B
biomass energy supply from wood, plant, and animal wastes.

C
capital stock the existing quantity of capital in a given region, including manufactured, human, and natural capital.

cartel a group of independent organizations working together to regulate production and prices; the OPEC cartel nations significantly influence oil production and price.

cogeneration the process of using waste energy to produce heat from electricity generation.

D
deregulation the process of converting a market dominated by a regulated monopoly or oligopoly to a market with competition.

diminishing returns a proportional increase (or decrease) in one or more inputs results in a smaller proportional increase (or decrease) in output.

E
economic efficiency an allocation of resources that maximizes net social benefits; perfectly competitive markets in the absence of externalities are efficient.

economic supply (of a resource) the amount of a resource that is available based on current prices and technology.

economies of scale expanded output increases returns per unit of input.

efficiency labeling labels on goods that indicate energy efficiency, such as a label on a refrigerator indicating annual energy use.

efficiency standards regulations that mandate efficiency criteria for goods, such as fuel economy standards for automobiles.

energy infrastructure a system that supports the use of a particular energy source, such as gas stations and roads that support gasoline-powered automobiles.

entropy a measure of the unavailable energy in a system; according to the second law of thermodynamics entropy increases in all physical processes.

estimated ultimately recoverable (EUR) supplies an estimate of the total amount of a nonrenewable resource that will ultimately be extracted.

F
flow the quantity of a variable measured over a period of time, such as the flow of a river past a given point measured in cubic-feet per second.

H
Hubbert curve a bell-shaped curve showing the production rate of a nonrenewable energy resource over time.

hydropower the generation of electricity from the energy in flowing water.

M
market failure the failure of certain markets to provide a socially efficient allocation of resources.

R
research and development (R) efforts to increase technical knowledge for the production of new products or improvement of existing products.

S
solar energy the energy supplied continually by the sun, including direct solar energy as well as indirect forms such as wind energy and flowing water.

solar flux the continual flow of solar energy to the earth.

solar hydrogen a virtually emissions-free system of energy relying on solar energy to release hydrogen gas from water, burning hydrogen to obtain useful energy, and obtaining water as a by-product.

stock the quantity of a variable at a given point in time, such as the amount of timber in a forest at a given time.

T
thermodynamic efficiency minimizing the energy used to produce a given output or achieve a given task.

throughput the total use of energy and materials as both inputs and outputs of a process.