If a utility has a high demand charge and a low energy charge, then it will probably not be economical to add a wind turbine, since a wind turbine primarily reduces energy purchases. Observations and Conclusions on Wind-Diesel Hybrid Systems Diesel generators vary widely in cost with different sizes. These units are not meant for continuous use and are more available to run on gasoline. Wind turbines are most economic where energy charges are high but are not effective at reducing demand charges. There will likely be few instances where the addition of an engine-driven generator will improve the overall economics of a wind turbine installation for an electric customer in Iowa.
Wind turbines are most economical where the energy charges are high.
Since wind turbines produce intermittent power, they are usually not effective in reducing demand charges. The installation of engine-driven generators is usually only economical where demand charges are very high and there is a specific short period of time when the customer's demand is measured. In general, adding an engine-driven generator to a wind turbine installation will likely only be economical when the utility's demand charges are high or when there are additional benefits for having backup power for the customer, such as not having grid interconnection available at a remote site. Wind Diesel Hybrids Large generation additions for or by utilities are increasingly being constrained by limitations on the bulk power transmission grid. The existing transmission grid has limited capacity to accept large amounts of additional generation in many areas, especially if they are some distance from the major load centers.