• Journal of The Korean Society of Agricultural Engineers
• /
• v.53 no.2
• /
• pp.53-60
• /
• 2011

This study was conducted to investigate the effect of hydropower factors (watershed, gross head), operation ratio and unit electricity cost on the benefit-cost ratio (B/C ratio) of small hydropower using agricultural reservoirs. The equation of B/C ratio was expressed as a function of watershed area, gross head, operation ratio and unit electricity cost. The benefit increased with watershed area, gross head and unit electricity cost, while the cost increased with watershed area and gross head but decreased with operation ratio. The B/C ratio increased with watershed area, gross head, operation ratio and unit electricity cost. While the effect of gross head on the B/C ratio decreased with watershed area, the effect of operation ratio and unit electricity cost on the B/C ratio increased with watershed area. The operation ratio is an important factor to affect the B/C ratio and therefore we need to develop hydropower for the heightened dams to expect high operation ratio due to continuous water release. The unit electricity cost is also an important factor to affect the B/C ratio and the B/C ratio was always below 1 unless unit electricity cost is over 60 Won/kWh under given conditions. The reservoirs with economic feasibility for small hydropower development were three in 21 when the equation of B/C ratio was appled to the study reservoirs. The results can be used to choose the appropriate reservoir with economic feasibility for development of small hydropower.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.17 no.6
• /
• pp.560-568
• /
• 2005

The cost accounting of electricity and heat produced from an energy system is important in evaluating the economical efficiency and deciding the reasonable sale price. The OECOPC method, suggested by the author, was applied to a 650 MW combined cycle cogeneration system having 4 operating modes, and each unit cost of electricity and heat products was calculated. In case that a fuel cost is ${\\}400/kg$ and there are no direct and indirect cost, they were calculated as follows; electricity cost of ${\\}23,700/GJ$ at gas-turbine mode, electricity cost of ${\\}15,890/GJ$ at combined cycle mode, electricity cost of ${\\}14,146/GJ$ and heat cost of ${\\}6,466/GJ$ at cogeneration mode, and electricity cost of ${\\}14,387/GJ$ and heat cost of ${\\}4,421/GJ$ at combined cycle cogeneration mode. Further, these unit costs are applied to account benefit on this system. Since the suggested OECOPC method can be applied to any energy system, it is expected to contribute to cost accounting of various energy systems.

• Journal of Energy Engineering
• /
• v.15 no.1 s.45
• /
• pp.14-22
• /
• 2006

Various pros and cons are raised as to the nuclear and renewable power portions. In order to generate scientific, objective, and comparative data, this study reviewed energy policies of some countries and derived 34 possible energy mix scenarios depending on the nuclear portion, the renewable portion and the make-up power sources. For each scenario, the unit electricity cost was calculated using the BLMP (Base Load Marginal Price) and SMP (System Marginal Price) methodology, which is currently adopted in Korean electricity market. The unit electricity cost for the current energy mix was 22.18 Won/kWh and those fir other scenarios spreaded from 19.74 to 164.07 Won/kWh excluding the transmission costs and profits of the electric utility companies. Generally, the increased nuclear power portion leads reduction in the unit electricity cost while the trend is reversed in the renewable power portion. Notable observation is that when the renewable power portion exceeds 20%, as the scenario cannot enjoy the benefit of cheap base load, the unit electricity cost at low demand time zone is increased.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.20 no.9
• /
• pp.624-630
• /
• 2008

When various kinds of outputs are produced from a single energy system, the methodology which allocates the common cost to each output cost is very important because it is directly related with the profit and loss of producers and purchasers. In the cost allocation methodology of the heat and the electricity on a cogeneration, there are energy method, work method, proportional method, benefit distribution method, exergetic methods, and so on. On the other hand, we have proposed a worth method which can be applied to any system. The definition of this methodology is that the unit cost of a product is proportion to the worth. Where, worth is a certain evaluating basis that can equalize the worth of products. In this study, we applied worth method to a steam-turbine cogeneration which produces 22.2 MW of electricity and 44.4 Gcal/h of heat, and then we allocated 2,578 $/h of common cost to electricity cost and heat cost. Also, we compared with various cost allocation methods. As the result, we conclude that exergy of various kinds of worth basis evaluates the worth of heat and electricity most reasonably on this system.

• Proceedings of the SAREK Conference
• /
• 2008.11a
• /
• pp.351-356
• /
• 2008

When various kinds of outputs are produced from a single energy system, the methodology which allocates the common cost to each output cost is very important because it is directly related with the profit and loss of producers and purchasers. In the cost allocation methodology of the heat and the electricity on a cogeneration, there are energy method, work method, proportional method, benefit distribution method, various exergetic methods, and so on. On the other hand, we have proposed a worth evaluation method which can be applied to any system. The definition of this methodology is that the unit cost of a product is proportion to the worth. Where, worth is a certain evaluating basis that can equalize the worth of products. In this study, we applied this methodology to a gas-turbine cogeneration which produces 119.2 GJ/h of electricity and 134.7 GJ/h of heat, and then we allocated 3,150 $/h of fuel cost to electricity cost and heat cost. Also, we compared with various cost allocation methods. As the result, we conclude that exergy of various kinds of worth basis evaluates the worth of heat and electricity most reasonably on this system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.21 no.4
• /
• pp.252-259
• /
• 2009

When various kinds of outputs are produced from a single energy system, the methodology which allocates the common cost to each output cost is very important because it is directly related with the profit and loss of producers and purchasers. In the cost allocation methodology of the heat and the electricity on a cogeneration, there are energy method, work method, proportional method, benefit distribution method, various exergetic methods, and so on. On the other hand, we have proposed a worth evaluation method which can be applied to any system. The definition of this methodology is that the unit cost of a product is proportion to the worth. Where, worth is a certain evaluating basis that can equalize the worth of products. In this study, we applied this methodology to a gas-turbine cogeneration which produces 119.2 GJ/h of electricity and 134.7 GJ/h of steam, and then we allocated 3,150 $/h of fuel cost to electricity cost and steam cost. Also, we compared with various cost allocation methods. As the result, we conclude that reversible work of various kinds of worth basis evaluates the worth of heat and electricity most reasonably.

• Proceedings of the KIEE Conference
• /
• 2003.11a
• /
• pp.422-425
• /
• 2003

CBP market which is the first stage of competitive electricity market has been operated and the KPX has been established since April, 2001 by restructuring plan for electricity industry. Baseload unit are settled with baseload CP and BLMP in CBP market. The other unit are settled with peakload CP and SMP. The difference of settlement between two groups occurs the profit changes of the unit. This paper analyzes the profit by units under settlement rule in CBP market. It analyzes the difference between market clearing price and variable costs, and fixed cost recovery through CP income. Finally, this paper suggests the plan how market was affected by the difference of fixed cost recovery by generators and how to improve Intermediate and peak load unit's profit.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.16 no.7
• /
• pp.673-682
• /
• 2004

The cost accounting of products on energy system is important for evaluating the economical efficiency and deciding the reasonable sale price. In the present, the suggested OECOPC method was applied to a combined cycle cogeneration, and each unit cost of electricity and heat products was calculated. In addition, the previous thermoeconomic methods were applied and calculated to equal system. As a result of comparing various methods, the unit costs by OECOPC method were calculated in the middle value of those. This result tells that OECOPC methods are most moderate. The suggested OECOPC method can apply any energy system. Hence this method is expected to make contribution to cost accounting on energy System.

• Proceedings of the SAREK Conference
• /
• 2009.06a
• /
• pp.1197-1202
• /
• 2009

Cost allocation on cogeneration is a methodology dividing the input of common cost to electricity cost and heat cost. In the cost allocation methodology of the electricity and heat on a cogeneration, there are energy method, work method, proportional method, benefit distribution method, reversible work method, various exergetic methods, and so on. In previous study, various cost allocation methodologies have been applied and analyzed on a gas-turbine cogeneration producing the 33.1 MW of electricity and the 32.2 Gcal/h of heat, a steam-turbine cogeneration producing the 22.2 MW of electricity and the 44.3 Gcal/h of heat, and combined-cycle cogeneration producing the 314.1 MW of electricity and the 279.4 Gcal/h of heat. In this study, we integrately analyze the results of previous studies and examine the generality and rationality each methodology. Additionally, a new point of view on the values of alternative electricity efficiency and alternative heat efficiency in the previous methodologies was proposed. As the integrated result, we conclude that reversible work method of various common cost allocation methodologies is most rational.

• Korean Journal of Chemical Engineering
• /
• v.36 no.1
• /
• pp.12-20
• /
• 2019

An energy storage system consisting of a battery and a power-to-methanol (PtM) unit was investigated to develop an energy storage system for renewable energy systems. A nonlinear programming model was established to optimize the energy storage system. The optimal installation capacities of the battery and power-to-methanol units were determined to minimize the cost of the energy system. The cost from a renewable energy system was assessed for four configurations, with or without energy storage units, of the battery and the power-to-methanol unit. The proposed model was applied to the modified electricity supply and demand based on published data. The results show that value-adding units, such as PtM, need be included to build a stable renewable energy system. This work will significantly contribute to the advancement of electricity supply and demand management and to the establishment of a nationwide policy for renewable energy storage.