Southern Co. and other utilities nationwide will have to invest as much as $1.5 trillion in new power plants, transmission lines and other new infrastructure over the next 20 years to meet growing demand for energy, the Atlanta company's chief executive said Wednesday.

"These are extraordinarily challenging times for the electricity industry," said Southern CEO David Ratcliffe, a guest host on CNBC's "Squawk Box" morning show. "We've got to invest major capital in new infrastructure. It will be a challenging time to meet the growth that this economy will have to have in new electricity."

Southern, one of the nation's biggest power companies, is the parent of Georgia Power.

Co-host Becky Quick didn't hesitate to bring home what the comments would mean for customers.

"Rates are going to go up?" she asked.

"Yes," Ratcliffe said.

Any rate increase by Georgia Power must be analyzed and approved by the Georgia Public Service Commission.

David Parker, a utility analyst with Robert W. Baird & Co., gave a similar forecast and said the $1.5 trillion will include:

• Between $600 million and $700 million for new nuclear, coal-fired or natural gas power plants.
• Hundreds of millions for additional transmission lines, especially in regions such as the Midwest, where solar and wind energy are being added.

Parker said a federal energy policy would help utilities and Wall Street because a nationwide energy plan would minimize regulatory uncertainty.

"(Not having a federal energy plan) raises risk," he said. "Not only for investors but for everybody."

Georgia consumers are already paying more than last year because of Georgia Power's ambitious capital spending program, which company officials said last year is bigger than any in its history.

The company will spend $9.1 billion between 2007 and 2011 on environmental controls and system expansion.

As a result, Georgia Power this year started collecting an additional $323 million under a three-year deal struck with state utility regulators. That breaks down to an increase of $5.24 on the typical household's average monthly bill.

Earlier in the show, Ratcliffe, a former chairman of the advisory board of the Federal Reserve Bank in Atlanta, said he considers energy prices one of the biggest threats to the economy. He doesn't expect prices to come down permanently but said they were beginning to moderate.

But higher natural gas and coal prices combined with the rapid industrialization of China and India will put continual pressure on energy costs, he said.

"The significant price pressure corresponds to the need for us to raise prices for our customers," Ratcliffe said.

— Staff writer Rachel Tobin Ramos contributed to this article.