Investors interested in stocks from the Solar sector have probably already heard of JinkoSolar (JKS) and Sunrun (RUN). But which of these two companies is the best option for those looking for undervalued stocks? 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, JinkoSolar has a Zacks Rank of #2 (Buy), while Sunrun has a Zacks Rank of #3 (Hold). Investors should feel comfortable knowing that JKS likely has seen a stronger improvement to its earnings outlook than RUN has recently. But this is just one factor that value investors are interested in.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.The Style Score Value grade factors in a variety of key fundamental metrics, including the popular P/E ratio, P/S ratio, earnings yield, cash flow per share, and a number of other key stats that are commonly used by value investors.JKS currently has a forward P/E ratio of 7.75, while RUN has a forward P/E of 21.22. We also note that JKS has a PEG ratio of 0.39. This metric is used similarly to the famous P/E ratio, but the PEG ratio also takes into account the stock's expected earnings growth rate. RUN currently has a PEG ratio of 4.24.Another notable valuation metric for JKS is its P/B ratio of 0.49. 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, RUN has a P/B of 1.75.Based on these metrics and many more, JKS holds a Value grade of B, while RUN has a Value grade of D.JKS stands above RUN thanks to its solid earnings outlook, and based on these valuation figures, we also feel that JKS 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 JinkoSolar Holding Company Limited (JKS): Free Stock Analysis Report Sunrun Inc. (RUN): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research