Indonesia is endowed with a full range of both renewable and fossil resources of energy, actively exploited to feed its growing economy. Emphasis has been on fossil, hydroelectric and geothermal resources rather than wind and solar. PLN (Perusahaan Listrik Negara) is the Indonesian State Electricity Company. It is an Indonesian government-owned corporation which has a monopoly on electricity distribution in Indonesia and generates the majority of the country’s electrical power, producing about 175 TWh annually. Only a small fraction of this originates from hydropower.

Indonesia has five large hydropower plants with a capacity over 250 MW: Cirata on Java (1008 MW), Saguling on Java (701 MW), Tangga on Sumatra (317 MW), Sigura-gura on Sumatra (286 MW), and Pamona on Sulawesi (260 MW). The Indonesian government aims to develop more hydropower with quite a strong focus on small and micro hydropower plants.

Capacity of PLN staff to understand the hydrology related to hydropower electricity generation needs to be enhanced. Also, the knowledge of the potential impact of climate change on hydropower requires additional capacity of PLN’s staff. Especially their ability to understand and judge feasibility studies undertaken by external consultants requires upgrading their level of knowledge. Also staffs’ capacity to understand climate risk assessment studies, as today required by most investors, should be further developed.

FutureWater was asked to develop and provide training on those two aspects (hydrology and climate change). Given the huge area of the country and PLN staff working in large distances from each other, it was decided to provide training in a eLearning setting. Initially about 25 staff will be trained and based on lessons learnt the training package will be adjusted to staff needs and further training will be undertaken.

The project should turn this renewable energy opportunity into a source of economic empowerment for the region and a sustainable source of electricity for the people living in North Sumatra. A pre-feasibility study is undertaken to the expected flows at the intake of the proposed Tripa hydro-electric power plant to indicate whether a more detailed feasibility study is feasible.

For the analysis of the expected flow at the intake a hydrological model, called HEC-HMS is used. This hydrological model simulates rainfall-runoff at any point within a watershed given physical characteristics of the watershed. The model is freely available, somewhat less data demanding, and easy to apply. The outputs of the model are analysed by means of streamflow hydrographs, and flow duration curves that serves as a basis for economic feasibility studies to the capacity of the proposed power plants. In addition, flood flows with recurrence intervals up to 10.000 years are analysed.

Emerging markets and low-income countries continue to need large investments in infrastructure to remove constraints on growth; create job opportunities; respond to urbanization pressures; and meet crucial development, inclusion, and environmental goals. In 2009, ADB estimated that an infrastructure investment of $8 trillion would be required during 2010–2020 to maintain current levels of growth in Asia.

Infrastructure for transport and communications, energy generation and transmission, and the supply of water and sanitation are critical for development. These types of infrastructure usually have long service lives, which renders both the region’s existing infrastructure stocks and its future infrastructure investments vulnerable to changes in climate conditions that may take place in the near and medium terms. One of five overarching reasons for concern cited by the fifth assessment report of the Intergovernmental Panel on Climate Change in 2014 was the existence of systemic risks “due to extreme weather events leading to breakdown of infrastructure networks and critical services such as electricity, water supply, and health and emergency services.”

The Technical Assistance study focusses on “building climate change resilience in Asia’s critical infrastructure”. The expected impact of the study is scaled-up support for effective climate change adaptation. The expected outcome of will be an enhanced knowledge base on climate change risks to critical infrastructure in South Asia and Southeast Asia. Specifically, by the end of the study it is expected that Asian Development Bank (ADB) and its Development Member Countries (DMC) will have a fuller understanding of the actions and innovation needed to make critical infrastructure in South Asia and Southeast Asia more resilient to climate change.

The study will focus on 11 countries in South and South-East Asia with three countries in specific: Indonesia, Sri Lanka and Vietnam.

Following the successful development of other hydropower facilities in Indonesia, a new project aims to study the potential of the “Romuku” run-of-river power plant in Central Sulawesi, Indonesia. The project should turn this renewable energy opportunity into a source of economic empowerment for the region and a carbon-emission-free and reliable source of electricity for the people of Sulawesi. A first step is to undertake a pre-Feasibility Study which will result in a go no-go decision for a more detailed Feasibility Study. This study will encompass various components. FutureWater will focus on the hydrological assessment. The objective is to undertake a first order assessment on the expected flow at the inlet of the proposed Romuku run-of-river power plant.

Landscape in Sulawesi, Indonesia

Data for the proposed site are scarce and available data have often missing values. The traditional method of relying on discharge observations to derive the flow duration curve is therefore not possible. As alternative a hydrological rainfall-runoff model can be used to generate discharge data on which flow duration curves can be derived. It is proposed to use HEC-HMS in this pre-feasibility phase. HEC-HMS is a hydrological model that simulates the rainfall-runoff at any point within a watershed given physical characteristics of the watershed. It can be used for studying interventions and for watershed management to determine the effect on the magnitude, quantity, and timing of runoff at points of interest. It is one of the most commonly used rainfall-runoff models, freely available and somewhat less data demanding.

This pre-Feasibility Study will result in a first order assessment of the expected flows into the proposed site location. For the Feasibility Study a more extensive analysis is needed, including more field data, detailed analysis of spatial rainfall patterns, more advanced rainfall-runoff model, advanced calibration of model, and an analysis of potential threats to future water flows (land-use changes, climate change).

The key output of the hydrological study will be a flow-duration curve – critical input for economic feasibility studies of run-of hydropower plant capacity.  The area below the curve and the maximum turbine-capacity can be used to asses primary (firm) power and secondary power generation.