5.3. Computation model results

An integrated energy system capable of utilising several resources such as wind energy, solar energy, hydroenergy and biogas for carrying out various tasks in a region is presented based on the design formulated earlier. The approach is based on minimisation of total annual cost, subject to a set of constraints on the requirements for various tasks. The efficiency values hijk used in the formulation for various pre-selected


resource–task combinations are listed in Table 4.1. The Kijk load factor computed using the relationship (Eq. (20)) is listed in Table 4.2. The effective plant load factor Ki and the diversity factor di assumed for resources are listed in Table 4.3. Capital cost values computed in Rs./kWh (computed in earlier [28,29]- techno-economic analyses) are listed in Table 4.4. The linear programming problem is solved using Lindo-LP package. The resulting optimal values are listed in Table 5.1. Optimum allocation of resources for various tasks is as follows:

E11: 3266.780 million units-mkWh (wood energy for task 1),
E12: 20795.340 million units (wood energy for task 2),
E13: 1271.720 million units (wood energy for task 3),
E16: 1892.580 million units (wood energy for task 6),
E22: 346.230 million units (biogas for task 2),
E24: 2588.360 million units (biogas for task 4),
E31: 33.020 million units (wind energy for task 1),
E35: 172.530 million units (wind energy for task 5),
E46: 1048.560 million units (solar energy for task 6),
E51: 1481.580 million units (hydroenergy for task 1),
E55: 1408.030 million units (hydroenergy for task 5),
E63: 280.730 million units (grid electricity task 3),
E64: 39.260 million units (grid electricity task 4),
E74: 12.630 million units (kerosene for task 4),
E76: 2.510 million units (kerosene for task 6),
E85: 31.380 million units (diesel for task 5), and
E86: 68.610 million units (diesel for task 6).

The optimal energy allocation is tabulated in Table 5.1. Total cost per year is about Rs. 11,930.28 million as against Rs. 18,711.08 million. Optimisation based on the cost minimisation objective shows that there is saving of about 19.19% in energy and 36.24% cost reduction in overall energy system.
Cost per unit (kWh) of energy with optimal allocation of energy is Rs. 0.31/kWh (as against Rs. 0.39/kWh without optimisation).


Optimisation is carried out with the objective of maximisation of efficiency of ‘ijk’ combination for all combinations and results are listed in Table 5.2. The efficiency of wood devices for heating is taken as 10%. In this case biogas is first preferred for cooking (about 79%) and the balance is used for lighting. When efficiency of end use devices (for resources-1) is increased (Task 1: efficiency 30%, Task 2: efficiency of 40% and Task 3: efficiency of 30%), then firewood is preferred for cooking and biogas for lighting. The results of this simulation are listed in Table 5.3. In the case of maximisation of efficiency criteria, the energy saved is about 19.98% and total cost is about Rs. 12766.53 million. These results are listed in Table 5.4.