NEW YORK (TheStreet) -- BP plc (BP), Total (TOT), China Petroleum & Chemical (Sinopec) (SNP), Yingli Green Energy Holding (YGE), LDK Solar (LDK) and ReneSola (SOL) are among the cheapest energy stocks.The current upswing in crude oil prices may support energy stocks to outperform broader markets during the upcoming weeks. Year-to-date, the S&P 500 Index gained 4.6%, while the S&P 500 Energy Index surged 12.0%. In the current market environment of volatile oil prices, the following 10 energy stocks are trading at deep discounts, offering bargain opportunities to investors. These stocks are selling at price-to-projected-earnings ratio of less than 9, while the S&P 500 index is trading at a PE ratio of 15.6. In comparison, Exxon Mobil ( XOM), Chevron ( CVX), ConocoPhillips ( COP), Apache ( APA) and Suncor Energy ( SU) have forward price-to-earnings multiples in the range of 9.3-18.5. The following 10 energy stocks have buy ratings in the range of 40%-82% and are expected to gain up to 56% over the next 12 months with a mean upside value of around 21%, according to analysts polled by Bloomberg. The stocks are ordered from cheap to cheapest based on forward earnings multiples.