NEW YORK ( TheStreet) -- Applied Materials ( AMAT), First Solar ( FSLR), MEMC ( WFR), GT Solar International ( SOLR), Woodward ( WWD), Amtech Systems ( ASYS), Satcon Technology ( SATC) and SunPower ( SPWRA) are alternative energy stocks with upside potential of up to 138%, based on analysts' consensus estimates of 12-month price targets.We recommend these eight alternative energy stocks as they have outperformed the broader indices to gain an average 21% during the last year. These stocks, riding on firm crude prices, could deliver earnings of 15% to 20% over the next year, analysts say. The stocks have average buy ratings of 54% and mean upside value of around 51%, according to analysts polled by Bloomberg. The stocks are stacked in terms of percentage upside, from great to greatest. 8. First Solar ( FSLR) manufactures solar modules with an advanced semiconductor technology, and is a provider of comprehensive photovoltaic system solutions. Higher selling costs and research and development expenses pressured profitability in the first quarter of 2011. Net income reported was $115 million versus $172 million in the same quarter last year. For 2011 first quarter, total revenue came in flat year-over-year at $567 million. Summarizing the business environment, Rob Gillette, CEO of First Solar, said, "Despite European market uncertainties, First Solar has good visibility into our demand for 2011." He added, "We continue to execute our cost roadmaps, invest in new module capacity, build our project pipeline, and develop promising new markets around the world." The company has updated its 2011 guidance with net sales estimated between $3.7 billion and $3.8 billion for the full year. Operating income is pegged at $900 million to $970 million, while 2011 earnings per share is estimated between $9.25 and $9.7. The stock has analysts' buy ratings of 49% and is expected to deliver 22% return over the next one year. The stock is trading at 12.4 times its estimated 2011 earnings.