The South Dakota Public Utilities Commission approved a settlement allowing NorthWestern Energy to refund $3 million in savings resulting from the federal tax reform that slashed the federal income tax rate to 21 percent from 35 percent effective Jan. 1., according to a Sept. 18 press release. The company agreed to a rate moratorium to avoid base rate increase until Jan. 1, 2021. Each residential electric customer will receive a one-time credit of $18 and natural gas customer will receive $9 by the end of next month.