Right now, a uniquely modified pickup truck is making its way across the country. Starting from Detroit and heading to San Francisco, the vehicles developers are seeking to draw attention to an overlooked fuel alternative. The truck uses a special fuel, something widely available throughout the country, but until now, not widely considered as a fuel for transportation: the truck is carrying three tanks of ammonia in its bed. In addition to being an economical alternative to petroleum fuels, the ammonia fueled vehicle has much cleaner emissions and almost no greenhouse gasses.
The NH3car (NH3 is the chemical formula for ammonia) is a demonstration project of a University of Michigan graduate student in physics who is studying the use of ammonia as an alternative fuel. The test vehicle can be run either on 100% gasoline or on an 80% ammonia/20% gasoline mixture, and can be switched from one to the other at any time. According to a news story, the test vehicle gets 27 miles per gallon whether it is running on gasoline or the gas/ammonia mix. When gasoline is higher that $2.10/gallon, it becomes more economical to use the fuel mix.
More importantly, however, the vehicle produces much cleaner emissions than a fossil fuel burning vehicle. Moving to an ammonia fuel system would drastically cut transportation CO2 emissions. Because there is no carbon in ammonia (molecularly, ammonia is one nitrogen atom and three hydrogen atoms), there is no carbon dioxide or carbon monoxide in the emissions from the ammonia combustion. According to the vehicle team, the only by-products are water vapor and nitrogen gas.
"Onthe basis of either weight or volume, ammonia’s the next best thing when liquid petroleum fuels can’t be used,” said Grannell, a University of Michigan doctoral student of applied physics. "I believe this is the only economically viable … replacement for liquid petroleum fuels, especially for transportation use."
One drawback to the ammonia fueled vehicle is that commercial ammonia needs to be manufactured. Unlike fossil fuels, it is not a resource that can simply be mined or pumped from the ground. And most commercial processes for manufacturing ammonia rely on natural gas as a feedstock.
An interesting synergy might be in place here. Presently, ammonia is used extensively as a farm fertilizer. Using ammonia as a fuel, when its principal use is as fertilizer, would be a cause for concern about the food versus fuel dilemma this causes, much the same as people have concerns about food versus fuel regarding E85 ethanol being derrived from corn, and about food cropland being taken away to be used instead for fuel cropland. However, as more farms move to organic production, the need for ammonia fertilizer should decline, and rather than having to worry about a slumping market, the excess production could be diverted to direct fuel use instead.
Ammonia fueled transportation may be a viable possibility. The NH3car team has also stated that the conversion from gasoline to ammonia could cost consumers less than $1,000. An important question would be whether or not the price of ammonia would remain stable if it began to be widely used as a fuel, or if its price would rise to make it uneconomical to use. Distribution would be another issue. As with other alernative fuel scenarios, the storage and distribution infrastructure for ammonia is not widespread and readily available for transportation uses. Ammonia needs to be stored in pressurized tanks and at low temperatures in order to remain as a gas. Like liquid natural gas or hydrogen, a whole new range of storage and distribution equipment would be needed in order to have widespread use of ammonia as a fuel. But with all of the potential benefits it offers, it may be worth exploring the possibilities it offers.
via: Ann Arbor News
Cross-posted from EcoGeek.org