Large Dams and Power Demand

Conventional power sector planning aims at providing reliable grid supply to consumers all over the country at the least cost. To achieve this, it largely concentrates on mega projects, which are considered suitable for large grid systems. Large hydro projects form an important part of the project portfolio in conventional power systems. Large hydro is said to be advantageous for the following reasons:

• Clean (low social and environmental costs)
• Renewable source of energy
• High untapped potential (estimated at 60 GW in India)
• Cheap

It is difficult to consider large hydro projects clean if we consider their social and environmental impacts. This presentation more specifically looks at two aspects, namely the costs and the potential of large hydro.

Large hydro projects take more than ten years to go through various stages, from planning to execution. In the case of the Narmada valley, in spite of its planned potential capacity of over 2,140 MW, only 90 MW had been added in the period of 25 years before the popular opposition to the project and the limitations on government support became serious constraints. This indicates that there are a number of practical difficulties and limitations for the realisation of the techno-economic potential of hydropower. At the national level, even without considering the possible large delays,(1) only 1,900 MW of annual capacity addition from hydro was planned for the ninth five-year plan (1997 to 2002), formulated by the government of India (GoI), in 1997-98. This needs to be considered in the context of official projections of annual capacity addition needs of more than 8,000 MW and possibilities of reduced demand by more than 30,000 MW over the next ten years, from efficiency measures. Thus, though the potential of large hydro appears to be very large, in reality, its role in meeting power demands is constrained.

The second advantage claimed in the case of large-hydro projects is its cost effectiveness. It is well known that the cost advantage of hydro projects vary drastically from case to case, depending on the site, water availability, particular needs of the power system and the availability of other options in technologies and fuels (such as gas and liquid fuels). Further, while weighing the advantages of hydro projects, one should be extra cautious about the high probability of time and cost overruns (World Bank (WB), 1996). These overruns make it problematic to compare the estimated cost of the hydro projects at the design stage with those of other projects. In India, during the eighth plan, the hydro power sector recorded the worst achievement in capacity addition in proportion to the target – only 27%. In addition, in India, it is often found that hydro projects are compared with options that are not really comparable and that the list of competing options considered is very limited. For example, one of the peaking hydro plants that we analysed was justified on the basis of a comparison with a thermal plant that was assumed to be operating at less than 20% Plant Load Factor (PLF)! (Maheshwar D.P.R., 1989). Options such as peaking gas turbine or pumped storage were not considered. Comparative costings, usually done well before taking an investment decision were not reworked while actually executing the decision.

Hence, contrary to usual practice, a rigorous and timely analysis is required to establish the cost-effectiveness of large hydro power even from the conventional planning perspective, leaving aside the debate on "externalities".

Most project assessment studies do not account for the full cost of the acceptable Resettlement and Rehabilitation (R&R) package or the full environmental cost. Incorporating these would radically change the economics of large hydro. Reworking the cost-effectiveness of hydro projects needs to account for these factors.

Thus, it is essential to look beyond the usual arguments about the cost-effectiveness and potential of large hydro projects. The role of large hydro needs to be reassessed in a wider perspective and through planning methodologies that are more inclusive as far as technological and fuel choices as well as planning processes and mechanisms are concerned. Apart from these general factors, many specific factors will have to be considered in dealing with a particular power system of a state or a country. In this article, we will elaborate on how, in the Indian context, the role of large hydro is changing and the steps that we feel are needed for properly assessing the role and viability of large hydro power.

Underlying the claims of certain advantages of hydro projects is the logic that guides the planning methodologies currently employed in the power sector. The conventional logic for hydropower, in the case of India, is as follows:

There exist large peaking shortages (>18%) along with energy shortages (~10%). Simultaneously, the demand is increasing rapidly (at a rate of 7% p.a.). As a result, the emphasis on peaking plants is essential. Hydro power is considered to be the one of the most appropriate peaking sources. In this context, in the case of India, it is pointed out that the proportion of hydel power generation, which ideally should be 40% of the total installed capacity, is falling steadily. The planning process then focusses on addressing the capital crisis.

This logic, involving sole reliance on supply through centralised generation with an emphasis on hydro projects, needs to be seen as an integral part of the paradigm that currently governs the power sector. It is essential to understand this in order to be able to investigate the role of hydropower in the near future. This conventional paradigm guiding the power sector could be visualised in terms of a vicious cycle, as shown in the diagram above.

Power sector planning starts with a high demand forecast and a painful realisation of the capital crisis. The planners tend to concentrate only on mega generation projects, which are seen as the only means to bridge the wide gap between demand and supply. In the process, several low-cost options receive insufficient attention, as each is said to be too small to bother about. While implementing large projects, some get delayed due to a shortage of funds or, at times, due to problems related to implementation. The neglect of low-cost options leads to high cost of power. Due to severe inequity in the Indian society, there is a strong demand for subsidised tariffs, especially for agricultural and residential sectors. Because they are politically convenient, large and ill-targeted subsidies are offered. This leads to a disincentive for consumers to use power in an efficient manner. At the same time, no action is taken to improve the efficiency of power utilisation. This, in turn, leads to rapidly rising demand and increasing financial losses in the sector. This situation reinforces the high demand forecasts and capital crisis, completing a vicious cycle. If the power sector has to come out of this vicious cycle, a substantially different approach needs to be adopted. Such an approach would involve redefining the current emphasis and paying close attention to the changing mandate of the power sector. The following section briefly explains the components of this process.

The first step in the planning exercise, the energy demand forecast (EDF), assumes that all demands that are finally out on the grid are justifiable demands that need to be satisfied to bring about development. By adding them up, the planning exercise arrives at a "need-based" projection of demand, without accounting for even the tariff elasticity of demand. At the state level, the demand projections are worse. The figure on page 52 shows the historic demand projections and actual demand met for different years for one state that did not have much power shortage.

The capacity addition plans that follow, restrict the list of options only to large centralised projects. This leaves many cost-effective options to meet the demand for services unattended. At times, even some of the centralised supply options are ignored. The highly economical options aimed at improving supply-side efficiency are rarely considered in the usual planning exercise. In fact, several plans consider the deterioration of plant performance. For example, the Working Group on Power (for the ninth five-year plan) made projections of capacity addition requirement on the assumption that plant performance would deteriorate.(2) This was despite the fact that measures to improve supply-side efficiency have played a major role in the recent past. The over-projection of capacity addition needs and the lack of sufficient emphasis on even the supply-side efficiency improvements can be established using a quote from the ninth five-year plan document. It states: "At the beginning of the eighth plan, the energy deficit was 7.8% and the peak deficit was 18.8%. With the targeted capacity addition of 30,538 MW, a peaking deficit of 20.7% and energy deficit of 9% was expected. However, at the end of the eighth plan, with the actual capacity addition of 16,422 MW, the peak deficit was restricted to 18.0% and energy deficit to 11.5% mainly due to a marked improvement in the Plant Load Factor of thermal plants."

In addition to these limitations, the capacity addition projections made during the planning exercise do not consider limitations on the available finances. As a result, the next level of planners (such as the Planning Commission) have to lower the targets for capacity addition. The planning then shifts to finding sufficient financial resources to implement the plan. Earlier, it simply meant asking for increased government budgetary support. Since the early 1990s, in the wake of limitations on government finances, a new route of allowing IPPs (Independent Power Producers) has become popular. But even private developers are finding it difficult to obtain finances in the absence of government guarantees. Hence, now, the central government has proposed to impose a levy on all power generated as a means of resource generation. All the while, the emphasis on building more large projects continues.

Despite the recent attention and action to increase supply-side efficiency, planning exercises usually continue with their supply bias. At best, the capacity released through efficiency improvements is seen as a means to reduce the gap between the projected and the actual realised capacity addition. Recently, the planning processes have been decentralised to the state-level to a large extent. Some of the state-level plans have even more serious problems. One state having a large peaking shortage has signed agreements for adding 1,300 MW of oil-fuelled power plants that would run as base load plants. Contracting them as peaking plants would have been ideal and would have also given substantial financial benefit compared to the present plan. Similarly, most plans do not consider the likely impact of increasing captive power generation in industries.

Some sanctioned projects get delayed due to a lack of funds or implementation problems. Such delays reinforce the shortage psychosis. A few projects also get held up due to popular opposition, because of problems related to R&R or serious environmental impacts (which are rarely considered in full). These projects then become contentious issues. The ensuing heated debate, which is usually portrayed as an environment versus development debate, effectively sidelines real issues. Removing such anomalies is essential for strengthening the financial health of the sector and it would radically redefine the need for added capacity as well as our emphasis.

Issues related to commercialisation of the power sector: Till the last decade, it was considered that "the basic responsibility of the power sector is to provide adequate electricity at the least economic cost, while ensuring reliability and quality of the supply". But, in the process, the power sector is making large operating losses, over US $ 2.5 billion p.a. (estimate for 1996-97) (Planning Commission, 1997). These losses are increasing rapidly and, at the same time, the capability of the state to absorb these losses is declining. Now, it would be impossible to add new capacity, in any major way, unless the power sector is able to recover the cost. Hence, commercial viability has become an important goal of the power sector. Already, in several states, the main reason for power shortages is the lack of paying capacity of utilities. To make matters worse, in the near future, the cost of supply is going to increase rapidly due to the addition of several IPP projects. State electricity boards will have to pass on this tariff impact to the consumers. Hence, despite being politically difficult, it is becoming essential to rationalise tariff (which includes a tariff increase for some sections). This is especially critical for sectors such as agriculture which receives the bulk of the subsidy and accounts for over 30% of total consumption. Changing from the connection-based tariff system to the consumption-based tariff system and an increase in revenue is essential. A tariff increase of over 500% for the agricultural sector is being talked about. This is expected to reduce agricultural consumption. But the demand forecasts do not consider the tariff sensitivity of demand.

Against this backdrop, the sector has three options. The first option is to continue in the "business as usual" (BAU) mode, i.e. to continue with: (a) the present emphasis on large projects and the related neglect of low-cost options and (b) irrational tariffs. In the BAU scenario, industries will continue to opt out of the grid and agricultural consumption will rapidly increase leading to high financial losses to the sector making it impossible to add new capacity in a major way. This will lead to an overall power shortage.

The second option involves tariff rationalisation and management improvements. This would help improve the financial situation of the sector along with some reduction in demand. But this relief will come at the cost of pricing out many of the rural consumers. This needs to be seen in the context of the prevailing ground reality where more than 50% of the irrigated land is being irrigated using electrical pumps (TERI, 1996-97). The pricing out can lead to substantial social tensions and associated heavy social cost.

The third route, which is the most desirable one, involves carrying out tariff and management improvements, choosing the low-cost options (for demand-supply matching) and trying to improve, on a priority basis, the end-use efficiency and reducing peak loads. It is essential that instead of planning projects to meet all demands put on the grid, we should try and prioritise the demands of different consumers. This route can lead to an increase in electricity bills within manageable limits, while being able to meet most of the reasonable demands for power.

The limitations on public resources combined with continued losses of the power sector has resulted in an increasing role for the private sector in power generation. This has meant an increased cost of capital (because of the higher rates of profits from the project). The private sector is also unwilling (and unable) to take large risks.

This has several implications especially for high-risk and long-gestation projects such as large hydro. The high cost of capital implies a preference for low gestation projects. The power demand situation is highly uncertain in several Asian countries. The uncertainty of industrial growth and increasing cost-effectiveness of captive generation are some of the factors driving these trends in India. Insufficiently worked out R&R plans that lead to popular opposition are also adding to the uncertainty of hydro projects. As a result, the private sector is less keen on getting involved in large hydro projects, unless a variety of risks are covered by the government. The ninth five-year plan acknowledges the very low interest of the private sector in hydro projects "on account of hydrological and geological risks". The plan recommends that public sector investments should be directed on a priority basis to hydro (along with transmission and distribution (T&D) improvements and improvement of power plant performance). This implies that highly cost-effective options of supply-side efficiency would have to compete with large hydro for accessing limited public funds.

Any effort to find a resolution for the problems mentioned above and to reassess the role of large hydro projects in overall power planning should begin from an investigation of ways to break through the vicious cycle. The following section focusses on two steps to break the vicious cycle: (a) expanding the choice of technologies and fuels considered during the planning exercise and (b) incorporating newer methods and mechanisms to plan and build power projects.

Expanding the Choice of Technologies and Fuels: Supply as well as demand-side efficiency improvements have a very large and cost-effective potential in India. The following three examples indicate the range of options and their sizeable potential:

It is estimated that agricultural consumption can be reduced by more than 40% if suitable improvements in pumps and piping are made (Boothra K.C., Bajaj N.K., 1994; Jain P.C. 1994; Patel S.M. and Pandey M.K., 1993; Sant Girish, Dixit Shantanu, 1996). In addition, simple improvements in irrigation practice that do not require major investments can reduce water (and, hence, power) use by another 20%. The cost of saved energy is usually less than a quarter of the cost of supply.(3)

Similarly, the household contribution to peak (which is about 30% of peak) can be substantially reduced by lighting improvements. Most utilities have not aggressively pursued the time-of-day tariff for industries, despite the availability of low-cost electronic meters.

The national appliance standards for efficiency are not mandatory and the existing standards need an urgent upgradation. The standards for pipe sizing, for example, are optimum for the electricity cost of Rs. 0.5/kWh, while the actual cost of supply is at least four times higher. If the standards were optimised and made mandatory for all new agricultural pump connections since 1991, by today India could have saved power equivalent to the production of an 800 MW base load plant. Upgradation of standards (without making them mandatory) can also lead to substantial savings (Sant Girish, Dixit Shantanu, 1996). Several other examples exist of means to collect such low-lying fruits.

The above list is not exhaustive by any means. There are several other low-cost options for meeting the demand for more power. The following list gives the potential of some of the important ones.

• The T&D losses are over 30%, which can be reduced to less than 15%, implying a potential of avoided capacity addition of nearly 13,500 MW.(4)
• A WB study in 1991 pointed out that "...demand unserved in FY 89 could have been reduced by approximately 50% through improved coordination in systems operation." The study further concluded that "improvements in the efficiency of system operations could provide approximately 10% of sector investment requirements through the eighth and ninth plans. It is important to stress that the savings could be obtained at very little cost (and without any increase in tariffs)". Most of these improvements, including the development of a national grid are yet to be carried out.
• The 12,000 MW oil-based projects that are planned can be converted to peaking plants. This would be an economic decision.
• Studies by several researchers have shown the significant potential of demand-side efficiency improvements. (Sant G., Dixit S., 1998,(a); Reddy Amulya Kumar N., et. al. 1991; Nadel S. et. al., 1991). Even the WB study for the state of Andhra Pradesh estimates that demand-side efficiency improvements can reduce the need for capacity addition to the tune of 20% of present capacity in the next decade (ESMAP, 1998). Taking the conservative estimate of the WB study, a capacity addition of 18,000 MW can be avoided nationwide in the next decade.
• The impacts of tariff rationalisation and plant performance improvement are not included here, but are likely to be sizeable.

All these options are substantially low-cost options. Most of them do not require major institutional restructuring. Taken together, they represent a potential that is much higher than what is hoped to be added in the form of hydro power plants (30,000 to 40,000 MW in next decade). Some of these would deliver primarily peaking benefit.

Despite such a situation, these options do not get the deserved priority. Planning techniques such as integrated resource planning (IRP) ensure that all available options are systematically included in the planning exercise and it ranks these options in the order of their costs. Adoption of techniques and tools such as IRP will halt the undue emphasis on long-gestation, centralised, bulky and high-cost projects such as hydel power projects.

The integrated plan described above can potentially offer very large benefits. But when such a plan is carried out along with peoples' participation, the benefits as well as the ease of implementation can be substantially increased.

One personal experience in this regard will help clarify the point. Once, we were talking to a group of villagers about energy conservation, when they were quick in pointing out one such opportunity for conservation that would be missed by most power planners. In a nearby village, a small irrigation dam was rendered useless due to minor defects in the gate and canal. The repairs had been pending for a long time. Helpless farmers in the command area of the dam dug wells and started using electric pumps with an estimated consumption of 4 million kWh (Sant G., Dixit, S. 1998,(b)). The repair of the dam gate could save all this. This example is indicative of the several inter-sectoral opportunities for efficiency improvement.

As mentioned earlier, the ability of farmers to pay for power is critical for sustaining agricultural development. It is argued that even paying for fuel and the operational cost of grid power is a big burden for most farmers. But surveys by some researchers have shown that farmers are willing to pay in kind. For example, by delivering say 1.2 kg. of woody biomass to the power station per kWh consumed (if the power station is not too far). To get the necessary amount of electricity, farmers can obtain the required biomass from agro-residues or by allocating less than 10% of land for biomass production. This is economical, as a farmer's net production increases despite allocating some land for biomass generation. This seems to be a very promising source for affordable power in India. And it can only be done with the cooperation and participation of people. In such situations, small-sized biomass-based power generation will play a major role in providing affordable power to farmers. Such opportunities for involving people in integrated power planning to increase the affordability of power for the rural population need to be looked into.

Considering these issues, we feel that immediate action should be taken to rationalise the power tariff (including metering of all electricity supplies) and implementation of proven low-cost options such as supply-side efficiency and some demand-side measures (market as well as non-market based). An integrated least-cost plan should be worked out in a participatory manner. Such plans should focus on maintaining the affordability of power, especially for rural consumers. The first two measures will give some breathing space and will improve the financial position of the power sector. The projects that pass the test of the least-cost plan should then be taken up.

After re-evaluating the cost, risks, and implementability of hydro projects, if they pass the test of the least-cost techniques, they can be taken up in the next step. The next step involves testing the options for social and environmental costs. This is a very contentious arena as there are no standardised methodologies to articulate costs and benefits on which consensus has been arrived. In the absence of such a consensual test, the only way to ensure a just and rational decision is to adopt a just and rational procedure on which consensus could be arrived. Such procedures should be democratic, transparent and participative. The following should be important steps in such a procedure:

Complete and detailed information on the technical design, R&R plan and other important aspects of the project should be made public. This should be followed by processes such as public hearings and open negotiations that ensure informed and genuine consent of affected people. Considering the possibility of differences, a dispute resolution procedure needs to be evolved.

This procedure should have the prior consent of persons affected by the project. Until such mechanisms (for disseminating information, feedback and dispute resolution) are evolved, we should not go ahead with the project.

Putting together such processes or arriving at an acceptable R&R mechanism is going to take time. It is not worth risking our money in bulky hydel projects until these steps have been successfully taken. Fortunately, the low-cost option does offer us the necessary time cushion. We should utilise it to complete detailed studies of various dam projects, considering all aspects, starting from hydrology, environmental costs, a revised cost-benefit analysis and possible R&R plans.

To summarise, we feel that though hydro would continue to play a significant role in the power sector, new large dams seem to have serious limitations. If options suggested by rational, integrated planning are opted for, the role of hydro options other than large hydro projects will be substantially more significant than today. These options include pumped hydro schemes, augmentation of capacity at base load hydro stations (to convert them to peaking), river run-off plants and small hydro (with limited social and environmental impacts).

Until now, this presentation was restricted largely within the conventional boundaries of the power sector planning. But the dual compulsion of reducing the overall (economic, social and environmental) cost of power while augmenting energy availability forces power planners to move beyond conventional boundaries. They have to resort to new approaches, which investigate hitherto neglected factors such as the nature of energy services required and pay attention to the quality of various forms of energy and their compatibility with the services required. These approaches naturally lead power planners into the ambit of not only energy policy but also development policy. Investigations into these factors question conventional assumptions about the 'power-energy-development' linkages. The next step lies in seeking answers to the question: "what exactly is power or energy required for?" Or, in other words, "what exactly is development?" In these changing times, power planners cannot overlook these issues.

Based on our experiences, we feel that work of a power planner should begin with understanding the very definition of development. Defining development in terms of gross domestic product (GDP) or even human development indices (HDI) is known to have serious limitations. These definitions and the related polices mainly rely on the 'trickle-down' mechanism of development, whose total failure could be witnessed in the rapidly increasing number of poor globally and in India, in particular. Commensurate with the growing compulsion that development should provide immediate, tangible and substantial relief to those who need it most, development should now be essentially seen as 'security of livelihoods to all'. With this clear idea of development, the focus of development policies should shift to 'strengthening, augmenting and enhancing livelihood opportunities' for all, especially for those whose livelihoods are under threat or stress. This, in turn, requires that the energy and power policies should be aimed at providing, at affordable rates and with top priority, the power and energy necessary for this strengthening, augmenting and enhancing of livelihoods.

This new paradigm changes the arena of power and energy planning drastically. It demands an integrated view towards planning for all inputs that are necessary for livelihood security – water, land, energy and biomass.(5) This will have to be in line with the mainstay of the new development strategy which could be articulated in terms of: decentralisation, rural biomass and renewable resource-based industrialisation, energy self-reliance, recycling of energy and materials and primacy of local institutions. This integrated view will create new opportunities for making energy and power available, such as hybridised conventional and non-conventional energy systems as well as centralised and de-centralised sources. It can also open up the possibility of using a part of irrigation waters for energy plantations and repayment of the energy cost through biomass. But the integrated view will also pose new challenges, for example, of evolving new, appropriate institutional and financial mechanisms, technological innovations (at times) and developing new economic relationships. In their routine work, power planners, even if they want to, do not get opportunities to work on these challenges.

In this context, we now look to the World Commission on Dams (WCD) process with a lot of expectation. We see WCD as a rare phenomenon that will help and facilitate research and analysis on the above-mentioned new opportunities and fundamental challenges. We sincerely hope that the WCD process will not take a narrow perspective and restrict itself to limited issues such as a comparison of proved and achievable potentials of hydro versus demand-side management and Integrated Resource Planning while remaining within the constraints of present institutional structures. Otherwise, its prime objective of investigating 'development effectiveness of dams' will remain unfulfilled.

This is a reproduction of a paper presented to the World Commission on Dams in 1998 by Prayas, a Pune-based NGO. The past work by Prayas' Energy Group includes evaluation of the economics of the Sardar Sarovar Project and the Maheshwar hydro power project, analysis of the Dabhol project, working out a least-cost plan for the state of Maharashtra and several regulatory intervention cases. Prayas comprises professionals with backgrounds in engineering, management and development studies. Prayas is on the advisory committee of the central and state Power Regulatory Commission.

1. Large delays in hydropower have been due to problems related to the availability of funds, geological surprises, inadequate R&R plans, environmental issues, etc. In the eighth plan, despite proposed capacity addition of the same order, only 27% could be realised.
2. The reason for such anomaly is more closely related to the internal dynamics of planning than the knowledge of planners.
3. The sector is also important because the irrigation loads in the post-monsoon period coincide with the annual peak period.
4. The savings are estimated as 15% of the present installed capacity.
5. These inputs are essential especially for the rural poor and the disadvantaged.

References:

1. Boothra K.C., Bajaj N.K., December 1994, Energy conservation in agricultural electric pumping system, National seminar on conservation of energy in agricultural pumping systems, Organised by Central Institute for Rural Electrification, Hyderabad.
2. UNDP/ESMAP, The World Bank, 1998, India: environmental issues in the power sector, Report No. 205/98.
3. Ninth five-year plan, Volume II, Government of India, 1997-98.
4. Jain P.C., December 1994, Energy conservation awareness through high efficiency of utilisation in pumping systems, National seminar on conservation of energy in agricultural pumping systems, Organised by Central Institute for Rural Electrification, Hyderabad.
5. Maheshwar D.P.R., Vol. VI A, March 1989, Narmada basin water development plan.
6. Nadel S. et. al., 1991, Opportunities for improving end-use electricity efficiency in India.
7. Gopinath, S. and Kothari, V., Washington DC, USAID, 1991.
8. Patel S.M. and Pandey M.K., 1993, Report on complete rectification of agricultural pumps in Gujarat state, Institute of Cooperative Management, Ahmedabad, 1993.
9. Planning Commission, 1997, Annual report on the working of state electricity boards and electricity departments, power and energy division.
10. Reddy Amulya, Kumar N., et. al. 1991, A development-focussed end-use oriented electricity scenario for Karnataka, Economic and Political Weekly (April 6 and 13)
11. Sant G., Dixit S., 1998,(a), Least-cost power planning: a case study of Maharashtra state.
12. Sant G. and Dixit S., Paper submitted to Energy for Sustainable Development.
13. Sant G., Dixit, S. 1998, (b) Towards an efficient and low-cost power sector, draft chapter on energy, prepared for the task force on Narmada valley set up by the Madhya Pradesh state government.
14. Sant G., Dixit S., May 1996, Agricultural pumping efficiency in India: the role of standards, Energy for Sustainable Development, Vol. III, No.1.
15. TERI Energy Data Directory and Yearbook 1996-97, Tata Energy Research Institute, New Delhi, India.
16. India power sector efficiency review, Vol. I, Main Report 1989, The World Bank.
17. India: long-term issues in the power sector, Executive Report, Vol. I, 1991, The World Bank.
18. Estimating construction costs and schedules: experience with power generation projects in developing countries, World Bank Technical Paper No. 325, Energy Series, The World Bank, 1996.