Investors interested in stocks from the Utility - Electric Power sector have probably already heard of Korea Electric Power (KEP) and Southern Co. (SO). But which of these two stocks presents investors with the better value opportunity right now? Let's take a closer look.We have found that the best way to discover great value opportunities is to pair a strong Zacks Rank with a great grade in the Value category of our Style Scores system. The Zacks Rank favors stocks with strong earnings estimate revision trends, and our Style Scores highlight companies with specific traits.Currently, Korea Electric Power has a Zacks Rank of #1 (Strong Buy), while Southern Co. has a Zacks Rank of #3 (Hold). This means that KEP's earnings estimate revision activity has been more impressive, so investors should feel comfortable with its improving analyst outlook. But this is only part of the picture for value investors.Value investors analyze a variety of traditional, tried-and-true metrics to help find companies that they believe are undervalued at their current share price levels.The Value category of the Style Scores system identifies undervalued companies by looking at a number of key metrics. These include the long-favored P/E ratio, P/S ratio, earnings yield, cash flow per share, and a variety of other fundamentals that help us determine a company's fair value.KEP currently has a forward P/E ratio of 8.88, while SO has a forward P/E of 17.88. We also note that KEP has a PEG ratio of 1.78. This popular metric is similar to the widely-known P/E ratio, with the difference being that the PEG ratio also takes into account the company's expected earnings growth rate. SO currently has a PEG ratio of 4.47.Another notable valuation metric for KEP 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 1.93.These metrics, and several others, help KEP earn a Value grade of A, while SO has been given a Value grade of C.KEP stands above SO thanks to its solid earnings outlook, and based on these valuation figures, we also feel that KEP is the superior value 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 Korea Electric Power Corporation (KEP): Free Stock Analysis Report Southern Company The (SO): Free Stock Analysis Report To read this article on Zacks.com click here.