Tactical trash? The Army has cracked the secret of converting garbage to fuel in the field.
The Tactical Garbage to Energy Refinery II prototype (TGER) is mounted on a trailer and can turn about a ton of garbage into electricity. A typical 550-person unit generates about 2,500 pounds of trash a day. And whether that’s paper, plastic, packaging or food waste, one standard 60-kilowatt diesel generator can handle the unit’s garbage, making synthetic gas from it.
TGER’s fuel can run a generator on approximately 75 percent within two hours; in under 12 hours, TGER can produce alcohol that, when blended with the synthetic gas, can run a generator on full power.
Giving soldiers at forward operating bases the ability to produce their own fuel ensures that it is always available -- and by removing the need for delivery, TGER dramatically reduces the risk to soldiers’ lives.
Fuel convoys travelling to and from base camps in Afghanistan and Iraq have been an ongoing target, routinely exposing soldiers delivering fuel to the risk of improvised explosive devices and enemy ambushes.
Managing waste entirely within the base will also reduce security risks by eliminating the need for a contractor who could be working for insurgents.
From the perspective of environmental impact, the zero-carbon footprint TGER is also very green.
Army Edgewood Chemical Biological Center (ECBC) worked with SAIC, TGER Technologies, Defense Life Sciences and Purdue University to develop the prototype. The team first tested it in a real battle lab -- the challenging conditions of Iraq in 2008.
Camp Victory based in Baghdad used the first two TGER prototypes over a period of 90 days.
"We picked a forward operating base in Iraq because we wanted to really stress the system,” explained EBRC senior technologist James Valdes. “All other energy systems had been tested in laboratories or under ideal conditions and temperature climates. What we really wanted to do was stress it with heat, sand and real-world trash."
In response to those tests, Valdes' team eliminated a system that made pellets from trash and instead created a horizontal gasifier with an auger device to rotate trash.
They also learned that a large proportion of the synthetic gas could not be used as fuel and was inert.
To fix this problem, the team adapted the technology to inject steam into the gasifier, ensuring a larger conversion of usable gas.
While the 2008 prototype yielded 155 BTUs of gas, the new TGER 2.0 prototype triples the energy output, producing 550.
TGER II in the tank
TGER 2.0 was further re-engineered to improve its performance.
For one thing, the team made it user-friendly with an automated touch-screen interface. Not only is data entry easier, but a single soldier can monitor every part of the machine, from oxygen levels in the gasifier-to-ethanol production to power output.
It now takes only one soldier to feed garbage and another to monitor the conversion, but ultimately Valdes hopes TGER will take only one individual soldier to run it.
“If you start off with 30 cubic yards of trash, you end up with one cubic yard of ash, and that ash has been tested by the Environmental Protection Agency. They call it a benign soil additive. You could actually throw it on your roses," Valdes said.
During testing this Autumn, the green tech was endurance tested to evaluate how long it could run at the highest garbage volume input before machine failure.
Next in the pipeline is developing a way to recapture excess heat generated by the machine with a heat exchanger; the captured energy should help with sanitation and heating water for the base.
TGER 2.0 could be useful beyond Army use as well: This tech would be fair game anywhere there is a concentration of people who need fuel and have garbage.
From camp sites and mess halls to hospitals and even survivalists, there are a range of potentials. After natural disasters like Hurricane Katrina, rapidly deployable technology like TGER II could support garbage, sanitation and fuel shortages that tend to emerge.
The tech also makes sense for companies that work in remote locations using base camps -- oil exploration, for example -- which have to find ways to get fuel and dispose of waste.
Ballet dancer turned defense specialist Allison Barrie has traveled around the world covering the military, terrorism, weapons advancements and life on the front line. You can reach her at firstname.lastname@example.org or follow her on Twitter @Allison_Barrie.