The Q1 earnings cycle is nearing its end. As of May 4, 2016, 81.3% of the market cap of the S&P 500 index have reported results. So far, overall first-quarter earnings have recorded a 7.5% year-over-year decline on a 1.9% slip in revenues. For more details, you may go through our Earnings Trend report.As far as the clean energy space is concerned, environmental considerations have been driving demand for alternative energy sources. In fact, demand for solar and wind energy got a major boost from the recent environmental tax credit extensions.Going ahead, U.S. Energy Information Administration (“EIA”) anticipates total renewables used in the electric power sector to increase 10% in 2016. A more comprehensive study by the Department of Energy’s National Renewable Energy Laboratory (NREL) shows that the country will be able to generate most of its electricity from renewable sources by 2050.These favorable demand growth trends notwithstanding, abundant availability of fossil fuels and the resultant drop in oil prices have emerged as key competitive challenges for the clean energy industry. Nevertheless, its long-term fundamentals remain favorable.Let’s take a look at a couple of clean energy stocks that are scheduled to report first-quarter earnings on May 11.Canadian Solar Inc. CSIQ, a Zacks Rank #5 (Strong Sell) stock with an Earnings ESP of 146.15%, is set to report results before the market opens. Last quarter, the company posted a positive earnings surprise of 40.00%. During its fourth-quarter earnings call, Canadian Solar provided an outlook for the first quarter of 2016. It expects shipments in the range of 1,085 megawatts (“MW”) to 1,135 MW. Total revenue is anticipated to be $645 million to $695 million, with gross margin of 12–14%. Going forward, Canadian Solar has plans to increase the capacity of its products.However, Canadian Solar is slowly losing ground in America despite promising prospects. The company’s falling revenues in the region is a growing concern. The company is also exposed to foreign currency fluctuations and geopolitical risks.The above chart indicates that Canadian Solar was able to deliver positive surprises in all of the last four quarters. The average positive earnings surprise was 102.43%.Stay tuned for our full earnings article to see how this stock finally fared this season.Hydrogenics Corporation HYGS will release quarterly results before the market opens. Last quarter, the company posted a negative earnings surprise of 11.11%. It carries a Zacks Rank #3 (Hold) and has an Earnings ESP of 0.00%.During the fourth-quarter conference call, the company said that it expects to receive significant orders and witness growth in mobility applications, which will drive margin expansion in 2016. The company believes that it will continue to hold the position of the global leader in industrial electrolyzers for hydrogen fueling station infrastructure. This should open a steady stream of revenues for the company, going forward. Hydrogenics also expects to see additional development in China, Korea, Japan, North America and Europe, which will, in turn, drive growth at the company through 2016.The above chart indicates that Hydrogenics missed earnings estimates in all of the last four quarters. The average negative earnings surprise was 67.38%.Bottom LineGiven a number of S&P 500 earnings releases scheduled for this week, investors are expected to keep an eye on the earnings releases by these clean energy companies.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 >>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 CANADIAN SOLAR (CSIQ): Free Stock Analysis Report HYDROGENICS CP (HYGS): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research