Project Selection: A MCDM approach

Site Selection for Hydro Power Plant using
Analytical Hierarchy Process (AHP)

Outline:
NHPC Limited (Formerly known as National Hydroelectric Power Corporation Ltd.), A Govt. of India Enterprise was established with the objective to plan, promote and organize an integrated and efficient development of hydroelectric power in all aspects. Since its inception in 1975, NHPC has grown to become one of the largest organizations in the field of hydropower development in the country. With its present capabilities, NHPC can undertake all activities from concept to commissioning of Hydroelectric Projects. The Case describes an AHP based approach to evaluate the sites among those identified to potentially set up hydroelectric power plants beyond the XI Plan.

Introduction
NHPC Limited (Formerly known as National Hydroelectric Power Corporation Ltd.), A Govt. of India Enterprise, was incorporated in the year 1975 with an authorized capital of Rs. 2000 million and with an objective to plan, promote and organize an integrated and efficient development of hydroelectric power in all aspects. Later on NHPC expanded its objects to include development of power in all its aspects through conventional and non-conventional sources in India and abroad.
At present, NHPC is a Mini Ratna Category-I Enterprise of the Govt. of India with an authorized share capital of Rs. 1,50,000 Million. With an investment base of over Rs.3,17,000 Million Approx. , NHPC is among the TOP TEN companies in the country in terms of investment.
Initially, on incorporation, NHPC took over the execution of Salal Stage-I, Bairasiul and Loktak Hydro-electric Projects from Central Hydroelectric Project Construction and Control Board. Since then, it has executed 13 projects with an installed capacity of 5175 MW on ownership basis including projects taken up in joint venture. NHPC has also executed 5 projects with an installed capacity of 89.35 MW on turnkey basis. Two of these projects have been commissioned in neighboring countries i.e. Nepal and Bhutan.
SALES Vs PROFIT
Presently NHPC is engaged in the construction of 11 projects aggregating to a total installed capacity of 4622 MW. NHPC has added 1970 MW during the 10th Plan period and planned to add 5322 MW during 11th Plan period. 8 projects of 7731 MW are awaiting clearances/Govt. approval for their implementation. Detailed Projects report is being prepared for 8 projects of 6505 MW.
Since its inception in 1975, NHPC has grown to become one of the largest organisation in the field of hydro power development in the country. With its present capabilities, NHPC can undertake all activities from concept to commissioning of Hydroelectric Projects.
Hydro Electric Power Summary
Hydroelectricity is electricity generated by hydropower, i.e., the production of power through use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy. Once a hydroelectric complex is constructed, the project produces no direct waste, and has a considerably lower output level of the greenhouse gas carbon dioxide (CO2) than fossil fuel powered energy plants. Worldwide, an installed capacity of 777 GWe supplied 2998 TWh of hydroelectricity in 2006.[1] This was approximately 20% of the world's electricity, and accounted for about 88% of electricity from renewable sources.[2]
The electricity sector in India is predominantly controlled by Government of India's public sector undertakings (PSUs). Major PSUs involved in the generation of electricity include National Thermal Power Corporation (NTPC), National Hydroelectric Power Corporation (NHPC) and Nuclear Power Corporation of India (NPCI). India was one of the pioneering states in establishing hydro-electric power plants. The installed capacity as of 2008 was approximately 36647.76. The public sector has a predominant share of 97% in this sector.
However the government must speed up the process of clearing new hydroelectric power projects and should rope in the private enterprise for the purpose of establishing small hydro schemes. This will require the government to take suitable policy initiatives. The advantages that hydroelectric power offer over thermal power plants are immense – 1. Hydropower is a renewable source of energy as it is generating by a combination of the unending rain cycle and the abrupt topography of the earth. 2. It is non-polluting and hence environment friendly. 3. Though hydroelectric power projects take a long time to be built, they have a very long life. The first hydro-project completed in 1897 is still in operation. 4. Cost of generation, operation and maintenance is lower than the other sources of energy. 5. Ability to start and stop quickly and instantaneous load acceptance/rejection makes it suitable to meet peak demand and for enhancing system reliability and stability. 6. Hydroelectric power plants offer higher efficiency (over 90 per cent) as compared to thermal power (35 per cent) and gas (50 per cent). 7. Cost of generation is free from inflationary effects after the initial installation. 8. Storage based hydro schemes often provide additional benefits of irrigation, flood control, drinking water supply, navigation, recreation, tourism, etc. 9. Hydropower projects, being located in remote regions, lead to development of interior backward areas in terms of infrastructure facilities like educational institutions, health centres, roads, telecommunication, etc.
Though concerns remains over the drawbacks of hydroelectric power plants – dislocation of population residing in the reservoir area, damage to aquatic life (partly controllable by measures like building fish ladders for the aquatic species moving upstream and using turbines and power plants of appropriate design so that fishes pass through it with least damage as they swim downstream), emission of greenhouse gases due to anaerobic decay of the plant material in the flooded area and a possibility of dam failure or a terrorist attack on it – the advantages of hydropower far outweigh the disadvantages.
Hence Indian government must make all efforts to increase the installed hydroelectric power capacity in the country despite the high initial cost incurred in building them in order to achieve its targets on power supply.

Power station | State | Operator | Units | Total capacity (MW) | Srisailam | Andhra Pradesh | APGenco | | 1670 | Nagarjunasagar | Andhra Pradesh | APGenco | 1 X 110, 7 X 100.8, 5 X 30 | 965 | SardarSarovar | Gujarat | SSNNL | 6X200, 5X140 | 1450 | Baspa-II | Himachal Pradesh | JHPL | 3 X 100 | 300 | NathpaJhakri | Himachal Pradesh | SJVNL | 6 X 250 | 1500 | Bhakra | Himachal Pradesh | BBMB | 5 X 108, 5 X 157 | 1325 | Dehar | Himachal Pradesh | BBMB | 6 X 165 | 990 | BairaSuil | Himachal Pradesh | NHPC | 3 X 60 | 180 | Chamera-I | Himachal Pradesh | NHPC | 3 X 180 | 540 | Chamera-II | Himachal Pradesh | NHPC | 3 X 100 | 300 | Pong | Himachal Pradesh | BBMB | 6 x 66 | 396 | Uri - I | Jammu & Kashmir | NHPC | 4 X 120 | 480 | Dulhasti | Jammu & Kashmir | NHPC | 3 X 130 | 390 | Salal | J& K | NHPC | 6 X 115 | 690 | Sharavathi | Karnataka | KPCL | | 1469 | Kalinadi | Karnataka | KPCL | | 1225 | Idukki | Kerala | KSEB | 6 X 130 | 780 | Omkareshwar | Madhya Pradesh | NHPC | 8 X 65 | 520 | IndiraSagar | Maharashtra | NHPC | 8 X 125 | 1000 | Loktak | Manipur | NHPC | 3 X 35 | 105 | Koyna | Maharashtra | MahaGenco | | 1960 | Rangit | Sikkim | NHPC | 3 X 20 | 60 | Teesta - V | Sikkim | NHPC | 3 X 170 | 510 | Tanakpur | Uttarakhand | NHPC | 3 X 40 | 120 | Dhauliganga-I | Uttarakhand | NHPC | 4 X 70 | 280 |

Requirements
According to the Government of India estimates, the power requirement in the country will increase to 200,000 MW by 2012 and to 400,000 MW by 2020. Hence India needs to exploit all its available natural resources to the fullest in order to bridge the widening demand-supply gap in the power sector.
Hydroelectricity thus assumes greater importance than before as India still has a huge untapped hydroelectric power generation potential. According to the Central Electricity Authority, which generates important statistics on the power generation and usage in the country, the viable hydro potential in India is 84,000 MW at 60 per cent load factor which is equivalent to 1,48,700 MW installed capacity.
In addition to this, 6872 MW from 1512 small hydro schemes can also be economically exploited. Further, the government agencies have identified 56 sites from pumped storage schemes with an aggregate installed capacity of 94,000 MW.
But despite India being one of the pioneering states in hydroelectric power in Asia, with Darjeeling power plant established in 1898 and Shimsa (Shivanasamudra) power plant established in 1902, the total installed capacity of hydroelectric power plants in the country was only 36647.76 MW in 2008.
Currently, the hydroelectric power plants generate only 21 per cent of the electricity consumed in the country with 76 per cent of the total electricity being generated by thermal power plants which are highly polluting and depend on non-renewable fossil fuels.
According to S K Garg, Chairman & Managing Director of NHPC Ltd which is India’s largest hydroelectric power company and which has been conferred Mini Ratna status by the government of India, a total of 12 projects with a total installed capacity of 5322 MW will be established by the company during the Eleventh Plan (2007-2012).

Sites evaluated 1. Bursar,J& K
2. KarmoliLumtiTulli ,Uttarakhand 3. GarbaTawaghat, Uttarakhand 4. ChungarChal, Uttarakhand 5. Lachen,Sikkim

Parameters for Assignments of Weights
The following parameters were identified to determine the suitability of the Power Plant at a particular location
Site Requirements
Each site has been further evaluated based upon the following parameters 1. Geology 2. Water Storage Capability 3. Seasonal Variations in Water Supply 4. Raw Material Availability 5. Water Flow Volume

Community Impacts 1. Relocation expenses 2. Local Resources Affected 3. Employment Potential
Environmental Impacts & Public Health 1. Flora and Fauna Submerged 2. Downstream Ecology 3. Construction Hazards 4. Long Term Effects
Land Use Impacts 1. Land Lost in Submersion 2. Cost and Difficulty 3. Terrain Access & Suitability for Construction
Economic Impacts 1. Cost of Alternatives 2. Total Capital Costs & Land Valuation 3. Transmission & Distribution Charges

The percent weight estimates of each of the five 1st level parameters and eighteen 2nd level parameters were calculated based on opinions from NHPC guidelines, consultants working in this industry and using case-studies.
The sites are rated on a discrete scale of (1-9) with 1 as the worst and 9 the best against each criterion as follows:- CRITERION | A | B | C | D | E | Geology | 4 | 6 | 8 | 9 | 8 | Water Storage Capability | 5 | 7 | 4 | 5 | 2 | Seasonal Variations in Water Supply | 6 | 4 | 5 | 7 | 2 | Raw Material Availability | 6 | 3 | 7 | 4 | 1 | Water Flow Volume | 7 | 5 | 4 | 3 | 1 | Relocation expenses | 2 | 6 | 9 | 9 | 9 | Local Resources Affected | 4 | 7 | 6 | 3 | 6 | Employment Potential | 5 | 6 | 3 | 5 | 3 | Flora & Fauna Submerged | 3 | 4 | 5 | 3 | 7 | Downstream ecology | 2 | 6 | 6 | 3 | 5 | Construction Hazards | 2 | 7 | 8 | 9 | 9 | Long term effects | 6 | 4 | 9 | 7 | 3 | Land lost in Submersion | 5 | 5 | 3 | 5 | 7 | Cost & Difficulty | 7 | 3 | 9 | 9 | 8 | Terrain Access & Suitability for Construction | 7 | 5 | 4 | 9 | 10 | Cost of Alternatives | 3 | 6 | 2 | 1 | 4 | Total Capital Costs & Land Valuation | 3 | 3 | 6 | 9 | 9 | Transmission and Distribution Charges | 5 | 7 | 5 | 7 | 8 |

Subsequently, the preference of each parameter in comparison to the other is calculated further across different parameters using the above ratings and the priority matrix at the 3rd hierarchy is determined.

Hierarchy As mentioned earlier, the goal of this problem is to choose the best location for Hydro power plant. We evaluated the 5 sites based on the criteria by following a 3 level hierarchy as shown below

The sites, viz. A, B, C, D, E make the 3rd level of hierarchy.

We used AHP to calculate weights for each criterion. Based on the composite weights, the final site was chosen.

Solution

The problem has 5 main criteria and 18 sub criteria. Hence the total number of comparison matrices is 24 (18+5+1).
At first, weights are determined for the main criteria as follows. * Normalize the matrix * Find out the relative weights * Check whether the matrix is consistent * Calculate Eigen value * Calculate Consistency Index (CI) * Find out Random consistency Index (RI) * Calculate Consistency Ratio (CR) as CR = CI/RI

All the calculations were carried out using MS Excel

Comparison matrix Criteria | Site Requirements | Community Impacts | Environmental Impacts & Public health | Land use impacts | Economic Impacts | Site Requirements | 1 | 3 | 4 | 1/2 | 1/4 | Community Impacts | 1/3 | 1 | 1/3 | 1/6 | 1/7 | Environmental Impacts &Public health | 1/4 | 3 | 1 | 1/3 | 1/8 | Land use impacts | 2 | 6 | 3 | 1 | 1/2 | Economic Impacts | 4 | 7 | 8 | 2 | 1 |

Normalized matrix Site Requirements | 0.1319 | 0.1500 | 0.2449 | 0.1250 | 0.1239 | Community Impacts | 0.0440 | 0.0500 | 0.0204 | 0.0417 | 0.0708 | Environmental Impacts &Public health | 0.0330 | 0.1500 | 0.0612 | 0.0833 | 0.0619 | Land use impacts | 0.2637 | 0.3000 | 0.1837 | 0.2500 | 0.2478 | Economic Impacts | 0.5275 | 0.3500 | 0.4898 | 0.5000 | 0.4956 |

The weights are as follows:

Site Requirements | 0.1551 | Community Impacts | 0.0454 | Environmental Impacts &Public health | 0.0779 | Land use impacts | 0.249 | Economic Impacts | 0.4726 |

Consistency Ratio = 0.064

* The same approach described above is followed to calculate weights of the 18 other criteria. One example of the same is given below

Comparison matrix Criteria | Geology | Water Storage Capability | Seasonal Variations in Water Supply | Raw Material Availability | Water Flow Volume | Geology | 1.0000 | 3.0000 | 3.0000 | 0.5000 | 4.0000 | Water Storage Capability | 0.3333 | 1.0000 | 1.0000 | 0.1667 | 1.0000 | Seasonal Variations in Water Supply | 0.3333 | 1.0000 | 1.0000 | 0.3333 | 3.0000 | Raw Material Availability | 2.0000 | 6.0000 | 3.0000 | 1.0000 | 3.0000 | Water Flow Volume | 0.2500 | 1.0000 | 0.3333 | 0.3333 | 1.0000 |

Normalized matrix NORMALIZED Table | Geology | Water Storage Capability | Seasonal Variations in Water Supply | Raw Material Availability | Water Flow Volume | Geology | 0.2553 | 0.2500 | 0.3600 | 0.2143 | 0.3333 | Water Storage Capability | 0.0851 | 0.0833 | 0.1200 | 0.0714 | 0.0833 | Seasonal Variations in Water Supply | 0.0851 | 0.0833 | 0.1200 | 0.1429 | 0.2500 | Raw Material Availability | 0.5106 | 0.5000 | 0.3600 | 0.4286 | 0.2500 | Water Flow Volume | 0.0638 | 0.0833 | 0.0400 | 0.1429 | 0.0833 |

The weights are as follows:

Geology | 28.26 | Water Storage Capability | 8.86 | Seasonal Variations in Water Supply | 13.63 | Raw Material Availability | 40.98 | Water Flow Volume | 8.27 |

Consistency Ratio = 0.053

* Similarly, the weights of each site, viz. A, B, C, D, E are calculated against each 2nd level criterion and the matrices are checked for consistency. * In the end, the composite weights for each site are calculated as follows:

The following tables give the composite weights at level 2.

Site Requirement | Geology | Water Storage Capability | Seasonal Variations in Water Supply | Raw Material Availability | Water Flow Volume | Weight | Weights | 28.26 | 8.86 | 13.63 | 40.98 | 8.27 | | A | 11.43 | 21.74 | 25.00 | 28.57 | 35.00 | 0.231662659 | B | 17.14 | 30.43 | 16.67 | 14.29 | 25.00 | 0.17734751 | C | 22.86 | 17.39 | 20.83 | 33.33 | 20.00 | 0.261542664 | D | 25.71 | 21.74 | 29.17 | 19.05 | 15.00 | 0.222143086 | E | 22.86 | 8.70 | 8.33 | 4.76 | 5.00 | 0.107304081 |

Community | Relocation expenses | Local Resources Affected | Employment Potential | Weight | Weights | 63.3346 | 10.6156 | 26.0498 | | A | 5.41 | 15.38 | 22.73 | 0.1098 | B | 16.22 | 26.92 | 27.27 | 0.2023 | C | 24.32 | 23.08 | 13.64 | 0.2141 | D | 27.03 | 11.54 | 22.73 | 0.2426 | E | 27.03 | 23.08 | 13.64 | 0.2312 |

Environmental | Flora & Fauna Submerged | Downstream ecology | Construction Hazards | Long term effects | Weight | Weights | 34.71 | 17.45 | 12.40 | 35.44 | | A | 13.64 | 9.09 | 5.56 | 20.69 | 0.1434 | B | 18.18 | 27.27 | 19.44 | 13.79 | 0.1837 | C | 22.73 | 27.27 | 22.22 | 31.03 | 0.2640 | D | 13.64 | 13.64 | 25.00 | 24.14 | 0.1877 | E | 31.82 | 22.73 | 27.78 | 10.34 | 0.2212 |

Land use impacts | Land lost in Submersion | Cost & Difficulty | Terrain Access & Suitability for Construction | Weight | Weights | 16.38 | 53.90 | 29.73 | | A | 20.00 | 18.92 | 20.00 | 0.1942 | B | 20.00 | 8.11 | 14.29 | 0.1189 | C | 12.00 | 24.32 | 11.43 | 0.1847 | D | 20.00 | 27.03 | 25.71 | 0.2549 | E | 28.00 | 21.62 | 28.57 | 0.2473 |

Economic Impacts | Cost of Alternatives | Total Capital Costs & Land Valuation | Transmission and Distribution Charges | Weight | Weights | 10.62 | 63.33 | 26.05 | | A | 18.75 | 18.92 | 15.63 | 0.1804 | B | 37.50 | 8.11 | 21.88 | 0.1481 | C | 12.50 | 24.32 | 15.63 | 0.2080 | D | 6.25 | 27.03 | 21.88 | 0.2348 | E | 25.00 | 21.62 | 25.00 | 0.2286 |

* The final composite weights for A, B, C, D, E are obtained as:

| Site Requirement | Community | Environment | Land use | Economic Impacts | | | 15.51 | 4.54 | 7.79 | 24.90 | 47.26 | 100.00 | A | 0.2317 | 0.1098 | 0.1434 | 0.1942 | 0.1804 | 18.57105947 | B | 0.1773 | 0.2023 | 0.1837 | 0.1189 | 0.1481 | 15.06245957 | C | 0.2615 | 0.2141 | 0.2640 | 0.1847 | 0.2080 | 21.516254 | D | 0.2221 | 0.2426 | 0.1877 | 0.2549 | 0.2348 | 23.45126371 | E | 0.1073 | 0.2312 | 0.2212 | 0.2473 | 0.2286 | 21.39896325 |

The final composite weights show that maximum value is 23.45126371. Since this weight occurs for site D, site D is the winner.

Conclusion

| Final Results | | | | | | | | Site Name | State | Percentage | ChungarChal | Uttarakhand | 23.45126371 | GarbaTawaghat | Uttarakhand | 21.516254 | Lachen | Sikkim | 21.39896325 | Bursar | Jammu & Kashmir | 18.57105947 | KarmoliLumtiTulli | Uttarakhand | 15.06245957 |

As it is evident from the above scores, based upon the various criteria evaluated in the problem, the best alternative among the sites is ChungarChal, Uttarkhand.

References

* Site evaluation for ranking study of potential hydro-power projects: An Indian perspective using spatial technologies- A.K. Charaborti, Water Resources Group, NRSA, Hyderabad, India

* National Hydro power corporation- Beyond 11th year plan http://www.nhpcindia.com/

* Power Plant Engineering – A.K. Raja, AmitSrivastava, Manish Dwivedi