Connected load is the sum of
ratings in kilowatts (kW) of equipment installed in the
con...
Demand: The demand of an installation or system is the
load that drawn from the source of supply at the
receiving terminal...
TERMS AND FACTORS
Load Factor
 It is defined as the ratio of the average load to the peak load
during a certain prescribe...
TERMS AND FACTORS
2. Utility Factor
 It is the ratio of the units of electricity generated per year
to the capacity of th...
3. Plant Operating Factor
 It is the ratio of the duration during which the plant is in actual service, to the
total dura...
5. Demand Factor
 The actual maximum demand of a consumer is always less than his
connected load since all the appliances...
7. Load Curve
 It is a curve showing the variation of power with time. It shows the
value of a specific load for each uni...
13. Hot Reserve
 It is that reserve generating capacity which is in operation
but not in service.
14. Spinning Reserve
 ...
FACTOR EFFECTING POWER
PLANT DESIGN
Following are the factor effecting while
designing a power plant.
(1) Location of powe...
The power plant pollutants of major concern
are:
A. From fossil power
plants
(i) Sulphur oxide
(ii) Nitrogen oxides
(iii) ...
 Besides this, pollutants such as lead and
hydrocarbons are contributed by automobiles.
 The air pollution in a large me...
Thus the emission can be classified as follow:
1. Gaseous emission
2. Particulate emission
3. Solid waste emission
4. Ther...
1. Gaseous Emission and Its Control:
 The various gaseous pollutants are:
 (i) Sulphur dioxide
 (ii) Hydrogen sulphide
...
2.Particulate Emission and Its Control:
• The particulate emission, in power plants using fossil fuels, is easiest
to cont...
3. Solid Waste Disposal
• From the fossil fuel fired power plants
considerable amount of solids in the form of ash
is disc...
4. Thermal Pollution
• Discharge of thermal energy into waters is
commonly called Thermal pollution.
• Thermal power stati...
How to reduce Thermal Pollution
• While considering the efficiency of the thermal
plant, it is desirable that the water fr...
The various types of pollution from nuclear power plants are:
 (i) Radioactive pollution
 (ii) Waste from reactor (solid...
 If the waste is discharged in the atmosphere, air and water will
be contaminated beyond the tolerable limits
 Some meth...
4. Atmospheric dilution. This method can be used for gaseous
radioactive wastes. But solid particles from the gaseous wast...
 Hydro-electric and Solar Power Generation plants have no
polluting effect on the environment.
 The hydro-electric proje...
 Further, the evaporation of water and
consequent rains may change their cycles.
Added to these, the average temperatures...
POWER  PLANT  ECONOMICS AND ENVIRONMENTAL  CONSIDERATIONS - SNIST
POWER  PLANT  ECONOMICS AND ENVIRONMENTAL  CONSIDERATIONS - SNIST
POWER  PLANT  ECONOMICS AND ENVIRONMENTAL  CONSIDERATIONS - SNIST
Upcoming SlideShare
Loading in …5
×

POWER PLANT ECONOMICS AND ENVIRONMENTAL CONSIDERATIONS - SNIST

4,594 views

Published on

Unit-VI Power Plant Economics And Environment

Published in: Engineering
  • Login to see the comments

POWER PLANT ECONOMICS AND ENVIRONMENTAL CONSIDERATIONS - SNIST

  1. 1. SNIST (JNTUH) – B.TECH (MECH) POWER PLANT ECONOMICS AND ENVIRONMENTAL CONSIDERATIONS Dr. S. VIJAYA BHASKAR Professor in Mechanical Engineering Sreenidhi Inst. of Science &
  2. 2. POWER PLANT ECONOMY  The main purpose of design and operation of the plant is to bring the cost of energy produced to minimum.  Effective utilization of resources, minimize the losses in order to increase the profit of the power corps
  3. 3. COST ANALYSIS  Capital Cost /
  4. 4. OPERATIONAL COST
  5. 5. FIXED COST / CAPITAL COST  The cost analysis of power plant includes fixed cost and running cost. 1. Fixed cost: (i) Land, building and equipment cost:  Cost of land and building will depend upon the location of the plant. If the plant is situated near the cities, the land will be costlier than the case if it is located away from the cities.  The cost of equipment or the plant investment cost is usually expressed on the basis of kW capacity installed.
  6. 6. (ii) Interest:  All the enterprises need investment of money and this money may be obtained as loan, through bonds and shares, or from owners of personal funds.  The interest on the capital investment must be considered because otherwise if the same amount was not invested in power plant, it would have earned an annual interest.  A suitable rate of interest must be considered on the capital invested.
  7. 7. (iii) Depreciation cost:  Depreciation accounts for the deterioration of the equipment and decrease in its value due to corrosion, weathering, and wear and tear with use.  It also covers the decrease in value of equipment due to obsolescence. It is required to replace the generating plant machinery after its expiry of useful life.  Therefore, a certain amount is kept aside every year from the income of the plant to enable the replacement of plant at the end of its useful life. This amount is called depreciation amount.  The following methods are used to calculate the depreciation amount:  Straight line method  Sinking fund method  Diminishing value method
  8. 8. Let P = Initial cost of plant S = Salvage value at the end of the plant life, n = Plant life in years, r = Annual rate of interest on the invested capital, A = The amount to be kept aside per year as depreciation amount. (a) Straight line method:  According to this method, annual amount to be set aside is calculated by using following formula:  In this method, the amount set aside per year as depreciation fund does not depend on the interest it may draw. The interest earned by the depreciation amount is taken as income.  This method is commonly used because of its simplicity. P - S n A =
  9. 9. (b) Sinking Fund Method:  In this method, the amount set aside per year consists of annual installations and the interest earned on all the installments. (C) DIMINISHING VALUE METHOD:  In this method the deterioration in value of equipment from year to year is taken into account and the amount of depreciation calculated upon actual residual value for each year. It thus, reduces for successive years.
  10. 10. (iv) Insurance: The costly equipment and the buildings must be insured for the fire risks, riots etc. A fixed sum is set aside per year as insurance charges. The insurance charge depends upon the initial cost of the plant and the insurance coverage. (v) Management cost: This includes the salaries of management, security and administrative staff, etc. working in the plant. This must be paid whether the plant is working or not. Therefore, this is included in fixed charges of the plant.
  11. 11.  In a thermal station fuel is the heaviest item of operating cost. The selection of the fuel and the maximum economy in its use are, therefore, very important considerations in thermal plant design.  It is desirable to achieve the highest thermal efficiency for the plant so that fuel charges are reduced.  The cost of fuel includes not only its price at the site of purchase but its transportation and handling costs also.  In the hydro plants the absence of fuel factor in cost is responsible for lowering the operating cost.  Plant heat rate can be improved by the use of better quality of fuel or by employing better thermodynamic conditions in the plant design.  The cost of fuel varies with the following: (1) Unit price of the fuel. (2) Amount of energy produced. (3) Efficiency of the plant.
  12. 12.  For plant operation labour cost is another item of operating cost. Maximum labour is needed in a thermal power plant using. Coal as a fuel.  A hydraulic power plant or a diesel power plant of equal capacity requires a lesser number of persons.  In case of automatic power station the cost of labour is reduced to a great extent. However labour cost cannot be completely eliminated even with fully automatic station, as they will still require some manpower for periodic inspection etc.
  13. 13. COST OF MAINTENANCE AND REPAIRS  In order to avoid plant breakdowns maintenance is necessary. Maintenance includes periodic cleaning, greasing, adjustments and overhauling of equipment.  The material used for maintenance is also charged under this head. Sometimes an arbitrary percentage is assumed as maintenance cost.  A good plan of maintenance would keep the sets in dependable condition and avoid the necessity of too many stand-by plants. Repairs are necessitated when the plant breaks down or stops due to faults developing in the mechanism.  The repairs may be minor, major or periodic overhauls and are charged to the depreciation fund of the equipment.  This item of cost is higher for thermal plants than for hydro-plants due to complex nature of principal equipment and auxiliaries in the former.
  14. 14. COST OF STORES  The items of consumable stores other than fuel include such articles as lubricating oil and greases, cotton waste, small tools, chemicals, paints and such other things.  The incidence of this cost is also higher in thermal stations than in hydro-electric power stations. SUPERVISION  In this head the salary of supervising staff is included. A good supervision is reflected in lesser breakdowns and extended plant life.  The supervising staff includes the station superintendent, chief engineer, chemist, engineers, supervisors, stores incharges, purchase officer and other establishment.  Again, thermal stations, particularly coal fed, have a greater incidence of this cost than the hydro-electric power stations.
  15. 15. TAXES  The taxes under operating head includes the following: (i) Income tax (ii) Sales tax (iii) Social security and employee’s security etc. (iv) Recently added goods and service tax(GST)
  16. 16. Types of Loads (i) Residential load: This type of load includes domestic lights, power needed for domestic appliances such as radios, TV, water heaters, refrigerators, electric cookers and small motors for pumping water. (ii) Commercial load: It includes lighting for shops, advertisements and electrical appliances used in shops and restaurants etc. (iii) Industrial load: It consists of load demand of various industries. (iv ) Municipal load: It consists of street lighting, power required for water supply and drainage purposes. (v) Irrigation load: This type of load includes electrical power needed for pumps driven by electric motors to supply water to fields. (vi) Traction load: It includes trams, cars, trolley, buses and railways.
  17. 17.  The load on power plants will always be changing with time and will not be constant because consumer of electric power will use the power as and when required.  Load curve is graphical representation between load in kW  and time.  It shows variation of load on the power station.  If the time is in hours then the load curve is known as daily load curve.  If the times is in days, the load curve is known as monthly load curve and if the time is in months, the load curve is known as yearly or annual load curve.  The daily load curve will be different for different type of consumers and different localities. These load curves may show different pattern during summer, winter and rainy season.
  18. 18. LOAD CURVES  The combined daily load curve for all types of consumers is shown in figure (a) and the approximated curve for simplicity is shown in figure (b).
  19. 19. TERMS AND FACTORS Connected load: Connected load is the sum of ratings in kilowatts (kW) of equipment installed in the consumer’s premises.  The connected loads in the premises of a consumer are shown in figure. Total load connected in the consumer’s premises: = 40 + 1000 + 60 + 40 + 20 + 500 + 25 + 60 = 1745W
  20. 20. Demand: The demand of an installation or system is the load that drawn from the source of supply at the receiving terminals averaged over a suitable and specified interval of time. Demand is expressed in kilowatts (kW) or other suitable units. Maximum demand or Peak load: It is the maximum load which a consumer uses at any time. It can be less than or equal to connected load.  If all the equipment fitted in consumer’s premises run to their fullest extent simultaneously then the maximum demand will be equal to connected load. But generally the actual maximum demand is less than the connected load because all the devices never run at full load at the same time.
  21. 21. TERMS AND FACTORS Load Factor  It is defined as the ratio of the average load to the peak load during a certain prescribed period of time.  The load factor of a power plant should be high so that the total capacity of the plant is utilized for the maximum period that will result in lower cost of the electricity being generated. It is always less than unity.  High load factor is a desirable quality. Higher load factor means greater average load, resulting in greater number of power units generated for a given maximum demand. Thus, the fixed cost, which is proportional to the maximum demand, can be distributed over a greater number of units (kWh) supplied.  This will lower the overall cost of the supply of electric energy.
  22. 22. TERMS AND FACTORS 2. Utility Factor  It is the ratio of the units of electricity generated per year to the capacity of the plant installed in the station.  It can also be defined as the ratio of maximum demand of a plant to the rated capacity of the plant.  Supposing the rated capacity of a plant is 200 mW. The maximum load on the plant is 100 mW at load factor of 80 per cent, then the utility will be = (100 × 0.8)/(200) = 40%
  23. 23. 3. Plant Operating Factor  It is the ratio of the duration during which the plant is in actual service, to the total duration of the period of time considered. 4. Plant Capacity Factor  It is the ratio of the average loads on a machine or equipment to the rating of the machine or equipment, for a certain period of time considered.  Since the load and diversity factors are not involved with ‘reserve capacity’ of the power plant, a factor is needed which will measure the reserve, likewise the degree of utilization of the installed equipment.  For this, the factor “Plant factor, Capacity factor or Plant Capacity factor” is defined as,  Plant Capacity Factor = (Actual kWh Produced)/(Maximum Possible Energy that might have produced during the same period)  Thus the annual plant capacity factor will be, = (Annual kWh produced)/[Plant capacity (kW) × hours of the year]  The difference between load and capacity factors is an indication of reserve capacity.
  24. 24. 5. Demand Factor  The actual maximum demand of a consumer is always less than his connected load since all the appliances in his residence will not be in operation at the same time or to their fullest extent.  This ratio of' the maximum demand of a system to its connected load is termed as demand factor. It is always less than unity. 6. Diversity Factor  Supposing there is a group of consumers. It is known from experience that the maximum demands of the individual consumers will not occur at one time.  The ratio of the sum of the individual maximum demands to the maximum demand of the total group is known as diversity factor. It is always greater than unity.  High diversity factor (which is always greater than unity) is also a desirable quality. With a given number of consumers, higher the value of diversity factor, lower will be the maximum demand on the plant, since,  Diversity factor = Sum of the individual maximum Demands/Maximum demand of the total group  The capacity of the plant will be smaller, resulting in fixed charges.
  25. 25. 7. Load Curve  It is a curve showing the variation of power with time. It shows the value of a specific load for each unit of the period covered. The unit of time considered may be hour, days, weeks, months or years. 8. Load Duration Curve  It is the curve for a plant showing the total time within a specified period, during which the load equaled or exceeded the values shown. 9. Dump Power  This term is used in hydro plants and it shows the power in excess of the load requirements and it is made available by surplus water. 10. Firm Power  It is the power, which should always be available even under emergency conditions. 11. Prime Power  It is power, may be mechanical, hydraulic or thermal that is always available for conversion into electric power. 12. Cold Reserve  It is that reserve generating capacity which is not in operation but can be made available for service.
  26. 26. 13. Hot Reserve  It is that reserve generating capacity which is in operation but not in service. 14. Spinning Reserve  It is that reserve generating capacity which is connected to the bus and is ready to take the load. 15. Plant Use Factor  This is a modification of Plant Capacity factor in that only the actual number of hours that the plant was in operation is used.  Thus Annual Plant Use factor is, = (Annual kWh produced) / [Plant capacity (kW) × number of hours of plant operation]
  27. 27. FACTOR EFFECTING POWER PLANT DESIGN Following are the factor effecting while designing a power plant. (1) Location of power plant (2) Availability of water in power plant (3) Availability of labour nearer to power plant (4) Land cost of power plant (5) Low operating cost (6) Low maintenance cost (7) Low cost of energy generation (8) Low capital cost
  28. 28. The power plant pollutants of major concern are: A. From fossil power plants (i) Sulphur oxide (ii) Nitrogen oxides (iii) Carbon oxide (iv) Thermal pollution (v) Particulate matter. B. From nuclear power plants (i) Radioactivity release (ii) Radioactive wastes (iii) Thermal pollution.
  29. 29.  Besides this, pollutants such as lead and hydrocarbons are contributed by automobiles.  The air pollution in a large measure is caused by the thermal power plants burning conventional fuels (coal, oil or gas).  The combustible elements of the fuel are converted to gaseous products and non- combustible elements to ash.
  30. 30. Thus the emission can be classified as follow: 1. Gaseous emission 2. Particulate emission 3. Solid waste emission 4. Thermal pollution (or waste heat)
  31. 31. 1. Gaseous Emission and Its Control:  The various gaseous pollutants are:  (i) Sulphur dioxide  (ii) Hydrogen sulphide  (iii) Oxides of nitrogen  (iv) Carbon monoxide etc.
  32. 32. 2.Particulate Emission and Its Control: • The particulate emission, in power plants using fossil fuels, is easiest to control. • Particulate matter can be either dust (particles having a diameter of 1 micron) which do not settle down or particles with a diameter of more than 10 microns which settle down to the ground. • The particulate emission can be classified as follows: • Smoke: It composes of stable suspension of particles that have a diameter of less than 10 microns and are visible only in the aggregate. • Fumes: These are very small particles resulting from chemical reactions and are normally composed of metals and metallic oxides. • Fly-ash: These are ash particles of diameters of 100 microns or less.
  33. 33. 3. Solid Waste Disposal • From the fossil fuel fired power plants considerable amount of solids in the form of ash is discharged. This ash is removed as bottom ash or slug from the furnace. • The fossil fuel fired system also discharges solid wastes such as calcium and magnesium salts generated by absorption of SO2 and SO3 by reactant like lime stone.
  34. 34. 4. Thermal Pollution • Discharge of thermal energy into waters is commonly called Thermal pollution. • Thermal power stations invariably will have to discharge enormous amounts of energy into water since water is one medium largely used to condense steam. • If this heated water from condensers is discharged into lakes or rivers, the water temperature goes up. The ability of water to hold dissolved gases goes down when the temperature increases. • At about 35°C, the dissolved oxygen will be so low that the aquatic life will dies • One of the Govt. Regulation states that ‘the max. temp of outlet water should not be more than 10C above atmospheric temperature
  35. 35. How to reduce Thermal Pollution • While considering the efficiency of the thermal plant, it is desirable that the water from a river or lake is pumped through the condenser and fed back to the source. • The rise of temperature will be about 10°C which is highly objectionable from the pollution point of view. • Hence, this waste heat which is removed from the condenser will have to be thrown into the atmosphere and not into the water source, in this direction following methods can be adopted : 1. Construction of a separate lake 2. Cooling pond 3. Cooling towers.
  36. 36. The various types of pollution from nuclear power plants are:  (i) Radioactive pollution  (ii) Waste from reactor (solid, liquid, gases)  (iii) Thermal pollution. i).Radioactive pollution: This is the most dangerous and serious type of pollution.This is due to radioactive elements and fissionable products in reactor.The best way to abate is the radioactive shield around the reactor. ii) Waste from reactor: Due to nuclear reactor reaction nuclear wastes (mixtures of various Beta and Gamma emitting radioactive isotopes with various half lives) are produced which cannot be neutralised by any chemical method. .
  37. 37.  If the waste is discharged in the atmosphere, air and water will be contaminated beyond the tolerable limits  Some methods of storage or disposal of radioactive waste materials are discussed below : 1. Storage tanks.The radioactive wastes can be buried underground (very deep below the surface) in corrosion resistance tanks located in isolated areas.With the passage of time these will become stable isotopes. 2. Dilution. After storing for a short time, low energy wastes are diluted either in liquid or gaseous materials. After dilution, they are disposed off in sewer without causing hazard. 3. Sea disposal. This dilution can be used by adequately diluting the wastes and this method is being used by the British.
  38. 38. 4. Atmospheric dilution. This method can be used for gaseous radioactive wastes. But solid particles from the gaseous wastes must be filtered out thoroughly since they are the most dangerous with higher half lives. 5. Absorption by the soil. Fission products are disposed off by this method.The radioactive particles are absorbed by the soil particles. But this is expensive. 6. Burying is sea. Solid nuclear wastes can be stored is concrete blocks which are hurried in the sea.This method is expensive but no further care is needed.
  39. 39.  Hydro-electric and Solar Power Generation plants have no polluting effect on the environment.  The hydro-electric project does not pollute the atmosphere at all, but it can be argued that the solar power stations in the long run may upset the balance in nature.To extend the argument to the logical end, imagine a very vast area of land is covered by solar collectors of different forms.Then the minimum required sun's rays may not reach the earth's surface.  This will certainly kill the vegetation on the earth and also the bacteria which are destroyed by sun's rays may survive giving rise to new types of health problems.
  40. 40.  Further, the evaporation of water and consequent rains may change their cycles. Added to these, the average temperatures of the earth and ocean may change.  This may result in new balances among the living creatures which cannot be easily predicted. Since we do not envisage such a large scale coverage of earth's surface in the near future, we can safely state that the solar energy power plants do not pollute the atmosphere. END

×