hydrocarbon+fuels

Most fuels in combustion reactions are hydrocarbons, and here are a few common examples:
 * methane (a major component of natural gas), CH 4
 * propane (like for gas grills), C 3 H 8
 * butane (lighter fluid), C 4 H 10
 * octane (major component of gasoline), C 8 H 18
 * ethanol (gasoline additive), C 2 H 5 OH

Coal, oil and natural gas are all hydrocarbon-based fossil fuels. These are typically mixtures of hydrocarbons that require separation.



__Crude Oil__

Crude oil is without a doubt the most important energy source on the planet. It formed hundreds of millions of years ago when organic plant material was buried under sediment and compressed underground. Crude oil is a complex blend of hydrocarbons that need to be extracted in order to be useful.

Crude oil is obtained by drilling, extracting, and transporting it to a refinery. Here, it undergoes "cracking", where it is separated by a form of fractional distillation, into many useful products.






 * The United States is the top consumer of crude oil - we use 27% of the world's supply of oil every year (nearly 7 billion barrels, or 300 billion gallons), and this number is climbing. Oil production in the U.S. is falling, making us more reliant on foreign oil every year.**




 * __Gasoline__**


 * In the transportation sector, the U.S. consumed 388 million gallons of gasoline //per day// in 2009; that year, we used 138 billion gallons of gasoline.**



Gas prices are affected primarily by changes in the cost of crude oil. Crude oil prices fluctuate with the supply and demand nature of crude on the global market. Market speculation can cause price spikes in times of political turmoil, but mainly consumer demand is to blame. With China as an emerging gasoline consumer, one can easily surmise that gasoline prices will only go up.



__Ethanol__

Ethanol is a gasoline additive (upwards of 10-15% by volume) that is designed to reduce U.S. reliance on foreign oil.

Some new Flex Fuel engines can run on 85% ethanol (called E85) and 15% gasoline.

Two major issues arise with ethanol:
 * It absorbs water readily, so its transportation and storage is a problem;
 * It mostly comes from fermentation of corn or sugarcane;
 * There is some debate over its affect on food prices - most experts agree that it raises US food prices 5%, and exported corn prices 15%.