In this paper, we conclude that Indonesia has vast potential for generating and balancing solar photovoltaic (PV) energy to meet future energy needs at a competitive cost. We systematically analyse renewable energy potential in Indonesia. Solar PV is identified to be an energy source whose technical, environmental and economic potential far exceeds Indonesia’s present and future energy requirements and is far larger than all other renewable energy resources combined. We estimate that electricity consumption in Indonesia could reach 9000 terawatt-hours per year by 2050, which is 30 times larger than at present. Indonesia has abundant space to deploy enough solar to meet this requirement, including on rooftops, inland reservoirs, mining wasteland, and in combination with agriculture. Importantly, Indonesia has a vast maritime area that almost never experiences strong winds or large waves that could host floating solar capable of generating >200,000 terawatt-hours per year. Indonesia also has far more off-river pumped hydro energy storage potential than required for balancing solar generation.

In this paper, we analyse 40 years of maximum wind speed and wave height data to identify potential sites for solar photovoltaic (PV) systems floating on seas and oceans. Maximum hourly wave height and wind speed data were segregated into 5 distinct categories. These categorisations were then combined at the nearest wind speed and wave height grid point for each sea location, generating a comprehensive wind–wave map via a geographic information system (GIS) visualisation. We find that regions around the equator are generally calm, i.e., free from strong winds and large waves. The most favourable locations are around the Indonesian archipelago, and the Gulf of Guinea on the west coast of tropical Africa. Our analysis indicates the huge potential of floating solar PV systems in calm tropical maritime regions, capable of generating about one million terawatt-hours per year in regions that rarely experience waves larger than 6 m or winds stronger than 15 m/s. This study furthers our understanding of alternative renewable energy options, emphasising the promising potential of offshore floating solar PV systems in the global energy transition.

The rapid fall in the cost of solar photovoltaics and wind energy offers a pathway to the deep decarbonization of energy at an affordable price. Off-river pumped hydro energy storage and batteries provide mature and large-scale storage to balance variable generation and demand while minimizing environmental and social impacts. High-voltage inter-regional interconnection and dispatchable capacity (existing hydro and geothermal) can help balance supply and demand. This work investigates an Indonesian energy decarbonization pathway using mostly solar photovoltaics. An hourly energy balance analysis using ten years of meteorological data was performed for a hypothetical solar-dominated Indonesian electricity system for the consumption of 3, 6 and 10 megawatt-hours (MWh) per capita per year (compared with current consumption of 1 MWh per capita per year). Pumped hydro provides overnight and longer storage. Strong interconnection between islands was found to be unnecessary for Indonesia, contrary to findings from similar modelling in countries at higher latitudes. Storage requirements for power and energy were found to be smaller than three kilowatts and 30–45 kilowatt-hours per person, respectively. Introducing gas turbines (burning hydrogen or synthetic methane) contributing around 1% of annual generation reduced the levelized cost of electricity (LCOE) by 14% and halved the storage requirements by allowing the system to ride through prolonged cloudy periods at lower cost. This work showed that Indonesia’s vast solar potential combined with its vast capacity for off-river pumped hydro energy storage could readily achieve 100% renewable electricity at low cost. The LCOE for a balanced solar-dominated system in Indonesia was found to be in the range of 77–102 USD/megawatt-hour.

The rapidly growing scale of solar photovoltaics and wind energy coupled with electrification of transport, heating and industry offers an affordable pathway for achieving deep decarbonization. Massive integration of variable solar photovoltaics and wind energy requires large-scale adoption of short (seconds-hours) and long (hours-days) duration energy storage. Currently, long-duration pumped hydro energy storage (PHES) accounts for about 95% of global energy storage for the electricity sector. This paper discusses the Global PHES Atlases developed by the Australian National University which identify 0.8 million off-river (closed-loop) PHES sites with a combined 86 million Gigawatt-hours of storage potential, which is about 3 years of current global electricity production. These Atlases show that most global jurisdictions have vast potential for low-cost PHES with small water and land requirements, and that do not require new dams on rivers. The low capital cost of premium PHES systems ($ per kilowatt-hour) is pointed out. Methods for creating shortlists of promising PHES sites from the Atlases for detailed investigation are developed.

Indonesia has vast solar energy potential, far more than needed to meet all its energy requirements without the use of fossil fuels. This remains true after per capita energy consumption rises to match developed countries, and most energy functions are electrified to minimize the use of fossil fuels. Because Indonesia has relatively small energy potential from hydro, wind, biomass, geothermal and ocean energy, it will rely mostly on solar for its sustainable energy needs. Thus, Indonesia will require large amounts of storage for overnight and longer periods. Pumped hydro comprises 99% of global energy storage for the electricity industry. In this paper, we demonstrate that Indonesia has vast practical potential for low-cost off-river pumped hydro energy storage with low environmental and social impact; far more than it needs to balance a solar-dominated energy system.

The decarbonization of the electricity system coupled with the electrification of transport, heat, and industry represents a practical and cost-effective approach to deep decarbonization. A key question is as follows: where to build new solar and wind farms? This study presents a cost-based approach to evaluate land parcels for solar and wind farm suitability using colour-coded heatmaps that visually depict favourable locations. An indicative cost of electricity is calculated and classified for each pixel by focusing on key factors including the resource availability, proximity to transmission infrastructure and load centres, and exclusion of sensitive areas. The proposed approach mitigates the subjectivity associated with traditional multi-criteria decision-making methods, in which both the selection of siting factors and the assignment of their associated weightings rely highly on the subjective judgements of experts. The methodology is applied to Australia, South Korea, and Indonesia, and the results show that proximity to high-voltage transmission and load centres is a key factor affecting site selection in Australia and Indonesia, while connection costs are less critical in South Korea due to its smaller land area and extensive infrastructure. The outcomes of this study, including heatmaps and detailed statistics, are made publicly available to provide both qualitative and quantitative information that allows comparisons between regions and within a region. This study aims to empower policymakers, developers, communities, and individual landholders to make informed decisions and, ultimately, to facilitate strategic renewable energy deployment and contribute to global decarbonization.