The Globe and Mail reports in its Friday edition that Alberta utility Atco has been ordered to refund $71-million to customers, the latest development in a long-running dispute between the company and the provincial watchdog over electricity rates. The Globe's Emma Graney writes, however, that this week's decision by the Alberta Utilities Commission is far from the end of the regulatory tussle. Atco chief executive officer Nancy Southern told shareholders at the company's annual meeting recently that Atco intends to challenge the commission over the issue in the Alberta Court of Appeal in October. At the heart of the case is the commission's electricity rate-setting formula, called performance-based regulation. The formula is designed to encourage efficiency by providing incentives for utility companies to reduce costs. The more efficiently a utility operates, the more money it saves. Those savings are then shared with customers through lower utility rates. Atco delivered $500-million in distribution-cost savings, which is being passed onto customers. But the commission found that those savings could not be clearly attributed to specific utility projects, programs or initiatives, as required by the commission's rules.