Investors with an interest in Utility - Electric Power stocks have likely encountered both Pampa Energia (PAM) and Southern Co. (SO). But which of these two stocks offers value investors a better bang for their buck right now? We'll need to take a closer look.Everyone has their own methods for finding great value opportunities, but our model includes pairing an impressive grade in the Value category of our Style Scores system with a strong Zacks Rank. The proven Zacks Rank emphasizes companies with positive estimate revision trends, and our Style Scores highlight stocks with specific traits.Pampa Energia and Southern Co. are sporting Zacks Ranks of #1 (Strong Buy) and #3 (Hold), respectively, right now. The Zacks Rank favors stocks that have recently seen positive revisions to their earnings estimates, so investors should rest assured that PAM has an improving earnings outlook. However, value investors will care about much more than just this.Value investors also tend to look at a number of traditional, tried-and-true figures to help them find stocks that they believe are undervalued at their current share price levels.Our Value category highlights undervalued companies by looking at a variety of key metrics, including the popular P/E ratio, as well as the P/S ratio, earnings yield, cash flow per share, and a variety of other fundamentals that have been used by value investors for years.PAM currently has a forward P/E ratio of 3.51, while SO has a forward P/E of 17.04. We also note that PAM has a PEG ratio of 0.54. This figure is similar to the commonly-used P/E ratio, with the PEG ratio also factoring in a company's expected earnings growth rate. SO currently has a PEG ratio of 4.26.Another notable valuation metric for PAM is its P/B ratio of 0.28. Investors use the P/B ratio to look at a stock's market value versus its book value, which is defined as total assets minus total liabilities. By comparison, SO has a P/B of 1.78.These are just a few of the metrics contributing to PAM's Value grade of A and SO's Value grade of C.PAM sticks out from SO in both our Zacks Rank and Style Scores models, so value investors will likely feel that PAM is the better option right now.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Pampa Energia S.A. (PAM): Free Stock Analysis Report Southern Company The (SO): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research