In physics, energy economics and ecological energetics, energy returned on energy invested (EROEI or ERoEI); or energy return on investment (EROI), is the ratio of the amount of usable energy acquired from a particular energy resource to the amount of energy expended to obtain that energy resource. When the EROEI of a resource is less than or equal to one, that energy source becomes an "energy sink", and can no longer be used as a primary source of energy.
Read more about Energy Returned On Energy Invested: Non-manmade Energy Inputs, Relationship To Net Energy Gain, Economic Influence of EROEI, Criticism of EROEI, EROEI Under Rapid Growth
Famous quotes containing the words energy, returned and/or invested:
“Much of the modern resistance to chastity comes from men’s belief that they “own” their bodies—those vast and perilous estates, pulsating with the energy that made the worlds, in which they find themselves without their consent and from which they are ejected at the pleasure of Another!”
—C.S. (Clive Staples)
“Then the LORD said to Moses, “Stretch out your hand over the sea, so that the water may come back upon the Egyptians, upon their chariots and chariot drivers.” So Moses stretched out his hand over the sea, and at dawn the sea returned to its normal depth. As the Egyptians fled before it, the LORD tossed the Egyptians into the sea.”
—Bible: Hebrew, Exodus 14:26,27.
“Whenever parents become overly invested in a particular skill or accomplishment, a child’s fear of failure multiplies. This is why some children refuse to get into the pool for a swimming lesson, or turn their back on Daddy’s favorite sport.”
—Cathy Rindner Tempelsman (20th century)