Co-generation Applications:
Steam turbines and gas turbines are used extensively to generate electricity. A major use of these turbines is in co-generation, where steam needed for other uses is also used either directly or indirectly to power a turbine for electricity production. Two classes of co-generators should be distinguished: The first which sells its power back to the utility at "avoided cost prices" and the other where the co-generator produces and uses its power without selling it back to the utility. This latter situation has a number of advantages for very large industries such as refineries and chemical companies. In this case a co-generator may have varying non-generation steam needs. Moreover, non-generation steam needs may be made to coincide with peak electricity needs. The co-generator could then match steam needs and power generation needs to further optimize energy use, steam use and energy production. The large co-generators that do not sell their power could benefit from using the VSI Generator. When steam production is varied, the steam turbine could operate at lower torque and rpm. The VSI Generator can use this type of power source where torque and rpm are varied. The co-generation unit could be operated to match varying steam needs and increase overall fuel use efficiency. Hence, large co-generation driven VSI Generators may have a significant place in industrial applications where direct sale of electricity to a utility is unattractive. The VSI Generator mobile cogeneration power plant along with the mobile ethanol power plant is generating a lot of excitement in the present need for immediate, economical and environmentally friendly electrical power.
Co-generation units in the .2 MW - 15 MW range use induction or synchronous generators. VSI Generators will cost less and have comparable efficiencies when compared to synchronous generators, will require even less interconnection equipment, and have none of the disadvantages of induction generators in terms of power factor and the "closed door effect." Therefore, the VSI Generator will displace both induction and synchronous generators in most co-generation applications of the .2 - 15 MW size. Co-generation applications that utilize internal combustion engines as a power source can benefit from the VSI Generator’s ability to match its output to the output of the prime mover. The VSI Generator can be matched to give maximum output and efficiency within 50 rpm above and below the speed of the engines optimum efficiency. Without the VSI Generator, the above applications use a 1200 rpm or 1800 rpm generator and lose more than 18% to 20% of the rated engine capacity, or install belts, pulleys, etc., with their maintenance, replacement problems, and additional losses. |
