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Table of contents:

Renewable Energy Glossary



Abatement refers to the process that results in the reduction of pollution and the adverse effects it has on the environment.


Absorptance can be described as the percentage ratio of the radiation energy absorbed by a surface to the total point falling on the surface.

Acceptable Daily Intake (ADI)

ADI can be described as the amount of a substance that may be consumed daily over a lifetime without any harmful effects.

Access Charge

Access charge refers to the levy paid by market participants to withdraw energy from the ISO-controlled grid. The access charge is capable of recovering the portion of the utility's transmission revenue requirement that is not recovered by VCU ( variable usage charge).


Acetogen is a microorganism that is concerned with anaerobic respiration during biogas production.

Active Solar Energy System

An active solar energy system refers to a system that is developed to convert the sun's radiation energy to usable energy for space, water heating, and electricity.

Acute Exposure

Acute exposure refers to a single or multiple short-term exposure that lasts less than 24 hours.

Acute Health Exposure

Acute health exposure is used to describe short exposures and the health effects that occur immediately after the exposure.

Adjusted Coefficient Of Performance (ACOP)

ACOP is a rating term used to measure the efficiency of heat pumps.


Addition refers to the changes made to an existing building that increases conditioned space.

Advanced Metering Infrastructure (AMI)

The AMI is a fully integrated system that consists of smart meters, communication networks, and data management sciences that allows two-way communication between utilities and customers.


An adsorber is an emission-controlling device that can remove VOCs from a gas stream due to gas holding onto a solid matrix like activated carbon.


Afterburner is an air pollution abatement device that takes away harmful organic gases through the process of incineration.

Aggregate Power Demand

Aggregate power demand refers to the sum that utility consumers consume within a specific time.

Automatic Generation Control (AGC)

AGC refers to the capacity of a system operator to remotely raise or lower a unit in response to load changes.

Air Barrier

An air barrier is used to describe any material that effectively restricts the flow of air.

Air Quality Index (AQI)

The air quality index refers to a scale (color-coded) that is used for reporting daily air quality.

Alternating Current

Alternating current is a current type where the flow of electric charge reverses direction occasionally, causing the voltage to change.

Alternative Energy

Alternative energy refers to renewable energy that can be derived from non-fossil fuel.

Ampere (A)

Ampere is a unit of electrical current. It is measured in coulombs per second.


An energy audit is an assessment of a home's energy use.

Automatic Meter Reading

AMR is a system of electric meters used for gathering data on a monthly basis without the need for physical reading of the meter.

Amorphous Silicon

Amorphous silicon is a material that has a disorderly atomic structure that can be deposited onto large substrates, which helps to create thin film photovoltaic cells which are manufactured in long sheets.

Anaerobic Digestion

Anaerobic digestion refers to the process whereby microorganisms break down substances in the absence of oxygen so as to produce oxygen.

Angle Of Incidence

The angle of incidence refers to the angle made by the sun ray line, which is perpendicular to a surface. The angle of incidence helps in the determination of the percentage of sunlight intercepted by a surface.

Annual Fuel Utilization Efficiency (AFUE)

AFUE refers to a measure of the heating efficiency of which the value represents the ratio of the transferred heat to the conditioned space that is supplied by the fuel energy over a year. The value is normally determined by applying federal test methods for furnaces.

Area Load

Area load is the total amount of electricity consumers use at a particular point in a utility's service territory.


Azimuth is the angular distance between the true south and the point on the horizon directly under the sun.



A baghouse is an air-controlling device that holds particles by passing gas streams forcefully through large permeable bags. This material is made of fiberglass.


A ballast is a device that supplies the starting voltage and also limits the current during normal operation in electrically discharging lamps.


Banking is an air district permit regulation that enables a facility to add up credits for reducing emissions beyond regulatory limits and ultimately use or sell those credits at a later date.

Base Load

Base load refers to the lowest power production level needed during a season or year.

Base Load Units/Generators

Base load units/generators can be described as an electrical generation unit that runs 100% of the time (24 hours a day).

Base Rate

The base rate refers to a section of the total electric/gas rate covering general business expenses. It is unrelated to fuel expenses.


A battery is a device that is employed to store energy and produce electric current by chemical action.

Battery Electric Vehicle (BEV)

A battery-electric vehicle can be described as a vehicle that is powered only by a battery and electric powertrain, which is capable of high speeds.

Beneficial Electrification

Beneficial electrification, also known as strategic electrification, refers to the process of replacing direct fossil use for electricity in such a way that both the overall emissions and energy costs will be reduced.

Bone Dry Tons (BDT)

Bone dry tons (BDT) is a biomass measurement unit with no water moisture content.

Bulk Power Supply

Bulk power supply refers to a collection of electricity generating plants, transmission lines and all other related terms. It is also known as a wholesale power supply.


A bid is an offer that both electric sellers and buyers propose to determine the energy prices in the market.

Binary Power Plant

A binary power plant is a power plant that helps to transfer heat from hot water to a working fluid that evaporates at a temperature lower than that of water.


Bioconversion refers to the process that involves the use of plants or microorganisms to convert one form of energy to another form (e.g., conversion of solar energy to gas with the aid of algae).


Bioenergy is the energy that is obtained from the combustion of organic and waste materials. Bioenergy can still be obtained from the conversion of organic materials to biofuels, e.g., methane.


Biofuel refers to the fuels that can be derived from renewable biomass material. Biofuels are generally regarded as a very clean fuel source.


Biogas is a type of gas that is obtained from the anaerobic decomposition of organic materials.

Biogenic Sources

Biogenic sources refer to plant and animal sources that emit air pollutants like volatile organic compounds.


Biomass refers to energy resources that are obtained from organic matter, e.g., agricultural waste, wood etc. Biomass also includes organic substances that may be used to make energy through chemical processes.


A blackout is said to occur when there is a power outage across a geographical area for a significant time.

Blockchain Technology

Blockchain technology refers to a decentralized and open transaction verification network that creates a local renewable energy market that enables extra energy to be sold through peer-to-peer trading without the involvement of any middleman.

Blower Door Test

The blower door test is a test that helps to measure the amount of air infiltration of a building.


A busbar can be described as a conductor that connects two or more circuits. It's normally made up of metal bars or high-tension cables.


Cadmium Telluride

Cadmium telluride is a polycrystalline thin film photovoltaic material that is made up of both cadmium and telluride cells.


Call-back is an option that is included in power sales contracts that allow suppliers to stop delivery when energy is needed to meet certain obligations.


Capacity refers to the highest amount of electrical power a generating unit or transmission line is capable of producing. Capacity is generally measured in M.W.

Capacity Factor

Capacity factor refers to the percentage measure that shows how much of a power plant's capacity has been used over time. It is calculated by dividing the generating unit's output within a particular period in time by the total number of hours in the period.

Carbon Capture & Sequestration

Carbon capture & sequestration refers to the process which involves the process of trapping CO2, compressing it, transporting and then injecting it into an appropriate geologic formation where the gas will be sequestered.

Carbon Intensity

Carbon intensity is the measure of the emitted carbon weight per unit of energy consumed.

Carbon Neutral

A reaction is said to be carbon neutral when there is no emission of carbon gases into the atmosphere.

Carbon Sequestration

Carbon sequestration refers to the intake and storage of carbon.

Chemical Energy

Chemical energy is the energy obtained when a chemical compound either combusts, transforms or decomposes to create a new compound.


Co-firing refers to a process that involves the use of different types of fuels to create thermal energy.


A combustor is the section of a power plant where the fuel burning occurs.

Concentrator P.V.

Concentrator P.V. is a photovoltaic P.V. module with optical components, e.g., lenses, which help direct and focus sunlight onto many P.V. cells.


Convection refers to a process of heat transfer that occurs due to the bulk movement of molecules within fluids such as gas or liquid.

Conventional Reservoirs

Conventional reservoirs refer to an aggregate of trapped steam or hot water in underground structures, mostly used to generate geothermal energy.


Data-Driven Asset

The data-driven asset is a specific percentage of a power plant equipped with software and sensor that enables information usage for digitalized, automated, or remote management.

DC Fast Charge (DCFC)

Dc fast charge, also known as a direct current fast charge, are charging stations that give a faster charging time compared to level 1 or level 2 charging stations.


Decommissioning is a group of operations that removes the structure and components of a power station at the end of its working life.

Deferral Accounting

An accounting procedure whereby assets and liabilities are carried forward unto a future date is known to be deferral accounting.


Demand is known to be the amount of energy being consumed at a particular time.

Demand Charges

Demand charges show the cost of extra investment needed to meet their load that is dependent on the customers' demand during a booking period.

Demand Side Management

Demand side management is the actions, initiatives or programs taken by the power supplying company or its customers to change the shift of timing of electricity use.

Demand Response

Demand response is an option that allows customers to reduce their demand charge by lowering their energy usage during peak periods.

Differential Revenue Requirement

The method used in calculating the difference in the utility overall generation cost without and with a qualifying facility is known as the differential revenue requirement.


Dino Tail is a device placed on the blades of wind turbines to reduce the noise produced by the turbines.

Direct Combustion

Direct combustion involves the combustion of material without initially converting the material into another form.

Direct current

Direct current is a type of current in which electrical charge flow flies in one direction.

Dispatchable/Plannable generation

Dispatchable generation is a source of electricity that has been used on demand and distributed at the grid operator's request to meet the market demands.


Dispatchability is a system or plant operator's capacity to control a generating unit's output.

Dispatch Stack

The list of supply sources in order of value to the system is distributed to serve a particular load level.

Distributed Energy Resources

Distributed energy resources are small energy resources that are able to be situated close to their point of consumption.

Distribution Generation

Energy generation placed on-site or at the point of consumption is known as distributed generation.


Distribution is the final phase of electric power delivery that carries energy from the transmission source down to every customer.

Dry Steam Geothermal Plant

A dry steam geothermal plant is a more complex and powerful system than a flash steam geothermal plant.

Dry Rock Formation

An underground location where rocks are heated at high temperature by the earth's heat where little or no water exist within the rock

Dry steam

Dry steam is a kind of steam that contains little or no liquid at all.


Earth Craft

Earth craft is a high-performance building certification project built in the year 1999, serving as a blueprint for energy and resource building throughout the southeast.

Electric Vehicle

An electric vehicle is a vehicle that has been run fully or partially on electricity.

Electric Vehicle Supply Equipment

EVSEs are charging stations or docks that supply electricity to an electric vehicle

Electricity/Energy market

Energy markets are auctions used to coordinate how electricity is produced from time to time.

Electricity System

Electricity systems are all the components given to produce, transmit, distribute and sell energy which includes the transmission and distribution grid.


Electrolysis is a chemical process that uses electricity to break down a substance into its constituent elements.

Energy Balance

Energy balance is known as the balance between the inward and outward flow of a facility or geographical area.

Energy Burden

Energy burden is the total amount of household income spent on energy bills.

Energy Carrier

An energy carrier is a substance that contains energy produced from the primary source and can be later converted to other forms even at a later place and time.

Energy Charge

Energy charge implies the total rate power suppliers charge their customers, most especially on their KWH electricity usage over a billing period.

Energy Data Solutions

Energy data solutions are analytics and insights to help energy stakeholders achieve utility, get solutions, shape the energy policy and utilize the benefits of clean energy

Energy Efficiency

Energy efficiencies are products and services that reduce the amount of energy required for buildings, processes or tasks.

Energy Efficient Mortgage

An energy-efficient mortgage is a term used to refer to any home mortgage whereby the E.E. features have subsided the underlining guidelines.

Energy Grid

The energy grid is an infrastructure used to convey energy from where it is supposed to be to the final consumer.

Energy Intensity

Energy intensity is the parameter that measures the energy efficiency of a country's economy.

Energy/ Fuel Diversity

Energy diversity can be referred to as the diversification of energy sources.

Energy KPI's

Energy key performance indicators are the benchmarks that show a company's progress in the energy sector.

Energy Mix

The energy mix is an array of primary energy sources used in a given area to meet the area's consumption needs.

Energy Star

Energy star is a program organized and administered by the U.S. Environmental Protection Agency in conjunction with the U.S. department of energy to promote energy efficiency

Energy Storage

Energy storage refers to the technologies and products used to store energy for later use.

Energy Transition

Energy transition refers to the transition of energy from a non-renewable energy source to a renewable energy source.

Engineering Procurement and Construction Sector

An EPC contract is a contract regulating the relationship with a single supplier that provides the engineering, procurement of materials and construction service needed to build a power station.


Equality is when individuals or a group of people are given the same resources or opportunities.


Equity is a situation whereby resources and opportunities are given to people to reach an equal outcome and take note of individual circumstances

Events Radar

Events radar is a public newsletter sent out in the first week of the month to list the NCSEA and partner clean energy events.

Experts Witness

An expert witness is a person authorized to testify because of his or her special knowledge in a special field relevant to the particular case.

External Combustion Engine

An external combustion engine is an engine that converts thermal energy to kinetic energy, with combustion taking place outside the chamber.

Extraction Well

An extraction well is a well sunk in the ground to extract steam for geothermal energy production.


Feed In Premium (FIP)

Feed-in premium is referred to as a price-based incentive mechanism used for renewable energies in which the producer is awarded a pre-established premium on the market price of energy.

Feed In Tariff (FIT)

A feed-in tariff is a price-based incentive mechanism for renewable energies, which gives a producer an all-inclusive tariff.

Feed Stock

A feedstock is raw materials to supply or power a plant, machine or industrial process.

Flash Steam

Flash steam is steam created by spraying hot water in a vessel, and the inside of the vessel is held below the atmospheric level causing more water to evaporate into steam.

Flash Tank

A Flash tank is a vessel that separates the steam from hot water by maintaining a low-pressure environment.

Fluidized bed boiler

A fluidized bed boiler is used to suspend fuel particles in mid-air by using jet turbulence of hot air and a bed of free-flowing granular matter.

Fixed Charge

Fixed charges are the charges that ascertain customers must pay before their meter starts to run.


A fixed rate is utility pricing that involves a set of rates per KWH.

Flash Steam Geothermal Plant

A Flash steam geothermal plant is a power plant, usually of small size, used to extract fluid composed of water and steam from an extraction well.

Flexible Fuel Vehicle

An FFV is a vehicle with a combustion engine that is made to run on gasoline and fuel made from alternative sources.

Flowing Water Hydroelectric Plant

A flowing water hydroelectric plant is a plant that transforms the potential and kinetic energy of water into electric power using a hydraulic turbine.


A franchise is a grant of authority from the North Carolina Utilities Commission for a business to act as a public utility.

Francis Turbine

Francis turbine is a propeller-type water turbine where the blades are curved to cause the turbine to spin as water finds its way to the center of the blade.

Free Cash Flow To Equity

Free cash flow to equity is the ratio between the cash flow raised by the investment project available to the shareholders and the capital contributed by shareholders to the project.

Fresnel Linear Concentrator

Fresnel linear concentrator is a linear concentrator that focuses the sun's energy on a receiver tube placed above several mirrors

Fuel rider

A fuel rider is known to be an annual rider to the rates of a public utility to recover the cost of fuel and fuel-related costs.

Fuel Switching

Fuel switching is the switching from coal-fired capacity to less polluting and more sustainable energy, e.g., gas.

Full Production

Full production is described as a declaration made once a plant has been built and is connected to the grid to be able to produce electricity.


A fumarole is a hole in the earth in a volcanic area in which hot gasses or smoke escapes.


Gas Synthesis

Gas synthesis refers to a process that results in the production of synthetic gas from coal.

Gas Turbine

A gas turbine is an engine that produces kinetic energy through the conversion of the thermal energy of hot air and fuel with the aid of a fast-spinning shaft.


Gasification refers to the process of transforming materials that are either solid or liquid to gas through the process of heating with steam or oxygen.

Generation Capacity

Generation capacity refers to the highest amount of electricity that a generator unit can produce when running.


Geothermal involves the process of transforming thermal energy into electricity.

Greenhouse Gas

Greenhouse gases refer to the type of gases that traps heat in the atmosphere.


Head refers to a measure that is used to quantify the pressure of failing water.

Heat Engine

A heat engine is a device that transforms thermal energy into kinetic energy.

Heat Exchanger

A heat exchanger is a machine that helps in the transfer of heat between two different substances.

Hydrothermal Fluid

A hydrothermal fluid refers to steam or water that is heated by the earth.

Hydropower Device

A hydropower device is a device that draws power from the force of running or falling water.



Impoundment can be described as the trapping of water in holding structures like dams or rocks.

Internal Combustion Engine

An internal combustion engine is a device that helps produce kinetic energy from the conversion of thermal energy through combustion in a chamber.

Intermediate Load

The intermediate load can be described as the load which is between the baseload and peak load.


An inverter is a device that helps to convert direct current (D.C) electricity to Alternating Current (A.C).



Joules is a unit of measurement of energy or work. It is normally denoted as (J), and it's the same as watt/second.


Landfill Gas

Landfill gas is created as a byproduct of the anaerobic digestion that occurs in landfills. It mostly consists of methane.


Load is the amount of energy that is needed on the grid at any time.

Levelized Cost Of Energy

The Levelized cost of energy is calculated by finding the cost of building and running a power plant over a particular time and dividing the output that the generating unit is expected to have.



Methanogens are microorganisms (bacteria) that produce methane through anaerobic respiration.

Micro Hydro

Micro hydro is a hydrothermal plant with a capacity that is below 100kW.

Molten Salt

Molten salts are salts that melt when subjected to high temperatures. It is also known to store heat.

Municipal Solid Waste Generator

A municipal solid waste generator is a device that makes use of waste/garbage for the production of fuel for direct combustion.


Natural Gases

Natural gases are the hydrocarbon gases that can be obtained from the earth. Natural gases are known to contain methane, ethane, propane and other gases.

Natural Gasoline

Natural gasoline refers to the liquids that have been extracted from natural gases.

No Observed Adverse Effect level (NOAEL)

NOAEL is used in risk assessment to note the level at which there is no significant increase biologically between the adverse effects of an exposed population and a non-exposed population.

Non-firm Energy

Non-firm energy refers to the type of energy in terms of electricity that is not demanded to be delivered or taken under an electric purchase contract.

Nuclear Energy

Nuclear energy refers to the energy that is derived both during the fission of heavy atoms and the fusion of light atoms.

NamePlate Rating

Nameplate rating is the highest amount of output (in megawatts) that a generation unit can give out under certain conditions.

Net meter

A net meter is a type of meter that is used to determine the exact difference between the current (electricity) that is gotten from the grid and the electricity that is put on the grid by a structure that consumes and also produces electricity.



Octane is a grading scale that is used to rate gasoline by its antiknock properties.


Ongoing operations and maintenance costs are required when operating a facility.


Parabolic Dish

A parabolic dish can be described as a bowl-shaped device that is used to reflect and concentrate sunlight.

Parabolic Trough

A parabolic trough is a concentrator that makes use of a parabola-shaped trough to focus sunlight linearly.

Partial Load

Partial load is a current (I) demand that only uses part of electrical power.

Particulate Matter

Particulate matter refers to the unburned fuel particles that are major components of the exhaust emissions of heavy-duty diesel engines.

Passive Solar Energy

Passive solar energy refers to the use of the sun's solar energy to meet the energy required by a building by means of its architectural design.

Peak Level

A peak level is attained when the number of air pollutants is well above average. A peak level can be attained in a very short period of time and can be maintained for a long.

Peak Load

Peak load is the highest electric output demand that is placed on a grid either by single or multiple loads over a particular amount of time.

Peak Load Power Plant

A peak load power plant is a power generation station that is used to produce large amounts of electricity during the time when there are peak loads.


Peat is a mixture of partially decomposed organic matter that has been deposited in a water environment for a very long period of time.


Penetration is the percentage of the total generation output that is accounted for by a specific generation unit/source.


A penstock is a pipe way that is used to transport water in a hydropower facility.

Phase-Change Materials

Phase-change materials refer to materials that absorb a large amount of heat when changing their state of matter from a solid to a liquid phase. Consequently, they release a lot of heat when changing from liquid to solid.


A photocell is a device that produces an electric reaction when exposed to light energy.


Photolysis refers to the process of chemical decomposition as a result of the materials being exposed to sunlight or other forms of energy.

Photovoltaic Cell

A photovoltaic cell is a cell that is capable of converting light energy into sunlight.

Pile Burner

A pile burner is a device that makes use of a separate furnace and a boiler to burn fuel and boil water in a simple 2-way process.


Pondage is a device used for storing water in such a way that the process of storing will not affect the flow in the primary waterway.

Power Plant

A power plant is a generating facility that produces energy.

Power Plant Entrainment

Power plant entrainment refers to a situation where small organisms which are drawn into a power plant are subjected to energy.

Power Pool

A power tool is a system of two or more interconnected utilities that operate to produce electricity in a secure way so as to meet up with the combined load.


Pyrolysis refers to the process of breaking down complex molecules in an anaerobic condition to produce solid, liquid or gaseous fuels.



Rad is a unit used to measure absorbed energy.


Radiation is the flow of energy in a rather open space via electromagnetic waves, e.g., light.

Reciprocating Engine

A reciprocating engine is an internal combustion engine that converts the kinetic energy of a crankshaft to thermal energy.

Recovered Energy

Recovered energy refers to a previously used energy/ heat which is reused for another purpose. It is also known as waste heat energy.


Reserve refers to the capacity of the power generation unit, which has been constructed in a bid to ensure service during peak load times.


Retrofit can be described as the changes to existing building structures which help to enhance energy efficiency and or decrease electricity demand.

Rooftop Solar

Rooftop solar refers to the solar electricity panels which are normally mounted on the rooftop of both commercial and residential buildings.



A semiconductor is a material that has the capacity to conduct electricity under certain conditions.

Small Hydro

A small hydro can be described as a hydro station that has a capacity between 100KW and 20Mw.


Smoke can be described as a form of air pollution that contains majorly secondary particles and other forms of gaseous air pollutants

Steam Turbine

A steam turbine is a device that helps to convert the thermal energy of steam to the kinetic energy of a spinning shaft.

Stoke Boilers

A Stoke boiler refers to a system that helps to feed fuel (in solid form) into the furnace of a steam boiler.

Synthetic Gas

Synthetic gas is a gas that consists of elements like hydrogen, carbon dioxide, and carbon monoxide that are produced through a human-controlled process.


Syngas is a synthesis gas that is produced from coal.


Thermal Energy

Thermal energy refers to heat energy. It is associated with the energy that occurs in the randomness of the atoms in a substance.

Thermal Mass

Thermal mass refers to the materials that help to store thermal energy.

Thermal Spraying

Thermal spraying can be described as a process that involves the subjection of either metallic or non-metallic substances to thermal energy such that the materials are in a molten state and then sprayed onto a surface as a coating.

Thermal Storage

Thermal storage refers to the keeping of thermal energy in a bank/reservoir.


A transformer is a device that is used to change the voltage on an A.C. electrical system.

Transmission System

A transmission system refers to a set of devices that help to transport electricity over high-voltage lines from generators to the various connection lines in the distribution system.

Turgo turbine

The Turgo turbine is similar to the Pelton turbine in almost every respect. However, it only uses one blade to capture the kinetic energy of water.


Utility-Scale Power Plant

A utility-scale power plant is a generation unit that delivers power to the transmission grid.


U-value is the measure of the rate at which heat flows through a building or material.


Volt (V)

A volt is a unit of electrical pressure or potential, which is calculated in joules/seconds.


Variability refers to the fluctuation in the amount of output of a generating unit that is out of the control of the operator.


Watts (W)

Watts is a unit of electricity that is measured in joules per second.


Weatherization is a process that involves the building up of resistance to the effects of weather changing and the increments of its energy efficiency.

Wild A.C.

Wild A.C. refers to an alternating current whose value varies in frequency.

Wind Power Density

Wind power density is a measure of wind force; it is measured in watts per meter.