CHEYENNE (WNE) — Consumer advocates with the Wyoming Public Service Commission are investigating a Black Hills Energy proposal to consolidate and raise natural gas rates.

The Office of Consumer Advocate, an independent division of the commission, is reviewing a recent Black Hills request to increase rates by an average of 17.3 percent across multiple service areas by 2020.

Earlier this month, Black Hills Energy asked the commission to consolidate the company’s four Wyoming gas utilities into one new legal entity, Black Hills Wyoming Gas. The company also submitted a rate review application to consolidate the rates, tariffs and regulations of existing gas territories in Wyoming.

Company executives say the rate changes will streamline service to 129,500 Wyoming customers and help Black Hills recover investments more reliably.

But, as proposed, some residential customers would see steep increases in their natural gas bills. In Casper and Gillette, customers could expect increases of 15-30 percent, and Cheyenne and Cody customers could see increases from 2-15 percent, according to the OCA.

Both residential and small commercial Laramie County consumers would see increases of 2-4 percent.

“We will be reviewing the application and conducting on-site audits to make sure [Black Hills] is only granted rates that are required to fairly compensate the company for the cost of delivering natural gas to its customers,” said OCA Administrator Bryce Freeman.

The OCA will investigate to determine if the rate increases are an accurate reflection of recent investment costs, said Christopher Leger, an attorney at the organization.