Glossary

Machines used in hydropower production that can adjust the power consumed by pumps or generated by turbines, given operators more flexibility.

Turbines which use low pressures from exiting flows to induce added airflows.

Services used to help ensure the reliable operation of the power system.  While they make up a relatively small component of all power system costs, they are a critical part of the overall power system. Examples include certified black start facilities, regulation service, and operating reserve.

Generating stations that produce a constant, steady supply of electricity 24 hours a day, 7 days a week.

The minimum amount of energy required by an electrical power system over a certain time period.

Hydropower equipment (i.e., turbines) designed to take into account the equipment’s direct or indirect biological effect on fish and other types of aquatic species.

Process of restoring an electric power station or a part of an electricity grid to operation without relying on the external electric power transmission network to recover from a total or partial shutdown.

Power produced by generating facilities required to maintain the transmission system’s reliability.

The section of a natural waterway located between the intake and the tailrace where any and all flow usually travels from the spillway.

The maximum amount of electricity that can be provided at a particular part in time. Capacity is expressed in watts (W) or in multiples of watts: Kilowatts (kW) : 1,000 watts Megawatts (MW) : 1 million watts Gigawatts : 1 billion watts

Hydropower project infrastructure components (i.e., dams, conduits, powerhouses, tunnels, and penstocks).

Reducing fossil fuel consumption, while at the same time increasing our use of electricity from renewable and non-emitting resources.

Energy, that when produced or used releases no or few greenhouse gas or particulate pollution into the earth’s atmosphere.

A system of two reservoirs that aren’t connected to naturally flowing water sources

A structure for transporting water (i.e., canals, tunnels, and/or pipelines)

Loss or failure of a power system component (i.e., a transmission line), or the loss or failure of individual equipment (i.e., generator or transformer).

A barrier which regulates the water released from a reservoir as it flows to the power generation unit.

Reducing output in a generation unit (i.e., ramping/shutting down operations) in response to market demand or operating requirements.

Utilizing digital capabilities to not just solve traditional hydropower challenges but also open access to new opportunities in the hydropower industry.

Electricity sources whose power output can be adjusted on demand by power grid operators.

Energy generation systems that are small and grid connect built nearby the load they serve.

Marks the final stage in electricity delivery to customers. Distribution systems carry electricity from the terminal station to consumers.

Facility used to channel part of a river through a canal or penstock. 

A water conduit that is either straight or curved (based on turbine installation). The draft tube maintains a column of water from the turbine outlet and the water level downstream.

Generating unit operation in a power system at a certain output level to meet electricity demand and produce energy at the lowest possible cost.

The consumption rate of electricity being consumed at a given instant over averaged over a specific time period.

Energy that a power plant generates (measured in millions of watt-hours, MWh) and that a customer consumes (measured in thousands of watt-hours kWh).

The rate of delivery of electrical energy (measured in watts or millions of watts (MW).

The quantity of electricity a generator produces over a given time period.

Consists of all the elements needed to produce, transmit, and distribute power to end use consumers.  This includes, but is not limited to, generators, elements of the transmission and distribution system, and substation components.

The process of replacing technology that runs on fossil fuels (i.e., coal, oil, and natural gas) with technologies that use electricity as their energy source.

The capture of energy produced at one time for later use, to reduce energy demand and energy production imbalances. Energy storage examples include batteries and pumped storage hydro.

Measure of the water quantity and quality needed by a particular ecosystem (i.e., river, stream, or lake) to remain healthy and sustainable.

A ladder-like structure, comprised, of stepped slopes and pools, for safe upstream fish passage, diverting the fish around hydropower projects.

A structure located on or around a dam that is used to enable the passage of migrating fish.

Pump and turbine units which operate at a constant speed.

The power system or individual unit’s ability to rapidly respond to supply and demand increases or decreases.

Volume of water (measured as cubic feet or cubic meters per second), passing a point in a given period of time.

In a natural waterway the magnitude, duration, timing, seasonality, and rate of change of flows.

An impoundment or reservoir directly located above a dam or intake structure at a hydropower plant. 

Generation ability to raise or lower output for the purpose of maintaining system frequency

A source of electrical power (i.e., hydro). 

An electro-mechanical machine that converts mechanical energy (typically steam, water, combusted gas, wind) into electric energy.   

Emissions that are produced when hydrocarbons (i.e., natural gas and oil) are burned. GHGs contribute to climate change, and include carbon dioxide, methane, and nitrous oxide. 

Energy that is lost as water flow, as water moves from the headwater to the tailwater of a dam.

The hydraulic head is a value that measures the amount of mechanical energy available in water in a river, stream or even lake.   The measurement of the amount of mechanical energy available in a water source (i.e., river or lake)

Type of waterpower that is less common, in which a turbine is placed in a riverbed or tidal area to directly capture the energy in the water flow.

The intermittent release of water through turbines to meet peak energy demands, causing fluctuations in the flow of water downstream.

Body of water caused by a flow-obstructing structure (i.e., a dam)

The amount of installed capacity that can be relied on for electricity production. 

An entity not operating as a public utility, but instead owns and operates facilities used to generate power (i.e., hydropower)

The maximum amount of electricity that a generator, generating station, or generating unit can produce.

Water diverting structure that channels water from a natural waterway and diverts it into the turbine.

An energy source that because of an outside factor (i.e., wind or sun) is not continuously available

One thousand watts and the commercial unit of electric power measurement One kilowatt is the flow of electricity needed to light ten 100-watt light bulbs

One thousand watts used for a one-hour time frame    Kilowatt Hour is the basic unit of electric energy measurement

Electrical power amount delivered or needed at any specific point(s) on a system.

A hydropower plant’s ability to adjust power output as electricity demand fluctuates over the course of the day.

The anticipated load requirements an electricity system will be required to meet

Additional capacity available to adapt to load variability and uncertainty.

Generally, has a peak capacity between 10MW and 100 MW.

One million watts or one thousand kilowatts   Megawatts are often used to measure generation station capacity and the rate for energy delivery.

Category: Very small hydropower generation    Peak capacity of less than 100kW, uses the natural flow of water to generate hydropower.

An economy that either emits no GHG emissions or offsets its emissions (i.e., through actions such as tree planting or employing technologies that can capture carbon before it is released into the air).

Additional capacity not connected to the system but can be made available to meet demand within a particular time frame.

An emerging technology that utilizes tidal currents or the power of waves to generate electricity.

Two reservoirs which are continuously connected to naturally flowing water sources. 

An operating mode for a generating station where power is produced solely during periods of peak demand.

Power plants operated to assist in balancing the electricity grid’s fluctuating power requirements.

Large pipe in a hydro generating station that moves water from the reservoir to a turbine.

Hydropower facility structure housing generators and turbines. 

Type of waterpower where water is stored in an elevated reservoir. When electricity generation is required, water is released into the penstock.

Increases or decreases in the speed of flows from the powerhouse into the tailwater, and lastly downstream.

The ability for a hydro generating station to adjust its output over time.

Capacity available to provide balancing services quickly and in real time.

A reservoir built downstream from a hydropower peaking plant which has the capacity to both store fluctuating discharges and also release them based on environmental flow needs.

The expansion, upgrade, and improvement of efficiency at current hydropower facilities.

Energy derived from a natural process that is replenished at a rate that’s equal to or faster than the rate at which it is being consumed. 

Body of water that has been built up behind a dam at a hydropower station.

The quantity of a specific energy resource.

Rotating inner portion of a generator consisting of a series of windings that surround the field poles. Inner portion of a generator that rotates.

Within the range between minimum and maximum output, which can have a deteriorating effect on plant equipment (i.e., vibration). 

Type of waterpower where water from a river simply flows directly into the penstock.

The part of the turbine that rotates, converting the energy of falling water into mechanical energy.

Sliding gates or other devices used to control water flow.

Peak capacity of less than 10 MW, in the stream or river a weir is needed.

A part of a dam that’s used to direct excess water to an area downstream.

Rapidly available capacity from generating units. These generating units are operating below their capability.

A hydropower system that utilizes a dam to store water in a reservoir. By releasing water from the reservoir, running the water through a turbine, activating a generator, electricity’s produced.

A hydropower project that is designed, constructed, and operated for the purpose of balancing social, environmental, and economic objectives on multiple geographic scales (i.e., national, regional, basin, and site). Sustainable hydropower internalizes every social, environmental, and social benefit and cost in a way that provides long-term net benefits to the resources’ public owners.

A channel which moves water away from a dam. 

The water directly downstream from a powerhouse or dam. 

The termination point at the end of a transmission system, which changes the transmission voltages into distribution voltages for the purpose of customer distribution.

A device that changes alternating current (AC) to a higher or lower voltage.

A cable or other conductor which transfers electricity from one place to another. 

A machine containing either a wheel or rotor. When fast moving water flows through the turbine, the wheel or rotor spins, generating hydroelectricity. 

A renewable energy source which fluctuates because of natural circumstances, with no control from the operator (i.e., wind and solar)

The pressure in an electrical circuit to cause energy to flow (measured in volts and thousands of volts, kV).

Waterpower is the process of converting kinetic energy (energy of motion) in the form of falling or flowing water into mechanical energy (kinetic energy turning the blades of a turbine), then into electrical energy (in this instance hydroelectricity). 

A small barrier built across a stream or river, that alters the water’s flow characteristics.

A gate that works to control the flow of water into a generator, which controls how much power the dam is able to generate.