Investigation of availability, demand, targets, economic growth, and development of Renewable Energy in 2017-2050: A case study in Indonesia

Abundant potential of renewable energy (hereinafter called RE) in Indonesia is predicted to replace conventional energy which continues to experience depletion year by year. However, until now, the use of RE has only reached 2% of the existing potential of 441.7GW. The main overview of this work is to investigate the availability of RE that can be utilized for electricity generation in Indonesia. National energy demand and targets in the long run during the 2017-2050 period are also discussed. Besides, government policies in supporting RE development are considered in this work. The results show that the potential of RE in Indonesia can be utilized and might replace conventional energy for decades. The use of RE for electricity generation can be achieved by employing a government policy that supports the investor as the executor of RE development. The selling price of electricity generated from RE is cheaper than electricity generated from fossils; this makes economy is more affordable for people. Finally, the target set by the government for utilizing RE as the main energy in Indonesia can be done by implementing several policies for the RE development. Thus, greenhouse gas emissions and the use of petroleum fuels can be reduced. search for contains keywords related to energy. This paper summarizes 7 categories, namely: energy potential (EP), renewable energy target (TRE), energy demand (ED), energy supply (ES), economic growth (EG), policy RE (PRE), risks and challenges of RE (RCRE). independent

The process of analysis is a very important thing to do in a study. There are two rare methods used in the study, namely analysis and categorization.
The analysis process is based on the arguments contained in the categorized literature. The arguments reviewed in the study are explained in detail in sections 3, while the fth section presents overall conclusion. The literature analyzed in this review was obtained from various databases including Science Direct, Web of Science, IEEE, and various research results both from government institutions and from universities. The database generally produces various elds of science such as the development of renewable energy that has high quality.

Analysis data
The literature review analyzed in this research is based on renewable energy sources that cannot be utilized optimally as shown in Fig. 1. Where the total potential of renewable energy found in Indonesia reaches 441.7 GW with an installed capacity of 9.07 GW. Meanwhile, the new energy can be utilized to date has only reached 2%. The analysis and review in this paper discuss the availability, demand, targets, economic growth, and development of RE in Indonesia in the period of 2017-2050. Renewable energy discussed includes geothermal, hydropower, bioenergy, wind power, solar power, and tidal/wave. Once the analysis of RE availability is done, energy targets and demand in the next few years are then discussed. Then, energy supply, economic growth, RE policies, risks, and RE challenges are described sequentially and nally concluded.

Categorization
There are 3 types of references used in the study, namely literature taken from academics, reports from industry, and documents about various policies.
The last 2 types of references were collected online by the author or through research submitted. Collection of academic literature was obtained from databases such as Science Direct, Web of Science, and IEEE using the keywords of potential renewable energy. In this stage, identi cation was carried out aiming to produce information contained in the literature according to their respective year of publication. The methodology used should be more inspirational and make sense to the reader. All reference sources reviewed in this paper focus on renewable energy. The process of searching literature was carried out based on criteria and selected whether they met the research objectives. Study selection as a reference was obtained from journals such as Renewable Energy, Target Energy, Energy Policy, Economic Growth, Renewable and Sustainable Energy, Energy Demand, and Energy Supply. The search for journal sources needed contains keywords related to energy. This paper summarizes 7 categories, namely: energy potential (EP), renewable energy target (TRE), energy demand (ED), energy supply (ES), economic growth (EG), policy RE (PRE), risks and challenges of RE (RCRE).
These topics are independent and are not yet connected to other researches.

Results And Discussion
The installed power plant capacity in Indonesia until 2018 was 56.509.53 MW. This capacity was supplied by PLN of 40,486.60 MW by private sector of 13.350.79 MW, and by rental power plants of 2.672.14 MW. Most of the sources of electricity generation in Indonesia are coal energy of 49%, PLTG/PLTGU/PLTMG of 27% from PLTD of 12%, PLTA/PLTM of 11%, PLTP of 3%, and the rest comes from RE. The capacity of this power plant continues to increase every year from 48.739.00 MW in 2014 [23,24].
Petroleum production in Indonesia in 2018 decreased to 283 million barrels (778 thousand b/d) compared to 2009 of 346 million barrels (949 thousand b/d) [2,25,26]. The decline in oil production was caused by several factors such as production wells that were no longer feasible. While the development of new wells for production was still very limited. However, until now, Indonesia has a dependency on petroleum. The available petroleum cannot meet the needs of the existing re neries, so the government of Indonesian continues to import from other countries such as the Middle East.
The number of Indonesia's oil imports from 2009-2018 reached more than 35% as shown in Fig. 2. (a).
In general, energy demand in 2018 reached 465.7 million barrels/year including biodiesel fuel. Total domestic oil production is 278.1 barrels, while the total amount of oil imported by the government of Indonesian from oil-producing countries is 165.4 barrels per year. The comparison of total oil production and import each year can be seen in Fig. 2. (b). In 2017, Indonesia was ranked the third-largest country in terms of crude oil imports after Singapore and Thailand at US$21.4 billion and US$ 20.1 billion, respectively. The total of Indonesia's oil imports was US$8.1 billion, Malaysia was US$3.9 billion, the Philippines was US$3.5 billion, Brunei Darussalam was US$1.6 billion, and Vietnam of US$93.2 million [27].
Natural gas consumption in Indonesia in 2018 was 1.7 million MMSCF for the industrial sector of feedstock/energy, electricity generation, city gas (household and commercial), and gas lift [2]. In addition, this natural gas is also an export commodity with an annual average of 1.2 million MMSCF in the form of LNG and gas. LPG consumption in 2018 was 7.5 million tons, supplied from import of 74% (5.5 million tons) and domestic production of 26% (2 million tons). In 2018, the total percentage of LNG exports to natural gas decreased to 40% compared to 2009 by 50% as shown in Fig. 3.
Conversion of kerosene to LPG by the government has increased the LPG consumption in the community. Meanwhile, the availability of LPG produced domestically is still very limited. Consumption of 3 kg LPG continues to increase due to subsidies from the government. Therefore, the government must anticipate this increase since in the implementation, it is considered mistarget.

Potential and Implementation RE in Indonesia
The availability of renewable energy which is quite a lot can replace the dependence of fossil energy. This can be done if the existing renewable energy can be utilized optimally. Thus, the global government's commitment to reduce greenhouse gas emissions can be achieved. As a result, it has encouraged the Government to increase the role of RE sustainably as part of maintaining domestic energy security and independence. Following the Government Regulation No. 79 of 2014 on the National Energy Policy, the target of RE in 2025 is at least 23% and 31% in 2050. Indonesia has very abundant potential of RE to achieve the primary energy mix target.
The total RE potential in Indonesia reached 442 GW in 2019 with an installed power of 9.32 GW or only 2% of the total that can be utilized. Total RE of 442 GW is sourced from marine energy potential of 17.9 GW, geothermal of 28.5 GW, bioenergy of 32.6 GW, wind power of 60.6 GW, hydropower of 75 GW, and solar power of 207.8 GW. While the implementation of RE sources only reached 2% from geothermal of 1.949 GW, bioenergy of 1,858 GW, wind of 147.1 MW, hydro of 5.417 GW, and solar power of 0.135 GW as shown in Fig. 1 [28,29].
The largest coal energy potential in Indonesia is located in the ve regions, namely Sumatra, Java, Kalimantan, Sulawesi, and Papua. The total amount of coal energy calculated in 2017 reached 125.177,59 million tons while coal reserves was calculated 24.239,96 million tons of coal. However, this number decreased by 2.885.05 million tons compared to 2016 [2]. Closely related to global economic conditions triggered by global oil prices. Indonesia has considerable coal reserves which are estimated to be depleted in the next 61 years (2070). Meanwhile, the potential of conventional  [28,29].
One of the RE sources in Indonesia that cannot be utilized properly is solar energy. The potential of solar energy can be found almost in all provinces in Indonesia. However, the utilization of this energy has not been optimal, even though solar energy can be used as electrical energy, heating, cooling, etc. The total potential of RE in Indonesia such as geothermal, solar, bioenergy, wind, hydro, mini-micro hydro, and tidal/wave reaches 239.970 MW.
Meanwhile, the total installed capacity of RE until 2019 reached 8.215.5 MW. The total of new RE that can be utilized until 2019 reached 17.452%. It is assumed to be very small compared to the existing potential as shown in Table 1.  Fig. 7.(a). The small potential of biomass in Jakarta is caused by the area of mapping and has been met by housing residents. Whereas for forest areas, it is almost certain that there are no more in Jakarta. Meanwhile, if compared to the forest area in Riau and Sumatra Utara provinces, it is far more than Jakarta. Furthermore, the potential source of biogas energy in Indonesia is also very adequate when used for energy, especially for electricity generation. The rst most potential sources of biogas energy are in Jakarta, Banten, and North Sumatera with 126.1 MW, 118.6 MW and 115.5 MW, respectively, as shown in Fig. 7.(b) [35,36]. The potential for biogas energy in Indonesia in 2016 reached 2.603 MW. The potential of biogas is much smaller than the potential of biomass reaching 30.051 MW. However, it is predicted that the potential of biogas will continue to increase along with the increase in other renewable energy sources, mainly from agricultural products. The high biogas in these three provinces can be due to the high number of the population so that the potential for biogas produced is more than the other provinces. Utilization of solar energy as electricity generation aims to increase national energy security, reduce dependence on the use of fossil fuels, and increase economic investment. In addition, it can make domestic industries are more e cient, reduce greenhouse gas emissions, and meet the government's To be able to support this energy production target, su cient fuel is needed with adequate availability. If the availability of this fuel is lacking, it is highly unlikely that targets for energy production and emission reductions can be achieved.
The government's RE targets in 2025 and 2050 are 23% and 31%, respectively, as shown in Fig. 9.(a) and 9.(b). It can be seen that the RE target becomes greater than the other energy mix. Meanwhile, the petroleum energy mix will decrease to 20% by 2050. The increasing population has driven the increasing demand for energy, especially for transportation and electricity. Meanwhile, fossil energy production (non-renewable) will continue to decline, forcing the government to import petroleum to meet domestic needs. To overcome fossil fuels that continue to experience depletion, the government has made several policies to support the use of RE nationally. The government's target is to meet national energy by building several electricity generators such as geothermal energy, solar energy, and bioenergy, hydropower, and wind power. Besides, the government made policy on the use of biofuels (B20), namely mixing diesel engine fuel with palm oil to reduce the use of fossil energy [26,28,37].

Energy Demand
National energy demand in 2050 is targeted at 548.  Fig. 10. The total amount of energy demand in 2050 is predicted to be still dominated by the transportation and industrial sector. This is due to industrial growth and the increase in the volume of motor vehicles accompanied by an increase in population which increases every year. Final energy demand by type of energy in 2050 shows that electricity demand will dominate by 35% (EM), 34% (SD) and 33% (LC), respectively [2,37]. The high demand for electricity can be in uenced by the increasing use of electronic devices, especially in the household sector. In addition, the substitution of the use of generators in the industrial and commercial sectors with fuel oil to using electricity on the grid.
Energy demand for the industrial sector in 2050 is estimated to reach 230.9 MTOE sourced from EM, SD of 194.3 MTOE and LC of 157.7 MTOE. The use of energy in this industry is divided into six parts including the cement industry, fertilizer, paper, ceramics, metals, and the food/beverage industry. The total amount of energy demand in the industrial sector reaches87%. For the transportation sector, energy demand is still dominated by fuels such as diesel, gasoline, biodiesel, bioethanol, gas, avgas, and aviation fuel. The transportation sector consumed 96% of fuel in 2018 and the rest was supplied by natural gas and biodiesel. The biggest energy demand for transportation in 2018 was dominated by motorcycles, i.e. 41%. Energy demand for air transportation in 2018 also increased and in 2050 demand for aviation fuel is predicted to reach 27.6 MTOE. Energy demand for the trucking sector in 2050 is projected at 43%. For passenger car transportation, although there is an upward trend in energy demand, its growth has been able to be tempered by the use of more e cient technology. Therefore, energy demand in 2050 is projected to increase from 6.7 MTOE in 2018 to 23

Energy Supply
In 2050, the primary energy supply is targeted to reach 943 MTOE compared to 2025 at 314 MTOE. The supply of primary energy for power plants is included in the modelling based on the assumption of generating capacity according to the electricity supply business plan (ESBP) which generates the primary energy requirements for each power plant [2,33,39,40]. In this case, 298 MTOE (32%) is sourced from coal energy. It is expected that the use of coal can increase added value to the process of coal gasi cation and coal liquefaction. Energy demand sourced from gas pipelines, LNG, and LPG in 2050 is predicted to be 222 MTOE (24%) of the total primary energy supply. Meanwhile, the supply of RE is around 29% (275 MTOE) in 2050. The increase in the supply of RE is in uenced by the optimization for the utilization of solar cell energy, geothermal energy, biomass, and water that is intended for electricity generation and fuel subsidies in the transportation sector. In the SD scenario, the primary energy supply is smaller than the energy mix (EM) scenario of 828 MTOE in 2050. However, in the SD scenario, the RE energy is greater than the EM scenario, which is 23% in 2025 and 32% in 2050. This gure is following the targets listed in the KEN and RUEN. In the special LC scenario, RE increases signi cantly by 58% in 2050 compared to 2025 by 36%. The comparison of the primary energy mix with SD and LC 2025-2050 scenarios is shown in Fig. 13.(a) and 13.(b).

Economic Growth
Indonesia's economic growth in 2017 and 2018 were 5.07% and 5.17%, respectively, as reported in the data from the Central Statistics Agency (CSA) [41]. In 2019, it increased to 5.3% and in 2045 it is targeted at 5.6%. ESBP stated that Indonesia's economic growth uses BAPPENAS scenario in 2028 of 6.45% [29]. This is one of the factors to consider in making scenarios of long-term domestic energy demand. Economic growth statistics are accompanied by energy demand in general.
Energy demand is closely related to economic activity, so the assumption of economic growth will be very sensitive to energy demand from the three scenarios developed as shown in Table 3. Indonesia's economic growth during the 2013-2018 period tended to decrease from 5.6% to 5.17% as a result of the global economic downturn due to nancial market uncertainty and declining trade volume at the world level. The assumption of economic growth is adjusted to the "Vision of Indonesia 2045" published by BAPPENAS [42,43]. The Indonesia's economic growth in the next few years is supported by rising domestic needs, including consumption and investment, as well as better export growth including in the manufacturing sector which is a major energy consumer in the industrial sector.

RE Policy
To accelerate the development of RE, the Government of Indonesia has established several regulations or policies which are considered to be very supportive: KEN mandates for RE mix target in the primary energy mix of at least 23% by 2025 and minimizes the use of petroleum less than 25% by 2025. In addition, energy e ciency is also targeted to decrease by 1% per year to encourage savings in energy use in all sector. Some targets in the KEN which are also considered in the projected energy demand include optimization of the use of natural gas for domestic use and priority use of fossil energy for national industrial raw materials. This policy is implemented to maximize the use of RE, minimize the use of petroleum, optimize the use of natural gas and RE, use coal as a mainstay of national energy supply, and use nuclear as a last resort. With the regulations set by the government, it is expected that the developers (investors) can work better and the targets set can be achieved.

Risks & Challenges RE
In the construction of RE project, investors sometimes need to evaluate the risks that may arise when construction or operations begin. Each RE project has different types of risks and obstacles [48]. A study conducted by the United Nations Environment Program (UNEP) elaborates some of the risks that are generally inherent in the development of RE projects as shown in Table 4 [49,50]. Environmental obligations are related to fuel handling and storage.
Long-term contracts can solve resource problems.
Fuel handling costs.
Emission control.
ogas Resource risks (eg reduction in quantity and quality of gas due to changes in organic raw materials).
Opposition planning is related to the smell problem.
Strict safety procedures are needed such as loss control such as firefighting equipment and services.
High level of wear.
nd Long waiting times and upfront costs (e.g. permit planning and construction costs).
Failure of important components (eg gear train/box, bearings, blades etc.).

Variability of wind resources
Offshore cabling.
Turbine makes and models.
Manufacturing guarantees from component suppliers.
Good wind source data.
Loss control e.g. Firefighting can be difficult if the location is off the coast or altitude.
Development of procedures that are generally used dal/Wave Survival in a harsh marine environment.
Various designs and concepts but without a clear winner.

Small scale and long waiting time
Most of the prototypes and technology demonstration projects.
Good resource measurement data.
othermal Drilling costs and risks that arise (blow out).
Important components that are damaged, such as pumps.
Long waiting time (Permission).
Limited operator experience and different aspects of technology at different locations. Maintenance can be neglected (especially in developing countries).

The electricity selling price
The price of electricity sales to customers from renewable energy is cheaper compared to conventional energy as shown in Table 5. Meanwhile, the cost of conventional energy production is cheaper than RE, except for the production of wind power plants. However, renewable energy has more advantages than conventional energy. The bene ts of include environment friendly, more lace emission, reusable, sustainable, and lower operational costs. Meanwhile, conventional energy has higher operational costs compared to RE despite lower production costs. In addition, conventional energy produces higher emissions than RE.

Conclusions
Investigation of the potential for RE regarding the amount of utilization, energy demand, and the target of power plant construction during the period of 2017-2050 has been completed. Various ndings have been presented and discussed earlier so that conclusions can be drawn as follows:  Total Export and Production of Natural Gas  (a) and 7.(b). Total potential RE of biomass and biogas for different province [35].