Power generation

Maximisation of power output (i.e. the power that is usable) is the ultimate goal of most MFC studies. The power output of an MFC is calculated from the measured cell voltage and the current as 

Normally, the voltage is measured across a fixed external resistor (Rext)/ while the current is obtained from Ohm s law (I = Thus, power out- 

As discussed above, the maximum cell voltage (Eceii) that can be measured in MFC is its OCV, which is always lower than the Eg f of the cell due to various potential losses. The MFC can be viewed as having two resistors linked in series, an external load (Rext) and an internal resistance (Rj J. The theoretical maximum power of the total system is therefore 

In MFC studies, our concern is the maximum power that can be used, that is, the power output (P ,ax)- Tho theoretical maximum power output can be expressed as 

Since OCV, other than is the maximum voltage that can be achieved in an MFC, we therefore generally use the following equation to determine the maximum power output. 

To make MFCs useful as a method to generate power, it is essential to optimize the system for power production. Power is calculated from a voltage and current as P = IE. The power output by an MFC is calculated from the measured voltage, E pcy across the load and the current as 

The current produced by a laboratory-scale MFC is calculated by measuring the potential across the load i.e., the external resistor, and using I = E/ c/R, . Thus, we can calculate power output as 

Based on the relationship / = E/ p -Z R, we can alternatively express power output in terms of the calculated current as 

Power output normalted by surface area. Knowing how much power is generated by an MFC does not sufficiently describe how efficiently that power is generated by the specific system architecture. For example, the amount of anode surface area available for microbes to grow on can affect the amount of power generated. Thus, it is common to normalize power production by the surface area of the anode, Aa , so that the power density produced by the MFC is 

Microbial Fuel Cells. By Bruce E. Logan Copyright 2008 John Wiley Sons, Inc. 

defiaed as the rate at which work is performed, is expressed ia terms of energy divided by time and is most commonly given in units of horsepower, as for the power suppHed by mechanical devices such as diesel engines, or in the SI units of watts, especially when measuring electrical power. One horsepower is equivalent to the amount of power needed to lift 33,000 pounds (14,982 kg) one foot (30.5 cm) in one minute. One watt is equivalent to the power required to perform one joule of work per second. In a simple direct-current circuit where potential is represented by E  

In the industrial arena, the term power generation most typically refers to the production of electrical or mechanical power via any of several energy conversion processes. Early examples of practical power generation devices include water-wheel-powered mills for grinding grain, which were reportedly used as early as 100 BC in the Balkans and areas of the Middle East, and wind-powered mills, which were widely used as early as the tenth century in the Middle East. 

The first centralized electric generating plant in the United States was Edison s three-unit steam-engine-based station, which suppHed electric power to light approximately 5000 electric lamps in a group of homes and businesses in New York City in 1882. Also in 1882, the first hydroelectric power plant went into operation in Appleton, Wisconsin, generating approximately 25 kW of power, enough to power more than 200 100-watt light bulbs. 

The widespread availabiHty of electrical energy completely transformed modem society and enabled a host of breakthroughs in manufacturing, medical science, communications, constmction, education, and transportation. Centralized fossil fuel-powered, steam-turbine-based power plants remain the dominant means of electricity production. However, hydropower faciHties such as the 1900-MW Hoover Dam Power Project located on the Arizona—Nevada border, commissioned by the U.S. Bureau of Reclamation during the 1930s, have also made significant contributions. 

In 1956, the world s first commercial nuclear power plant started operation in England. By the 1960s, many nuclear power plants were built worldwide. At the end of the twentieth century, nuclear generating plants are used widely by U.S. electric utiHties. Since 1984, these plants have provided the second largest share of total U.S. electricity generation, 21% of annual GW-h generated, behind coal-fired power plants (see Nuclearreactors). 

FERC was created in October 1977 as a result of the passage of the Department of Energy Organization Act. At that time, the 57-year-old Federal Power Commission (FPC) was eliminated and FERC took over many of the FPC s responsibiUties. 

In 1986, Congress passed the Electric Consumers Protection Act (ECPA), which set the foundation for more efficient relicensing of hydropower facihties, enhanced competition among apphcants for relicensing, and ensured a balance between environmental interests and the need for hydropower development. 

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

Entities involved in long-term contracts with electric utihties, such as fuel supphers and NUGs selling power to utihties, also have concerns that some utihties or industrial customers will not be able to honor their contracts under the new, more competitive system. Einahy, some utihties are concerned that they wih not be adequately reimbursed for opening up their transmission systems to competitors. The potential competitors in turn are concerned that utihties whl not provide unbiased access to their transmission systems if the utihties themselves are also in business of marketing power. There has also been some debate regarding which transmission facihties are eligible for open access. This is because some facihties are considered local distribution systems by utihties, which feel they should not be opened to competitors. 

EERC beheves that 137 utihties wih be required to open up their transmission networks. As of mid-1996, the NOPR is stih being debated. However, several states have adopted preliminary plans to open up the transmission networks of their regulated utihties by the year 2000 or shortiy thereafter. 

Fuel cells operate much like a battery, using electrodes in an electrolyte to generate electricity. But, unlike a battery, fuel cells never lose their charge as long as there is a constant source of fuel. 

Fuel cells can be used to power a variety of portable devices, from handheld electronics such as cell phones and radios to larger equipment such as portable generators. Other potential applications include laptop computers, personal digital assistants (PDAs), and handheld video cameras—almost any application that has traditionally used batteries. These fuel cells have the potential to last more than three times as long as batteries between refueling. 

In addition to these smaller applications, fuel cells can be used in portable generators, such as those used to provide electricity for portable equipment. Thousands of portable fuel cell systems have been developed and operated worldwide, ranging from 1 watt to 1.5 kilowatts in power. The two primary technologies for portable applications are polymer electrolyte membrane (PEM) and direct methanol fuel cell (DMFC) designs. 

Department of Energy s Office of Fossil Energy has a joint program with fuel cell developers to develop the technology for stationary power applications includes central power and distributed generation. 

The joint government-industry fuel cell program is aimed at giving the world s power industry a revolutionary new option for generating electricity with efficiencies, reliabilities, and environmental performance beyond conventional electricity generation. 

Offshore structures are relatively self-sufficient they provide electrical generators, water desalinators, sleeping facilities, communication stations, and modern amenities. Production platforms are connected by pipelines or floating storage units to onshore operations. Key process elements of oil and gas recovery include wellhead, production manifold, production separator, water injection pumps, gas compressors, glycol process to dry gas, oil and gas export metering, and main oil-line pumps. 

Steam turbines Gas turbines Wind turbines Water turbines Diesel engines 

These devices are connected to electric generators, where fuel cells produce electricity 

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I- emissions from central power generation corresponding with the amount of electricity imported... 

This is particularly important when considering the effect that combined heat and power generation (cogeneration) has on utility waste. 

Combined heat and power cogeneration). Combined heat and power generation can have a very significant effect on the generation of utility waste. However, great care must be taken to assess the effects on the correct basis. 

When electricity is bought from centralized power generation companies, the price tends to be more stable than fuel costs, since power generation companies tend to negotiate long-term contracts for fuel supply. 

Steam costs vary with the price of fuel. If steam is only generated at low pressure and not used for power generation in steam turbines, then the cost can be estimated from local fuel costs assuming a boiler efficiency of around 75 percent (but can be significantly higher) and distribution losses of perhaps another 10 percent, giving an overall efficiency of around 65 percent. 

With respect to fuels utilized as heating fuels for industrial furnaces, or as motor fuels for large diesel engines such as those in ships or power generation sets, the characteristics of primary importance are viscosity, sulfur content and the content of extremely heavy materials (asphaltenes) whose combustion can cause high emissions of particulates which are incompatible with antipollution legislation. 

The European regulations have set SO2 emission limits for industrial combustion systems. They range from 1700 mg/Nm for power generation systems of less than 300 MW and to 400 mg/Nm for those exceeding 500 MW between 300 and 500 MW, the requirements are a linear interpolation (Figure 5.24). To give an idea how difficult it is to meet these requirements, recall that for a fuel having 4% sulfur, the SO2 emissions in a conventional boiler are about 6900 mg/Nm this means that a desulfurization level of 75% will be necessary to attain the SO2 content of 1700 mg/Nm and a level of 94% to reach 400 mg/Nm. ... 

Beam pumping and electric submersible pumps (ESP) require a source of power. On land it may be convenient to tap into the local electricity network, or in the case of the beam pump to use a diesel powered engine. Offshore (ESP only) provision for power generation must be made to drive down hole electric pumps. 

The storage of chemicals, lubricants, aviation fuel and diesel fuel is normally on the platforms, with chemicals kept in bulk storage or in drums depending on the quantities. A typical diesel storage would be adequate to run back-up power generators for around a week, but the appropriate storage for each item would need to be specified in the FDR... 

Laborelec is the laboratory of the Belgian electricity industry. The laboratory is in charge of solving and anticipating the technical challenges related to the power generation, transmission and distribution of electricity. 

V. Carl, E. Becker, A. Sperling - Siemens Power Generation Group, Germany. 

Stale of the art, 8 chapters inch 60 Fig.. Months with special focus on TOFD, Thickness Gauging, Aerospace, Power Generation... 

Fossil Power Generation - Boiler and Heat Exehanger Tubes... 

This technology has since been introduced to the fossil power generating industry. To-date, several major utilities including the Termessee Valley Authority, Baltimore Gas and Electric and American Electric Power, as well as many others, have employed this technology to assess the condition of power-generating boiler tubes. 

Laser-based profilometry systems have also been adapted for unique applications in nuclear power generating plants. Applications where quantitative information with regard to surface condition for mechanisms such as surface pitting and flow-assisted corrosion are candidates for this NDT method. 

Power Generated in Industrial Countries by Nonfossil Fuels (1990)... 

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