Closed Loop vs. Conventional Ethanol
The E3 BioFuels closed-loop system is far more efficient than a traditional ethanol plant at converting corn into eco-friendly, clean-burning ethanol. As the difference in energy balance indicates, E3 BioFuels' plant operation is more than 20 times as efficient in fossil-fuel consumption as a conventional ethanol plant, and as much as six times more energy-efficient if you take a "corn-to-consumer" perspective.
What does E3 BioFuels do differently to achieve such a superior result?
Biogas vs. natural gas
Most ethanol plants use natural gas or coal to provide the thermal energy needed to create ethanol from corn. Ethanol plants are power-hungry: a normal ethanol plant requires 36,000 BTUs of energy for each gallon of ethanol produced. Buying that much energy can become very expensive, not to mention causing negative environmental effects associated with mining, refining, and burning fossil fuels.
E3 BioFuels, on the other hand, uses biogas created on-site to provide the necessary thermal energy. Because we create our own energy source on-site (or more accurately, harvest clean solar energy by way of our middleman, the humble cow), to provide the necessary heat for the boiler, there is no cost associated with the purchase of fossil fuels. Corn byproducts, including cellulose from the corn stalks, also go into the biogas brew.
The ethanol made here is not only clean but also cheap—this is perhaps the first ethanol plant to achieve both.
—Vinod Khosla, Wired, Oct. 2006
And not only does the E3 BioFuels system make a positive environmental impact by replacing fossil fuels, but the creation of biogas actually reduces the amount of methane (23 times as potent a greenhouse gas as carbon dioxide) released into the atmosphere.
Wet cake vs. dried grain
Ethanol is not the only product created when corn is turned into alcohol. About one-third of the corn—the starch—is converted into ethanol, and another one-third into thin stillage, which is used in the anaerobic digesters for heat and biogas. The other one-third, a combination of protein, oils, and fibers called distiller's grain, is usually sold as feed for cattle. However, this grain is wet when it exits the ethanol plant, and traditionally equipment costing several million dollars must be used to dry it before transport in order to prevent spoilage.
At a typical ethanol plant, the amount of energy needed to dry the grain is immense, constituting almost a third of the total energy requirement. Much of the grain's nutritional content is lost in the drying process. And let's not forget the polluting fossil fuels burned in the trucks or trains used to transport the dried "distiller's grain" to its end destination for feed.
In contrast, the E3 BioFuels plant has no need to dry the grain produced by the ethanol plant; our consumer, the cow, is already on-site. The wet by-product, called wet cake, can be taken a short distance to the E3 BioFuels feedlot or dairy and fed to the cattle there, sharply reducing transportation costs and pollution, and eliminating the need for expensive drying altogether.
Thus, a "closed-loop" system.