Energy and Human Ambitions on a Finite Planet, 2021a

427
electron
is a fundamental particle typically found in the outer parts of atoms, surrounding the nucleus.
Electrons have negative charge equal <strong>and</strong> opposite to that of protons, but are 1,836 times lighter
than the proton, at 0.511 MeV. 77, 78, 198, 202, 239, 244, 245, 255, 395, 422, 423, 425, 426, 429,
430, 433–435, 438
electron-volt
(eV) is a unit of energy, defined as the energy (work) it takes to push a charge of one fundamental
charge unit (see entry for Coulomb) through an electric potential of one Volt. 1 eV is equivalent
to 1.6 × 10 −19 Joules. 78, 198, 223, 248, 428, 432
element
pertains to a single atom on the Periodic Table. For instance, hydrogen, helium, <strong>and</strong> carbon are
all elements. 376, 379, 424, 432
energy
is defined as the capacity to do work. The SI unit is the Joule. 68, 73, 77, 174, 334, 379, 423–425,
427, 431, 434, 437, 438
energy density
describes how concentrated energy is in a substance, quantified as energy per unit mass. In
chemical contexts, anything around 10 kcal/g or higher is considered energy–dense, while
substances at about 1 kcal/g or lower are poor. Carbohydrates <strong>and</strong> proteins are middling,
around 4 kcal/g, while fat is 9 kcal/g, <strong>and</strong> therefore among the more energy–dense substances.
121, 122, 175, 228, 230, 231, 236, 237, 254, 256, 264, 277, 290, 380, 398, 425, 426, 428
energy efficiency ratio
(EER) refers to the energy gain by a heat pump, usually in the context of cooling rather than
heating. Its units are odd, defining how many British thermal units (thermal energy)maybe
moved per Watt-hour of input energy, but relating to ε cool (defined in Eq. 6.10 (p. 95)) by a simple
numerical factor: EER 3.41ε cool . Sometimes seen as SEER to represent a seasonal average EER
value. 97, 98, 426
energy intensity
measures the energy use of a society relative to its economic scale. A typical value may be about
5 MJ/$. 19, 336
energy trap
refers to a phenomenon in which energy shortage motivates aggressive pursuit of alternative
energy schemes, but that pursuit requires substantial energy investment—forcing an even more
acute but voluntary energy shortage, which is politically difficult. 132, 301, 310, 311
enriched
see enrichment. 258, 262
enrichment
refers to the process of increasing the concentration of a particular isotope within a sample of
235
an element. Usually, this term is applied to the concentration of U from its natural 0.72% to
3–5% for power plants or >20% (typically ∼85%) for weapons. 258, 427
entropy
is a measure of how many ways a system can be configured for some fixed energy level. The
entropy of a closed system cannot decrease. 90, 396, 420
Environmental Economics
is an offshoot of neo-classical economics that adds a layer of pricing to capture “externalities,”
or environmental costs not normally included in market price. 323
EPM
Electric Power Monthly. 215, 426
© 2021 T. W. Murphy, Jr.; Creative Commons Attribution-NonCommercial 4.0 International Lic.; Freely available at:
https://escholarship.org/uc/energy_ambitions.