GILLETTE -- Electric customers in Gillette could see their rates go up 8 percent to 15 percent.

Black Hills Power has notified its wholesale customers in Wyoming and South Dakota that rates will be increasing.

About 58 percent of Gillette's power comes from Black Hills Power.

City Administrator Mike Muirhead says the amount of the increase isn't known right now because the city is trying to negotiate with the company.

The last time Black Hills increased its wholesale rates for Gillette was in 1995.

The rate increase must be approved by the City Council before it goes into effect.