Ocean Thermal Energy Conversion (OTEC) is a renewable energy technology (RET), that harnesses energy from the temperature differences between warm surface and cold deep-sea water. OTEC can generate a continuous stream of renewable electricity, functioning as a baseload energy source. To achieve this the ocean water temperature difference must be at least 20°C, favouring locations close to the equator where surface water temperatures are typically higher. Small Island Developing States (SIDS) such as Aruba have been identified as potential markets for OTEC, as many of them are located within such regions and exhibit favourable conditions for OTEC.

OTEC has the highest ocean energy resource potential of all ocean energy technologies. However, of the 44PWh/year in global resource potential very little is being harnessed. With OTEC currently in a pre-commercial phase it has faced challenges advancing to the commercial phase. A large contributing factor to this is a lack of financing and government support for the technology. The technology has a high capital cost with a relatively modest amount of operational plants built to date, providing a limited track record. Furthermore, on smaller scales the technology is generally not economically viable as it experiences considerable economies of scale, becoming substantially more economic with larger plant capacities. This results in a phenomenon known as the “valley of death” where smaller pre-commercial OTEC plants are not commercially attractive but results from such facilities are needed to convince financiers that the risk of building such plants is manageable.
To overcome this “valley of death” research exploring the technological and economic feasibility of implementing OTEC is vital to bolster confidence among investors and governmental bodies. This thesis project aims to contribute to this by conducting a techno-economic, power system model and stakeholder and institutional analysis exploring OTEC’s implementation in Aruba with the main research question:

Is it technically and economically feasible to implement OTEC in Aruba’s energy system and if so what technical, economic and social factors play a role?

The research is conducted using power system modelling as well as qualitative analysis. A concep- tual model of Aruba’s power system based on fully renewable technologies has been developed in a modelling and simulation tool. In this work on and offshore wind, land-based utility scale and floating PV and OTEC are analysed with Battery Energy Storage System (BESS) for storage capacity. The model has been formulated as an optimisation of a generation problem to assess cost-optimal solu- tions for generation investments to meet demand while satisfying all constraints. This is firstly done for a reference scenario in 2030, 2040 and 2050 and subsequently for alternative scenarios in 2050. Based on these optimisation and stakeholder and institutional analysis results, the feasibility of OTEC’s implementation in Aruba is evaluated and recommendations are provided on whether and how OTEC could be implemented...

Indonesia has recently made a target to shift to more sustainable and renewable energy sources through its energy transition commitment to achieve net zero emissions by 2060. It is widely reported in various literature that the country has significant solar energy potential. At the moment of writing, the current solar PV in construction, potentially the largest in Indonesia, is the Cirata floating solar PV project with an installed capacity of 145 MWp. This study shows that the technical potential of floating solar PV in Indonesia is 33 GWp at 5% water occupancy. Meanwhile, this study finds that the economic potential of floating solar is significantly lower than its technical potential, with only 6.4 GWp at 5% water occupancy. There are various support schemes to increase the economic potential of floating solar in Indonesia. The FSPV can become an alternative solution to renewable energy sources for Indonesia’s energy transition plan. In addition, a potential scenario is provided in this study to achieve the energy transition in Indonesia.

This thesis delved into methods regarding optimizing subsidy policy for accelerating renewable energy in Indonesia. The method used objective programming to maximize subsidy efficiency from both a private and governmental perspectives.

The Indonesian aims to greatly increase the share of renewable energy sources in the electricity generation mix. Rooftop solar photovoltaics (RTSPV) are a potential generation method that can be used in support of this, with Bali chosen as a case study. No estimates of the total technical and economic potential of RTSPV on Bali exist in academic literature. Low spatial resolution statistical methodologies exist to estimate the technical potential of RTSPV, but these are not accurate on the sub-national scale of Bali. Methodologies with a medium spatial resolution are most suitable for an area of the scale of Bali, however existing methodologies cannot be used due to incomplete cadastral data. In this thesis a novel methodology is introduced that allows the use of incomplete cadastral data, in combination with land use data, to estimate the total rooftop area in a region at a medium spatial resolution. The total rooftop area is then used to estimate the total technical potential and the total economic potential. Using this method, the rooftop area of Bali is estimated to be 130 km2, and the technical potential 22.9 TWh/year. The economic potential for RTSPV is estimated to be zero, as RTSPV cannot compete with conventional generation methods at current capital costs (CAPEX) of RTSPV components of 1200 USD/kWp. It is estimated that at a CAPEX of less than 870 USD/kWp sufficient electricity can be generated annually to fulfill the estimated annual demand of Bali of 5.7 TWh. 96% of the entire technical potential can be achieved at or below the cost per kWh of conventional generation methods if the price of RTSPV installations decreases to below 650 USD/kWp. If the compensation paid by the Indonesian state electricity company PLN for RTSPV electricity that is supplied
to the grid is increased from 65% to 100% of the consumer electricity price, residential RTSPV installations can become economically viable at the current CAPEX of 1200 USD/kWp. This thesis will enrich existing literature on RTSPV potentials by introducing a novel methodology that can be applied in other regions with incomplete cadastral data. In addition, it provides a blueprint to estimate RTSPV potentials for other parts of Indonesia, and it supports policy makers by giving insight in factors that influence the economic potential of RTSPV on Bali and in Indonesia as a whole.

The Indonesian government has announced a national strategy to achieve net-zero emissions through energy transition and justice. However, there are no extensive studies that assess the impact of this strategy and the growing demand in the Kalimantan power system. Therefore, this thesis project aims to conduct a techno-economic and energy justice analysis of the power system with the research question: “What is the optimum configuration of renewable energy integration in the interconnected Kalimantan power system in 2050 to achieve net-zero carbon emissions while considering some energy justice parameters?” The research is conducted using spatiotemporal power system modelling as well as qualitative analysis. This research concludes that RE integration and transmission system interconnection could lower the levelized system costs in 2050. The LCOE from the Kalimantan power system model could decline from 72 USD/MWh in 2021 to 31 USD/MWh in 2050. The electricity generation mix could evolve from 90% fossil fuel in 2021 to 100% RE plus battery storage in 2050, consisting of 76% hydro, 11% solar, 9% biomass, and is supported by 3% battery storage. It includes achieving net-zero carbon emissions and improving energy justice in terms of affordability, availability, and intra- and inter-generational equity in the Kalimantan power system.

Following the Paris Agreement of 2015, Indonesia aims to reduce emissions by 29% by 2030, compared to the business as usual scenario. In Indonesia it is expected that between 2015 and 2030 the electricity demand could triple and the total energy demand could increase by 80%. Bioenergy would account for more than half of all renewable energy in 2030 in Indonesia. However, the expansion of energy crops contributes to negative effects like deforestation, loss of biodiversity, and competition with food production. An other problem Indonesia currently deals with is the large amount of degraded land. A solution to these problems would be to cultivate biomass on degraded land. Bamboo can be used as a biomass feedstock, as it meets all selection requirements to be produced on degraded land. This thesis report quantifies the extent and finds the location of degraded land in Indonesia. Also, the technical and economic potential of bamboo cultivation on the degraded land locations is assessed. The research question that will be answered is: how much degraded land would be needed to cover Indonesia’s electricity demand by 2030, when using bamboo as a biomass feedstock, and how likely is this land available? This research question is answered by first doing a geographic information system (GIS) analysis. Through the QGIS software, the degraded land locations in Indonesia which are suitable for bamboo plantations can be found. This is done by layering multiple datasets on top of each other in four steps. Next, the technoeconomic potential analysis is done by calculating how much degraded land would be needed to cover a certain percentage of Indonesia’s electricity demand by 2030, and calculating the levelized cost of electricity (LCOE) of different biomass conversion technologies. The results show that between 0.21% and 49.9% of Indonesia’s total land area can be considered degraded according to different scenarios. The suitable area for bamboo plantations lays between the 0.01% and the 13% of Indonesia’s total land area. Using these areas the potential electricity that can be reached lays between the 0.4732 TWh for gasification, 0.3533 TWh for combustion, 0.3506 TWh for anaerobic digestion, and 0.1266 TWh for pyrolysis. The area needed to cover 25% of Indonesia’s electricity demand by 2030 ranges from 2.05.6% of Indonesia’s total land cover when using different conversion technologies. For 100% electricity demand this area increases to the range of 8.122.4% of Indonesia’s total land cover. The LCOE goes from 13 US$ct./kWh for gasification, to 16 US$ct./kWh for combustion, 22 US$ct./kWh for anaerobic digestion, and finally to 45 US$ct./kWh for pyrolysis. The result show that when using the least strict degraded land scenarios, it would be possible to cover a significant amount of Indonesia’s electricity demand. However, it is not likely that these scenarios will be applied. The definition of degraded land, still is not completely clear, and extensive field research needs to be done to validate the degraded land results. This research shows that bamboo cultivation on degraded land for electricity generation in Indonesia might not be applicable to generate large amounts of electricity. Nevertheless, it can be applied on smaller scales and it is a step in the right direction of Indonesia’s energy transition. Finally, some recommendations for future research can be made. First of all, uncertainty exists about the datasets used to assess the extent of degraded land in Indonesia. It is recommended that the datasets are validated through field research. Furthermore, in this research an assumption for the yield of bamboo is made, which can be tested against the actual yield of a bamboo plantation on degraded land in Indonesia. Also, socioeconomic and environmental effects of bamboo plantations are not considered, which provides the opportunity to address these in further research. Finally, other end uses like biofuel, other conversion technologies like cofiring, and pretreatment technologies to enhance the conversion efficiency can be evaluated in more detail in future research.

The Indonesian government has set a target to increase new and renewable energy sources in the energy mix by 23% in 2030 and 31% in 2050, which are to be met by investing in hydropower and geothermal energy capacity mainly. However, Indonesia has abundant other renewable energy potentials, which are largely untapped. The Java-Madura-Bali (Jamali) system is Indonesia's largest electricity system. Integration of variable renewable energy resources requires flexibility options such as grid expansion and short- and long-term electricity storage. This research aims to fill the knowledge gap in the literature on the effect that different carbon emission reduction limits have on the Jamali power system design in 2050. This was done by studying the potential of various promising renewable energy technologies (solar photovoltaics, on- and offshore wind, Ocean Thermal Energy Conversion (OTEC), geothermal and hydropower) in combination with short- and long-term storage (lithium-ion batteries and hydrogen storage) and grid expansions to mitigate renewable variability. For this purpose a techno-economic model was developed that optimizes operation and capacities of generation, storage and network simultaneously. The model simulates the system dynamics in the Jamali system in 2050 and was implemented in Python for Power System Analysis (PyPSA). It was found that there is an exponential relationship between system costs and carbon emission reductions in the Jamali power system. Additionally, only moderate system cost increases were found up to 80% emission reductions compared to the reference scenario with no emission mitigation efforts. At higher carbon reduction scenarios the solar capacities reach their maximum installable capacities. As a result, system cost increase exponentially due to the need for OTEC and offshore wind capacities. The high costs increases by offshore wind can be explained by the uniform costs and coarse resolution of the model. In low carbon scenarios high battery capacities were found and network expansion is limited. It is concluded that the Jamali network cannot smooth the variability of wind throughout the power system, therefore, without storage capacities the system cost almost double. On the other hand, the network remains important to transport electricity from rich renewable regions to large demand centers. Based on the results three recommendations were proposed related to the reconsideration of the energy targets for 2050, strategy to achieve the targets and present policies.

Indonesia is facing a challenge in fulfilling its future energy demand given the combination of a consistently high economic growth and a fast-growing population. The country also needs to increase the integration of renewable energy into the electricity system. Wind energy, one of the renewable energy alternatives, is severely underutilized in Indonesia. Accordingly, the Indonesian government aims to increase the installed wind farm capacity by twelvefold within the next five years. This research aims to fill a knowledge gap in the literature by determining economic potential of onshore and offshore wind energy in Indonesia and formulating recommendations for institutional changes to proliferate wind energy development. A techno-economic analysis is performed by means of a GIS-based modelling to determine the technical and economic potential. Based on the analysis, onshore and offshore wind technical potential amounts to 17.6 – 30.9 GW and 470.6 – 595.6 GW, respectively. Meanwhile, the LCOE of wind energy can be as low as 6.1 (onshore) and 13.4 (offshore) USD ct/kWh. However, only up to 8.0% and 1.4% of the onshore and offshore wind technical potential, respectively, is economically feasible under the current regulations. An institutional analysis is then conducted to identify the institutional barriers hampering wind energy development. The analysis focuses on the institutional environment (L2) and governance (L3) layer of Williamson’s four layers of institutions framework. Barriers related to electricity pricing (L2) include regulatory uncertainty and a low purchase price of RE-based electricity. Furthermore, the barrier in infrastructure planning (L2) is the low amount of additional wind farm capacity being planned and the inconsistency in planning. Issues on property rights allocation (L2), i.e. ownership transfer and foreign ownership restrictions on wind energy projects, have been addressed in recently enacted laws. Lastly, barriers in contracting (L3) encompass prolonged negotiations between PLN and IPPs, poor law and contract enforcement, insufficient coordination and leadership in the multi-layered governance, and limited availability of project funding. Three institutional recommendations are derived based on the identified barriers. First, the Government shall create an electricity pricing masterplan, which entails a phased implementation of economic policy instruments. Second, project funding should be provided by sustaining the Government’s subsidy to PLN and promoting local participation and ownership in the projects. Third, an independent regulator dedicated to the electricity sector should be formed to ensure sufficient stakeholder involvement and monitor the actors’ activities in this sector. Future research can perform a similar study at the regional level, particularly at provinces with promising economic wind energy potential. Furthermore, future studies can involve a comprehensive design of institutions and a roadmap for wind energy development in Indonesia.

Indonesia has set ambitious targets to increase renewable energy in the energy and electricity mix for 2025 and 2050. Solar photovoltaic (PV) is one of the renewable energy technology types that could play an important role in this transition, given the high resource potential compared to other countries and the global declining costs. The Ministry of Energy and Mineral Resource (MoEMR) has recognized the potential of solar energy and has expressed the intention to increase the share in the electricity mix (which currently is less than 1%) by focusing primarily on rooftop solar PV systems. However, utility-scale solar PV power plants could also play an important role, given the economies of scale advantages relative to rooftop systems. Unfortunately, a financial roadblock can be identified for the further development of utility-scale solar PV: the maximum allowed electricity prices that state electricity company Perusahaan Listrik Negara (PLN) pays for electricity produced by a solar power plant, are often lower than the levelized cost of electricity (LCOE). This creates an financially unattractive situation. This situation calls for insight into the economic potential of utility-scale solar PV and how this can be increased. However, no studies could be found that (1) look at how policies interventions can help to overcome the financial barrier and increase the economic potential and (2) assess the economic potential quantitatively not just in terms of LCOE but also in terms of the potential capacity and electricity generation given the maximum electricity price regulations that are in place.