A cooler-than-average year and growing conservation efforts have actually led to a decrease in overall power consumption in the state, Hawaiian Electric Co. (HECO) reported in its quarterly earnings report on Tuesday. “Although the number of customers grew during the quarter, they reduced their usage of electricity in response to weather conditions and the higher cost of electricity during the quarter,” said Constance Lau, president and chief executive officer of Hawaiian Electric Industries, Inc. (HEI), HECO’s parent company. High energy costs and recent rate hikes also likely prompted residents and businesses to cut back. Lau said the “cooler and less humid weather and customer conservation” meant yet another quarterly decline in its electric utility income down about $1.1 compared to the same quarter last year. Having earlier projected consumption to increase by more than 3 percent this year, HECO now expects the decline to continue for the rest of 2006. If it does, it will be the first time in nearly a decade that annual power consumption has gone down rather than up.