Micro Hydro Power

A recent feasibility study for a future micro hydro power (MHP) system gave me the chance to visit a nearby community with an existing MHP. The area is a remote part of Apayao in the Cordillera mountains of North Luzon and takes a full 24 hours travel time from Manila (including a 5 hour walk from the nearest road head). The community is 21km from the nearest grid point - making it unattractive for grid extension. The MHP is used for electrification of the entire community and to drive the community rice mill. The mini grid delivers electricity to each of the 36 households between 6 - 9 pm and 4.30 - 6 am, used to power 2 or 3 light bulbs. A household pays a monthly tariff of 10 pesos (10 pence) per installed bulb. The collected tariff is used for maintenance and repair of the system.

The community depends on a nearby river for household water usage, irrigation, washing, cleaning clothes, fishing, and now for electricity. The canal intake can be seen here, a weir has been constructed to divert some of the rivers flow. The weir, made from available materials such as boulders, tree trunks, leaves and earth has been reconstructed after being washed away by floods from typhoons.

The canal diverts water 1 km from the intake at the river to the forebay of the MH system. It gives the water sufficient head (the vertical height the water has to fall to the power generation site) to be used for power generation - here only 8 metres. The canal is constructed with concrete and earth, and large piping to cross a number of intersecting channels. It took the community 5 years to dig the canal, beginning a long time before funding was sourced for the project.

The water is channeled down 12" HDPE piping (known as the penstock) into the powerhouse. The design flow of the system is 120 litres per second. The energy from this volume of water and 8 metres head can generate around 5 kW of electricity.

The penstock delivers the water to the turbine and generator (electromechanical components)that converts the energy in the water to electrical energy. A crossflow turbine is used, coupled to the 5kW generator by 3 v-belts. The operator can be seen directing the water guide vane to control the generated power. The tail water is channeled out of the powerhouse and returned to the river. A transmission line connects the community to their MHP system.

SIBAT has 14 installed MHP systems around the Philippines. 2 more installations and 6 feasibility studies for future sites are ongoing.