Monte Carlo Simulation and Modeling of Schedule, Cost and Risks of Dasu Hydropower Project

HPP (Hydropower Projects) are very complex and risky in nature. For HPP, it is extremely important not only to identify risks but also to adopt proper mitigation measure to complete the project with in defined schedule and budget. Attempt has been made in this paper to identify critical risks associated with Dasu HPP and their mitigation measure to complete the project within predefined time and budget. The research methodology involved the questionnaire survey for identification of potential risks with their probabilities and impact. Pert-Master (Oracle Risk) software was used for simulation purposes. After feeding all data in the software, Monte Carlo simulation was run at 1,000 iterations to generate most probable duration of project, most probable cost of the project, critical risks sensitive to duration, critical risk sensitive to cost and statistically analyzed critical tasks/activities, which need due consideration for successful completion of project. Simulated schedule and budget was compared with planned one to find possible deviations, which may be eliminated by using mitigation measures proposed in the last section of the paper.

The salient features of Dasu HPP are mentioned in Table 1.

Monte Carlo Simulation and Modeling of Schedule, Cost and Risks of Dasu Hydropower Project
The main focus of this research is to devise a methodology to complete HPP well in planned time and budget. Despite of good economic feasibility, Dasu HPP faces many risks due to its complexity of design, As Dasu HPP is a public sector project therefore, it has its own complexities and riskiness due pros and cons of Public sector. Through this research, an attempt has been made to use software based analysis and simulation of scheduling and cost for Dasu HPP and developed methodology can be used as a guideline for the other HPP on Indus and other rivers in Pakistan.The study will also give policy options to Policy makers and other stakeholders about completion of projects in terms of expected cost overrun, expected completion time and critical risks of the project to determine true cost-benefit analysis of the project.

Overview of Previous Relevant Researches
Mubin and Mubin [4]

Adopted Methodology
The research methodology involved the questionnaire survey for identification of potential risks with their probabilities and impact. Data was collected from most relevant stakeholders and professionals working in HPP.
Pert-Master software has been used as primary tool for simulation and modeling of project schedule and cost.

Probability of Occurrence and Impact of Risks
There PMI (Project Management Institute), USA has given a standard for calculating Possibility of Occurrence and Impact Factor of risk given as can been seen from Table 3.
There is a lot of subjectivity in PMI approach of calculating Possibility of Occurrence and Impact factor of each risk as mentioned in Table 2. It is very difficult to categorize the probability of occurrence in percentage terms and therefore researcher find difficulty in judging the risk and marking them as Very High Chances (90%) to High Chances (75%) and so on. Therefore, for this purpose, a mechanism has been developed in consultation with all process owners and stakeholders for selecting probability of each risk. Tables 3-5 give opportunity to the risk professional to select a frequency with a base frequency of 50%. Neutral position of a risk, according to this mechanism will be 50% frequency. If there is a positive possibility of occurrence of risks, frequency higher than 50% will be selected. More the chances of occurrence, higher will be the frequency or vice versa. Similarly, the mechanism developed by the author, gives a risk professional the opportunity to assign separately the impact of risk in terms of time, cost or quality. Sometimes, it happens in an HPP, where cost is not too much implicit, it reduces the impact factor negatively downwards, however, it other indirect impact on time or quality is significant, which isignored if we use the PMI approach.
To avoid the subjectivity of PMI approach to identify, analyze and quantify risks, a quantitative approach has been used and mentioned in Table 4 and will be used for selecting an impact factor to a risk in a three dimensional context of time, cost and quality to have three risk numbers separately [4].

Data Collection
Data was collected on designed questionnaire from 220 professionals associated to hydro power projects in various capacities working with national and international consultant organizations, contractors and client departments such as WAPDA, Planning Commission, P&D Department, etc. Professionals were targeted for giving response on the questionnaire that hold design, contract administration, procurement, execution, environment, geology, health & safety and infrastructures of HPP. The questionnaire was responded by 156 professionals. Every participant of the survey was to provide the frequency and impact of each risk. Knowing the fact that the impact of a risk can be upon any of variables like time, cost and quality, hence, in the questionnaire the respondents were asked to give their inputs for afore mentioned possibilities of occurrence and impact factor for each identified risk.

Simulation and Modeling
The schedule for Dasu, HPP was prepared in Primavera P6 software and then imported to Pert-Master software. All 130 identified risks were uploaded on the software and assigned to their relevant activities of the schedule to prepare the Risk-Based (simulated) Schedule and to find modeled cost of project. The basic aim of simulation was to find the deviation of Schedule and Budget from originally planned project. Moreover, it was intended to find the critical risks associated to the project. Simulation worked out most probable duration of project, most probable cost of the project, critical risks sensitive to duration, critical risk sensitive to cost and criticality index of activities.

Results from Software
After entering the software desired data regarding the activities and the risks, Monte Carlo Simulation was run on the schedule and simulated schedule of project was obtained which was further used to compare the different scenarios of project in terms of cost, delays and completion of the project. The main results are as follows:

Simulated Schedule (Duration) of Dasu HPP
Two scenarios were considered in Monet Carlo simulation schedule of Dasu HPP i.e. simulation with risk and simulation without risk. However, variation in activity duration vis-à-vis optimistic duration, pessimistic duration and most likely duration was in given in both scenarios. Simulation uses 80:100:120 distributions of optimistic, most likely and pessimistic duration of various project activities. The initial planned duration of project is 2556 days, which was worked out by conventional method of planning and estimation. Planned finished date is 29 th September, 2021. Against these deterministic values of duration and finish date of project, the simulated (most probable) duration and finish date for the Dasu HPP comes out to be 3113 days and 9 th March, 2023 respectively considering no risks in simulation.  Fig. 1(a-b).
The Duration Sensitivity of a task is a measure of the correlation between its duration and the duration (or dates) of the project (or a key task or summary). Pert-Master analysis calculated top ten duration sensitive activities with respect to chances to overall delay of Dasu HPP are mentioned in Fig. 2.

Simulated Cost and Cost Sensitive Activities
The planned deterministic cost of project is PKR 406,128 Million

Top Ten Critical Risks Evaluated by the Pert-Master Software Impacting Schedule and Cost of Dasu HPP
Simulation worked out top ten critical risks influencing duration and cost of the project described in Table 6.

Top Ten Critical Activities (Tasks) Evaluated by Pert-Master
The CI (Criticality Index) is proportion of iteration out of total simulation cycles i.e. 1,000 in which it remained critical. CI is a statistical evaluation of critical activities, which is much more reliable as compare to Critical Path of project activities calculated by CPM (Critical Path Method) of project scheduling. After simulation, top ten activities vis-à-vis criticality index were analyzed by the software as mentioned Table 7.   initially planned cost. Based on the analysis, the project stakeholders of Dasu HPP should focus on time and cost sensitive activities, critical project risks as well as the critical activities to complete the project successfully.