 SI prefixes in combination with SI units, for example, giga for 109 and tera for 1012 can give gigawatt (= 109 W) and terawatt (= 1012 W), respectively. The International System of Units (SI) is independent of whichever scale is being used. Use with non-SI units (e.g. "giga-dollars", "giga-miles") is uncommon although "megabucks" is in informal use representing a large sum of money rather than exactly a million dollars.
