Fossil fuels, hydrogen, and ammonia are all just energy transport means. These materials are not a “source” of energy… they are all made from available energy sources and represent a viable means of transporting energy which I will refer to as a “fuel”.
For applications such as transportation, a high energy density fuel is required which can easily be handled. While hydrogen may be employed by society as a means of storing and transporting energy, the technology is in its infancy and is not yet commercially viable.
One alternative “fuel” which is immediately available is ammonia, NH3. Ammonia is normally a gas with a characteristically pungent odor. Ammonia is commonly used as fertilizer. Although in wide use, ammonia is both caustic and hazardous just as gasoline is. In 2006, worldwide production was estimated at 146.5 M tonnes.
Ammonia, as used commercially, is often called anhydrous ammonia. This term emphasizes the absence of water in the material. It can be handled in ways similar to gasoline and can be burned using fairly standard internal combustion engine technology. Ammonia continues to be used as a refrigerant in industrial processes such as bulk ice-making and industrial food processing. It is increasingly popular in commercial applications, such as in grocery store freezer cases and refrigerated displays.
To make ammonia, all we need is a source of energy such as solar or wind power, nitrogen from the air, and water. Storage and handling technologies for ammonia is well understood and it is safely used by farmers throughout the nation every day. Solutions of ammonia (5-10% by weight) are used as household cleaners, particularly for glass. These solutions are irritating to the eyes and mucous membranes (respiratory and digestive tracts), and to a lesser extent the skin. The toxicity of ammonia solutions does not usually cause problems for humans and other mammals, as a specific mechanism exists to prevent its build-up in the bloodstream .
The gas is flammable (autoignition temperature: 651 °C) and can form explosive mixtures with air (16-25%). Anhydrous ammonia corrodes copper- and zinc-containing alloys, and so brass fittings should not be used for handling the gas. Liquid ammonia can also attack rubber and certain plastics. Although ammonia is regulated in the United States as a non-flammable gas, it still meets the definition of a material that is toxic by inhalation and requires a hazardous safety permit when transported in quantities greater than 13,248 L (3,500 gallons) .
Ammonia ignites at 651°C based fuels offer a great potential for universal use but suffer from the disadvantage that pure ammonia cannot be used in high-speed engines because its flame speed is too low. Omachron Technologies Inc. has developed a simple means of allowing conventional internal combustion engines to burn ammonia.
In addition, ammonia can also be doped with environmentally friendly chemical additives to make it compatible in high-speed engines. Ammonia can already be used in low-speed engines and in fuel cells. It is already produced in large quantities and it can easily be made on a distributed basis thereby allowing a decentralized production and distribution infrastructure. Production facilities can easily be expanded.
The key is to look at means of producing ammonia efficiently from solar and wind energy.
Ammonia is not a “magical fuel” but it can easily be made from renewable energy sources, stored with existing technology, produces only water vapor and nitrogen as bi-products when burned, and is not more dangerous to handle than gasoline or propane.
 Ammonia is converted to carbamoyl phosphate by the enzyme carbamoyl phosphate synthetase, and then enters the urea cycle to be either incorporated into amino acids or excreted in the urine.
Repeated exposure to ammonia lowers the sensitivity to the smell of the gas: normally the odour is detectable at concentrations of less than 0.5 ppm (parts per million), but desensitized individuals may not detect it even at concentrations of 100 ppm.
The permissible exposure limit (PEL) in the United States is 50 ppm (35 mg/m³), while the IDLH concentration is estimated at 300 ppm.
 The U. S. Occupational Safety and Health Administration (OSHA) has set a 15-minute exposure limit for gaseous ammonia of 35 ppm by volume in the environmental air and an 8-hour exposure limit of 25 ppm by volume. Exposure to very high concentrations of gaseous ammonia can result in lung damage and death.