The Arizona Corporation Commission on Jan. 9 opened a docket to conduct a regulatory audit and a rate review of Arizona Public Service Company after the agency received complaints of large bill increases from the utility’s electric customers. The commission said that the significant number of complaints indicate inadequate customer outreach efforts after the recent rate increase and that the utility might be making profits beyond what was authorized.

The utility was required to engage in outreach and education, in order to inform customers of rate plan options after the commission approved a rate increase. The outreach efforts are intended to help customers minimize bill increases or even lower their bills. In August 2017, the commission approved a 3.3 percent overall revenue, the first base rate increase in five years, raising monthly residential bills by 4.5 percent, according to the company’s website.

The commission directed staff to use 2018 as a test year for the review because it was the first full calendar year since the rate increase. A final report is due by May 3.

APS is the principal subsidiary of Pinnacle West Capital Corp.