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Cleantech Glossary: Industry Terms and Definitions

Frequently Used Cleantech Terms and Definitions



The process of a region, community, building, person, etc. adjusting their surroundings and behavior to climate change. Examples of this include sea walls, air conditioning, irrigation systems in drought-stricken areas, more robust emergency planning, and more. If climate change is a wound, adaptation is a bandaid.


Also known as dual-use solar, agrovoltaics refers to land that is used for both solar power generation and agriculture. This can include livestock grazing (like sheep), habitats for pollinators, or growing crops. The use of agrovoltaics is also beneficial for solar plant managers because it decreases the maintenance requirements of the surrounding land.

Anaerobic digestion

A biological process that breaks down organic matter in the absence of oxygen. Biogas, the main product of anaerobic digestion, consists primarily of methane (CH4) and carbon dioxide (CO2), along with trace amounts of other gases. Methane is a potent greenhouse gas, and its capture through anaerobic digestion prevents its release into the atmosphere, reducing overall greenhouse gas emissions. Biogas can be utilized as a renewable fuel for various purposes. Biogas produced from anaerobic digestion can be used for heat and power generation or can be used in the combined heat and power (CHP) process. Digestate, the residue remaining after anaerobic digestion, is a nutrient-rich material that can be used as a biofertilizer in agriculture.

Angel investor

An angel investor, or private investor, is a high-net-worth individual who invests in startups in exchange for eventual equity and profit. They most often invest in the early stages of a startup, such as the seed funding round.


Batchable Computing

A computing process that can be paused or ramped up and down within seconds; also known as flexible or pausible computing. Batchable computing centers can help manage the load on the grid by powering down in a time of high demand or powering up when there is low demand and excess supply. You can learn more in this article on Solar Power World.

Battery Storage

A system of batteries, usually lithium-ion batteries, that can be charged by renewable energy. These batteries can store energy for several hours and release it onto the grid when demand increases. Also referred to as battery energy storage systems (BESS).


Energy and storage systems that directly supply buildings and homes with energy, such as rooftop solar or battery storage systems. This energy does not come from a central power plant or grid, which means a utility is not involved in providing or charging the consumer for this energy use. They are “behind the meter” because the use of these energy sources is not counted by an electric meter/utility. An important caveat: many ‘behind-the-meter’ sources are still connected to the electric grid, both to allow the producer to sell excess supply and to draw from the grid when their rooftop or storage systems cannot meet user demand.

Biomass energy

Energy produced from organic matter, such as plants, crops, agricultural residues, and organic waste. Biomass can be burned directly or converted into biofuels. It involves converting biomass through processes like combustion or biochemical conversion to produce heat, electricity, or biofuels.

Blue hydrogen

Hydrogen is used as a fuel by heavy industry. Fuel cells create hydrogen through a chemical reaction called electrolysis, which creates water and heat as byproducts. Like grey hydrogen, blue hydrogen uses natural gas to power the electrolysis process. However, blue hydrogen also uses carbon capture and sequestering technology, which could roughly halve the amount of carbon produced. Learn more about the colors of hydrogen in Greentech Media's guide.

Brown hydrogen

Hydrogen is used as a fuel by heavy industry. Fuel cells create hydrogen through a chemical reaction called electrolysis, which creates water and heat as byproducts. When the electricity used to catalyze electrolysis is powered by coal or oil, it is called brown hydrogen. This is not considered a low-carbon energy source. Learn more about the colors of hydrogen in Greentech Media's guide.



CAISO stands for California Independent System Operator, which oversees the operation of California's bulk electric power system, transmission lines, and electricity market generated and transmitted by its member utilities. It is also involved in infrastructure planning for new sources of energy. CAISO is an Independent System Operator (ISO).

Carbon neutral

According to The World Economic Forum, a carbon-neutral plan aims to cancel out the carbon emissions of a company through both reduction efforts and offset programs. Unlike the term 'net zero', carbon neutral usually only refers to carbon (CO2) and may only cover one scope of a company's emissions. In contrast, net zero goals or programs account for all greenhouse gases, often across multiple scopes or parts of the supply chain.

Carbon sink

A natural or artificial reservoir that accumulates and stores some carbon-containing chemical compound for an indefinite period. Carbon sinks help to remove carbon dioxide from the atmosphere, which is a greenhouse gas that contributes to climate change. The two main types of carbon sinks are natural (forests, ocean, soil) and artificial (i.e. concrete)


Also known as an emissions trading system, a cap-and-trade system sets a limit (cap) on the total amount of greenhouse gas emissions allowed within a specified jurisdiction or industry sector. Emission allowances are distributed or auctioned off, and participants must hold sufficient allowances to cover their emissions. Participants can buy or sell allowances in a market, allowing for flexibility in emission reductions and providing an economic incentive to invest in cleaner technologies.

Cell (solar)

A solar cell is the next step of the solar value chain after the wafer. Metal conductors are added to each wafer surface and treated so they can conduct electricity. A special coating is applied to ensure the absorption of solar energy rather than reflection. According to the Department of Energy, "most cell types require the wafer to be exposed to a gas containing an electrically active dopant, and coating the surfaces of the wafer with layers that improve the performance of the cell."

Chief Financial Officer (CFO)

A Chief Financial Officer (CFO) is a high-level executive in a company responsible for managing the organization's financial operations, financial planning, and reporting. The CFO typically reports directly to the CEO and plays a crucial role in guiding the company's financial strategy and decision-making. Job responsibilities include: developing and implementing the company’s financial strategy; assessing financial risks; identifying growth opportunities; managing debt and equity; financial reporting and filings; and communicating with investors and shareholders.

Chief Risk Officer (CRO)

A Chief Risk Officer (CRO) is a senior executive in a company responsible for overseeing the organization's risk management strategies and processes. The role of the CRO is to identify and assess potential risks that could impact the company's operations, finances, reputation, and overall performance. They work to implement risk mitigation strategies and ensure the company's resilience to various internal and external threats.

Chief Sustainability Officer (CSO)

A Chief Sustainability Officer (CSO), also known as a Chief Corporate Social Responsibility Officer (CCSRO) or Chief ESG Officer, is a senior executive in a company responsible for developing, implementing, and overseeing the organization's sustainability strategy and initiatives. The role of the CSO is to ensure that the company operates in a socially and environmentally responsible manner while aligning sustainability goals with the overall business strategy. Their responsibilities may include: developing a sustainability strategy; stakeholder engagement; sustainability reporting; implementing energy efficiency programs; social responsibility initiatives and ESG; complying with regulations; and managing external partnerships.

Clean technology/cleantech

Comprises a diverse range of products, services, and processes that harness renewable materials and energy sources, dramatically reduce the use of limited natural resources, and reduce or eliminate pollution and toxic wastes.

Community Choice Aggregator (CCA)

A local governmental entity or organization that procures electricity on behalf of residents, businesses, and public entities within a designated community. CCAs provide an alternative to traditional investor-owned utilities by allowing communities to have more control over their energy sources and generation methods. Procurement can include sourcing electricity from renewable energy projects, such as solar or wind farms, or purchasing power from the wholesale market.

Community solar

Community solar, also known as shared solar or solar gardens, is a cooperative approach to solar energy generation that enables multiple participants within a community to access and benefit from the production of solar power. It allows individuals or organizations who are unable to install solar panels on their own properties to still access clean and renewable energy, while also promoting community engagement and participation in sustainable energy initiatives. In a community solar project, a solar array or group of solar panels is installed in a centralized location, such as a nearby field, rooftop, or dedicated solar farm. Interested community members, including homeowners, renters, businesses, or nonprofit organizations, can then subscribe or purchase shares in the community solar project. Participants in a community solar program typically receive credits or discounts on their electricity bills based on their share of the solar energy generated by the system. These credits represent the portion of solar power that the individual's share contributes to the overall production. As a result, participants can enjoy the financial benefits of solar energy without the need for on-site installations or maintenance.


A comptroller (pronounced "controller") is a senior financial executive in an organization responsible for overseeing and managing its financial operations. Their primary focus is to ensure the company's financial stability, accuracy, and compliance with financial regulations.

Conference of the Parties (COP)

The annual United Nations Climate Change Conference, usually followed by a year; i.e. COP22

Corporate Social Responsibility Manager (CSR)

A Corporate Social Responsibility (CSR) Manager is a professional responsible for developing, implementing, and managing the corporate social responsibility initiatives and strategies of a company. Their role revolves around ensuring that the organization operates in a socially responsible manner and contributes positively to society, the environment, and various stakeholders.


When energy supply exceeds demand and no energy storage is available; also known as wasted energy. This is caused by an outdated grid system. In 2021, an estimated 14.9 TWh of otherwise viable renewable energy was curtailed. This is the equivalent of $610 million in lost revenue or enough energy to power the city of Chicago for a year. You can learn more in this article in Solar Power World.

Critical Issues Analysis (CIA)

When building a solar or wind farm, developers must analyze a chosen parcel of land for its suitability. Developers will usually hire an environmental consultant to assess the land via a “critical issues analysis”, or CIA. The CIA will account for endangered species, flood and fire risks, impact on the local community, and more. The average CIA takes several weeks to perform, and almost 90% of land parcels will be deemed unsuitable for building. Some developers are moving towards automated environmental due diligence software to provide this information quickly; otherwise, the CIA stands as a major barrier to implementing more renewable energy projects.


Decentralized energy

Energy that is generated close to where it will be used, as opposed to being generated by a central source like a power plant. Examples include rooftop solar, battery energy storage systems (BESS), or other components of a microgrid. Instead of running through the grid, these types of energy are often consumed at or near the source.

Demand Side Management (DSM)

Demand Side Management, also called demand side response or just demand response, is a strategy used by utilities to encourage customers to alter their energy demand and use patterns. This is done to ensure that demand does not exceed supply, thereby stabilizing the grid and preventing the need for scheduled blackouts. This can be done by homeowners using appliances such as smart thermostats or other smart technology, like some electric vehicle chargers. Larger companies may use similar Al software to curb use, or mechanisms such as batchable computing as a long-term DSM strategy.

Department of Energy (DOE)

The Department of Energy (DOE) is part of the executive branch of the United States of America. Established in 1977, it originally covered the development of nuclear energy and weapons. Now, the DOE also manages national energy policy, research, energy production, and energy conservation. The DOE executes energy policies that are decided by the current administration in office.

Deregulated Electricity Market

Demand Side Management, also called demand side response or just demand response, is a strategy used by utilities to encourage customers to alter their energy demand and use patterns. This is done to ensure that demand does not exceed supply, thereby stabilizing the grid and preventing the need for scheduled blackouts. This can be done by homeowners using appliances such as smart thermostats or other smart technology, like some electric vehicle chargers. Larger companies may use similar Al software to curb use or mechanisms such as batchable computing as a long-term DSM strategy.


A distributed energy resource management system (DERMS) is a type of software used to manage distributed energy resources (DER). This can include rooftop solar, electric vehicle fleets, battery energy storage systems (BESS), and more. DERMS helps utilities or other power managers control energy flow to the grid, shift energy loads, or provide emergency demand response. This software is sometimes referred to as a “virtual power plant” because it helps automate the management of energy resources. DERMS may require other systems, like a distribution management system (DSM), an outage management system (OMS) or a supervisory control and data acquisition (SCADA) system, to provide full functionality (source: Next Kraft-werke).

Direct Corporate Purchasers

Direct corporate purchasers, often referred to as direct purchasers or corporate buyers, are businesses, organizations, or institutions that directly acquire renewable energy or clean power sources to meet their electricity needs. This approach involves entering into power purchase agreements (PPAs) with renewable energy providers, such as wind farms, solar installations, or hydroelectric facilities, or investing in on-site renewable energy projects.

Distributed energy resources (DER)

Small energy generators that, unlike centralized power plants, are distributed throughout the grid to be located close to the point of use, such as rooftop solar, electric vehicles, battery energy storage systems (BESS), fuel cells, or combined heat and power units.

Distribution lines

Distribution lines are lower-voltage power lines that deliver electricity from substations to homes, businesses, and other consumers.


Demand-Side Management (DSM) refers to a set of strategies implemented by utilities and energy providers to influence consumer energy use patterns. The goal of DSM is to save costs, reduce peak demand, and enhance energy efficiency. It includes initiatives like promoting energy-saving behaviors, encouraging off-peak usage, and implementing demand response programs. DSM aims to achieve energy conservation and grid stability by managing consumer electricity demand effectively.



A certification mark placed on a product or service that indicates it meets specific environmental standards or criteria. Ecolabels provide information to consumers, businesses, and organizations about the environmental impact of a product or service throughout its life cycle. The criteria can vary depending on the ecolabeling program and may include factors such as resource conservation, energy efficiency, waste reduction, sustainable sourcing, or reduced emissions. Ecolabels are typically awarded by third-party organizations or government agencies that have established rigorous standards and assessment processes. These organizations assess and certify products or services based on their environmental performance, taking into account factors like raw material sourcing, manufacturing processes, packaging, transportation, and end-of-life disposal.

EDAM (Energy Day Ahead Market)

An EDAM (Energy Day Ahead Market) is an electricity market where market participants (such as generators, suppliers, and consumers) trade electricity for delivery the next day. It helps participants plan and manage electricity needs efficiently, ensuring a balanced and cost-effective supply of electricity. This market promotes transparency and competition, benefiting both producers and consumers in the electricity sector.


Edison Electric Institute - Association that represents all U.S. investor-owned electric utilities.


U.S. Energy Information Administration - An independent arm of the U.S. Department of Energy responsible for collecting, analyzing, and disseminating energy information to promote sound policymaking, efficient markets, and public understanding of energy and its interaction with the economy and the environment.


Environmental Impact Statement - Under United States environmental law, is a document required by the National Environmental Policy Act (NEPA) for certain actions "significantly affecting the quality of the human environment.

Electric Arc Furnace

An electric arc furnace (EAF) is a furnace that melts metals, like steel, using electricity. This method is used to produce steel from recycled scrap metal. Overall, EAFs contribute to a cleaner steelmaking process due to their use of recycled materials, lower carbon pollution, energy efficiency, and production flexibility.

Electric Co-op/Cooperative

An electric cooperative (co-op) provides electricity to its members, who are also its owners. Unlike traditional utilities, co-op members have a direct say in how the organization is run by electing a board of directors. Co-ops are nonprofit and reinvest any profits to improve services or lower costs. They focus on serving rural areas and aim to provide affordable, reliable electricity with a community-oriented approach. Electric cooperatives play a vital role in expanding electricity access to underserved regions and are governed by principles of local ownership and community development.

Electricity meter

A physical device that shows how much energy a home, building, or other types of infrastructure consumes directly from (or feeds into) the grid. A utility will use this number to know how much to charge the customer.


The process of converting an existing system or process to use electricity as its primary energy source. This can include the replacement of fossil fuel-powered vehicles with electric vehicles, the installation of solar panels on homes and businesses, or the construction of new power lines to support the increased demand for electricity.


A process that uses electricity to cause a chemical reaction, typically involving the splitting of a compound into its constituent elements or ions. It is commonly used to produce gases like hydrogen and oxygen from water. In recent years, electrolysis has gained attention for its potential role in the production of green hydrogen. By using electricity from renewable sources, electrolysis can split water into hydrogen and oxygen without generating greenhouse gas emissions.

Electric Co-op/Cooperative

An electric cooperative (co-op) provides electricity to its members, who are also its owners. Unlike traditional utilities, co-op members have a direct say in how the organization is run by electing a board of directors. Co-ops are nonprofit and reinvest any profits to improve services or lower costs. They focus on serving rural areas and aim to provide affordable, reliable electricity with a community-oriented approach. Electric cooperatives play a vital role in expanding electricity access to underserved regions and are governed by principles of local ownership and community development.

Embodied carbon

The carbon emissions of a product or service throughout its entire life cycle. For a building, this can include the emissions from extracting and refining building materials such as steel, the vehicles used to transport materials and employees to the building site, and emissions from the process of installation. Operational carbon refers to the emissions that come from powering and heating the building and required upkeep. Learn more from Carbon Cure's explainer.

Encapsulant (solar)

Solar encapsulant is a material placed between the front and back sheets of a solar panel in the manufacturing process. It protects the solar cells inside from moisture, dust, and other environmental concerns that could reduce the efficiency of the panel. Encapsulants can be made from ethylene-vinyl acetate (EVA) or polyvinyl butyral (PVB), which are both highly transparent and resistant to UV radiation.


EPC stands for engineering, procurement and construction. This is a type of project contract where the contractor is in charge of virtually every aspect of the project – sometimes also called a "turnkey" project because the contractor manages everything and the buyer simply "turns the key" at the end. EPC projects are used to undertake construction works by the private sector on large-scale and complex infrastructure projects, such as solar and wind farms, transmission lines, and other energy-related infrastructure.


Electric motor vehicle - A motor vehicle powered by an electric motor that draws current from rechargeable storage batteries, fuel cells, photovoltaic arrays, or other sources of electric current.


An externality refers to the indirect and unintended costs or benefits arising from human activities that are not accounted for in the market price of goods or services. Negative externalities are borne by society as a whole or future generations rather than by the entities responsible for the emissions or pollution. This creates a market failure, as the true costs and impacts are not adequately considered, leading to an inefficient allocation of resources. For example, gas-powered vehicles create air pollution, which can cause respiratory problems such as asthma. The national healthcare cost of treating asthma, however, is not reflected in the cost of a gallon of gas.


Federal Energy Regulatory Commission (FERC)

The Federal Energy Regulatory Commission (FERC) is a federal agency that regulates the price, terms and conditions, transmission, and wholesale sale of electricity and natural gas between states and also regulates the transportation of oil by pipeline. FERC is the federal counterpart to state utility regulatory commissions.

Flexible load

A flexible load, also known as a demand response resource, refers to the ability of an electricity-consuming device, system, or process to adjust its power consumption patterns in response to external signals or market conditions. Flexible loads can increase or decrease their energy usage, shift their operation to off-peak hours, or temporarily reduce their electricity demand to support grid stability, optimize energy use, and participate in demand-side management programs. Examples of flexible loads include electric vehicle charging stations, heating, ventilation, and air conditioning (HVAC) systems with adjustable settings, and industrial processes that can be scheduled to align with periods of low electricity prices.

Floating wind

Floating wind turbines, also known as offshore floating wind turbines or floating wind farms, are a type of renewable energy technology that involves wind turbines mounted on floating structures anchored to the seabed in deep waters, typically far from the shore. Unlike traditional fixed-bottom offshore wind turbines, which are installed on the seabed, floating wind turbines can be deployed in deeper waters where the seabed is unsuitable for traditional foundations. The core component of a floating wind turbine is the floating platform, which is designed to be stable in the water, allowing the wind turbine to operate effectively in the open sea. The floating platform is anchored to the seabed using mooring lines, chains, or other tethering mechanisms to keep it in position and maintain stability in rough seas. The electricity generated by the floating wind turbine is transmitted through underwater cables to an onshore substation, where it is integrated into the grid and distributed to consumers.


Energy sources that are part of a utility pass through the meter to a consumer. Any energy that comes directly from the grid is front-of-meter.


Geothermal energy

A renewable source of energy derived from harnessing the Earth's heat stored beneath its surface. It involves extracting hot water or steam from geothermal reservoirs to generate electricity or provide direct heating and cooling. It can also be directly used for heating applications in homes, buildings, and industrial facilities.


Greenhouse Gases - Gases such as methane and carbon dioxide which absorb infrared radiation and trap the heat in the atmosphere, thus contributing to global warming.

Gigawatt (GW)

1,000 megawatts.

Gigawatt-hour (GWh)

1,000 megawatt-hours.

Global carbon cycle

The process by which carbon is exchanged between the biosphere, the geosphere, the hydrosphere, and the atmosphere.

Green roof

A green roof, also known as a living roof or vegetated roof, is a roofing system that incorporates vegetation, soil, and other layers to create a living and functional space on top of a building. It involves the installation of a specially designed structure to support the growth of plants, which provides numerous environmental, aesthetic, and energy efficiency benefits. It usually consists of a base layer, insulation, a waterproof membrane (such as rubber), a drainage layer, a root barrier, a growing medium (such as soil), and vegetation. Green roofs offer a range of benefits, including improved energy efficiency, reduced stormwater runoff, enhanced biodiversity, improved air quality, and aesthetic appeal. They can help mitigate the urban heat island effect, provide insulation, and create pleasant green spaces for recreational use or urban agriculture, contributing to more sustainable and livable cities.

Green Hydrogen

Hydrogen is used as a fuel by heavy industry. Fuel cells create hydrogen through a chemical reaction called electrolysis, which creates water and heat as byproducts. When the electricity used to catalyze electrolysis is renewable, the result is referred to as 'green hydrogen.' Learn more about the colors of hydrogen in Greentech Media's guide here.

Grey hydrogen

Hydrogen is used as a fuel by heavy industry. Fuel cells create hydrogen through a chemical reaction called electrolysis, which creates water and heat as byproducts. When the electricity used to catalyze electrolysis is powered by steam methane reformation, which typically uses natural gas as the fuel source, it is called grey hydrogen. Learn more about the colors of hydrogen in Greentech Media's guide.

Ground-Mounted Solar System

A solar array that is installed into the ground using steel poles. This can be done in any large open space. Compared to roof mounting, ground mount can be positioned at any angle and utilize solar trackers.


Hard-To-Abate Industry

A hard-to-abate industry is a sector that is particularly difficult to decarbonize due to the nature of its processes, its reliance on technologies, or the carbon pollution associated with its activities. These industries usually have high energy demand or produce carbon pollution as a byproduct of its operations. Examples include heavy manufacturing, transportation, and mining.


"Heat-as-a-Service" (HaaS) is a subscription model where heating solutions are provided and maintained by a service provider rather than owned by the customer. Customers pay a recurring fee for access to heating equipment, without the burden of ownership, installation, or maintenance.

Heat Battery

A heat battery is used to store thermal energy for later use. It functions like a conventional battery stores electrical energy, but instead of electricity, it stores heat energy. The stored heat energy can then be released and used when needed, such as for heating purposes or to generate electricity using a heat engine.

Heat Pump

A heating and cooling device that can be installed in a home. A heat pump works by transferring heat from outdoors to indoors in the winter and transferring heat from indoors to outdoors in the summer. Heat pumps are energy efficient, and can help lower energy use as well as emissions. You can learn more in this short explainer video from BC Hydro.

Heat storage

Renewable heat storage refers to the process of capturing and storing thermal energy generated from renewable sources like solar, geothermal, or biomass for later use. This technology allows for the efficient and on-demand utilization of heat energy, addressing the intermittent nature of many renewable heat sources. Various methods are employed for renewable heat storage, including the use of insulated tanks, phase-change materials, or underground thermal reservoirs. By storing excess heat during periods of high availability and releasing it when needed, renewable heat storage systems help to increase the overall efficiency and reliability of renewable heating systems, reducing the reliance on conventional fossil fuels for space heating, water heating, and industrial processes.


Independent System Operator (ISO)

An Independent System Operators is an independent and federally regulated entity that coordinates regional electric transmission and ensures customer access to a stable electric grid. ISOs were formed by the Federal Energy Regulatory Commission to encourage utilities to work together and avoid discriminatory or inflationary practices. There are also Regional Transmission Organizations (RTOs), which cover more geographic area. Together, there are 7 ISO and RTOs in the United States.

Industrial Heat

Industrial heat is heat energy used in manufacturing, heating, or other industrial processes. It's usually produced by burning fossil fuels or using renewable energy sources like solar.

Ingot (solar)

The second step of creating a solar panel involves turning high-grade polysilicon into cyndrilical ingots. This is done by melting the poly at very high temperatures.

Investor-Owned Utility (IOU)

An Investor-Owned Utility is a utility company, usually large, that is owned by investors and/or is publicly traded.


Interconnection refers to the linking together of separate electrical systems, such as power plants, substations, and distribution networks, to form an integrated and reliable grid. The goal of interconnection is to enable the transfer of electrical energy between different regions or areas efficiently and safely.


An IPO, or Initial Public Offering, is when a company "goes public" and offers shares/stocks of its company on the stock market. A company must meet requirements set by the Securities and Exchange Commission (SEC) before going public.


Independent Power Producer or Non-Utility Generator - An entity, which is not a public utility, but which owns facilities to generate electric power for sale to utilities and end-users... may be privately held facilities, corporations, cooperatives such as rural solar or wind energy producers, and non-energy industrial concerns capable of feeding excess energy into the system.



1,000 watts. Roughly what is produced by 3 solar panels at a given time. A typical refrigerator requires 300-800 watts to run.


The amount of energy produced by a kilowatt in one hour.


LED lights

A light-emitting diode (LED) light is an energy-efficient alternative to incandescent lights. Their high-efficiency rate is partially due to how little heat they emit. Incandescent lights, in comparison, release 90% of their generated energy as heat. According to the Department of Energy, LEDs use at least 75% less energy and last up to 25 times longer than incandescent lighting.

LEED certification

The Leadership in Energy and Environmental Design (LEED) is a widely-recognizing green building rating system established by the U.S. Green Building Council.

Levelized Cost of Energy (LCOE)

Levelized cost of energy (LCOE) is the average net present cost of electricity generation for a generator over its lifetime. This is used to compare traditional energy sources against renewables like wind and solar, which have high initial building costs but zero ongoing fuel cost. The measure is often used to determine if a particular energy project is a good investment and to compare different sources of energy on a regular basis.

Lithium-ion Battery

According to the Clean Energy Institute, "A lithium-ion (Li-ion) battery is an advanced battery technology that uses lithium ions as a key component of its electrochemistry. During a discharge cycle, lithium atoms in the anode are ionized and separated from their electrons. The lithium ions move from the anode and pass through the electrolyte until they reach the cathode, where they recombine with their electrons and electrically neutralize." The electric vehicle market and energy battery storage systems (BESS) primarily use lithium-ion batteries.

Load shedding

See "peak shaving."

Load Shifting

Involves shifting load from peak to off-peak periods. Popular applications include the use of storage water heating, storage space heating, cool storage, and customer load shifts to take advantage of time-of-use or other special rates.


Maximum peak load

The highest amount of energy that a specific consumer will take from the grid in a set amount of time; can also refer to the amount of energy demand that the entire grid experiences over a period of time. 

Megawatt (MW)

One million watts. Roughly equivalent to the amount of energy 3,000 solar panels would produce at a moment of peak sunlight. Roughly equivalent to the average power demand of 1,800 American homes. This unit represents demand or capacity — the amount of power that can be produced/used at a given time.

Megawatt-hour (MWh)

The amount of energy that a 1MW power source produces over the course of an hour. If running non-stop, a 1MW power source will produce 24 MWh over the course of one day. This is just [energy x time]. Though they will produce the same amount of energy under ideal conditions with full sun exposure, a 1MW solar farm in New Mexico will produce many more MWh over the course of a year than a 1MW solar farm outside Seattle, as the solar farm in New Mexico will receive more hours of sunlight.


Methane is a hydrocarbon gas that is produced where little to no oxygen is present. It can be emitted from a variety of sources both natural and man-made, including natural gas combustion, wetlands, dairy farm manure, landfills, wastewater, or the burning of biomass (natural and human-caused). According to NASA, after carbon dioxide, methane is responsible for about 23% of climate change in the twentieth century.


Localized power-grids that can disconnect from the traditional grid to operate autonomously and help mitigate grid disturbances to strengthen grid resilience.


Actions taken to reduce greenhouse gases emissions and increase carbon sinks to combat climate change. Examples include reducing the use of fossil fuels, planting trees, restoring ecosystems, installing energy efficient technology, building renewable energy plants, etc. If climate change is a wound, mitigation is the healing process.

Multi-use solar

Multi-use solar, also known as dual-use or co-located solar, refers to the practice of combining solar photovoltaic (PV) installations with other land uses or infrastructure to maximize the efficiency and benefits of available space. This approach involves integrating solar panels into areas that serve additional functions, such as agriculture, parking lots, or water bodies. Multi-use solar projects are designed to simultaneously generate clean electricity and maintain the primary use of the land or structure. Multi-use solar installations offer several advantages, including land conservation, improved land productivity, and enhanced renewable energy generation. For example, agricultural solar projects may provide shade for crops or livestock while generating electricity, or solar canopies over parking lots can offer shelter to vehicles while generating power. This approach optimizes land utilization, making it especially valuable in areas with limited available space.


Net Metering

Arrangement for utility customers to get credit for electricity they put out onto the grid (usually in the context of residential solar). If your home is generating more power than it's using at any given time, the meter spins backwards. So if your panels net out 1 kWh of electricity into the grid, that's 1kWh deducted from your bill. Each state is different, but usually the net calculation is done yearly: total electricity consumed minus total electricity added to the grid from panels.

Net Metering Wars, The

Series of utility campaigns (particularly APS in Arizona) to end net metering, or make it financially unattractive through added fees or unfavorable rates. They claim that regular ratepayers are unfairly forced to subsidize solar customers. Disputes over net metering legislation have occurred Arizona, California, and Florida.

Net zero

Negating the greenhouse gas emissions (GHG) of something with offset activities that absorb GHG, creates a "net zero emissions" scenario. These offset activities can include carbon capture and storage, reforestation (planting trees), adding renewable energy to the grid, and waste and landfill management. A company with a net zero goal may purchase offset credits or sign pledges to pay for programs – they do not usually undertake the offset campaign themselves. Critics of the "net zero" concept argue that it gives polluters too much leeway and time to cut their emissions, while others doubt the legitimacy of some carbon offset programs and instead argue for a zero-carbon approach.


NIMBY is an acronym for "Not In My Backyard", and refers to individuals and communities who oppose development near their homes, despite recognizing the need for the infrastructure overall. This is a major blocker for solar and wind projects in rural areas. NIMBY reasoning includes aesthetic complaints, concerns about health or safety, concerns about the impact on property values, or noise. Many of these concerns spread among communities via purposeful disinformation spread by entities with stakes in the fossil fuel industry. A NIMBY might condone the concept of the infrastructure (such as a solar farm) in general but reject it being near their home; others, however, may disapprove of the infrastructure anywhere. Efforts to mitigate NIMBYism often involve engaging communities early in the planning process, providing information, addressing concerns, and seeking mutually beneficial solutions. Building trust, fostering open communication, and incorporating community feedback can help strike a balance between local interests and broader community development goals.


NJERDA stands for "New Jersey Economic Research and Development Authority." It provides financial assistance, grants, loans, and other resources to businesses, municipalities, research institutions, and nonprofit organizations engaged in projects related to energy efficiency, renewable energy, environmental sustainability, and emerging technologies. The authority also collaborates with public and private stakeholders to identify and pursue strategic opportunities for economic development. NJERDA conducts research, collects data, and performs economic analysis to inform policy decisions and guide investment priorities.


The New York State Energy Research and Development Authority. NYSERDA offers analysis, information, and programs to help New Yorkers increase their energy efficiency. NYSERDA collaborates with a host of stakeholders to help reduce emissions, create clean energy jobs, and protect the environment.


Offshore wind

Wind turbines that are installed in bodies of water, including lakes, oceans, or other coastal waters. Wind speeds are faster at sea, so these turbines generally produce more electricity and are larger compared to those on land.


An offtaker is a party, such as a utility company or large consumer, that agrees to purchase electricity from a project, like a renewable energy plant, typically under a long-term contract. This arrangement helps secure financing for the project and ensures a steady revenue stream by guaranteeing a buyer for the generated energy.


Peak shaving

When a large energy consumer, such as a major corporation or industrial center, will reduce power consumption (also called “load shedding”) to avoid a spike in energy consumption that can’t be matched with supply and therefore could destabilize the grid. This is one strategy of “demand side management.” Peak shaving may be done by reducing actual consumption, shifting to a battery source, or activating an on-site generator. In contrast to load shifting, peak shaving reduces overall consumption while load shifting moves the time of consumption while maintaining the same total consumption level. Learn more from Next Kraft-werke.

Pink hydrogen

Hydrogen is used as a fuel by heavy industry. Fuel cells create hydrogen through a chemical reaction called electrolysis, which creates water and heat as byproducts. When the electricity used to catalyze electrolysis is powered by nuclear energy, it is called pink hydrogen. Learn more about the colors of hydrogen in Greentech Media's guide.

Poly or Polysilicon

A high-purity form of silicon used in the first step of creating a solar panel. Polysilicon is melted at high temperatures to create ingots, which are then sliced into wafers. Much of the current polysilicon production in the global solar supply chain is a high-carbon process. Several producers are changing the energy mix of their factories, materials, and processes to create low-carbon polysilicon. Learn more about the global solar supply chain at ultralowcarbonsolar.org

Power plant

Power plants generate electricity from a variety of sources, including fossil fuels, nuclear power, and renewable energy sources such as solar and wind.

Power Purchase Agreement (PPA)

With a physical PPA, the energy buyer agrees to purchase power from a renewable energy project at a pre-arranged price. The power is physically delivered to the buyer from the generation site.


A long-term (years to decades) energy contract between two parties. The energy buyer agrees to purchase power from an energy project (and associated RECs) at a pre-arranged price. The power is physically delivered to the buyer from the generation site.

Public utility commission (PUC)

A Public Utility Commission (PUC), also known as a Public Service Commission (PSC) or Regulatory Commission, is a government agency at the state or regional level responsible for regulating and overseeing public utilities and services. These utilities typically include electricity, natural gas, water, telecommunications, and transportation. The primary role of a PUC is to ensure that these essential services are provided reliably, affordably, and in the public interest, while also setting rates, enforcing regulations, and resolving disputes between utilities and consumers. Public Utility Commissions play a crucial role in safeguarding the interests of consumers, promoting fair competition, and ensuring the efficient and equitable delivery of utility services. They make decisions on issues like utility rate adjustments, infrastructure investments, environmental compliance, and consumer protections, helping to balance the needs of utility companies and the public. PUCs vary by jurisdiction, but they typically act as quasi-judicial bodies with the authority to set policies and regulations that govern the operation and expansion of public utilities within their purview.


Photovoltaic - A method of converting solar energy into direct current electricity using semiconducting materials that exhibit the photovoltaic effect.


Renewable Energy Certificates (RECs)

When renewable energy producers generate electricity, they earn RECs, which represent the clean energy characteristics of that electricity. RECs can be purchased by utilities to help them meet clean energy goals (such as a Renewable Portfolio Standard) mandated by their state, or by companies looking to offset their emissions.

Renewable Portfolio Standard

A Renewable Portfolio Standard (RPS), also known as a Renewable Energy Standard (RES) or a Clean Energy Standard (CES), is a regulatory policy implemented at the state or national level that mandates a specific percentage or quantity of electricity generation to come from renewable energy sources. RPS policies are designed to promote the adoption of clean and sustainable energy technologies, such as wind, solar, geothermal, and hydropower, within the energy mix. They often include timelines and targets to encourage utilities and power providers to invest in and procure renewable energy to meet these requirements.

Retail Electricity Supplier

A retail electricity supplier, often referred to as an energy retailer or electricity provider, is a company or entity that sells electricity directly to residential, commercial, and industrial consumers. These suppliers offer consumers a choice in selecting their electricity provider, allowing them to consider various pricing plans, contract terms, and renewable energy options. Retail electricity suppliers operate within the competitive retail electricity market and may purchase electricity from wholesale electricity generators or produce their own power.


Modifying an existing building, structure or object with new equipment or technology. Retrofitting is a key solution to reducing the emissions of the building sector. This could include upgrading lights to LED, installing an energy monitoring system to identify energy waste, improving a building's insulation, installing a heat pump, and more.


Scope 1 Emissions

The greenhouse gases emitted by a company's direct operations -- this can be their product, the company office, company cars, etc. Scope emissions are used by companies to evaluate the greenhouse gas emissions, or pollution, from their entire value chain. The definition of each scope was developed by the Greenhouse Gas Protocol, the world's most widely used accounting system for tracking emissions.

Scope 2 Emissions

The greenhouse gases emitted by a company's indirect operations — namely emissions from the purchased electricity it uses. Scope emissions are used by companies to evaluate the greenhouse gas emissions, or pollution, from their entire value chain. The definition of each scope was developed by the Greenhouse Gas Protocol, the world's most widely used accounting system for tracking emissions.

Scope 3 Emissions

The greenhouse gases emitted by a company's upstream and downstream activities — transportation, the customer use of the product, investments, and the end-of-life disposal or recycling process. Scope emissions are used by companies to evaluate the greenhouse gas emissions, or pollution, from their entire value chain. The definition of each scope was developed by the Greenhouse Gas Protocol, the world's most widely used accounting system for tracking emissions.

Seed funding/seed capital

The first stage of fundraising for a startup company. This money can come from the company's founder(s), family members and friends, angel investors, and venture capital firms. In exchange, funders will often receive equity in the company or a share of eventual profits. When a bank or investor sees a startup as too risky, entrepreneurs can turn to seed funding to start their project. This is often a smaller amount, around $100K to $1 million. Seed capital is often used to invest in more research, develop a robust business plan, pay employees, etc.

Series A

The funding step that comes after seed funding. Series A funding is usually provided by venture capital firms, and funds average around $15-25 million. According to CoreSignal, "a startup must have a business plan to develop a business model directed at a long-term profit" in order to attract investors in this round. 

Series B

Series B funding comes after Series A funding. Acording to CoreSignal, this round "is used to expand market reach and meet the raised demands" as well as to pay new hires. The average funding in 2020 for Series B rounds was $33 million.

Series C

Series C is the last round of funding for a startup. According to CoreSignal, this round is for companies looking to "develop new products, conquer new markets, or acquire competitor companies in other regions. Also, it could be used to support the startup for an initial public offering." A Series C round can usually net around $55-60 million.


In the context of energy contracts, "sleeving" refers to a specific arrangement where a third party, such as an intermediary or broker, facilitates the purchase and sale of energy between a generator (often a renewable energy project) and a corporate buyer (also known as the off-taker). Sleeving is commonly used in power purchase agreements (PPAs) for renewable energy projects.

Sodium-ion battery

A sodium-ion battery, often called a Na-ion battery, is a rechargeable energy storage device that utilizes sodium ions as the primary carrier of electrical charge. It is an emerging alternative to lithium-ion batteries. Like lithium-ion batteries, sodium-ion batteries consist of two electrodes—an anode (typically made of carbon-based materials) and a cathode (composed of sodium metal compounds)—separated by an electrolyte. During charging, sodium ions migrate from the cathode to the anode, and during discharge, they move back to the cathode, allowing for the flow of electrical current. Sodium-ion batteries have gained attention due to the abundance of sodium as a natural resource, making them a potentially more cost-effective and sustainable alternative to lithium-ion batteries. However, sodium-ion technology faces several challenges, including lower energy density compared to lithium-ion batteries, issues related to electrode material stability, and the need for optimized electrolytes and electrode designs.

Solar array

A solar array is a collection of multiple solar panels that are connected together. They are typically mounted on a frame or rack and oriented to face the sun for maximum energy production. An array can consist of up to thousands of panels, and can be used in applications from small residential systems to large utility-scale projects.

Solar inverter

A piece of electrical equipment that converts the direct current (DC) output of a photovoltaic solar panel or battery into alternating current (AC) that can be fed into the electrical grid or used at the point of production.

Solar Investment Tax Credit (ITC)

A federal-level "dollar-for-dollar" reduction in the income taxes that a person or company claiming the credit would otherwise pay the federal government. The ITC is based on the amount of investment in solar property. Thus, both the commercial and residential ITC are credits equal to 26 percent of the basis that is invested in eligible property that has projects that began in 2021 and 2022.

Solar module

A solar module or panel the fully assembled device that converts sunlight into electricity. It is made up of solar cells, which are connected together and mounted on a frame to form a single unit. The modules can be installed individually or as a large array.

Solar panel

See solar module.

Solar piles

Adjustable steel poles used to mount solar panels. These come in different sizes and are specifically tailored to a project.

Solar tracker

A solar tracker is a device made for utility-scale solar that moves and tilts a panel or solar array towards the sun throughout the day to maximize the amount of sunlight that the panels receive. Solar trackers use sensors and motors to adjust the angle and direction of the panels, ensuring that they are always facing the sun at the optimal angle for maximum energy production. By following the sun's path throughout the day, solar trackers can increase the energy output of a solar panel or array by up to 25% compared to fixed solar installations.


A company in the initial stages of operation – consists of one or more entrepreneurs with an idea for a product or service. The cleantech space is home to many startups. You can learn more about cleantech investing and startups from the Cleantech Leaders Roundtable and their Investors Roundtable.


Substations are smaller power stations that step down the voltage of electricity from transmission lines to a lower voltage that can be used by homes, businesses, and other consumers.

Supply chain

A supply chain is a set of consecutive steps that go into creating a product from start to finish and delivering that product. This could look like extraction of raw materials, manufacturing, assembly of product, packaging and shipping, retail, acquisition by customer, and disposal. There has been increased attention recently to the end-of-life disposal and recycling aspect of the supply chain as consumers become aware of a product's externalities, or unintended impacts, once it has been fully used.

Sustainable Supply Chain Manager

A Sustainable Supply Chain Manager is a professional responsible for developing, implementing, and managing sustainable practices within a company's supply chain. Their role involves integrating environmental, social, and ethical considerations into the supply chain processes to reduce environmental impact, improve social responsibility, and promote sustainable sourcing and production.


The grid

A network of interconnected power lines that delivers electricity from power plants to homes, businesses, and other consumers. Key components of the grid include power plants, transmission lines, substations, and distribution lines.

Thin film PV (solar)

A type of solar technology that converts sunlight into electricity using thin layers of photovoltaic material deposited on a substrate like glass or plastic. Unlike traditional solar panels, which use thick silicon wafers, thin film solar cells are much thinner. They may have lower efficiency but offer cost advantages and flexibility. Compared to traditional solar panels, thin film solar cells are cheaper to produce because they require less material and have simpler manufacturing processes. They can be used on curved surfaces, integrated into buildings, and incorporated into portable solar devices.

Tracker or Solar Tracker

A specialty mounting platform and software that tilts solar panels throughout the day to maintain maximum exposure to sunlight.

Transmission lines

Transmission lines are high-voltage power lines that carry electricity from power plants to substations.

Transmission sharing

Transmission sharing refers to the practice of multiple entities, such as utilities or power producers, jointly utilizing the same electrical transmission infrastructure to transport electricity. This approach allows for the efficient and cost-effective transfer of electricity across different regions, enabling broader access to diverse energy sources and optimizing the use of existing transmission lines. Transmission sharing can enhance grid reliability, reduce congestion, and promote the integration of renewable energy resources.


Ultra low-carbon solar

While solar energy produces no emissions in its operations, the way the components of a solar panel are produced (polysilicon, ingot/wafers, cells, modules) can vary in their emissions. A solar panel produced in a factory that operates on coal, for example, has a higher level of embodied carbon than one produced in a hydro, wind, or solar-powered facility. In fact, how solar PV is produced can have as much as a 50% impact on the total embodied carbon of a solar panel. Most of the current solar supply chain is located in China, which has a high carbon footprint. There is a new movement spearheaded by groups like the Clean Energy Buyers Alliance and the Ultra Low-Carbon Solar Alliance to start manufacturing more solar in low-carbon economies, such as the US, the EU, South America, and other countries that have a high percentage of renewables in their energy mix.

Utility-Scale Solar

Solar power that is normally produced on the ground ("ground-mounted") and fed into the grid, usually to a utility and with a PPA. Utility-scale solar is usually defined by size, although requirements vary by group. The Solar Energy Industries Association defines a solar project as “utility-scale” if it has a name-plate capacity of 1 megawatt (MW), while NREL marks it at 5 MW.


Vehicle-to-grid (V2G)

Vehicle-to-Grid, or V2G, is a technology that enables electric vehicles (EVs) to not only receive power from the grid but also to send surplus energy back to the grid. This two-way flow of electricity allows EV batteries to be used as energy storage resources, contributing to grid stability and supporting the integration of renewable energy sources.

Venture capital

Unlike an angel investor, venture capital (VC) firms consist of multiple people who are hired to invest money on behalf of others. VC firms prioritize growth in their investments and prefer to have some control over the operations of the company they are investing in.

Virtual Power Plant (VPP)

Decentralized units that consume, store, or produce electricity are connected and operated by one centralized control system. A VPP allows small units to easily trade electricity and provides a center of control for power managers. VPP’s are also well-equipped to handle the intermittency challenges of a renewable energy grid.

Virtual Power Purchase Agreement (VPPA)

You can buy renewable energy “virtually” along with RECs through a Virtual Power Purchase Agreement. In a VPPA, the energy buyer and seller agree on a pre-arranged price for the power coming out of a renewable project. But that power is sold into the market rather than traveling to the buyer (as with a physical PPA). If the market rate for power exceeds the VPPA price, the producer sends the buyer the difference. If the market rate is less than the VPPA price, the buyer covers the difference.


Wafer (solar)

A wafer is the third step or component of the solar panel value chain. Solar ingots are sliced very thinly into solar wafers. Many solar manufacturing facilities that specialize in ingot production also produce wafers.



The acronym YIMBY stands for "Yes In My Backyard", which is a response to the NIMBY movement. YIMBYs advocate for the support and implementation of various projects and developments in local communities. The YIMBY movement advocates for policies and regulatory frameworks that streamline the approval process, reduce bureaucracy, and encourage innovation and investment in community development.


Zero carbon

A product, service, building, etc. that releases no carbon emissions into the atmosphere. Pillars of a zero-emissions society include renewable energy, energy efficiency programs for buildings, energy storage on the grid, and addressing embodied carbon of products and services. At its core, zero carbon requires cutting the use of fossil fuels and other things that emit greenhouse gases.