. the volume/weather variance is primarily due to an increase of 153 gwh , or 1% ( 1 % ) , in billed electricity usage , including an increase in industrial usage , partially offset by the effect of less favorable weather on residential and commercial sales . the increase in industrial usage is primarily due to expansion projects in the pulp and paper industry , increased demand for existing customers , primarily in the metals industry , and new customers in the wood products industry. .