It’s lights out for the Aquila era.

After more than a year of hearings, paperwork and shareholder votes, the Missouri Public Service Commission approved the merger between Aquila and Great Plains Energy on Tuesday by a 2-1 vote.

Great Plains Energy is the holding company for Kansas City Power & Light. After the $1.7 billion deal is complete, KCP&L will manage all electric services formerly run by Aquila in Missouri. Aquila’s natural gas utilities in Iowa, Nebraska, Kansas and Colorado — plus a Colorado electric utility — will be sold to South Dakota-based Black Hills Corp.

Commissioners Terry Jarrett and Connie Murray approved the merger while Robert Clayton voted against it. Commission Chairman Jeff Davis and newly appointed Commissioner Kevin Gunn didn’t vote. Mr. Davis recused himself from the merger case after complaints that he spoke with utility executives last year about the plan before it was publicly announced.

Aquila spokesman Al Butkus said the companies have a tentative agreement to close their deal on July 14. The transition from Aquila to KCP&L should move quickly.

“We’ve been working on it since January,” Mr. Butkus said. “All the employees will be going to one of the two companies, either KCP&L or Black Hills. Those decisions have already been made, and they know when and where to report.”

Katie McDonald of KCP&L said she couldn’t give an exact timeline for when Aquila customers would start to see changes in service. The company cannot set specific dates for billing changes and other moves until it has reviewed the 200-page report the commission released after it approved the deal.

Mr. Butkus said Aquila customers would receive information in the mail in mid-July informing them of all new emergency contact numbers and billing practices. Until then, customers should stick with current Aquila information.

St. Joseph Light & Power had carried electricity into Northwest Missouri for nearly 120 years when Aquila — then called UtiliCorp United — absorbed Light & Power on Dec. 31, 2000, and pledged to usher in a new era of electricity.

The new era ends this month.

Clinton Thomas can be reached at clintonthomas@npgco.com.