Iran's removing subsidy from energy carrier in four years ago leads to spike electricity price dramatically. This abrupt change increases the interest on distributed generation (DG) because of its several benefits such as lower electricity generation price. In Iran among all type of DGs, because of wide natural gas network infrastructure and several incentives that government legislated to support combined cooling, heat and power (CCHP) investors, this type of technology is more prevalent in comparison with other technologies. Between existing CCHP technologies, certain economic choices are to be taken into account. For different buildings with different load curves, suitable size and operation of CCHP should be calculated to make the project more feasible. If CCHP does not well suited for a position, then the whole energy efficiency would be plunged significantly. In this paper, a model to find the optimal size and operation of CCHP and auxiliary boiler for any users is proposed by considering an integrated view of electricity and natural gas network using GAMS software. Then this method is applying for a hospital in Tehran as a real case study. Finally, by applying COMFAR III software, useful financial parameters and sensitivity analysis are calculated.

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Abstract. With the development of distributed generation (DG) technologies and the implementation of policies to encourage their applications, The Combined Cooling, Heating, and Power (CCHP) systems is expected to play a greater role in the commercial buildings in the future. CCHP is a promising efficiency improvement and carbon mitigation strategy, but careful operation mode is required to achieve a reasonable system performance according to energy consumption characteristics of buildings and technical features of equipments [1]. This paper presents an energy dispatch method which minimizes the cost of energy (e.g., cost of electricity from the grid and cost of natural gas into the gas turbine and boiler) base on the energy hub concept and by regarding carbon market rules. The system includes combined heating power (CHP) module, auxiliary boiler, absorption chiller, utility grid and electrical, thermal, and cooling loads. In fact, by solving this model, optimal energy flow will be determined regarding both the amounts of electric, thermal, and cooling loads in each time interval and prices of electricity and natural gas at the same time, by considering environmental constrains. In the cost function of this model, the total economic benefit of this system is maximized during total daily operation time. The results of an optimal operation model have been discussed economically and a case study has been investigated.

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Abstract. Cost of annual energy loss occurs in distribution networks is an important issue in distribution systems planning, design and operation & discos are pleased to be informed about financial worth of loss extract from their profit to evaluate economic feasibility of improvement projects. there are several dominating factors involved in distribution loss cost evaluation, but most of the times price of loss occurs in distribution systems is calculated regardless of location, consumption pattern and etc, but recent changes in Iran distribution power system including removing energy subsidies, deregulation, increase in distributed generation units and trend toward loss reduction had been resulted in much more importance to have actual price of distribution network losses. In this paper, Distributed generation units penetration level influence on distribution networks worth of loss is investigated, power delivered to distribution systems from these resources is directly connected to loads and no transmission cost is involved, in the proposed formulation this difference between centralized and decentralized generation is covered. It is shown that distribution worth of loss follow a U-shape trajectory by increase in distributed generation units' penetration level.