There are also other alternatives for transportation fuel. Various chemical processes can convert the carbon and hydrogen in coal, natural gas, plant and animal biomass, and organic wastes into short hydrocarbons suitable as transportation fuels. Examples of such fuels are Fischer-Tropsch diesel, methanol, dimethyl ether, or syngas. Such diesel was used extensively in World War II by the Germans, who had limited access to crude oil supplies. Today South Africa produces most of country's diesel from coal.. A long term oil price above 35 USD may make such liquid fuels economical on a large scale (See coal). Some of the energy in the original source will be lost in the conversion process. Compressed natural gas can itself be used as a transportation fuel. Also coal itself can be used as transportation fuel, historically coal has been used directly for transportation purposes in vehicles and boats using steam engines.
Carbon dioxide in the atmosphere can be converted to hydrocarbon fuel with the help of energy from another source. The energy can come from sunlight using natural photosynthesis which can produce various biofuels such as biodiesel, alcohol fuels, or biomass which can be broken down into the fuels mentioned above. The energy could also come from sunlight using future artificial photosynthesis technology . Another alternative for the energy is electricity or heat from renewables or nuclear power . Compared to hydrogen, many hydrocarbons fuels have the advantage of reusing existing engine technology and existing fuel distribution infrastructure.
…
