Sep 6, NASA's Alternative-Fuel Aircraft Projects: Green Technology Articles: Eco20/20

First in 2009, and then again in 2011, NASA conducted Alternative Aviation Fuels Experiments. In the first experiment, the fuels were made of coal and natural gas. In the 2011 tests, the fuel was made of animal fat, an abundant byproduct of the meat industry. Disparage that as fully as you desire, no defense of the meat industry will be made here. Nevertheless, animal byproducts do exist, so the decision to test them as a fuel produced from a renewable resource was considered a valid recycling option.

Source: http://www.eco20-20.com/NASAs-Alternative-Fuel-Aircraft-Projects.html

Hydropower Technology Fuel Cells