HYDROPOWER is a power plant that utilizes the potential of natural resources, specifically by utilizing the flow of water or water energy with different heights between two positions (head) so that it is converted into kinetic or rotational energy (turbines) which then converts it to electrical energy. by connecting to an alternator or generator so that it can generate electricity. The water flow referred to above can be rivers or waterfalls and also includes existing infrastructure facilities such as dams, reservoirs or large-scale water reservoirs, irrigation and others.
Power plants that utilize water energy are classified according to the Ministry of Energy and Mineral Resources and PLN as follows.
- PLTA (Hydroelectric power plant) is a power plant that utilizes water energy with a generated energy capacity greater than 10 MW (>10 MW).
- PLTM (Mini Hydro power plant) is a power plant that utilizes water energy with a generated energy capacity of between 1 MW up to 10 MW (1 MW – 10 MW).
- PLTMH (Micro Hydro power plant) is a power plant that utilizes water energy with an generated energy capacity of less than 1 MW (<1 MW).
In general, the system configuration of the hydropower location scheme is divided into 2 types, namely the Water storage scheme and the Run off river scheme.
A. Water Storage System Scheme
Water storage system schemes or storage schemes. In general, this scheme requires large dams that are complex planning and are expensive to build.
Hydropower with a water storage scheme has a generating capacity at the “Large Hydro” level with a power generation capacity above 100 MW, development and construction are generally carried out directly by the government through the ministry of public works and entered into national strategic projects.
A dam is generally built with a multi-functional purpose so that it is not only for electricity generation, another function of the dam is to provide seasonal water storage for domestic water use, agriculture (irrigation) or for flood prevention, tourism, fisheries, etc.
A dam causes massive accumulation of water by flooding a valley upstream, so it has a big impact on the ecology of the river by changing the seasonal flow patterns, then a common problem with large dams is their accumulation of silt, which requires enormous effort to clean.
B. Run Off River System Scheme
The Run Off River system scheme or water flow diversion scheme is generally used in hydropower with a “Small Hydro” level. The water flow in the river diverted by weir to intake through the water channel (waterway / headrace) and collected in a forebay (headpond / headtank) then the water is dropped through a rapid pipe (penstock) to the water turbine inside power house then the water out from turbine and returns to the river through the tailrace / tailwater.
Run Off River scheme is often used in hydropower because of simpler planning, lower cost and more environmentally friendly. Diversion weirs installed in rivers have minimal impact on the river because of diversion weirs have no impact on seasonal flow downstream of the structure.
In Indonesia, Hydropower with the Run Off River scheme was introduced by the Dutch in the early 19th century during the colonial period. At that time the Dutch government developed and built dozens of Hydropower with the Run Off River scheme to provide a source of electrical energy for processing facilities in plantations, mineral mining, and electricity supply for colonial settlements.
At this time, the development and construction of a hydropower with the Run Off River scheme, can be done by the government or by the private sector and the electricity can be used for their own needs (such as for factories, rural electricity, tourism areas, etc.) or for sale to PLN.