NEW YORK (MarketWatch) -- Energy stocks fell back Tuesday from gains in the previous session. Eenrgy stocks in the S&P 500 SPX -0.09% dropped 0.5%, on average. First Solar Inc. FSLR -1.96% fell 1.4%, Valero Energy Corp. VLO -1.60% declined 1.4%, Alpha Natural Resources ANR -1.11% dipped 1.6% and Nabors Industries NBR -1.85% moved down by 2%. Exxon Mobil Corp. XOM -0.53% and Chevron Corp. CVX -0.52% fell 0.5% each.