Unit-V-Power Plant Economics and Environment.pptx

Power tariff types, load distribution parameters, load curve – comparison of site selection criteria – relative merits and demerits – capital and operating cost of different power plants – pollution control technologies including waste disposal options for coal and nuclear power plants.

1. UNIT V POWER PLANT ECONOMICS AND ENVIRONMENT Power tariff types, load distribution parameters, load curve – comparison of site selection criteria – relative merits and demerits – capital and operating cost of different power plants – pollution control technologies including waste disposal options for coal and nuclear power plants.

2. Electricity Rates Or Power Tariff 1. Flat Rate Tariff In this tariff, different types of consumers are charged at different rates of cost per unit (1kWh) of electrical energy consumed. Different consumers are grouped under different categories. Then, each category is charged money at a fixed rate similar to Simple Tariff. The different rates are decided according to the consumers, their loads and load factors. Graphically, it can be represented as follows: 2. Simple Tariff In this type of tariff, a fixed rate is applied for each unit of the energy consumed. It is also known as a uniform tariff. The  rate per unit of energy does not depend upon the quantity  of energy used by a consumer. The price per unit (1 kWh) of energy is constant. This energy consumed by the consumer is recorded by the energy meters.

3. 3. Block Rate Tariff In this tariff, the first block of the energy consumed (consisting of a fixed number of units) is charged at a given rate and the succeeding blocks of energy (each with a predetermined number of units) are charged at progressively reduced rates. The rate per unit in each block is fixed. 4. Two Part Tariff In this tariff scheme, the total costs charged to the consumers consist of two components: fixed charges and running charges. It can be expressed as: Total Cost = [A (kW) + B (kWh)] Rs. Where, A = charge per kW of max demand (i.e. A is a constant which when multiplied with max demand (kW) gives the total fixed costs.)      B = charge per kWh of energy consumed (i.e. B is a constant which when multiplied with units consumed (kWh), gives total running charges.)

4. 5. Three Part Tariff In this scheme, the total costs are divided into 3 sections: Fixed costs, semi-fixed costs and running costs. Total Charges = [A + B (kW) + C (kWh)] Where, A = fixed charges,              B = charge per kW of max demand (i.e. B is a constant which when multiplied with max demand (kW) gives the total fixed costs.)              C = charge per kWh of energy consumed (i.e. C is a constant which when multiplied with units consumed (kWh), gives total running charges.)

5. Load Distribution Parameters

6. Basic structure of the electric power system

7. LOAD CURVE

8. LOAD CURVE It is a graphical representation which shows power demands for every instant during a certain time period. It is drawn between load in kW and time in hours. If it is plotted for 1 hour, it is called hourly load curve and if the time is considered is of 24 hours, then it is called daily load curve. When it is plotted for one year (8760 hours), then it is called annual load curve . The area under the load curve represents the energy generated in the period considered. If the area under the curve is divided by the total number of hours, then it will give the average load on the power station. The peak load indicated by the load curve represents the maximum demand of the power station.

9. LOAD DURATION CURVE

10. Constant and variable demand load curve

11. Residential Load Curve

12. Commercial Load Curve Commercial loads of shops, offices and hospitals

13. Industrial Load Curve Industrial load curve for one shift

14. Street Lighting Load Curve

15. Urban Traction Load Curve

16. COST OF ENERGY GENERATION Fixed Cost or Capital Cost It is the cost required for installing the complete power plant. This cost includes the cost of land, buildings, equipment, transmission and distribution lines, cost of planning and designing the plant and many others. It also consists of interest, taxes, depreciation, insurance etc.

17. 1. Land, building and equipment cost The cost of building can be reduced by eliminating the superstructure on the boiler house and turbine house. To reduce the cost of equipment, unit system may be adopted. Cost can also be reduced by simplifying the piping system and eliminated the duplicate system such as steam headers and boiler feed heaters.

18. 2.In terest The money needed for the investment in an enterprise may be obtained as loans, bonds and shares. Interest is the difference between money borrowed and money returned. The rate of interest may be simple and it is expressed as percentage (%) per annum or it may be compounded. A suitable rate of interest must be considered on the capital invested.

19. 3. Depreciation cost It is the amount to be set aside per year from income to meet the depreciation caused by the age of service, wear and tear of machinery. It also covers the decrease in value of equipment due to obsolescence.

20. The following methods are generally used to calculate the depreciation cost. (i) Straight line method ( ii) Sinking fund method ( iii) Diminishing value method.

21. Straight line method

22. Sinking fund method

23. Diminishing value method In this method, the amount set aside per year decreases as the life of the plant increases. The following example gives a clear idea of this method. Say, the equipment cost as Rs . 40,000. The amount set aside is 10% of the initial cost at the beginning of the year and 10% is the remaining cost with every successive year. Therefore,

24. Diminishing value method The main disadvantage of this method is that it requires heavy investments in the early years when the maintenance charges are minimum and it goes on decreasing as the time passes but the maintenance charges increase.

25. 4 . Insurance : A fixed sum is set aside per year as the insurance charge. The annual premium may be 2 to 3% of the equipment cost but the annual installment is quite heavy when the capital cost of the equipment is high. 5 . Management cost : This cost includes the salary of management employees working in the plant. It must be paid whether the plant is working or not. Therefore, this cost is included in the fixed cost.

26. Operating Cost or Running Cost 1 . Cost of fuel 2 . Lubricating oil, grease and water cost 3 . Cost of maintenance and repairs 4 . Cost of operating labour 5 . Cost of supervision 6 . Taxes 7 . External cost 8 . Internal cost

27. COMPARISON OF SITE SELECTION CRITERIA OF VARIOUS POWER PLANTS Site Selection Criteria for Power Plants (i) Site requirements (a) Access (b) Air quality (c) Air space restrictions (d) Buffering (e) Floodplain (f) Fuel delivery (g) Need for power (h) Site adaptability (i) Site expandability (j) Site geography (k) Site size (l) Solid waste management (m) Transmission (n) Water discharge (o) Water supply

28. (ii) Community impacts (a) Aesthetics (b) Archeological and historical sites (c) Labour availability (d) Number of relocations (e) Public attitude

29. (iii) Public health and safety concerns (a) Degradation of local air quality (b) Attainment status (c) Sensitive populations (d) Dust (e) Noise (f) Operational odors (g) Wastewater treatment

30. (iv) Environmental impacts (a) Air quality (b) Protected species (c) Wildlife and natural lands (d) Wildlife impacts from operation

31. (v) Land use and economic impacts (a) Land acquisition (b) Prime agricultural land ( c) Industrial forests (d) Delivered cost of energy (e) Local tax impact (f) Property values

32. Pollution from thermal power plant Coal-Fired Power Plants are the largest contributor of hazardous air pollutants. Sulfur dioxide ( SO 2 ) Nitrogen Oxide ( NOx ) Carbon Dioxide (CO2)

33. POLLUTION AND POLLUTION CONTROL TECHNOLOGIES FOR THERMAL (COAL) POWER PLANT The demand for electric power is continuously increasing. The power plants are simultaneously facing the problem of impurities and pollution in atmosphere. The main pollutants from the thermal plants are dust and objectionable gases such as CO, CO2, SO2, NO2, and ash. The pollution from the thermal plant is also discharges large quantity of heat to the atmospheric air and the water is used for condensing the steam.

34. CO 2 ~ carbon dioxide pollution, making energy use the single largest source of greenhouse gases. Pollution

35. SO 2 S ulfur dioxide combined with nitrogen oxide react with water and oxygen in the atmosphere to form acidic compounds, which can mix with natural precipitation and fall to the earth as acid rain . Sulfur dioxide can also combine with nitrogen oxide and other particles to form particulate matter . Pollution

36. Pollution NO x When nitrogen oxide (chemically) reacts with volatile organic compounds (VOC’s) and sunlight ground-level ozone or smog is formed.

37. Pollution Controls Control of CO2 Cleaning coal Improved ESP Design Increasing the height of chimney Control of SO2 Desulpherisation of fuel Use low sulphur fuels Use of tall stacks Flue gas cleaning Control of NOx Reduction of combustion temperature Reduction of combustion timing Increasing equivalence ratio 1.6 to 1.8.

38. Bag House Filter

39. Waste Disposal Options for Thermal Power plant

40. Nuclear waste Disposal Disposal of Low Level Solid Waste

41. Nuclear waste Disposal Underground Disposal of High Level Waste

42. Nuclear waste Disposal nuclear solid waste in canister

43. Nuclear waste Disposal Nuclear Waste gas Disposal