The Arizona Corporation Commission has approved about an 8% rate hike for APS customers.

But the real numbers are still being finalized.

That will most likely result in a monthly increase of $10-12 for the average customer of Arizona Public Service. 

During a commission hearing, APS President Ted Geisler said the rate increase will cover costs already spent by the utility.

"We are borrowing more capital from lenders than ever before in order to secure a reliable grid for future summers. But this is not a sustainable business model, and we have pulled every lever that we can," Geisler said.

In a written statement, an APS spokesperson said the price increase will help cover costs already incurred by the utility to upgrade its electric system and infrastructure investments.

Daniel Pozefksy is chief counsel with the state’s Residential Utility Consumer Office. It had proposed just a 2.5% increase.

“It is on them to use their capital for decisions that will affect their credit metrics, not you," Pozefksy said. 

The Corporation Commission also approved a new surcharge for rooftop solar customers, which final rate is also yet to be determined.