Geothermal and water potential energy in Indonesia – the challenge

Share the article:

President Joko Widodo had an ambitious plan of generating additional 35,000 MW of electricity power for current installed capacity of 50,000 MW. This projection is based on the underlying assumption that electricity demand will grow proportionally alongside economic growth, which is assumed as 6-7% per year. The latest Business Plan for Electricity Generation (as translated from RUPTL: Rencana Umum Pengadaan Tenaga Listrik) shows that only around 3,000 MW, or equal to a mere 8% of 35,000 MW target that will be generated from renewable energy sources.

At the end of 2015, delegates on behalf of 195 countries declared their commitment of reducing greenhouse gas emission as a mitigation of climate change. The governments agreed on the need for global emissions to peak as soon as possible, recognizing that this will take longer for developing countries [1]. Indonesia was represented by 223 delegates who were committed to the global emissions plan, although as a developing nation the deadline should be exceptionally behind than the developed nations. Nevertheless, local emission reduction plan must be considered as far as mitigation plan is concerned. Indonesia will face difficult situation to fulfill both electricity plan target and the green policy, if it is not planned painstakingly.

A big proportion of current supply comes from fossil energy, which are coal, oil, and gas. Coal accounts for more than half of electricity power plant capacity. In the second place comes natural gas, utilized as gas turbine fuel. Strategy for future power supply seems to put coal as the base load champion, with others such as natural gas, hydro power, geothermal, and new renewable follow subsequently based on the capacity.

The Ministry of Energy has been campaigning natural gas as internal combustion engine fuel, to substitute gasoline and diesel power plant since 1986. The transition process is almost complete now, as the diesel power plant utilization is very low and even on as a peaker only. Indonesia has some potential and proven natural gas resources. Speaking with numbers, Indonesia is on 13th position of the country with the biggest gas reserves, topping others ASEAN nations.


Geothermal energy is energy available in the form of heat contained in the earth crust; main utilization are for electricity generation and district heating. Characteristics of geothermal include: capability to provide base load power; no seasonal variation; immunity from weather effects and climate change impacts; compatibility with both centralized and distributed energy generation; resource availability in all world regions, particularly for direct use. (International Energy Agency).

Indonesia’s geothermal installed power is currently on the second place on the world ranking. Yet, it is less than 5% the geothermal potential that has been exploited [2]. Four largest geothermal location are all located in Java island, the most populated island in Indonesia. Daradjat, Salak, Kamojang, and Wayang Windu geothermal power plants account for 255 MW, 345 MW, 200 MW, and 227 MW installed capacity respectively. However, the exploration result shows bigger potential on Sumatera island. Current operating power plants in Sumatera are Ulubelu, Sibayak, and Sarulla, with 110 MWe, 11.3 Mwe, and 330 MWe rating power respectively. As the second biggest island in Indonesia and densely populated, Sumatera has not fully developed yet, especially in the infrastructure part. Rural residents in Sumatera still face a limitation of electricity access due to lack of power supply and also reliable transmission and distribution. Even the most populated city in Sumatera, Medan still has frequent power outage.

Electricity supply is a prime factor for an economic growth in the specified area. Industries, logistic process, and other trading activities all require electricity power. Construction and operation of power plants need human capital, creating a job market that will foster the economic growth. Education is vital to develop human capital in the area, so ensuring a decent education infrastructure is essential. Many students on rural area in Sumatera are still using traditional lamp to study. A big part of them have not been exposed to the Internet; yet, this leads to lack of information. Development plant for rural area should really consider electricity supply, as the demands of electricity will also increase alongside the economic growth. Ironically, the area which are lacking are the island with rich energy source such as the other islands than Java.

The only impediment for geothermal well development is the interest conflict with forest conservation as almost all of the geothermal well are located on protected forest area. Eventually, several geothermal well drilling project were delayed due to bureaucracy matter. Ministry of Environment and Forestry should work with Ministry of Energy to stop the ineffective license licensing paper works, of which have postponed many projects. Ministry of Environment and Forestry could impose mandatory reforestation action to be done by the project owner, in order to preserving the environment in the future. For example, Pertamina Geothermal Energy sowed fifty thousands of tree seed near Kamojang area in the 2011. The reforestation is vital to maintain ground water deposit, from which steam for power plant is produced.

Second obstacle for geothermal development is the uncertainty of drilling cost, making the financial risk higher than other energy project. The development process of geothermal power plant consists of exploration, production drilling, plant construction, and electricity production. Surprisingly, just exploration and drilling account for 42% of overall projects costs (Jennejohn 2009). This fact makes investor less assured to invest in geothermal energy projects. Without secure financial contract and subsidy, it is challenging to seek for investor for geothermal project.

The project began by exploration process, searching for the hot fluid reservoir which trapped between hot rocks. Proven fluid reservoir location then studied both in geophysics and engineering, in order to determine the trajectory of well will be drilled. After all engineering calculations had been done, the drilling process commenced until one well is ready for production. Meanwhile, the construction of power plant began simultaneously. Other production wells then drilled and tested until the accumulation of power reached the expected value. As the power achieved, the power plant had to be ready for operation to produce elecricity. However, the exploration and drilling process continued to maintain the production capacity of existing wells.

Drilling a geothermal well

The drilling in geothermal is started by drilling a big vertical hole until reaching around 1000 ft depth. After drilling finished, a string of steel casing with smaller diameter than the hole size are inserted into the drilled hole. Right after the casing are successfully inserted, some cement slurry is pumped into the casing hole until it filled the gap between the ground formation and steel casing. While waiting for the cement to dry, next section drilling equipment are prepared. Next section is started all over from drilling the excess cement inside the casing and new hole. The second section hole usually is drilled until 3000 ft depth; however, the trajectory is not vertical anymore but forming a certain degree with earth’s gravitational axis.  Repeated steps are done until 2 or 3 hole sections ahead, of which depth reaching 7000 ft. Actually, the depth depends on the drilling plan of each well, which is based on where the fluid reservoir located. The last step is completion of well; placing a wellhead and controlling equipment on top of the drilled well.

Water power

Water power (hydroelectric power) is a form of potential energy contained in water  which is used to move a turbine. Potential energy difference  exists in two water constituents with height difference. Higher level difference means more power potential. As water is an abundant resource in Indonesia, water power is very promising as an alternative energy. The most challenging obstacles for water power plant are environmental issues and high project cost.

The indirect effect of water power reservoar

Building a dam to contains millions cubic of water is essential. Actually it is the most resource-intensive process of a hydroelectric power plant construction. Hydroelectric acts like the solar and wind power plant, negligible operating cost but high capital cost. However, we would speak the indirect effect of dam construction project to the environment and social.

The area needs for water reservoir is huge, as a power plant needs million of cubic debit. When looking to the indirect effect, it might be a counter productive effect if the reservoir is being built in a rain forest or peat land with high carbon content. The inundation of rain forest lowland could lead to more GHG emission, the methane which is much more stronger than the carbon dioxide itself. The life cycle study and environmental impact consideration become the most challenging part to be taken in to account.

As per RUPTL (literally translated as the Business Plan of Electricity Power Development), water power plant surpasses other renewable sources for now and future installed capacity. The government seems more convenient to be committed in the most mature renewable energy technology, the water power. However, the development of water power plant should be focused on under-developed area like Kalimantan and Papua. The technology for PLTMH (micro hydroelectricity power plant) is easy to access and installed in those area. The massive micro generation plan for remote area implementation could solve the lack of electricity transmission issue amidst the transition of wider implementation in the next 20 years.

The forecast

International Energy Agency forecast electricity demand in 2035 to be dominated by renewable. The usage of fossil fuels for electricity generation is decreasing, except for natural gas. Even though the share of coal in power generation is decreased to 30.72% from 39.91% in 2012, there will be slight increase of coal power generated. Renewable account for 28.72% share on world electricity generation; slightly below is natural gas with 26.15%. Nuclear forecast to only have a tenth of share in world electricity power. “Of the 5.9 trillion kWh of new renewable generation added over the projection period, hydroelectric and wind each account for 1.9 trillion kWh (33%), solar energy for 859 billion kWh (15%), and other renewable (mostly biomass and waste) for 856 billion kWh (14%)” (International Energy Agency , 2016).

Agency for Assessment and Application of Technology (as translated from BPPT: Badan Pengkajian dan Penerapan Teknologi) proposed a different scenario for electricity supply. Coal still accounts for more than 50% electricity supply in Indonesia, as the mineral supplies are enormous (BPPT, 2015). Nuclear will not grow until 2030. Renewables will grow significantly, especially geothermal and hydro power as two biggest electricity supplier from renewable energy side. Other renewable like wind, solar, biomass, and tidal energy follow behind with slight growth. The projection shows the optimist plan of geothermal and hydro power plant in the future. While in the present, the development of geothermal well still facing technical difficulties that lead to high cost; and hydro power plant construction sites often intersect with forest conversation site.

Conclusion, geothermal and hydroelectricity power are too good to be true without proper support and clear ambition. Without additional incentive from outside the electricity pricing contract, I am reluctant that these two growing in the next 5 years. Coal is getting cheaper and easier to get.

Digiprove sealCopyright secured by Digiprove © 2020 Ronald Sukianto
Share the article:

Leave a Reply

Your email address will not be published. Required fields are marked *