Planning of Energy Saving with Cogeneration System

PT Dua Kelinci is one of the largest food industries in Pati Regency one of whose products is egg peanut which needs huge electric and heat energy so that energy saving needs to be done. One of the efforts of energy saving is by conducting cogeneration (merging between electric and heat). This research started from a data collection, i.e. finding out the need of electricity and heat in the process of egg -peanut manufacture by a cogeneration technology at PT Dua Kelinci. The research method includes technical analysis and economic analysis. From the technical analysis, it is found that the electric energy saving by using cogeneration 103.680 kW and the heat energy saving is 4,075 TJ/year. From the economic analysis it is seen that before using cogeneration the cost that should be expended is USD 75.209,61 while after using cogeneration the cost is USD 60.6014,04 therefore from the economic aspect there is energy saving as much as USD 15.19,57/year.


Introduction
PT Dua Kelinci which is located in the 6.3 km of Pati-Kudus street is one of the biggest industries in Pati, and has a lot of equipment that requires a lot of electrical energy of 4950 kVA from PLN. With that much electric power then PT Dua Kelinci is considered as one of the large electric energy users so that if the electricity is not efficiently used then a lot of energy is wasted. In order that the energy is not wasted, there are a lot of things to do one of which is energy saving. To do energy savings there are several alternatives which can be taken, which include improving the quality of electrical power, the use of energy -saving devices, energy management, the application of cogeneration and so on.
The electric power source of PT Dua Kelinci comes from two sources, i.e. PLN-Pati of 2770 KVA using two transformers and from PLN-Kudus of 2180 KVA which also uses two transformers. The division of the load is illustrated in the scheme as follows. Cogeneration or Combine Heat And Power (CHP) is a technology which combines two energies, i.e. heat and electricity [1]- [4]. The illustration of the use of cogeneration can be seen in Figure 1. Distribution of electrical load from PLN Kudus as shown in Figure 2.  There are sixteen general principles of energy management proposed by Craig B. Smith in his book Energy Management Principles, which are general principles that need to be learned before an energy management program is undertaken. These principles include a review of the history of energy use, energy audits, analyzing the us ed energy, using more efficient equipment, using more efficient processes, energy retention (heat recovery and waste reduction), operation and maintenance, material replacement, material economy (recovery cuts, rescue and recycling), selection of material quality, the used energy collection, energy reduction, use of alternative energy sources, energy conversion, energy s torage, and economic evaluation [6].
This paper presents an analysis of the five heating and cooling of energy saving system for high performance mid-level apartments in two Canadian regions: Calgary and Montreal [2]. Rade M. Ciric and Zoran Kuzmanovic present a feasibility analysis of biogas power plants for the combined heat and power plants including different aspects such as the available biomass resources, heat and power production, verification of requirements for connecting power plants to networks, as well as economic feasibility analysis [4].

Research Method
The sequence is done in this method are (1) Collect data consists of observations Flow Production Process, (2) Calculated for Electricity and Heat, (3) After knowing the demand for electricity and heat then determine whether to cogeneration or not, (4) Having considered necessary cogeneration then determine the fuel used, (5) Perform feasibility studies, (6) after the feasibility study, we will find that our plans if feasible or not feasible then continue if it does not stop [3,7,8]. Energy use PT Dua Kelinci is electrical energy in supply of PLN and Genset while heat energy derived from Boiler and Thermal Oil, and a new one this month PT Dua Kelinci using CNG (Compress Natural Gas). By looking at the beginning of system energy usage PT Dua Kellinci and make observations in PT Dua Kellinci then there are several processes that can be done as cogeneration application that requires electrical energy and heat energy. One was in the process of making eggs beans that require electrical energy and heat simultaneously. So the authors try to assess the application of cogeneration in t he production of eggs beans in PT Dua Kellinci. For more details on the making of the energy consumption eggs beans will be depicted in Figure 4. . Initial Condition System on Making Peanut Egg [9] After looking at the initial condition of the use of energy resource on the egg peanut manufacturing process in PT Dua Kelinci, a scheme of cogeneration system i s then created as described in Figure 5.  Figure 5 shows that the implementation of cogeneration or CHP is more efficient, it is seen from the use of three types of energy sources into one source of energy that is CNG as required roasting machine and the main fuel cogeneration that can generate heat and electricity, electricity from cogeneration is used to meet the electrical needs of the roasting machine and the heat generated from the cogeneration results are used in boiling spices so as to meet all the energy needs in the manufacture of peanuts. more details can be seen in the result and analysis

Results and Analysis 3.1. Initial Energy Before Using Cogeneration
The Electrical energy calculation here is divided into two, those are the calculation of electrical energy at the Peak Load Time (PLT) and the calculation of electrical energy at the Outside Peak Load Time (OPLT), the result as shown in Table 1

The resulting plan Energi Cogeneration
The Electrical energy calculation here is done without using Peak Load Time (PLT) and the calculation of electrical energy at the Outside Peak Load Time (OPLT), the result can be seen in Table 2. Hence, the comparison between the initial energy use and the cogeneration use will be shown in Table 3.

Emission in Initial Condition
The emission of the electric use from PLN is by multiplying the baselin emission fac tor with the generated energy [10]. By using the electrical emission factor of JAMALI (Java Madura Bali) that is 0.725 kgCO 2 /kWh, the generated energy is 414,720 kWh/year. The Green House Gas (GHG) emission of the PLN is 0,725x414.720 which equals to 300.672 kgCO2/year or equals to 300,67 tonCO2/year. The GHG emission of LPG is 0,525 TJ/yarx20 Ton C/TJx0,99x 44 tonCO 2 /12 tonC=38,115 ton CO 2 /year.

GHG Emission Using Capstone Microturbine C-30
Before calculating the emission what should be calculated is the amount of fuel consumption of Capstone Microturbine C-30 that is:

The Reduction of Green House Gas (GHG) Emission
The Reduction of GHG Emission is by reducing the emission before using cogeneration and after using cogeneration, 1026,785 tonCO2-895,9 ton CO 2 =130,885 ton CO 2 . If the reduction of greenhouse gas emission (CO 2 ) amounts 130,885 ton CO 2 /year and to analogize that 1 kg of CO2/year is equal to planting 1 lush tree, then using Capstone microturbine C-30 is the same as planting as many trees as 130.885 kg/13 kg per tree=100.885 trees and by an analogy in which 4,5 ton CO2 can be absorbed by one hectare of tree then 130,885 ton of CO 2 divided 4,5 equals to 29,085 hectares of tree.

Analyzed Cost Method
Analyzed Cost Method can be used to investigate the characteristics of an economy based on the total annual expenditure and the total annual income [ 8]. The total annual expenditure of cogeneration covers the ivestment cost, fuel cost, operational and maintenance cost [8]. The total annual income covers income of the electric energy use, heat energy use, excess of heat energy and carbon emission trade. Before proceeding to the economic analysis, there are some assumptions to know, i.e. the price of one unit of Capstone Microturbine C-30 which amounts $ 40.000,00, with bank interest of 10%, operation and maintenace $0,0054/kWh.

Total Annual Expenditure
The total annual expenditure covers investment, fuel cost, and operation as well as maintenance. a. Investment Cost Investment cost is investment cost which should be paid every year. With a 10% interest and an estimated lifespan of 9 years then the annual investment cost is

Total Annual Income Total
The total annual income in this chase is revenue to be earned within a year covering revenue of electricity usage, revenue of heat consumption, electricity excess revenue, heat excess revenue, and revenue of carbon emissions trading. a. Revenue of the electricity use The  Table 5.

Total Net Revenue
After knowing the total annual cost that should be spent and the total annual revenue, then the net revenue can be found by reducing the total annual revenue by the total annual cost.
Total Net Revenue=total annual revenue-total annual cost =USD126.049,86-USD110.747,83 =USD 15.302,03 To determine the savings that can be done after applying the cogeneration system using two capstone microturbine C-30 described in the comparison table between initial condition and cogeneration, it can be seen in Table 6. In the initial conditions, the company has to pay electricity and heat costs of USD 75,209.61 whereas when using cogeneration it only needs to pay the cost of electricity and heat costs as well as getting USD 60,014.04 thus the total saving is USD 15,195.57.

Conclusion
From the research it can be concluded that: a. The application of cogeneration technology at PT Dua Kelinci with the excess of electricity sales of 103,680 kW, the excess of heat sales of 4,075 TJ/year, and the greenhouse emission trade of 130.88 tonCO2 which can be assumed as planting trees of 29 hectares. b. In the initial conditions, the company has to pay electricity and heat costs of USD 75,209.61 whereas if using cogeneration it only needs to pay the electricity and heat costs amounting USD 60,014.04 thereby the total saving is USD 15,195.57 per year.