Nebraska's largest utility will keep electricity rates flat next year and give customers a small credit on their bills starting in February. The Nebraska Public Power District's board approved the 2020 rates on Thursday. Next year will be the seventh year in a row of stable rates for NPPD's retail customers. The utility says retail customers will also receive a monthly credit of between 2% and 4% of their bills in 2020. NPPD's wholesale customers, which include cities and some rural public power districts, will receive slightly larger credits of about 6.2% a month on average in their bills.