Hydropower converts the energy of moving water into useful power. In modern usage, hydropower and hydroelectric power usually mean electricity generated when water drives a turbine connected to a generator. However, not every hydroelectric power plant uses a large dam.
This guide explains the main types of hydropower plants, gives examples of hydroelectric power, and shows where cooling systems are used inside generating units.
What Is Hydropower and How Is It Used?
Hydroelectric energy is renewable energy produced from water in motion. Water rotates a turbine, and a generator converts the mechanical energy into electricity.
What is hydropower used for? Its primary purpose is electricity generation. Some plants provide scheduled power, while others respond quickly to changes in demand. Pumped-storage facilities move water between two reservoirs to store energy for later use. Reservoir projects may also support water supply, flood management, navigation, or irrigation, although these are not forms of electricity generation.
Hydropower is used in national grids, regional systems, industrial facilities, and remote installations. Plant type depends mainly on how water is stored and delivered to the turbine, not simply on generating capacity.
Main Types of Hydropower Plants and Examples
The three main types of hydroelectric power plants are impoundment, diversion or run-of-river, and pumped storage.
| Type | Water arrangement | Typical role | Example |
|---|---|---|---|
| Impoundment | Water stored behind a dam | Scheduled generation and flow regulation | Hoover Dam |
| Diversion or run-of-river | River flow directed through a channel or penstock | Generation with limited storage | Small river diversion station |
| Pumped storage | Water moved between upper and lower reservoirs | Grid-scale energy storage | Bath County Pumped Storage Station |
| Offshore or emerging hydropower | Energy captured from marine water movement | Developing renewable generation | Tidal-stream installation |
Impoundment Hydropower
Impoundment hydropower is the most familiar hydroelectric power example. A dam creates a reservoir, and controlled releases send water through turbines. Storage gives the operator greater control over when electricity is produced. These facilities may provide scheduled generation, peak support, or both.
Hoover Dam is a well-known example. An impoundment plant is defined by its storage and water-release arrangement, not simply by dam size.
Diversion or Run-of-River Hydropower
Diversion hydropower channels part of a river through a canal, tunnel, or penstock before returning it downstream. Run-of-river plants usually have little storage, so their output follows available river flow more closely.
These plants show why “hydro dam” does not describe every facility. Some use a small weir, while others operate without a large storage dam. Design depends on head, seasonal flow, environmental requirements, and grid demand.
Pumped-Storage Hydropower
Pumped-storage hydropower connects upper and lower reservoirs. When electricity is abundant, pumps move water uphill. When demand rises, water flows back through turbines to generate electricity.
It is an energy-storage system rather than a new primary energy source. The Bath County Pumped Storage Station is a prominent example. Pumped storage supports peak demand, grid balancing, and the integration of variable solar and wind power.
Why Do Some Sources List a Fourth Type?
The U.S. Department of Energy presents three main types: impoundment, diversion, and pumped storage. The International Hydropower Association also discusses offshore hydropower, which captures energy from tides, waves, or ocean currents.
This is a difference in classification, not a contradiction. The three-type model suits conventional plants; offshore technology can be treated as a fourth, emerging category.
Where Cooling Is Required in a Hydropower Unit
Regardless of plant type, rotating equipment produces heat. A unit may require cooling for guide bearings, thrust bearings, lubricating oil, generator air, and auxiliary systems. The arrangement depends on the turbine-generator design; not every station uses the same cooler.
Guide and thrust bearings support the shaft and rely on a controlled oil film. Heat must be removed to maintain the required oil temperature and viscosity. An internal bearing oil cooler may sit in the oil reservoir, while an external system pumps oil through a separate heat exchanger. See internal and external bearing oil coolers for the structural differences.
Cooler selection requires more than an equipment name. Engineers must review heat load, oil and water temperatures, flow rates, pressures, allowable pressure drop, water quality, fouling, materials, and installation space. Nozzle positions and mounting dimensions also matter in replacement work.
JED supplies hydropower heat exchangers and bearing oil coolers for new and replacement units. The solution may be a custom bearing oil cooler or an external shell and tube heat exchanger. Final construction must follow the project drawing and confirmed operating conditions.
Need a Heat Exchanger for a New or Replacement Hydropower Unit?
JED can manufacture from approved drawings or perform thermal selection from confirmed working conditions. Our experience includes a thrust-bearing cooler replacement for Lianghekou Hydropower Station, with pressure and leakage testing completed for delivery.
For a new unit or replacement cooler, send the available drawings and operating data. Our engineers can review the information before manufacturing and identify missing or conflicting requirements.
Frequently Asked Questions
Can a hydropower bearing oil cooler be replaced using the original drawings?
Yes. Original drawings can be reviewed to reproduce installation dimensions, connections, and construction details. Current operating conditions should also be confirmed because the required duty may have changed.
What information is needed to evaluate a replacement cooler?
Useful information includes drawings, dimensions, connection sizes, oil and water flow rates, inlet and outlet temperatures, pressures, materials, and installation space. Photographs and nameplate data can help but do not replace essential design information.
Can the new cooler match the existing mounting and pipe connections?
Yes, when accurate drawings or site measurements are available. Dimensions, tolerances, nozzle orientation, and any proposed changes should be confirmed before production.
How is a hydropower heat exchanger checked before shipment?
The inspection plan follows the project specification. Typical checks may include dimensional inspection, material verification, pressure testing, and leakage testing. Acceptance criteria and documentation should be agreed before manufacturing.