Investors interested in stocks from the Alternative Energy - Other sector have probably already heard of HF Sinclair (DINO) and Ormat Technologies (ORA). But which of these two stocks is more attractive to value investors? We'll need to take a closer look to find out.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 proven Zacks Rank emphasizes companies with positive estimate revision trends, and our Style Scores highlight stocks with specific traits.Currently, HF Sinclair has a Zacks Rank of #1 (Strong Buy), while Ormat Technologies has a Zacks Rank of #3 (Hold). Investors should feel comfortable knowing that DINO likely has seen a stronger improvement to its earnings outlook than ORA has recently. 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.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.DINO currently has a forward P/E ratio of 4.06, while ORA has a forward P/E of 67.07. We also note that DINO has a PEG ratio of 0.30. 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. ORA currently has a PEG ratio of 6.10.Another notable valuation metric for DINO is its P/B ratio of 1.43. The P/B is a method of comparing a stock's market value to its book value, which is defined as total assets minus total liabilities. By comparison, ORA has a P/B of 2.55.These metrics, and several others, help DINO earn a Value grade of A, while ORA has been given a Value grade of D.DINO has seen stronger estimate revision activity and sports more attractive valuation metrics than ORA, so it seems like value investors will conclude that DINO 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. It’s a little-known chemical company that’s up 65% over last year, yet still dirt cheap. With unrelenting demand, soaring 2022 earnings estimates, and $1.5 billion for repurchasing shares, retail investors could jump in at any time. 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 HF Sinclair Corporation (DINO): Free Stock Analysis Report Ormat Technologies, Inc. (ORA): Free Stock Analysis ReportTo read this article on Zacks.com click here.Zacks Investment Research