Renewable technologies, including solar, wind, tidal/wave and geothermal, seeks to capture the plentiful forms of energy that are currently being frittered away by Mother Nature. A few technologies, though, are seeking to turn lead to gold, figuratively speaking; they’re finding ways to capture the energy in the stuff we discard and transform it into fuel that we can use.

A friend of a friend who worked at Changing World Technologies first exposed me to this idea a few years ago. Using a process called thermo depolymerization (TDP), primarily organic feedstocks (like turkey offal) can be processed to yield fuel oil. Its first plant converts 250 tons of turkey waste into 20,000 gallons of oil and fertilizer (the nitrogen-based by-products of the process), at a cost of $80 per barrel. Keep in mind that crude petroleum is currently selling at over $120 per barrel.

Innovation in the world of waste has continued. Here are a few other companies I was able to find that are innovating in this space:

• Enertech Environmental: Converts sewage into a solid energy form (called SlurryCarb) that can be used in a manner similar to coal. The process removes the bulk of the water through a more efficient mechanical process, rather than boiling/evaportation. A plant coming online later this year in southern California will convert solid waste from 5 municipalities around Rialto into 145 tons of SlurryCarb daily. An existing company facility has been operating successfully in Japan for years.
• Solena Group: Uses sodium bicarbonate, a waste by-product from coal plants, to grow algae, which is gasified to create a feedstock for electric power plants. The company is in discussion to put up a 40 MW plant in Kansas using its technology.
• GreenFuel Technologies: Also grows algae for biofuel, although using CO2 from flue gases. Companies that would otherwise have to pay for the sequestration of CO2 can, according to the company, create a profit by growing algae and selling it to biofuel reformers. The algae can be converted to biodiesel through transesterification and ethanol through fermentation of the remaining biomass.
• Blue Marble Energy: Uses algae cultivated in polluted water to create biodiesel and ethanol. Should be a boon for China, which has no shortage of the stuff.
• BlueFire Ethanol: Converts biowaste to ethanol using concentrated acid hydrolysis. A $30 million plant due to be installed in southern California by the end of 2009 should yield 3.2 million gallons of ethanol annually.
• Poet Energy: Uses primarily corn cobs to produce ethanol in a low-temperature process. Its 65 million gallon per year plant inaugurated in Indiana last year is the largest ethanol production plant in the world.
• Coskata: This company’s process converts organic feedstocks into syngas via gasification technologies, and then proprietary microbes convert the syngas into ethanol. After proving the viability of its technology through a 40,000 gallon/yr plant early next year, it plans on scaling to a 100 million gallon/year plant elsewhere by 2011.
• DuPont Danisco: Uses corn stover and sugarcane bagasse, agricultural wasteproducts, to create ethanol. A joint venture between DuPont and Genencor, its 250,000 gallon/year demonstration facility will be built in 2009.
• Mascoma: Uses wood chips as the source of cellulose to produce ethanol. It has recently decided to build its first facility in Michigan, in part funded by the state.

Are flue gas, corn stover, sugarcane bagasse, wood chips, turkey offal, and municipal waste the only feedstocks with which to produce biofuels? Not even close. In fact, a recent study suggests cow manure processed anaerobically could supplant 3% of the US’s electricity production and erase 4% of the carbon dioxide which would have otherwise been created by coal-fired production.

I think all of this innovation is fascinating, and deserves the tax incentives they need to get past the very high bar set by the low price of coal (provided there aren’t any taxes/penalties assessed on high-CO2 coal use). The products produced recently from solar energy—food scraps, wood chips, algae, sewage, and municipal waste—ought to be recaptured so we can allow coal and petroleum to continue to sequester CO2 underground.