Biofuels

Last year's record high oil prices have renewed mainstream interest in alternatives to fossil fuels. Current products like corn-based ethanol, with its quick-burning consistency and negative effect on global food prices, might soon be seen as a hiccup in the story of sustainable, green fuels. A new generation of bio-fuels, as well as new approaches to established fuel sources, are making a cleaner, greener future seem like more than a mere pipe dream.

Jatropha

Jatropha is the new darling of the bio-diesel movement. The bush-like plant grows in semi-arid and rocky regions where agriculture is impossible. Its seeds contain large amounts of oil, which is extracted and converted into usable fuel. Jatropha has already been tested in airplanes. Air New Zealand was the first to complete a successful test flight using a jet-fuel/jatropha-fuel mixture in one engine.

Algae and Switchgrass

Algae is another promising bio-fuel source. It can produce 15 times more oil than corn has the ability to grow virtually anywhere – freshwater, salt water, even polluted or contaminated water.

Fat growing switchgrass isn't able to produce the amazing amount of oil that algae is, but the hearty plant that populates fields in Middle America is a readily available, non-food alternative to current corn and sugar-based fuels.

Used Cooking Oil

Recycling waste products as fuel is the dream of every environmentalist. Some mechanically savvy drivers have found a way to convert their diesel engines to run on vegetable oil. The process of preparing this fuel requires a little chemistry skill, but this is the best avenue for individuals who want greener cars but don't want to wait for the R&D process that the other fuels on this list will need to undergo before they hit the mainstream.

Corn, Sugarcane, and the Future

People might disagree that corn-based fuel is fading from importance. Farmers and venture capitalists who invested in the ethanol industry certainly don't want their product to be overtaken by these next-generation upstarts. Perhaps the answer lies in the husks and stalks of corn plants, which have sugars that can be converted into fuel by a process that is only a bit more complicated than the one currently used to make fuel from the kernels.

Brazil has invested in ethanol made from sugarcane. While there are questions about effects on food prices and destruction of rain forests to make way for cane fields, Brazil stands by its industry and points to the fact that cane fuel burns 90% cleaner than fossil fuels.

Camelina

Camelina is a feed crop that is being noticed by farmers who are intent on getting into the bio-fuel game. The plant is part of the mustard family. It is a hot topic in the industry right now because it is a nearly perfect candidate for crop rotation. It can easily be rotated with staple crops like wheat.

Palm Oil

Countries like Malaysia and Indonesia are championing the use of palm oil as a bio-fuel because they can produce massive quantities (and thereby cash in). Palm oil is an edible oil from the palm fruit. As with sugarcane in Brazil, questions about farming practices and rain forest destruction have put palm oil fuel on the blacklist in some European countries.

Straw

Japan is striving to find a use for the waste that is generated from rice production. Rice straw has been used for a variety of things over the years (hats, woven baskets, sleeping mats), but never as a fuel. The country is racing with China and other major rice producers to develop this potentially lucrative energy source.

Major wheat producers are pushing similar ideas for wheat straw. The process for converting straws into fuel is a bit more daunting than converting other sources, but the economic potential is enough to warrant an attempt.

Waste

Garbage as fuel? Here's the catch: you could easily end up putting more pollution into the air. Energy companies have been getting quite creative, capturing landfill gases and converting them into natural gas.

Fat Trees

The word "tallow" is usually used to refer to the excess fat taken off meat products and used in cooking. But the tallow tree, an extremely fast growing tree, is potentially one of the best sources for natural plant oils. The oil is also used for medicinal purposes in Australia.

Using Microbes as a Refinery

Complicated refining processes have been the major drawback to most bio-fuels. Scientists have been studying a potentially earth-shattering idea: using microbes to naturally convert plant material into sugars that can be used to create ethanol. Potentially, this could make the discussion about which source is best irrelevant.