The TGER prototypes were fabricated and commissioned at Purdue University and conformed to the following selection criterion:

a. Approach the problem as a “dual optimization” to develop a system which will simultaneously eliminate as much waste as possible while producing as much useful energy as possible.

b. Design of the TGER must be “tuned” to the operational context to ensure an easily available and reliable volume of military waste.

c. The TGER should be designed to be contiguous with both the input source of wastes and the end user for the output energy product, avoiding any reprocessing or transport costs.

d. The TGER must be operationally and tactically deployable via military airframe and able to be transported on the ground via standard military trailer.

e. The TGER should not need additional manpower or machinery costs for waste separation.

f. The process must minimize parasitic costs such as manpower, water, external energy, etc.

g. The refining process should have minimal residual waste.

h. Additional concerns of hazardous waste, safety, and troop use must be consid­ered, and operation should be amenable to unskilled labor.

The selection of gasification and biocatalytic fermentation has strategic value in that both methods are well-demonstrated technologies supported by high levels of research by the Department of Energy and, in the long course, are very likely to improve as new advances are achieved.

Significant new advances in gasification include the introduction of integrated sensors and automated computerized control systems for the process. These recent advances have resulted in gasification technologies with reliable and efficient con­version of waste to energy. Significant recent advances in biocatalytic fermentation include advances in genetically modified or modified via directed evolution enzymes and micro-organisms. Using methods developed at the Laboratory of Renewable Resources Energy at Purdue University, several commercial entities have broken new thresholds in domestic ethanol production techniques by applying new biocat­alysts and processes, the result being the economically viable production of ethanol for fuel [8]. Current advances in enzymatic design and development bode well for further methods to reduce what would normally be considered unusable biomass waste (e. g. paper fines from shredded cardboard and other cellulosic wastes) into usable energy, allowing more energy to be harnessed from the same waste stream.

During the commissioning phase of the TGER, the system was able to deliver reliable power with very low parasitic costs required to operate the system internally. The core processes, gasification and fermentation for conversion of waste to energy, worked very well and the unique hybrid combination of thermochemical and bio­catalytic technologies proved itself to be of considerable merit. These technologies could easily scale up to support military installations such as hospitals and major troop areas by converting waste into power, hot water, and usable fuel while elim­inating costly waste removal expenses. Installation biorefineries could provide cost savings for US and overseas bases, reduce dependence on petroleum-based energy and support environmentally responsible initiatives, highlighting DoD’s support of renewable energy resource technologies.