3.1 HYDROELECTRIC POWER

Hydroelectric

are electricity produced from hydropower.

Hydropower

the harnessing of flowing water using a dam or other type of diversion structure to create energy that can be captured via a turbine to generate electricity

Gross Head

total difference in elevation between the water surface in the stream at the diversion and the water surface in the stream at the point where the water is returned after having been used for power;

Net Head

is the head available for energy production after deducting losses in friction, entrance, unrecovered velocity head in the draft tube, etc..

Hydraulic efficiency

the ratio of the net head to gross head.

Overall efficiency (Turbine-Generator)

represents the fraction of the mechanical energy of the fluid converted to electrical energy. Also known as product efficiency.

Power Capacity

the maximum power which can be developed by the generators at normal head with full flow. Also known as maximum power.

Firm Power

is the power a plant can be expected to deliver 90% of time. Also known as minimum power.

Impoundment (Reservoir)

the most common type of hydroelectric power plant. An impoundment facility, typically a large hydropower system, uses a dam to store river water in a reservoir. Water released from the reservoir flows through a turbine, spinning it, which in turn activates a generator to produce electricity. The water may be released either to meet changing electricity needs or to maintain a constant reservoir level.

Transmission lines

conduct electricity for homes and businesses.

Dam

store water.

Penstock

carries water to turbines.

Generators

rotated by the turbines to generate electricity.

Turbines

turned by the force of the water on their blades.

Diversion (run-off river)

a type of hydro power plant, this facility channels a portion of a river through a canal or penstock. It may not require the use of a dam.

Intake / Weir

under Diversion (run-off river): it is used to collect water which will be used for power plant. From weir, water will enter to the intake gate leading to the connecting tunnel which go out into the run off river. After pass connecting tunnel, water will pass waterway. Also known as low head dam.

Desilting Basin

under Diversion (run-off river): is to settle out the particulate matters floating in the water to the bottom of the construction. The water which is used for the turbine can therefore be separated from these solids. This function is very important because to protect other micro hydro power plant components from the impact of sand.

Spillway

under Diversion (run-off river): are designed to permit controlled overflow at certain points along the channel or weir.

Headrace / Waterway

under Diversion (run-off river): usually follow contours of the hill to keep the elevation of the channeled water and keep the potential energy stable on the value.

Forebay / Surgetank

under Diversion (run-off river): is used to control water output difference between penstock and head race. Moreover, its function as final separation impurities in the water such as sand and wood. The function of forebay tank is also as desilting basin (sand trap).

Penstock

under Diversion (run-off river): is water supplier from head tank which will rotate the turbine. This connects a high elevation to a lower elevation to the turbine

Powerhouse

under Diversion (run-off river): it contains the main equipments to change potential energy become electricity, they are turbine, generator, and control panel

Turbine and Generator

under Diversion (run-off river): are used to change water potential energy which is fallen through penstock become electricity. Turbine is connected with a pulley on the generator so between water side and electricity still separated. To regulate changing electic is used AVR (Automatic Voltage Regulator) on the generator.

Tailrace

under Diversion (run-off river): after water rotate turbine then water will be returned again to the river through specific tunnel which is called tail race.

Pump Storage

a type of hydropower plant. it works like a battery, storing the electricity generated by other power sources like solar, wind, and nuclear for later use. It stores energy by pumping water uphill to a reservoir at higher elevation from a second reservoir at a lower elevation. When the demand for electricity is low, a pumped storage facility stores energy by pumping water from a lower reservoir to an upper reservoir. During periods of high electrical demand, the water is released back to the lower reservoir and turns a turbine, generating electricity.

Kalayaan Pumped Storage Power Plant

this was built in 1982, it is the first of its kind in Southeast Asia and the only pumped storage facility in the Philippines. This serves as large peaking facility for the Luzon Grid but its primary function is to provide frequency regulation and control. In the daytime, a period with a high demand for power, the plant generates electricity. But at night, a period of low demand period of low demand. pumps water from Laguna Lake into Caliraya, an ingenious way of storing energy

> 30 MW

Large Hydropower

10-30 MW

Small Hydropower

> 100 KW < 10 MW

Mini Hydropower

</= 100 KW

Micro Hydropower

Impulse Turbine

this is a type of hydropower turbines. it generally uses the velocity of the water to move the runner and discharges to atmospheric pressure. The water stream hits each bucket on the runner. There is no suction on the down side of the turbine, and the water flows out the bottom of the turbine housing after hitting the runner. This turbine is generally suitable for high head, low flow applications.

Pelton Turbine

are impulse turbines where one or more jets impinge on a wheel carrying on its periphery a large number of buckets. Each jet issues water through a nozzle with a needle valve to control the flow.

They are only used for high heads from 60 m to more than 1000 m.

The axes of the nozzles are in the plan of the runner The axes of the nozzles are in the plan of the runner.

Turgo Turbine

is a variation on the Pelton and is made exclusively by Gilkes in England. The Turgo runner is a cast wheel whose shape generally resembles a fan blade that is closed on the outer edges. The water stream is applied on one side, goes across the blades and exits on the other side.

Cross Flow Turbine

a type of impulse turbines. It is drum-shaped and uses an elongated, rectangular-section nozzle directed against curved vanes on a cylindrically shaped runner. It resembles a "squirrel cage" blower. This turbine allows the water to flow through the blades twice. The first pass is when the water flows from the outside of the blades to the inside; the second pass is from the inside back out. A guide vane at the entrance to the turbine directs the flow to a limited portion of the runner. This turbine was developed to accommodate larger water flows and lower heads than the Pelton.

Reaction Turbine

this is a type of hydropower turbines. it develops power from the combined action of pressure and moving water. The runner is placed directly in the water stream flowing over the blades rather than striking each individually. These are generally used for sites with lower head and higher flows than compared with the impulse turbines.

Francis Turbine

these are reaction turbines, with fixed runner blades and adjustable guide vanes, used for medium heads. In this turbine the admission is always radial but the outlet is axial.

Kaplan Turbine

these are axial-flow reaction turbines; generally used for low heads from 2 to 40 m. The Kaplan turbine has adjustable runner blades and may or may not have adjustable guide- vanes.

Department of Energy

This is a national agency who regulates hydropower in the country.