Carbon Plan: Glossary of Terms

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A-B
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U-Z
Advanced Nuclear

Advanced nuclear is one of several low- or zero-emitting technologies being considered by Duke Energy, alongside practices such as carbon capture and renewables. Newer nuclear facilities employ several techniques that supposedly improve public safety. These include small modular reactors (SMRs) that generate less than 300 megawatts, and designs that use a high-temperature gas, liquid metal, or molten salt as a coolant instead of regular water. [Source]

Advanced Nuclear Plants (ANPs)

Zero-emitting “Generation IV” ANPs considered in the Carbon Plan include water-cooled small modular reactors (SMRs) which are intended to improve safety, efficiency, and cost benefits over existing nuclear plants; gas-cooled reactors; and sodium-cooled reactors. All are scheduled for commercial readiness by the early 2030s.

Battery Storage

Battery storage, or battery energy storage systems (BESS), are devices that can temporarily store the energy generated by renewables (e.g. solar and wind), and then release that energy when needed. Developing battery storage technologies is essential for accelerating fossil fuel retirements by ensuring electric grids have a reliable, consistent supply of renewable energy. [Source]

Biomass

Biomass is organic material from plants and animals that contains stored biochemical energy. Biomass can be burned directly for heat or converted to liquid and gaseous fuels. Unfortunately, the processes used to produce biomass, such as clearcutting forests for wood pellets, are frequently extractive and environmentally harmful. [Source]

BIPOC

An acronym for Black, Indigenous, and People of Color. BIPOC collectively refers to individuals and communities who identify as non-white. Many BIPOC communities have historically faced disproportionately adverse environmental impacts, resulting in inequitable social and health outcomes. Securing environmental justice, and a fair distribution of benefits to BIPOC communities, are increasingly seen as core goals of the modern environmental movement.

Capacity

A power plant’s capacity is the power (often expressed in megawatts) it can produce when running at full capability. Whether it is running (i.e. generating electricity) or not, a power plant’s capacity does not change (except for a minor amount in summer versus winter due to the fact that heat reduces a power plant’s ability to generate electricity). Capacity Factor is the actual or expected long-term average power the plant produces, which can range from 5% to 95%, and is a measure of the plant’s availability. 

Carbon

The term “carbon” is used throughout the Carbon Plan as a shorthand for carbon dioxide (CO2) emission rate (usually expressed in short tons per year).

Carbon Dioxide Equivalent (CO2e)

In addition to carbon dioxide, there are several other important greenhouse gases with the potential to drive global warming, with varying potencies and atmospheric lifespans. For example, methane (CH4) is far more effective at trapping solar heat than carbon dioxide (CO2), but methane also dissipates from our atmosphere much faster. A carbon dioxide equivalent, or CO2e, is a measure used to compare emissions from various greenhouse gases on the basis of their global warming potential. [Source]

Carbon Neutrality

A carbon-neutral entity must counterbalance any CO2 it releases into the atmosphere with an equivalent amount of CO2 it removes. This can be achieved through direct carbon removal projects such as reforestation, or by purchasing carbon offset credits to compensate for emissions. The terms “carbon neutral” and “net zero” are often, but not always, used interchangeably. [Source

Carbon Plan

The Carbon Plan is a road map for reducing climate-changing carbon emissions in North Carolina. North Carolina law requires the Carbon Plan to reduce electric power sector greenhouse gas emissions by 70% below 2005 levels by 2030 (with some exceptions allowed) and attain complete carbon neutrality by 2050. The Carbon Plan must also be reviewed and updated every two years.

Climate Resilience

The ability to adapt to, prepare for, and effectively respond to natural hazards caused by climate change. [Source

Combined Cycle (CC)

A combined-cycle power plant uses a gas turbine and a steam turbine in sequence to produce energy. CC plants are much more efficient than traditional single-cycle CT plants, producing up to 50% more electricity from the same fuel. The waste heat from the gas turbine is routed to the nearby steam turbine, which generates extra power. [Source]

Combustion Turbines (CT)

A single-cycle CT plant burns fuel to produce a jet of hot air and combustion products which spin a turbine and a generator to produce electricity. The energy-depleted jet is exhausted to the atmosphere. While future CTs may be enabled to transition to zero-carbon fuel, current CT plants burn fossil fuels and emit carbon. 

CRIRP

The Carbon Plan Integrated Resource Plan represents the application of Duke Energy’s IRP to meet North Carolina’s state energy goals. In North Carolina, the terms “CRIRP” and “Carbon Plan” are often used interchangeably. The CRIRP will be updated by the NC Utilities Commission every two years, with its first update scheduled before the end of 2024. It is expected that this will combine carbon planning and integrated resource planning into one process for Duke Energy moving forward. [Source]

Cumulative Impacts

People and communities are not impacted by multiple pollution sources in isolation—they compound as “cumulative impacts.” To truly protect public health, permitting agencies tasked with regulating air pollution must holistically consider all emission sources that affect a community’s well-being.

Decarbonization

The reduction or elimination of carbon dioxide emissions from a process such as manufacturing or the production of energy. (Oxford Dictionary) 

Duke Energy Carolinas/Duke Energy Progress

Duke Energy is one of the largest electric power holding companies in the United States. Within North Carolina, Duke Energy maintains two distinct operating subsidies. For resource planning and carbon management, the Carbon Plan considers the two companies as a single system and includes their service areas in both North and South Carolina.  Duke Energy Carolinas (DEC) primarily serves central and eastern North Carolina (with additional coverage in the state’s High Country), covering approximately 24,000 square miles and 2.5 million residential, commercial, and industrial customers. Duke Energy Progress (DEP) serves a separate set of customers and operates its own network of power generation, transmission, and distribution facilities. DEP primarily supplies electric service to central and western North Carolina, covering approximately 32,000 square miles and 1.5 million customers.

Energy Efficiency

Energy efficiency (EE) describes the amount of energy used to perform a given task or produce a given result. Describing something as “energy-efficient” means it’s designed or operated in a manner that minimizes wasted energy and reduces energy consumption without sacrificing the quality of the outcome. For example, energy-efficient homes and buildings use less energy to heat, cool, and run appliances and electronics, while energy-efficient manufacturing facilities use less energy to produce goods. [Source]

In the context of the Carbon Plan, energy efficiency is the annual percentage reduction in electricity load that is achieved through improved grid management and customer programs. If an annual EE of 1% to 1.5% is achieved for 15 years, the generation offset is 16% to 25% respectively.

Environmental Justice

The fair treatment and meaningful involvement of all people, regardless of race, color, national origin, or income, with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies. [Source

Equity

In the context of climate change, equity means fairness in how the benefits and burdens of reducing carbon emissions are distributed among different communities. These benefits and burdens include environmental impacts, access to clean energy, workforce transition, affordability, and community engagement.

Fossil Fuels

Fossil fuels, including coal, oil, and natural gas, are formed from ancient and energy-rich deposits of fossils and rock. Fossil fuels are dirty sources of energy; burning them releases carbon dioxide and other greenhouse gasses into the atmosphere. These gasses trap solar heat within the Earth’s atmosphere, causing rising temperatures and fueling catastrophic climate change around the world. [Source]

Geothermal

Geothermal heat pumps use the steady temperatures just several feet below the surface as a heat sink for electrifying heating and cooling in any environment. It is considered a renewable and sustainable source of energy because the heat emanating from the earth’s interior is essentially inexhaustible on human timescales. Geothermal energy can be harnessed for a variety of uses, including electricity generation, direct heating, and even cooling systems. [Source

Gigawatts (GW)

A unit of electrical power equal to one billion watts. Gigawatts are commonly used in referring to the power capacity or the energy output (gigawatt-hours) of generating plants or various generating sectors such as solar or nuclear. They can also be used to measure the total energy-generating capacity of a state or country. One gigawatt of energy is enough to power roughly 750,000 homes. [Source 1] [Source 2]

Grid

An energy grid is an interconnected network for electricity delivery from providers to consumers. The grid links providers and consumers through a system of transmission and distribution lines, operated by one or more control centers. This network of power lines, substations, and equipment allows for the efficient and reliable distribution of electrical energy over long distances to meet the needs of consumers. It forms the backbone of our electrical power supply system and enables the delivery of electricity from various sources to end-users. [Source 1] [Source 2]

Grid Edge Programs

“Grid Edge refers to the “edge” of the electricity network, or grid, where the Companies’ electricity reaches customers’ homes and businesses. These programs include energy efficiency (“EE”) and demand-side management (“DSM”) programs, certain rate designs, voltage control efforts, renewable energy programs, electric transportation programs and behind-the-meter generation and storage.” (Duke CPIRP Filing, Appx. H).

HB 951

In 2021, the North Carolina General Assembly passed House Bill 951, also known as “Energy Solutions for North Carolina.” HB 951 sets goals of reducing utility companies’ statewide carbon emissions by 70% below 2005 levels by 2030, and attaining complete carbon neutrality by 2050. [Source]

Hydrogen-capable or Hydrogen-enabled

In the Carbon Plan, “hydrogen-capable” describes fossil-fueled CT and CC generation plants able to use hydrogen alongside other traditional fuels, with the goal of transitioning to 100% carbon-free generation. While hydrogen itself is clean-burning and more energy efficient than gas or coal, it requires a substantial investment in land and water resources that could conflict with North Carolina’s agriculture, recreation, and ecology.

Hydrogen Hub

A network of hydrogen producers, consumers, and local connective infrastructure to accelerate the use of hydrogen as a clean energy carrier that can deliver or store tremendous amounts of energy. [Source]

Hydropower

Sometimes referred to as hydroelectric power, this process generates power by harnessing the energy of moving or falling water. It is one of the oldest and most widely used sources of clean energy. Hydropower relies on the water cycle, so the amount of precipitation that drains into rivers and streams in a geographic area determines the amount of water available for producing hydropower. [Source]

Integrated Resource Plan (IRP)

An IRP is a “roadmap” that identifies potential plans for a utility to meet future energy production and demand requirements while considering the associated risks and benefits to its customers. [Source

Intervenor

Third-party individuals or groups formally involved in legal or regulatory processes. Intervenors are full participants in the proceeding and make legal arguments, conduct discovery, file testimony, cross-examine witnesses, and are subject to cross-examination by the other parties in the case if called to testify. 

Least Cost

Regulators traditionally require public utilities to conduct extensive economic analyses to identify a “least cost” approach to proposed generation, distribution, and servicing changes. This is done to accommodate growth at the lowest possible cost to customers. However, these economic analyses seldom take into account the environmental and social costs associated with these policy changes. This is particularly true in North Carolina, where Duke Energy does not take into account the staggering health and environmental costs of fossil fuels—estimated by researchers to be 17-27 cents/kWh for coal, and ~10 cents/kWh for gas

Load Management

A strategy for balancing and controlling the demand for electricity with the supply of energy from renewable sources like wind and solar. This allows utilities to reduce the demand for electricity during peak usage times, which can, in turn, reduce costs by eliminating the need for peaking power plants. [Source]

Methane

Methane (CH4) is a primary component of natural gas. Methane is also an extremely potent greenhouse gas (GHG), far more effective at trapping solar heat than carbon dioxide (CO2). Its presence in the atmosphere affects the Earth’s temperature and climate system. [Source

Natural Gas

Natural gas is a fossil fuel, primarily methane, produced through a process called hydraulic fracturing (also known as fracking). Fracking forces water, chemicals, and sand down a high-pressure well to break up shale and other sedimentary rock formations, releasing gas to be collected at the surface. Fracked natural gas has become a commonly used energy source, but it is highly controversial due to environmental, climate, and safety concerns. 

Net Zero

A net-zero process or entity counterbalances or cancels out any carbon it emits through carbon removal projects such as reforestation. The terms “net zero” and “carbon neutral” are often, but not always, used interchangeably. While the concept of “zero-carbon” is also sometimes merged with these terms, a zero-carbon process creates no carbon emissions at all. [Source]

North Carolina Utilities Commission (NCUC)

The North Carolina Utilities Commission is a state regulatory body, created by the NC General Assembly to oversee the rates and services of all investor-owned public utilities in North Carolina. These include companies that provide electricity, telephone service, natural gas, water, and wastewater. As part of its regulatory oversight, the NCUC is responsible for creating and enforcing a statewide Carbon Plan.

Offshore Wind

Offshore wind farms generate electricity from wind blowing across the sea. They are considered more efficient than onshore wind farms, thanks to higher wind speeds, greater consistency, and lack of physical interference that the land or human-made objects can present. [Source

Onshore Wind

Onshore, or land-based, wind energy is the power that’s generated by wind turbines located on land driven by the natural movement of the air. Onshore wind farms are usually constructed in less-populated areas where buildings and obstacles don’t interrupt airflow, such as fields or rural areas. [Source

Pathway

In the context of the Carbon Plan, a pathway is a possible future scenario that details the evolution of today’s energy generation resource mix to future combinations that achieve zero-carbon emissions by 2050. The pathway is produced by computer modeling and simulation. At each timestep—typically annually—the model satisfies the projected electricity needs of customers while optimizing cost, reliability, risk, and carbon reduction. Many alternative pathways are investigated, and then a subset is chosen that meets the objectives and includes all likely outcomes. Duke Energy has chosen three pathways in its draft Carbon Plan with varying costs, risks, and carbon reduction schedules.

Photovoltaic (PV) Cells

Solar farms with panels of PV cells are a category of renewable energy in the Carbon Plan. PV cells are the component of solar panels that convert solar radiation to either DC electricity (which is stored in on-site batteries for future use) or AC electricity (which is sent to the grid). 

Portfolio

The combination of energy resources, technologies, and strategies that Duke Energy uses to generate electricity and meet its energy needs. This portfolio can include various energy sources, such as coal, natural gas, nuclear, renewable energy (like wind and solar), and energy efficiency measures. [Source 1] [Source 2 (Chapter 3)]

Public Comments

Input given by the public to governmental bodies about proposed legislation or regulation during a period—and by means—set aside and prescribed by law. In North Carolina, utility consumers may submit comments about any docketed matter to the NC Utilities Commission. Statements can also be mailed to the Commission. In either case, after two or three business days, statements are made part of the official record for the proceeding and can be viewed on this website via the assigned docket number. The Commission does not respond to consumer statements but does consider them, along with all other evidence, in reaching its decisions. [Source 1] [Source 2]

Pump Storage Hydro Facility

These hydroelectric energy storage systems are designed to store energy by transferring water in both directions between two reservoirs located at different elevations. Excess electricity generated during periods of low demand is used to pump water to the higher reservoir. When demand is high, water flows downhill to the lower reservoir, passing through a turbine to generate power. [Source]

Ratepayer

A customer of a public utility company.

Renewable Energy

Renewable energy is energy from sources that are naturally replenishing but flow-limited. Renewable resources are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time. Major types of renewable energy sources include wind, solar, and geothermal. [Source]

Reserve Margin

“The amount of unused available capability of an electric power system (at peak load for a utility system) as a percentage of total capability.” [Source]

Retirement (of Power Plants)

The retirement of coal-fired power plants refers to the process of power plants shutting down permanently, and ceasing the operation of particular power generation facilities. This can happen due to age, inefficiency, or technological advancements, but especially because of the urgent need to stop using fossil fuels. Power plants are now competing with cleaner, more efficient, and lower-cost renewable energy sources such as wind and solar power. [Source]

Short Tons

A commonly used unit for measuring carbon dioxide or other greenhouse gas emissions in the U.S. A short ton is equal to 2,000 pounds.

Smart Grid

An advanced and digitally enhanced electrical grid system that uses modern technology and communication to improve the efficiency, reliability, and sustainability of electricity generation, distribution, and consumption. Smart grids include computer systems to manage the newer devices and components. This new technology enables better communication between Duke Energy and their customers, which helps them prevent and repair outages, and read household energy meter faster and more accurately. [Source]

Storage

The process of capturing and retaining energy in a form that can be used later. It involves accumulating extra energy when it is available and then releasing it when needed, with the continuous demand for energy in our homes, industries, and transportation systems. [Source

System Reliability

The ability of a power system to withstand instability, uncontrolled events, cascading failures, or unanticipated loss of system components. In other words, the ability to consistently depend on power delivery to homes, buildings, and devices, even in the face of physical and cyber events that cause power disruptions. Key aspects of system reliability include a steady supply of energy; resilience (withstanding and recovering from unexpected events; redundancy (backup mechanisms and additional power sources or grid connections); predictability; quality; and safety. Electric utilities in North Carolina are required to plan and operate their system so that every customer can expect not more than one power outage in ten years from preventable causes. [Source]

Vertically Integrated Monopoly

In a regulated wholesale market, utilities are typically vertically integrated monopolies, meaning they are solely responsible for generating, transmitting, and distributing electricity to their customers. Duke Energy is a prime example of this, controlling every part of the power generation-to-delivery process. [Source]

Zero-Carbon

A “zero-carbon” product, process, entity, or service does not produce any carbon emissions. Zero-carbon energy sources—such as wind, nuclear, and solar—create no carbon emissions when generating electricity. While the terms “zero-carbon” and “net zero” are sometimes used interchangeably, net zero refers to counterbalancing or canceling out any carbon produced through carbon removal, while zero-carbon means no carbon is given off at all. [Source]

 

 

Advanced Nuclear

Advanced nuclear is one of several low- or zero-emitting technologies being considered by Duke Energy, alongside practices such as carbon capture and renewables. Newer nuclear facilities employ several techniques that supposedly improve public safety. These include small modular reactors (SMRs) that generate less than 300 megawatts, and designs that use a high-temperature gas, liquid metal, or molten salt as a coolant instead of regular water. [Source]

Advanced Nuclear Plants (ANPs)

Zero-emitting “Generation IV” ANPs considered in the Carbon Plan include water-cooled small modular reactors (SMRs) which are intended to improve safety, efficiency, and cost benefits over existing nuclear plants; gas-cooled reactors; and sodium-cooled reactors. All are scheduled for commercial readiness by the early 2030s.

Battery Storage

Battery storage, or battery energy storage systems (BESS), are devices that can temporarily store the energy generated by renewables (e.g. solar and wind), and then release that energy when needed. Developing battery storage technologies is essential for accelerating fossil fuel retirements by ensuring electric grids have a reliable, consistent supply of renewable energy. [Source]

Biomass

Biomass is organic material from plants and animals that contains stored biochemical energy. Biomass can be burned directly for heat or converted to liquid and gaseous fuels. Unfortunately, the processes used to produce biomass, such as clearcutting forests for wood pellets, are frequently extractive and environmentally harmful. [Source]

BIPOC

An acronym for Black, Indigenous, and People of Color. BIPOC collectively refers to individuals and communities who identify as non-white. Many BIPOC communities have historically faced disproportionately adverse environmental impacts, resulting in inequitable social and health outcomes. Securing environmental justice, and a fair distribution of benefits to BIPOC communities, are increasingly seen as core goals of the modern environmental movement.

Capacity

A power plant’s capacity is the power (often expressed in megawatts) it can produce when running at full capability. Whether it is running (i.e. generating electricity) or not, a power plant’s capacity does not change (except for a minor amount in summer versus winter due to the fact that heat reduces a power plant’s ability to generate electricity). Capacity Factor is the actual or expected long-term average power the plant produces, which can range from 5% to 95%, and is a measure of the plant’s availability. 

Carbon

The term “carbon” is used throughout the Carbon Plan as a shorthand for carbon dioxide (CO2) emission rate (usually expressed in short tons per year).

Carbon Dioxide Equivalent (CO2e)

In addition to carbon dioxide, there are several other important greenhouse gases with the potential to drive global warming, with varying potencies and atmospheric lifespans. For example, methane (CH4) is far more effective at trapping solar heat than carbon dioxide (CO2), but methane also dissipates from our atmosphere much faster. A carbon dioxide equivalent, or CO2e, is a measure used to compare emissions from various greenhouse gases on the basis of their global warming potential. [Source]

Carbon Neutrality

A carbon-neutral entity must counterbalance any CO2 it releases into the atmosphere with an equivalent amount of CO2 it removes. This can be achieved through direct carbon removal projects such as reforestation, or by purchasing carbon offset credits to compensate for emissions. The terms “carbon neutral” and “net zero” are often, but not always, used interchangeably. [Source

Carbon Plan

The Carbon Plan is a road map for reducing climate-changing carbon emissions in North Carolina. North Carolina law requires the Carbon Plan to reduce electric power sector greenhouse gas emissions by 70% below 2005 levels by 2030 (with some exceptions allowed) and attain complete carbon neutrality by 2050. The Carbon Plan must also be reviewed and updated every two years.

Climate Resilience

The ability to adapt to, prepare for, and effectively respond to natural hazards caused by climate change. [Source

Combined Cycle (CC)

A combined-cycle power plant uses a gas turbine and a steam turbine in sequence to produce energy. CC plants are much more efficient than traditional single-cycle CT plants, producing up to 50% more electricity from the same fuel. The waste heat from the gas turbine is routed to the nearby steam turbine, which generates extra power. [Source]

Combustion Turbines (CT)

A single-cycle CT plant burns fuel to produce a jet of hot air and combustion products which spin a turbine and a generator to produce electricity. The energy-depleted jet is exhausted to the atmosphere. While future CTs may be enabled to transition to zero-carbon fuel, current CT plants burn fossil fuels and emit carbon. 

CRIRP

The Carbon Plan Integrated Resource Plan represents the application of Duke Energy’s IRP to meet North Carolina’s state energy goals. In North Carolina, the terms “CRIRP” and “Carbon Plan” are often used interchangeably. The CRIRP will be updated by the NC Utilities Commission every two years, with its first update scheduled before the end of 2024. It is expected that this will combine carbon planning and integrated resource planning into one process for Duke Energy moving forward. [Source]

Cumulative Impacts

People and communities are not impacted by multiple pollution sources in isolation—they compound as “cumulative impacts.” To truly protect public health, permitting agencies tasked with regulating air pollution must holistically consider all emission sources that affect a community’s well-being.

Decarbonization

The reduction or elimination of carbon dioxide emissions from a process such as manufacturing or the production of energy. (Oxford Dictionary) 

Duke Energy Carolinas/Duke Energy Progress

Duke Energy is one of the largest electric power holding companies in the United States. Within North Carolina, Duke Energy maintains two distinct operating subsidies. For resource planning and carbon management, the Carbon Plan considers the two companies as a single system and includes their service areas in both North and South Carolina.  Duke Energy Carolinas (DEC) primarily serves central and eastern North Carolina (with additional coverage in the state’s High Country), covering approximately 24,000 square miles and 2.5 million residential, commercial, and industrial customers. Duke Energy Progress (DEP) serves a separate set of customers and operates its own network of power generation, transmission, and distribution facilities. DEP primarily supplies electric service to central and western North Carolina, covering approximately 32,000 square miles and 1.5 million customers.

Energy Efficiency

Energy efficiency (EE) describes the amount of energy used to perform a given task or produce a given result. Describing something as “energy-efficient” means it’s designed or operated in a manner that minimizes wasted energy and reduces energy consumption without sacrificing the quality of the outcome. For example, energy-efficient homes and buildings use less energy to heat, cool, and run appliances and electronics, while energy-efficient manufacturing facilities use less energy to produce goods. [Source]

In the context of the Carbon Plan, energy efficiency is the annual percentage reduction in electricity load that is achieved through improved grid management and customer programs. If an annual EE of 1% to 1.5% is achieved for 15 years, the generation offset is 16% to 25% respectively.

Environmental Justice

The fair treatment and meaningful involvement of all people, regardless of race, color, national origin, or income, with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies. [Source

Equity

In the context of climate change, equity means fairness in how the benefits and burdens of reducing carbon emissions are distributed among different communities. These benefits and burdens include environmental impacts, access to clean energy, workforce transition, affordability, and community engagement.

Fossil Fuels

Fossil fuels, including coal, oil, and natural gas, are formed from ancient and energy-rich deposits of fossils and rock. Fossil fuels are dirty sources of energy; burning them releases carbon dioxide and other greenhouse gasses into the atmosphere. These gasses trap solar heat within the Earth’s atmosphere, causing rising temperatures and fueling catastrophic climate change around the world. [Source]

Geothermal

Geothermal heat pumps use the steady temperatures just several feet below the surface as a heat sink for electrifying heating and cooling in any environment. It is considered a renewable and sustainable source of energy because the heat emanating from the earth’s interior is essentially inexhaustible on human timescales. Geothermal energy can be harnessed for a variety of uses, including electricity generation, direct heating, and even cooling systems. [Source

Gigawatts (GW)

A unit of electrical power equal to one billion watts. Gigawatts are commonly used in referring to the power capacity or the energy output (gigawatt-hours) of generating plants or various generating sectors such as solar or nuclear. They can also be used to measure the total energy-generating capacity of a state or country. One gigawatt of energy is enough to power roughly 750,000 homes. [Source 1] [Source 2]

Grid

An energy grid is an interconnected network for electricity delivery from providers to consumers. The grid links providers and consumers through a system of transmission and distribution lines, operated by one or more control centers. This network of power lines, substations, and equipment allows for the efficient and reliable distribution of electrical energy over long distances to meet the needs of consumers. It forms the backbone of our electrical power supply system and enables the delivery of electricity from various sources to end-users. [Source 1] [Source 2]

Grid Edge Programs

“Grid Edge refers to the “edge” of the electricity network, or grid, where the Companies’ electricity reaches customers’ homes and businesses. These programs include energy efficiency (“EE”) and demand-side management (“DSM”) programs, certain rate designs, voltage control efforts, renewable energy programs, electric transportation programs and behind-the-meter generation and storage.” (Duke CPIRP Filing, Appx. H).

HB 951

In 2021, the North Carolina General Assembly passed House Bill 951, also known as “Energy Solutions for North Carolina.” HB 951 sets goals of reducing utility companies’ statewide carbon emissions by 70% below 2005 levels by 2030, and attaining complete carbon neutrality by 2050. [Source]

Hydrogen-capable or Hydrogen-enabled

In the Carbon Plan, “hydrogen-capable” describes fossil-fueled CT and CC generation plants able to use hydrogen alongside other traditional fuels, with the goal of transitioning to 100% carbon-free generation. While hydrogen itself is clean-burning and more energy efficient than gas or coal, it requires a substantial investment in land and water resources that could conflict with North Carolina’s agriculture, recreation, and ecology.

Hydrogen Hub

A network of hydrogen producers, consumers, and local connective infrastructure to accelerate the use of hydrogen as a clean energy carrier that can deliver or store tremendous amounts of energy. [Source]

Hydropower

Sometimes referred to as hydroelectric power, this process generates power by harnessing the energy of moving or falling water. It is one of the oldest and most widely used sources of clean energy. Hydropower relies on the water cycle, so the amount of precipitation that drains into rivers and streams in a geographic area determines the amount of water available for producing hydropower. [Source]

Integrated Resource Plan (IRP)

An IRP is a “roadmap” that identifies potential plans for a utility to meet future energy production and demand requirements while considering the associated risks and benefits to its customers. [Source

Intervenor

Third-party individuals or groups formally involved in legal or regulatory processes. Intervenors are full participants in the proceeding and make legal arguments, conduct discovery, file testimony, cross-examine witnesses, and are subject to cross-examination by the other parties in the case if called to testify. 

Least Cost

Regulators traditionally require public utilities to conduct extensive economic analyses to identify a “least cost” approach to proposed generation, distribution, and servicing changes. This is done to accommodate growth at the lowest possible cost to customers. However, these economic analyses seldom take into account the environmental and social costs associated with these policy changes. This is particularly true in North Carolina, where Duke Energy does not take into account the staggering health and environmental costs of fossil fuels—estimated by researchers to be 17-27 cents/kWh for coal, and ~10 cents/kWh for gas

Load Management

A strategy for balancing and controlling the demand for electricity with the supply of energy from renewable sources like wind and solar. This allows utilities to reduce the demand for electricity during peak usage times, which can, in turn, reduce costs by eliminating the need for peaking power plants. [Source]

Methane

Methane (CH4) is a primary component of natural gas. Methane is also an extremely potent greenhouse gas (GHG), far more effective at trapping solar heat than carbon dioxide (CO2). Its presence in the atmosphere affects the Earth’s temperature and climate system. [Source

Natural Gas

Natural gas is a fossil fuel, primarily methane, produced through a process called hydraulic fracturing (also known as fracking). Fracking forces water, chemicals, and sand down a high-pressure well to break up shale and other sedimentary rock formations, releasing gas to be collected at the surface. Fracked natural gas has become a commonly used energy source, but it is highly controversial due to environmental, climate, and safety concerns. 

Net Zero

A net-zero process or entity counterbalances or cancels out any carbon it emits through carbon removal projects such as reforestation. The terms “net zero” and “carbon neutral” are often, but not always, used interchangeably. While the concept of “zero-carbon” is also sometimes merged with these terms, a zero-carbon process creates no carbon emissions at all. [Source]

North Carolina Utilities Commission (NCUC)

The North Carolina Utilities Commission is a state regulatory body, created by the NC General Assembly to oversee the rates and services of all investor-owned public utilities in North Carolina. These include companies that provide electricity, telephone service, natural gas, water, and wastewater. As part of its regulatory oversight, the NCUC is responsible for creating and enforcing a statewide Carbon Plan.

Offshore Wind

Offshore wind farms generate electricity from wind blowing across the sea. They are considered more efficient than onshore wind farms, thanks to higher wind speeds, greater consistency, and lack of physical interference that the land or human-made objects can present. [Source

Onshore Wind

Onshore, or land-based, wind energy is the power that’s generated by wind turbines located on land driven by the natural movement of the air. Onshore wind farms are usually constructed in less-populated areas where buildings and obstacles don’t interrupt airflow, such as fields or rural areas. [Source

Pathway

In the context of the Carbon Plan, a pathway is a possible future scenario that details the evolution of today’s energy generation resource mix to future combinations that achieve zero-carbon emissions by 2050. The pathway is produced by computer modeling and simulation. At each timestep—typically annually—the model satisfies the projected electricity needs of customers while optimizing cost, reliability, risk, and carbon reduction. Many alternative pathways are investigated, and then a subset is chosen that meets the objectives and includes all likely outcomes. Duke Energy has chosen three pathways in its draft Carbon Plan with varying costs, risks, and carbon reduction schedules.

Photovoltaic (PV) Cells

Solar farms with panels of PV cells are a category of renewable energy in the Carbon Plan. PV cells are the component of solar panels that convert solar radiation to either DC electricity (which is stored in on-site batteries for future use) or AC electricity (which is sent to the grid). 

Portfolio

The combination of energy resources, technologies, and strategies that Duke Energy uses to generate electricity and meet its energy needs. This portfolio can include various energy sources, such as coal, natural gas, nuclear, renewable energy (like wind and solar), and energy efficiency measures. [Source 1] [Source 2 (Chapter 3)]

Public Comments

Input given by the public to governmental bodies about proposed legislation or regulation during a period—and by means—set aside and prescribed by law. In North Carolina, utility consumers may submit comments about any docketed matter to the NC Utilities Commission. Statements can also be mailed to the Commission. In either case, after two or three business days, statements are made part of the official record for the proceeding and can be viewed on this website via the assigned docket number. The Commission does not respond to consumer statements but does consider them, along with all other evidence, in reaching its decisions. [Source 1] [Source 2]

Pump Storage Hydro Facility

These hydroelectric energy storage systems are designed to store energy by transferring water in both directions between two reservoirs located at different elevations. Excess electricity generated during periods of low demand is used to pump water to the higher reservoir. When demand is high, water flows downhill to the lower reservoir, passing through a turbine to generate power. [Source]

Ratepayer

A customer of a public utility company.

Renewable Energy

Renewable energy is energy from sources that are naturally replenishing but flow-limited. Renewable resources are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time. Major types of renewable energy sources include wind, solar, and geothermal. [Source]

Reserve Margin

“The amount of unused available capability of an electric power system (at peak load for a utility system) as a percentage of total capability.” [Source]

Retirement (of Power Plants)

The retirement of coal-fired power plants refers to the process of power plants shutting down permanently, and ceasing the operation of particular power generation facilities. This can happen due to age, inefficiency, or technological advancements, but especially because of the urgent need to stop using fossil fuels. Power plants are now competing with cleaner, more efficient, and lower-cost renewable energy sources such as wind and solar power. [Source]

Short Tons

A commonly used unit for measuring carbon dioxide or other greenhouse gas emissions in the U.S. A short ton is equal to 2,000 pounds.

Smart Grid

An advanced and digitally enhanced electrical grid system that uses modern technology and communication to improve the efficiency, reliability, and sustainability of electricity generation, distribution, and consumption. Smart grids include computer systems to manage the newer devices and components. This new technology enables better communication between Duke Energy and their customers, which helps them prevent and repair outages, and read household energy meter faster and more accurately. [Source]

Storage

The process of capturing and retaining energy in a form that can be used later. It involves accumulating extra energy when it is available and then releasing it when needed, with the continuous demand for energy in our homes, industries, and transportation systems. [Source

System Reliability

The ability of a power system to withstand instability, uncontrolled events, cascading failures, or unanticipated loss of system components. In other words, the ability to consistently depend on power delivery to homes, buildings, and devices, even in the face of physical and cyber events that cause power disruptions. Key aspects of system reliability include a steady supply of energy; resilience (withstanding and recovering from unexpected events; redundancy (backup mechanisms and additional power sources or grid connections); predictability; quality; and safety. Electric utilities in North Carolina are required to plan and operate their system so that every customer can expect not more than one power outage in ten years from preventable causes. [Source]

Vertically Integrated Monopoly

In a regulated wholesale market, utilities are typically vertically integrated monopolies, meaning they are solely responsible for generating, transmitting, and distributing electricity to their customers. Duke Energy is a prime example of this, controlling every part of the power generation-to-delivery process. [Source]

Zero-Carbon

A “zero-carbon” product, process, entity, or service does not produce any carbon emissions. Zero-carbon energy sources—such as wind, nuclear, and solar—create no carbon emissions when generating electricity. While the terms “zero-carbon” and “net zero” are sometimes used interchangeably, net zero refers to counterbalancing or canceling out any carbon produced through carbon removal, while zero-carbon means no carbon is given off at all. [Source]