Power supplies operating costs

Economics Power-recoveiy units have no operating costs in essence, the energy is available free. Furthermore, there is no incremental capital cost for energy supply. Incremental installed energy-system costs for a steam-turbine driver and supply system amount to about 800 per kilowatt, and the incremental cost of an electric-motor driver plus supply system is about 80 per kilowatt. By contrast, even the highest-inlet-pressure, largest-flow power-recoveiy machines will seldom have an equipment cost of more than 140 per kilowatt, and costs frequently are as low as 64 per kilowatt. However, at bare driver costs (not including power supply) of 64 to 140 per kilowatt for the power-recovery driver versus about 30 to 80 per Idlowatt for... 

The nontransformer isolated topologies are used for board-level converters. These are in distributed power systems where an intermediate bus voltage is distributed throughout the system and each board within the system has its own power supplies. The bus voltage is always a safe level that is not deemed lethal to the operator of the equipment, therefore dielectric isolation is optional. I still heartily recommend transformer isolation in most applications. The added cost... 

Power will be purchased from a nearby company. (One of the major reasons for locating here was the presence of low-cost, plentiful power.) A gas-fired plant for 125 psig steam will be built. This must be able to supply enough power to operate agitators and cooling-water pumps associated with the reactors when there is a power failure. Gas will be purchased from a local company. Drinking water will be purchased from the community of Martins Ferry, Ohio. Process and cooling water will be obtained from the Ohio River. Both will require treatment before they can be used in the plant. 

Timer-controlled systems are simple, low-cost systems which involve timing of flow through an orifice. Most include a sight glass or other means of checking the amount batched. A number of variables, such as changes in power supply, constriction of the measuring orifice and increased viscosity of the admixture can introduce considerable error. Timer-controlled units must be recalibrated frequently, and the plant operator must be alert to verify the proper admixture dose by observation of the calibration tube. They have been successfully used with... 

The excitation lamp is enclosed within a compartment which is designed to shield the detector and its associated electronic circuits from the heat generated by the lamp. A small fan flushes cool air into the upper compartment that houses the detection devices. The trigger mounted at the instrument s handle is used to operate a dual shutter that opens and closes the excitation and emission apertures simultaneously. The hand-held instrument is low cost (a/ 2,000), simple to operate, and weighs only a little over 1 kg without the power supply ( 5 kg). A photograph of the prototype instrument is shown in Figure 2. 

Power Supply and Process Control Unit. Electrodialysis systems use large amounts of direct current power the rectifier required to convert AC to DC and to control the operation of the system represents a significant portion of a plant s capital cost. A typical voltage drop across a single cell pair is in the range 1 -2 V and the normal current flow is 40 mA/cm2. For a 200-cell-pair stack containing 1 m2 of membrane, the total voltage is about 200-400 V and the current about... 

Energy management is a functionality that aims at the achievement of a reliable and efficient operation of an autonomous power system. The first objective is related to the capability of the system to serve the loads with minimum interruptions caused by insufficient power supply. The second objective is related to the minimisation of fossil-fuel generator costs and thus the cost of produced energy. An increased renewable penetration level, makes the fulfilment of these... 

The annual operating costs are also shown in Table 3. The raw materials costs were estimated from the average purchase cost of crude olive oil in Portugal in 1994. Supplies were empirically calculated from the scale-up study and include water, electric power, fiiel, maintenance, assurances, transports and expedient articles. The labour costs were determined for 4 shifts of 2 persons each, plus supervising personal. With a depreciation time of ten years and an interest rate of 10%, the total annual capital costs was estimated to be 212PTE/kg of oil feed. Several other economical indicators, such as the internal rate of return of the plant, showed a promising economical feasibility for this project. 

The total product cost per unit of time may be divided into the two classifications of operating costs and organization costs. Operating costs depend on the rate of production and include expenses for direct labor, raw materials, power, heat, supplies and similar items which are a function of the amount of material produced. Organization costs are due to expenses for directive personnel, physical equipment, and other services or facilities which must be maintained irrespective of the amount of material produced. Organization costs are independent of the rate of production. 

Fuel cells, especially PEMFCs, can be used for various applications ranging from portable power supply for use in consumer electronic devices to stationary deployment for combined heat and power generation. Another potential application is transportation, in which fuel cell systems are developed for the propulsion of cars. The performance, operating conditions, costs, and durability requirements differ depending on the application. Transportation applications demand stringent requirements on fuel cell systems. Only the durability requirement in the transportation field is not as rigorous as the stationary application, although cyclic durability is necessary. 

---