Fossil fuels are the major energy source for electricity in Malaysia. Considering the issues related to energy security and the severity of climate change it is imperative to explore alternative and sustainable energy sources. One such alternative that can be explored as a solution is Ocean Thermal Energy Conversion (OTEC). OTEC is a renewable energy source that generates electricity from the thermal gradient between the surface and the deep seawater. The optimal condition for implementing OTEC technology is a temperature difference of at least 20°C between the surface and the deep seawater in the tropical and sub-tropic regions. Malaysia as a tropical country possess the ideal condition for OTEC. Aside from generating a base energy supply, an OTEC operating plant can be diversified to produce fresh water and integrate deep seawater technologies such as marine cultures, agriculture, and air-conditioning. Hence, OTEC technology can contribute to the UN's Sustainable Development Goals (SDGs) by addressing global problems, including clean energy, freshwater production, and food security. This paper discusses the overview of OTEC technology and the present status of OTEC development in Malaysia. The authors hope that this review will provide useful insights on the ongoing projects and aspiration of materializing OTEC in Malaysia in the near future.

Energy transition on small islands is limited by the scarce availability of land, restricting large-scale implementation of onshore renewable energy technologies such as solar photovoltaics and wind power. Ocean energy technologies provide novel opportunities for land-constrained islands to achieve 100% renewable energy systems. While wave power is increasingly implemented in energy system modelling research, ocean thermal energy converters are not yet a standard technology in renewable energy technology portfolios. This research aims to study the impacts of ocean thermal energy converters on the energy system of the Maldives through a structured sensitivity analysis for the two scenario clusters covering e-fuel import and domestic production. The ocean thermal energy conversion plants are modelled using spatially and temporally resolved resource data and cost assumptions from a global upscaling scenario, considering the technology's current development stage. Results show that ocean thermal energy converters play a limited role in 'purely' cost-optimised sub-scenarios due to the availability of very low-cost offshore floating photovoltaics, making it difficult for them to compete. Nevertheless, reduced requirement of energy storage technologies due to the stable electricity production of ocean thermal energy converters offers an option to diversify the renewable energy technology portfolio with only a minor increase in cost.

The current focus of offshore wind industry and academia lies on regions with strong winds, neglecting areas with mild resources. Photovoltaics' cost reductions have shown that even mild resources can be harnessed economically, especially where electricity prices are high. Here, we study the technical and economic potential of offshore wind power in Indonesia as an example of mild-resource areas, using bias-corrected ERA5 data, turbine-specific power curves, and a detailed cost model. We show that low-wind-speed turbines could produce up to 6,816 TWh/year, which is 25 times Indonesia's electricity generation in 2018 and 3 times the projected 2050 generation, and up to 166 PWh/year globally. Although not yet competitive against current offshore turbines, low-wind turbines could become a crucial piece of the global climate mitigation effort in regions with vast marine areas and high electricity prices. As low-wind-speed turbines are not yet on the market, we recommend prioritizing their development.

Indonesia strives for a renewable energy share of 23% by 2025. One option to contribute to this goal is Ocean Thermal Energy Conversion (OTEC). Despite a global theoretical potential of up to 30 TW, its economically deployable share remains unknown. This paper proposes a novel methodology, which enables to determine OTEC's economic potential for any regional scope considering technical, economic and natural variables. The methodology was tested for 100 MW_e OTEC in Indonesia on a provincial and national level. Against a regionally variable electricity tariff of 6.67–18.14 US$ct.(2018)/kWh, the national economic potential is 0–2 GW_e with a Levelized Cost of Electricity (LCOE) as low as 15.6 US$ct.(2018)/kWh. With an annual electricity production of 0–16 TWh, OTEC could provide up to 6% of Indonesia's electricity demand in 2018. The capacity factor, capital expenses and discount rate are the most sensitive variables of the LCOE on average. A nationally uniform feed-in tariff of 18 US$ct.(2018)/kWh or more could increase the economic potential significantly. The proposed methodology can be a helpful quick-scan tool for determining economically interesting OTEC sites for follow-up in-depth feasibility studies. Limitations are discussed and future research, amongst others upscaling scenarios with cost reducing effects like technological learning, is recommended.

Ocean thermal energy conversion (OTEC) is a Renewable Energy Technology (RET) with a global theoretical potential of up to 30 TW. However, OTEC's economic potential is unknown as it is still an immature technology with no commercial plant operating. This paper reviews recent academic and industrial literature since 2005 to provide an overview and critical discussion of current practices in assessing OTEC's economics. Seven knowledge gaps are identified; (1) Current economic analyses focus on individual plants instead of the collective economic potential within spatial boundaries; (2) Natural, location-specific influences on the real net power output are mostly omitted. There is uncertainty about (3) the capital costs on both system and component level as well as the (4) operational costs and properties like useful lifetime. (5) The impact of interest rates and its selection are often not argued for in literature. (6) Technological learning is predominantly omitted in OTEC literature and if treated, it deviates from insights on technological learning. (7) Economic analyses are mostly limited to the Levelized Cost of Electricity (LCOE), while other tools like payback period and Internal Rate of Return (IRR) are neglected. These shortcomings originate mainly from the lack of experience and long-term operational data. For each knowledge gap a recommendation for future research is proposed resulting in a research agenda on OTEC and its economics.