Earth Day, celebrated on April 22 since the last 46 years, honors the importance of environmental conservation initiatives. And with global warming showing no sign of easing, we should all take a personal pledge to save our planet in whichever way we can. While this seems an entirely socially responsive idea, there is much that even the investment world can do. After all, plenty of clean energy stocks and ETFs are cycling around the market. We can invest in the futuristic companies that deal with earth compositions like sun, water and wind to produce renewable energy for a cleaner earth. Also, the core energy sector investors who are pulling their hair out trying to understand the course of oil price and the related impact on energy ETFs can turn to clean ETFs to see what’s cooking up in this alternative energy sector. Here’s our tribute to clean energy stocks and ETFs on Earth Day. Let’s find out how green their returns have been lately and delve a deeper into their prospects. Rise in the Concept of Clean The entire alternative energy space including solar has been in a tight spot in the last one year. Though not directly related, the ongoing energy market rout had a ripple effect on this segment. However, there are specific drivers in this field, mainly Barrack Obama’s ‘Climate Change Action Plan’. As per a report from White House, the average cost of a solar electric system has declined 50% since the start of 2010. Also, since President Obama took office, solar power has seen twenty-fold growth. Meanwhile, the U.S. government approved of a five-year extension to the Investment Tax Credit (ITC) and Production Tax Credit (PTC) for solar and wind companies. It also approved a one-year extension for a range of other renewable energy technologies (read: Solar ETFs Soar on Tax Credit Extension). These alternative sources are turning cheaper and their global reach is widening. Also, the sector may now march ahead thanks to the ‘great decoupling’ with conventional energy sources (read: Solar ETFs to Shine in 2016?). Plus, the Paris Climate deal is also feeding hopes into the rise of clean ETFs. In December, global leaders assembled in Paris at the COP 21 meet to chalk out an elaborate and comprehensive plan to lower carbon emissions and arrest the rise in the global temperature to 2 degree Celsius by the end of this century (read: Support the Environment and Profit with Fossil Fuel Free ETFs). Per the treaty, rich countries like the U.S. and those in Europe assure $100 billion per year to relatively underprivileged nations to help them to curb emissions of greenhouse gasses by 2020. This is expected to put an end to the fossil fuel era. Notably, the solar and wind power industry finds a place in the top 11% section of the Zacks Industry Rank suggesting bullish fundamentals for the green energy space in the coming months. All in all, wind is in favor of the clean energy stocks and companies which emit lesser greenhouse gases. Investors can play this winning trend via a host of clean ETFs on the occasion of Earth Day. Below we highlight three such ETFs that have held their heads high in a volatile 2016. These ETFs were in the green in the four-week and year-to-date frames (as of April 21, 2016) (see all alternative energy ETFs here). PowerShares WilderHill Progressive Energy Portfolio (PUW) The $23.1-million ETF holds 40 stocks which are ‘in transitional energy technologies significant in improving the use of fossil fuels and nuclear power’ per the issuer. No stock accounts for more than 3.9% of the basket. PowerShares Cleantech Portfolio (PZD) This $71.3-million product provides global exposure to stocks engaged in the cleantech industry. A company is considered cleantech if it produces any knowledge-based product or service that improves operation, performance, productivity or efficiency, while reducing costs, inputs, energy consumption, waste or pollution. The fund is heavy on the U.S. (56%) followed by Switzerland (7.7%) and Denmark (5.8%). Holding 56 stocks in its basket, the fund puts 53.4% weight in the industrial sector followed by 27.1% in IT and 6.6% in materials stocks. First Trust ISE Global Wind Energy Index Fund (FAN) FAN gives exposure to the global wind energy industry. It holds 42 stocks with each holding no more than 7.4% share. European firms dominate the fund’s return while American firms take just 14.1% share. FAN has managed $46.5 million in its asset base. 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 PWRSH-CLEANTECH (PZD): ETF Research Reports FT-GLB WIND EGY (FAN): ETF Research Reports PWRSH-PRG EGY (PUW): ETF Research Reports To read this article on Zacks.com click here. Zacks Investment Research 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