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U.S. Department of Energy
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Cost-benefit analysis of variable-speed generators applied to peakshaving/cogeneration systems. Topical report, December 1988-May 1989

Technical Report ·
OSTI ID:7153894
Variable-speed operation of engine-generator sets can achieve maximum fuel efficiency at any rpm, taking advantage of the engine's ability to operate at speeds above (and below) the normal, fixed speed. Thus, it is possible to produce more power for a given engine size, reduce operating costs, and, in many cases, reduce capital costs for a given power rating. Two approaches to variable-speed generation are considered: one approach using a doubly-fed machine plus a power converter and another approach using a conventional generator plus a power converter. In the capital cost and operating cost comparisons the approach using a doubly-fed machine proves superior. The following figures apply to that approach. Constant operation at any level below full load results in operating cost savings with variable-speed generation. For 150 kW systems studied, variable-speed peakshaving can save from $4,000 to $8,000 in operating costs per year, and variable-speed cogeneration can save up to $24,000 in operating costs per year, assuming typical gas and electrical charges. Capital costs for the same systems can be reduced by as much as $5,000 for peakshaving and $8,000 for cogeneration.
Research Organization:
Electronic Power Conditioning, Inc., Corvallis, OR (USA)
OSTI ID:
7153894
Report Number(s):
PB-90-131533/XAB
Country of Publication:
United States
Language:
English