Arizona utility regulators remain hopeful that a new federal plan to reduce carbon emissions will be overturned. This comes after a federal appeals panel this week rejected the state’s request to temporarily halt a key rule.

Under the Clean Power Plan, Arizona needs to reduce carbon emission from existing fossil fuel power plants by about 34 percent from 2005 levels in the coming years. Those requirements and others led Arizona to join more than two dozen states in filing suit against the Environmental Protection Agency.

Meanwhile, Arizona and other states had also requested a stay that would prohibit the EPA from implementing the rule to reduce carbon emissions from power plants.

Arizona Corporation Commissioner and Acting Interim Chairman Doug Little said while he is disappointed at the court’s recent decision not to halt the rule, he still believes the case is winnable. Little warned that Arizona ratepayers will be severely hurt by the rule, particularly in rural areas.

Environmentalists, however, argue the plan is critical for mitigating the impacts of climate change.

The court is set to consider the case later this year.