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United States Department of Agriculture

Agricultural Research Service

Title: Hybrid Electric Power Generation with Wind and Diesel

Author
item Clark, Ray

Submitted to: Agricultural Engineering International Conference
Publication Type: Proceedings
Publication Acceptance Date: July 31, 2002
Publication Date: July 31, 2002
Citation: Clark, R.N. 2002. Hybird electric power generation with wind and diesel. Agricultural Engineering International Conference Proceedings. American Society for Agricultural Engineers. Paper No. 024186.

Interpretive Summary: Many farms and communities exist in remote places where it is unlikely that they will ever be connected to large utility girds. These farms and communities depend on costly diesel fuel for electric power generation and often store several months supply of diesel fuel on site. Electrical costs at these locations often range from 30 to 50 cents per kilowatt-hour (kWh). Reducing the fuel expense by using local, renewable energy sources is the focus of wind/hybrid research and development. One way to reduce diesel fuel usage is to add wind turbines to the existing diesel mini-grid so that diesel generator sets run less and save fuel. Larger wind plants have more potential for fuel savings, but require sophisticated electronic grid controls. Constructing a hybrid system that works, developing the necessary controls, and evaluating the performance were primary objectives of this study. While testing, the hybrid system performed well; however, it did not quite meet all the specified performance and reliability goals. The average frequency and voltage were within specified limits, though some very occasional voltage and frequency excursions were observed. In general the power quality was good. The fuel efficiency increased from 2.63 kWh per liter for diesel only to 4.01 kWh per liter with hybrid system without storage and to 10.09 kWh per liter with battery storage. The potential run time in wind only was greatly increased when the battery storage was added. The wind energy penetration varied from 0% to 100%, depending upon wind conditions and the village load. When wind power was sufficient to curtail the diesel generator sets, control was smooth and stable providing for the entire village load without having to burn fuel. Some systematic improvement in the control logic will be necessary to increase the average time between power outages, especially with the rotary converter controller.

Technical Abstract: Wind/hybrid operation data were collected using an independent hybrid test grid consisting of three diesel generator sets, AOC 15/50 and Enertech 44/40 wind turbines, two resistive load banks, pre-commercial controls, with a simulated village load. Two configurations were tested, one using a synchronous condenser that included no storage and one with 110 kW of battery storage with a rotary converter. The fuel efficiency increased from 2.63 kWh per liter for diesel only to 4.01 kWh per liter with hybrid system without storage and to 10.09 kWh per liter with battery storage. The potential run time in wind only was greatly increased when the battery storage was added. When wind power was sufficient to curtail the diesel generator sets, control was smooth and stable providing for the entire village load without having to burn fuel.

Last Modified: 10/25/2014
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