By vchal @

In The Wall Street Journal, Phred Dvorak discusses the possibilities and drawbacks of using ammonia as a fuel source. He writes:

Ammonia is made by producing hydrogen, then adding nitrogen. It is made in massive volumes globally—the bulk as a building block for fertilizer and the rest for uses ranging from refrigerants for skating rinks to the smelly household cleaning liquids most people are familiar with.

While plants benefit from the nitrogen portion of ammonia, the clean-fuel industry is interested in its hydrogen content.

Hydrogen, one of the world’s most common elements, can burn like oil, gas or coal but doesn’t emit carbon dioxide when it does, making it a favorite of clean-energy advocates for decades.

But hydrogen has drawbacks, too, which have stymied its development as a green fuel. It rarely occurs by itself, and separating it out of compounds such as water or methane—the main ingredient of natural gas—is expensive and takes more energy than the hydrogen delivers when it is used.

Pure hydrogen also is extremely hard to transport and store. The atom is so small it tends to seep out of seams and welds in pipes and tanks. It takes up so much space at normal temperatures that the only way to carry it long distances is to compress it or liquefy it at minus 253 degrees Celsius, just above absolute zero.

Even hydrogen supporters say it likely will be decades before the technology develops to transport it around the world, so until then it likely will need to be produced very close to where it is used.

Ammonia, though, can burn like pure hydrogen—with no carbon emissions—and is much easier to store and ship. Around 180 million metric tons of the chemical is produced, roughly 10% of which is traded globally.

Most of the hydrogen for that ammonia is made from natural gas in a process that generates a lot of carbon dioxide. Companies such as CF vent much of that CO2 into the atmosphere. But they are starting to roll out plans to store it deep underground instead, which would reduce emissions sharply.

Companies are also working on ways to scale up the production of hydrogen from water, using renewable energy—a much greener technology.

Read more here.