Renewable Energy, 5th Edition

Units and conversion factors

Powers of 10

Prefix	Symbol	Value	Prefix	Symbol	Value
atto	a	10−18	kilo	k	103
femto	f	10−15	mega	M	106
Pico	p	10−12	giga	G	109
Nano	n	10−9	tera	T	1012
Micro	µ	10−6	peta	P	1015
Milli	m	10−3	exa	E	1018

G, T, P, E are called milliard, billion, billiard, trillion in Europe, but billion, trillion, quadrillion, quintillion in the United States. M is universally used for million.

SI Units

Basic Unit	Name	Symbol
Length	Meter	m
Mass	Kilogram	kg
Time	Second	s
Electric current	Ampere	A
Temperature	Kelvin	K
Luminous intensity	Candela	cd
Plane angle	Radian	rad
Solid angle	Steradian	sr