13) Renewable Energy Group Inc is an Iowa-based biodiesel manufacturer.
Renewable Energy Group operates a network of refineries in the US and Europe. The company's fuel emits at least 50% less greenhouse gas emissions compared with traditional diesel, according to the company's website.
12) Pacific Ethanol Inc is a California-based producer of ethanol.
Pacific Ethanol owns refineries across the Midwestern US. It was founded by Bill Jones, California's former Secretary of State.
11) Motech Industries Inc is the fifth-largest manufacturer of solar cells in the world.
Motech Industries is based in Taiwan.
10) Jiangsu Akcome Science & Technology Co Ltd manufactures photovoltaic solar panels.
Jiangsu Akcome Science & Technology is based in Zhangjiagang, China, and also invests in and operates solar power stations in China.
9) Inox Wind Ltd is a manufacturer of wind turbines.
Inox Wind is the only company based in India to make the list.
The company provides solutions for wind farm projects all over India, according to its website, including site acquisition, wind assessment, and maintenance of the turbines.
8) Hanergy Thin Film Power Group Ltd is a Hong Kong-based solar panel manufacturer.
Hanergy Thin Film Power Group's thin-film panels are flexible and lightweight, making them easy to use in a variety of applications — like on the surface of a solar-powered car or mobile electronics.
7) Guodian Technology & Environment Group Corp Ltd is based in Beijing.
Guodian Technology and Environment Group provides environmental-protection and energy-conservation solutions.
The company's business is split into two parts: The first provides technology to coal power plants in China that reduces emissions and maximizes energy efficiency. The second — the company's environmental protection division — offers sulphur oxide control, denitrification, and water treatment technologies.
6) Green Plains Inc is a Nebraska-based producer of ethanol.
Green Plains' ethanol is a high-octane fuel made from crops like corn and wheat.
The fuel is domestically produced, and the company is working to create green jobs in rural communities.
5) Global Pvq SE is a German-based manufacturer of photovoltaic solar panels.
Global PVQ was formerly known as Q-Cells.
4) GCL-Poly Energy Holdings Ltd is a Hong Kong-based manufacturer of green energy.
GCL-Poly is an industry leader in cogeneration — the process of using a power plant to generate useful heat and electricity at the same time.
The company also works on projects that generate energy by incinerating organic waste.
3) First Solar Inc is an Arizona-based manufacturer of solar panels.
First Solar has installations across the globe. The company's thin-film panels have approximately half the carbon footprint of traditional solar panel installations.
First Solar says its technology emits 89-98% less greenhouse gas compared to traditional methods of electricity generation.
2) CropEnergies AG is the leading European manufacturer of sustainably-produced biofuels.
CropEnergies, based in Mannheim, Germany, makes fuels out of renewable crops. Such biofuels, like CropEnergies' bioethanol, emit less carbon dioxide than gasoline or diesel.
CropEnergies had a knockout 2017, increasing revenue by 31%, according to company documents.
1) Canadian Solar Inc is one of the three biggest solar companies in the world by revenue.
Based in Toronto, Canadian Solar has developed a high-efficiency solar panel that the company says is more reliable than competing technology and works in a wider range of temperatures.
Canadian Solar has reduced its amount of carbon dioxide emitted per megawatt of electricity generated by 42% since 2012, according to the company's most recent Corporate Sustainability Report.
Canadian Solar also has an ongoing initiative to replace kerosene lamps in sub-Saharan Africa with solar-powered lights and has donated solar panels to Virunga National Park in Rwanda — a UNESCO World Heritage site, and home to endangered mountain gorillas — to phase out the use of diesel in the park.
