Cramer's Green Day Stocks: "There is pressure for companies to become more green", Cramer said on his April 16 "Mad Money" show. These are green stocks he picked that week. For instance, he likes Foster Wheeler (FWLT) as a play on cleaning up pollution, making the bold prediction that the stock will go to $105. Foster Wheeler is "a leader in fluidized bed boilers," Cramer said. Power plants use boilers to convert coal, gas or wood into energy, and the best part about Foster Wheeler's boilers is that they're "flexible," allowing power plants to cut sulfur dioxide and nitrogen oxide emissions.

Powershares Clean Energy portfolio: This exchange-traded fund invests in companies that focus on green and renewable sources of energy and technologies that facilitate cleaner energy. Carbon fiber company Zoltek (ZOLT) is on this list, along with chipmaker Applied Materials and other pure plays such as Ballard Power Systems (BLDP) and Energy Conversion Devices (ENER) .

Powershares Clean Energy portfolio: This exchange-traded fund invests in companies that focus on green and renewable sources of energy and technologies that facilitate cleaner energy. Carbon fiber company Zoltek (ZOLT) is on this list, along with chipmaker Applied Materials and other pure plays such as Ballard Power Systems (BLDP) and Energy Conversion Devices (ENER) .

Powershares Clean Energy portfolio: This exchange-traded fund invests in companies that focus on green and renewable sources of energy and technologies that facilitate cleaner energy. Carbon fiber company Zoltek (ZOLT) is on this list, along with chipmaker Applied Materials and other pure plays such as Ballard Power Systems (BLDP) and Energy Conversion Devices (ENER) .

Alternative Energy Stocks: This is a list of profitable companies in the alternative-energy business, including Fuel-Tech (FTEK) , which is in the air-pollution-control business, and SunPower (SPWR) , which makes high-efficiency silicon solar cells.

Alternative Energy Stocks: This is a list of profitable companies in the alternative-energy business, including Fuel-Tech (FTEK) , which is in the air-pollution-control business, and SunPower (SPWR) , which makes high-efficiency silicon solar cells.

This portfolio includes BorgWarner (BWA) , a company with about 70% of its sales coming from technologies that increase fuel efficiency and reduce emissions.