Advanced Coal Technologies - Includes supercritical, ultra-supercritical, circulating fluidized bed, carbon capture and storage and integrated gasification combined cycle technologies.

Ash - Impurities consisting of silica, iron, alumina, and other noncombustible matter that are contained in coal. Ash increases the weight of coal, adds to the cost of handling, and can affect its burning characteristics.

Baseload Capacity - The generating equipment normally operated to serve loads on an around-the-clock basis.

Capacity - The amount of electric power delivered or required for which a generator, turbine, transformer, transmission circuit, station or system is rated by the manufacturer.

Cap-and-Trade - A market-based system of limiting emissions in which a limited number of emissions permits are issued in the aggre-gate (cap); these permits are then freely exchanged in markets (trade).

Carbon Capture and Storage (CCS) - The capture, compression, transport and storage of CO₂ emissions.

Carbon Dioxide (CO₂) - A colorless, odorless, non-poisonous gas that is a normal part of Earth’s atmosphere. Carbon dioxide is a product of fossil fuel combustion as well as other processes. It is considered a greenhouse gas because it traps heat radiated by the earth into the atmosphere.

Chicago Climate Exchange (CCX) - Currently North America’s only legally binding rules-based greenhouse gas (GHG) emissions allowance trading system, and the world’s only global system for emissions trading based on all six greenhouses gases. Members make voluntary commitments to meet annual GHG emission reduction targets; those who reduce below the target have surplus allowances to sell or bank; those who emit above the targets comply by purchasing CCX Carbon Financial Instruments contracts. AEP is a founding member of CCX.

Climate Change - Changes in climate that depart from normal variability, representing significant changes in averages or extremes.

Congestion - A condition that occurs when insufficient transfer capacity is available to implement all of the preferred schedules for electricity transmission simultaneously.

Demand - Rate at which electric energy is delivered to or by a system or part of a system, generally expressed in kilowatts or megawatts, at a given instant or averaged over any designated period of time.

Demand Response (DR) - The planning, implementation and monitoring of utility activities designed to encourage consumers to modify their patterns of electricity usage.

Emissions - Anthropogenic releases of gases to the atmosphere. In the context of global climate change, they consist of greenhouse gases.

Energy Efficiency - Refers to programs that are aimed at reducing the energy used by specific end-use devices and systems, typically without affecting the services provided. These programs reduce overall electricity consumption (reported in megawatt hours), often without explicit consideration for the timing of program-induced savings. Such savings are generally achieved by substituting technically more advanced equipment to produce the same level of end-use services (e.g., lighting, heating, motor drive) with less electricity. Examples include high-efficiency appliances, efficient lighting programs, high-efficiency heating, ventilating and air conditioning (HVAC) systems or control modifications, efficient building design, advanced electric motor drives and heat recovery systems.

Extra-high Voltage (EHV) - The electric utility industry generally considers EHV to be any voltage of 345 kV or higher.

Fossil Fuels - Hydrocarbon fuels derived from fossils: specifically coal, petroleum and natural gas.

Greenhouse Gas (GHG) - Collective term for gases such as carbon dioxide that trap heat in the atmosphere and contribute to climate change.

Grid - An interconnected network of electric transmission lines and related facilities.

Independent System Operator - An independent, federally regulated entity that coordinates regional transmission in a non-discriminatory manner and ensures the safety and reliability of the electric system.

Load - An end-use device or customer that receives power from the electric system. Load should not be confused with demand, which is the measure of power that a load receives or requires.

Plant Efficiency: - The percentage of total energy content of a power plant’s fuel that is converted into electricity. The remaining energy is lost to the environment as heat.

Portfolio Standards - Guidelines or requirements that total electricity supply include one or more set minimum for particular sources, such as renewable energy.

Rate-making Authority - A utility commission’s legal authority to fix, modify, approve or disapprove rates, as determined by the powers given to the commission by a state or federal legislature.

Reliability - The degree of performance of the elements of the bulk electric system that results in electricity being delivered to customers within accepted standards and in the amount desired. Reliability may be measured by the frequency, duration and magnitude of adverse effects on the electric supply. Electric system reliability can be addressed by considering two basic and functional aspects of the electric system — adequacy and security.

Renewable Energy Resources - Energy resources that are naturally replenishing but flow-limited. They are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time. Renewable energy resources include: biomass, hydro, geothermal, solar, wind, ocean thermal, wave action and tidal action.

Transmission System - An interconnected group of electric transmission lines and asso-ciated equipment for moving or transferring electric energy in bulk between points of supply and points at which it is transformed for delivery over the distribution system lines to consumers, or is delivered to other electric systems.

Wind power plant - A group of wind turbines interconnected to a common utility system through a system of transformers, distribution lines and (usually) one substation.