Investors with an interest in Utility - Electric Power stocks have likely encountered both NiSource (NI) and WEC Energy Group (WEC). But which of these two companies is the best option for those looking for undervalued stocks? Let's take a closer look.The best way to find great value stocks is to pair a strong Zacks Rank with an impressive 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, NiSource has a Zacks Rank of #2 (Buy), while WEC Energy Group has a Zacks Rank of #3 (Hold). The Zacks Rank favors stocks that have recently seen positive revisions to their earnings estimates, so investors should rest assured that NI has an improving earnings outlook. However, value investors will care about much more than just this.Value investors also try to analyze a wide range of traditional figures and metrics to help determine whether a company is undervalued at its 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.NI currently has a forward P/E ratio of 19.16, while WEC has a forward P/E of 22.49. We also note that NI has a PEG ratio of 2.87. This popular figure is similar to the widely-used P/E ratio, but the PEG ratio also considers a company's expected EPS growth rate. WEC currently has a PEG ratio of 3.57.Another notable valuation metric for NI is its P/B ratio of 2.23. The P/B ratio pits a stock's market value against its book value, which is defined as total assets minus total liabilities. For comparison, WEC has a P/B of 2.74.Based on these metrics and many more, NI holds a Value grade of B, while WEC has a Value grade of C.NI has seen stronger estimate revision activity and sports more attractive valuation metrics than WEC, so it seems like value investors will conclude that NI is the superior option right now. Zacks Names "Single Best Pick to Double" From thousands of stocks, 5 Zacks experts each have chosen their favorite to skyrocket +100% or more in months to come. From those 5, Director of Research Sheraz Mian hand-picks one to have the most explosive upside of all. As one investor put it, “curing and preventing hundreds of diseases…what should that market be worth?” This company could rival or surpass other recent Zacks’ Stocks Set to Double like Boston Beer Company which shot up +143.0% in little more than 9 months and NVIDIA which boomed +175.9% in one year.Free: See Our Top Stock and 4 Runners Up >>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 NiSource, Inc (NI): Free Stock Analysis Report WEC Energy Group, Inc. (WEC): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research