The stock price of Capstone Turbine Corp. went up 7 cents Friday after research firm Cowen & Co. initiated coverage with an outperform rating. Shares in the Chatsworth manufacturer of natural gas-powered micro-turbines opened Friday at $1.12 and closed at $1.19, an increase of 6.25 percent. Cowen put a target price of $1.90 on the stock, a 59 percent premium to its current price. A report from Cowen said that Capstone should increase its market penetration due to the fuel flexibility and efficiency of its micro-turbines. The company is modeling positive earnings before interest, taxes and depreciation for fiscal year 2015 and an operating margin in the mid-teens by fiscal year 2017, the report said.