1. Energy Density:
* High energy content per unit volume: This means a lot of energy can be stored in a small space, leading to efficient transportation and storage. Gasoline, for instance, has a high energy density.
* High energy content per unit mass: This is important for applications where weight is a concern, such as aviation. Kerosene is favored here.
2. Ease of Handling and Storage:
* Liquid at ambient temperature and pressure: This makes storage and transportation easier and safer than handling gases or solids.
* Non-corrosive: It shouldn't damage the storage tanks, pipelines, or engines.
* Safe to handle: It shouldn't be easily ignited or explosive under normal conditions.
3. Combustion Characteristics:
* Complete combustion: It should burn cleanly and efficiently, producing minimal pollutants. This minimizes harmful emissions like carbon monoxide, particulate matter, and unburnt hydrocarbons.
* Stable combustion: The fuel should burn smoothly and consistently, without causing engine knocking or misfiring.
* High flame speed: This ensures efficient energy release in the engine.
4. Availability and Cost:
* Abundant supply: A readily available fuel source is crucial for widespread adoption.
* Affordable price: The cost of the fuel must be economically viable for its intended use.
5. Environmental Impact:
* Low emissions: Minimizing pollutants during combustion is crucial for environmental protection. This includes greenhouse gases (CO2), nitrogen oxides (NOx), sulfur oxides (SOx), and particulate matter.
* Sustainable sourcing: The production and extraction of the fuel should have a minimal environmental footprint. This is driving interest in biofuels and other renewable alternatives.
The ideal fuel would excel in all these categories, but often there are trade-offs. For example, a fuel might have a high energy density but produce significant pollution, or be readily available but expensive to extract. The "best" fuel therefore depends heavily on the specific application and its priorities.
