Not far behind a request for higher electric rates, Xcel Energy is asking regulators to approve natural gas rates that would boost the average residential bill by $7.59 a month.

The utility is seeking an increase of $l90 million in revenue. Xcel said in filings submitted last week to the Colorado Public Utilities Commission that the increase will pay for investments it has made and for higher plant-related costs.

The request follows one by Xcel in late November for electric rate increases, or $355.5 million more in revenue. The average residential bill would climb nearly 10% a month.

The PUC will hold hearings and take testimony and public comments on both requests.

In both cases, Xcel Energy said the rate increases would cover investments the company has made over the past few years. Xcel Energy-Colorado President Robert Kenney said in a letter to the PUC that the company’s investments in its natural gas facilities over the past two years include inspecting nearly 600 miles of aging transmission lines, rebuilding infrastructure and overhauling more than two dozen regulator stations and other gas facilities.

Xcel’s proposal incorporates a rate of return on equity of 10.75%. That’s the percentage of profit regulators allow a utility to earn on its investments.

Kenney said Xcel’s rates have been below the national average for the past 10 years, but he knows that people “are facing challenging economic times.” He said Xcel has expanded its energy assistance programs and has invested $10 million of company money to increase help for customers who need it.

However, the Utility Consumer Advocate, which represents the public before state regulators, has criticized Xcel’s rate increases in recent years. Joseph Pereira, UCA deputy director, assailed the company’s  request for higher electric rates as too big given current economic conditions and questioned Xcel’s investment decisions.

He was critical of the proposed gas rate increase as well.

“This increase is a significant increase and it’s a significant increase within the context of all the other spending that the company is doing. It matters that it is filed at the same time as an electric rate case,” Pereira said. “It’s an ever-growing pancake stack of rates.”

State officials have set a goal of reaching net-zero carbon emissions by 2050 based on 2005 levels, but Xcel continues to make big investments in its natural gas system, Pereira said. Given the trajectory, the company needs to shrink its system, he added.

If the PUC approves Xcel’s gas rate request, the increase would take effect in October. The average residential bill would rise to $74.41 a month from $66.82. The monthly bill for small businesses would go up $36.47 on average, rising to $316.03 from $279.56.

The electric rate increase, if approved, would start in September.

Xcel has 1.6 million electric customers and 1.5 million natural gas customers in Colorado, with overlap between the groups.

Pereira commended Xcel for expanding its assistance for customers having trouble paying their utility bills, but said the company needs to focus on affordability more broadly.

“What we’re seeing is the impact of growing and unaffordable utility rates extending far into the middle class and putting pressure on all customers,” he said.