Sixteen electric utilities surveyed state that use of ANNs significantly re
duced errors in daily electric load forecasts, while only three found other
wise. Data for five gas utilities reinforces this result: the mean absolute
percentage error (MAPE) for ANN daily gas demand forecasts was 6.4%, a 1.9
% improvement over previous methods. Yet ANNs were not always best, implyin
g opportunities for further improvement. The economic value of error reduct
ion for electric utilities was assessed by examining operating decisions. F
or 19 utilities surveyed, an average of $800000/year per utility is estimat
ed to be saved from use of ANN-based forecasts. Most benefits resulted from
improved generating unit scheduling; the utilities estimated such benefits
to be up to $143 annually per peak MW of demand for each 1% improvement in
MAPE. This estimated worth of accuracy improvement (roughly 0.1% of annual
generation O&M costs) is confirmed by solving generation scheduling and di
spatch models under various levels of forecast accuracy. (C) 1998 Elsevier
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