Glossary

Wind: Slievecallan, Ireland

Additionality

Where renewable power procurement increases renewable generation, either directly by financing a new renewable project or by creating positive market pressure that encourages new investment.

aGW

A value reflecting the average hourly electricity demand for a defined time period.

Bilateral Trading or Agreements

In bilateral energy markets, electric utility providers build and own their own generating facilities or do so jointly with other utilities, from long-term purchase arrangements with independent facility developers and operators, or engage in transactions with neighboring utilities to their mutual benefit. Thus these utilities can optimize their generation mix and limit their exposure to fluctuations in fuel prices, construction costs, regulatory requirements, and other economic factors over time by managing their portfolios of self-owned resources and power purchase arrangements.

Biomass

Electricity from biomass is produced when bagasse, a natural byproduct of the sugar cane production process, is used to feed a boiler to produce steam and power.

Capacity

When used to describe the level of renewable power generation, capacity refers to the maximum amount of power a (or several) renewable site(s) could generate at any one time.

Capacity Markets

The capacity market is the U.K. government's primary policy for ensuring the security of electricity supply. It offers payments to power generators for being available to generate at certain times, and to demand response providers for being able to reduce electricity demand.

Capacity Mechanism

An Energy Market Reform (EMR) mechanism to help the U.K. meet its carbon reduction and ensure a security of electricity supply.

Capacity Payments

The Capacity Payments Mechanism is a fixed revenue system of payment for participants offering generation capacity in the Single Electricity Market (SEM). The mechanism features a fixed "pot" of money that is calculated on an annual basis by the regulatory authorities, with technical assistance from the System Operators.

Distribution

A distribution network carries electricity from high voltage substations, converts it to the lower voltages used by consumers and delivers it to homes and businesses.

EcoLogo Program

EcoLogo® is the largest, most respected environmental leadership standard and certification mark in North America and it continues to gain recognition worldwide. Products and services bearing the EcoLogo® meet stringent standards. Brookfield Renewable Partners has 23 hydroelectric facilities in British Columbia, Ontario, Québec and Louisiana that meet the requirements of the Ecologo® Program.

Feed-in-Tariff

A payment made to households or businesses generating their own electricity using methods that do not contribute to the depletion of natural resources, proportionate to the amount of power generated.

Gigawatt (GW)

A measure of power – the rate that electricity is generated or consumed at a point in time. One gigawatt is 1,000 megawatts.

Gigawatt Hour (GWh)

A measure of energy use or generation over time.

Green Certificate

A general term for a tradable commodity proving that electricity is generated using renewable sources. Typically one certificate represents generation of 1 MWh of electricity. The term Renewable Energy Certificate (REC), and other terms, may also be used for similar market instruments. Find out more in our Renewable Buyers Guide.

Green Tariff

A Green Tariff is a supply agreement where the electricity supplied is matched by purchases of renewable power or Green Certificates that your energy supplier produces on your behalf. Find out more in our Renewable Buyers Guide.

Grid

This is a collective term for the entire interconnected network that delivers electricity from producers to consumers. It consists of everything from the high voltage transmission lines to the distribution network that delivers renewable power to homes and businesses.

Gross / Mandatory Pool

A centralized energy trading system, where all electricity is traded through the pool. Throughout bids and contracts, the system operator obtains all the information needed for scheduling and ensuring reliability.

Guarantee of Origin (GoO)

Certificates are issued by national regulators in the European Union (EU) for every MWh of eligible renewable output.

These certificates are used by suppliers to report the average mix of electricity they have bought to supply their customers.

Hydro

Hydropower or hydroelectricity converts the natural flow of water into electricity when falling water turns the blades of a turbine connected to a generator. Hydro’s advantages as a sustainable, flexible and proven asset class, along with its low operating costs and many environmental advantages, position it as the most attractive and valued renewable technology. The amount of electricity a hydropower installation can produce depends on the quantity of water passing through a turbine (the volume of water flow) and on the height from which the water falls (the amount of head). The greater the flow and the head, the more electricity produced.

There are different types and sizes of hydropower installations, ranging from micro hydro plants that provide electricity to only a few homes to mega installations. Some hydropower facilities include dams to increase the head of a waterfall or to control the flow of water and reservoirs to store the water for future energy use (storage dam), while others produce electricity by immediately using a river's water flow (run-of-river).

Interconnector

Transmission grids are often interconnected so that energy can flow from one country to another. This helps provide a safe, secure, reliable and affordable energy supply for everybody.

Low Impact Hydropower Institute Certification (LIHI)

The Low Impact Hydropower Institute is a non-profit organization dedicated to reducing the impacts of hydropower generation. It provides certifications to hydropower projects that have eliminated or reduced their environmental impact pursuant to LIHI’s criteria.

Megawatt (MW)

A measure of power – the rate that electricity is generated or consumed at a point in time. One megawatt is equivalent to 1,000 kilowatts (KW). One kilowatt is 1,000 watts.  

Megawatt Hour (MWh)

A measure of energy use or generation over time.

Net / Voluntary Pool

Trades are made through bilateral contracts and the pool is used to reconcile minor imbalances between supply and demand. Generators can either offer a price or declare to the system operator the quantity of energy they propose to generate. Market participants are self-scheduling, with the system operator simply coordinating the schedules declared by participants. The system operator also deals with transmission constraints and ensures that supply meets demand. Voluntary pools are used in California and in the Nordic region

Nodal Pricing

A means of calculating the wholesale price of electricity at any given time. Nodal pricing, also known as ‘locational marginal pricing’, anticipates the demand for electricity at a particular location, or ‘node’, based on current usage. An algorithm then calculates the cost of reallocating the available supply to meet that anticipated demand, and therefore an appropriate price to be charged.

Paris Agreement

The first instrument in history to unite the world under a single agreement to tackle climate change. It was enacted within the United Nations Framework Convention on Climate Change and includes provisions to limit greenhouse gas emissions and help developing nations switch to renewable power. 

Peak Load

Maximum of electrical power demand.

Power Marketing

Wholesale and retail power transactions performed by companies in energy markets.

Power Purchase Agreement (PPA)

A Power Purchase Agreement (PPA) is a contract between a power producer and buyer to supply energy. There are three types of PPA: a physical PPA, a virtual or synthetic PPA and an onsite PPA.

PPAs are generally long-term agreements that provide a price hedge against energy costs and protection against market volatility. Agreements can facilitate new renewable generation and provide a transparent way to source renewable power. Find out more in our Renewable Buyers Guide.

Pumped Storage

This versatile and flexible hydro technology allows water to flow in two directions between an upper and lower reservoir. This capability allows pumped storage facilities to store large amounts of potential electrical energy. This can produce electricity at peak times with facilities replenished during periods of lower pricing and demand. Pumped storage is effectively the world’s largest rechargeable battery and a cost-effective way to store large amounts of potential electrical energy.

Renewable Power

Energy generated from natural resources that are not depleted as a result of use such as wind, solar, and hydroelectric power as well as tidal, biomass and geothermal generation.

Run of River

A type of hydroelectric power that harnesses energy from the downward travel of water.

Single Electricity Market (SEM)

The SEM is the electricity market across the Republic of Ireland and Northern Ireland. It is made up of Day Ahead, Intraday and Balancing, into which all electricity generated on or imported onto the island of Ireland must be sold, and from which all wholesale electricity for consumption on or export from the island of Ireland must be purchased. 

Solar

Solar is a method of converting energy from the sun into electricity. Photovoltaic cells, commonly referred to as ‘solar panels’, do this via a phenomenon known as the photovoltaic effect.

Terawatt (TW)

A measure of power generation. One terawatt is equivalent to 1,000,000 MW.

Terawatt Hour (TWh)

A measure of energy use or generation over time.

Transmission

The movement of electricity from a renewable power generation site, such as a wind farm, to high voltage electrical substations before it is distributed to homes and businesses.

Vertically Integrated

In energy, a company that is vertically integrated is one that manages all the stages required to provide electricity – from generation and transmission, to delivery and accounting.

Wholesale Market

Where energy is traded in a market system, the wholesale market refers to the trading system used for the buying and selling of energy from producers to market participants, such as energy utilities.

Wind

One of the fastest-growing renewable power technologies, wind power harnesses the earth’s natural air currents to produce clean electricity with no emissions. Wind can be harnessed directly to produce electricity when it spins the blades of a wind turbine, which drives an electric power generator. Advances in aerodynamics and materials have made electricity generation from wind turbines increasingly cost competitive.

Wind Farm

A cluster of wind turbines which is usually connected to the electricity grid of a utility for widespread consumption of its electricity. Wind farms are located in areas with strong wind resource and can range from a few to over 100 turbines.