# A Regret-Enhanced DEA Approach to Mapping Renewable Energy Efficiency in Asia's Growth Economies
###### Abstract  
Renewable energy (RE) is pivotal to achieving both environmental sustainability and long-term energy security, yet systematic evidence on the efficiency of RE investment across South and Southeast Asia remains sparse. This study introduces a rejoice-regret utility cross-efficiency DEA (RRUCE-DEA) framework that fuses conventional quantitative efficiency measurement with the behavioral insights of regret theory. Applying the model to 16 countries shows India as the benchmark for efficient RE investment allocation, followed closely by Pakistan and Indonesia. The Philippines, Malaysia, and Vietnam also post strong results, whereas Sri Lanka and Thailand reveal moderate performance with clear room for improvement. At the lower end of the spectrum, Cambodia, Myanmar, and Afghanistan encounter significant hurdles that must be overcome to achieve a successful clean energy transition. A sensitivity analysis further explores how variations in the regret aversion and rejoice-regret coefficients affect the RRUCE-DEA outcomes. The findings provide actionable guidance for policymakers and investors seeking to channel resources toward a cleaner, more sustainable regional energy portfolio. r 2025 15 May  
As governments, businesses, and individuals recognize the imperative to transition away from fossil fuels, investment in RE projects like solar, wind, and hydroelectric power has skyrocketed (2018, 2018), as presented in Figure 1. According to the International Renewable Energy Agency (IRENA), global renewable energy capacity increased by 10.3% in 2021 alone, with investment reaching a record USD 303.5 billion (2018). As shown in Figure 2, the data underscore the increasing importance of renewable energy investments globally, with both established economies and emerging markets recognizing the benefits of transitioning to cleaner energy alternatives. It also emphasizes the crucial role China plays in shaping the renewable energy landscape. However, the varying trajectories of investment among the different categories highlight the complex interplay of economic, political, and environmental factors that influence decision making in the renewable energy sector. This robust momentum is mirrored in the South Asian context, where countries like India are emerging as renewable energy leaders. India, for instance, has set a goal to achieve 450 GW of RE capacity by 2030, with an investment goal of USD 500 billion (2018). This commitment has spurred a surge in solar installations and wind farms across the country, transforming its energy mix and reducing dependency on coal. Within South Asia, other nations are also making noteworthy strides. Bangladesh, despite facing energy poverty challenges, has embarked on an impressive journey by installing one of the largest solar home systems globally, benefiting millions of households (2018). In the Association of Southeast Asian Nations (ASEAN), this surge is particularly evident, reflecting a growing recognition of the imperative to diversify energy portfolios and promote sustainable growth (2018). As economies in the region continue to expand, the demand for energy is soaring, prompting many ASEAN member states to embrace renewable alternatives (2018). For instance, Thailand has emerged as a regional leader, with goals to generate 35% of its total energy from renewable sources by 2037 (2018). Similarly, Indonesia, with its abundant geothermal potential, is investing significantly in this clean energy source to meet its burgeoning energy demands while reducing its carbon footprint. According to data from the ASEAN Centre for Energy, the region's total renewable energy capacity increased by over 60% between 2014 and 2019, underlining the substantial progress made (2018). Figure 1: Renewables’ share of total energy supply  
However, challenges such as policy alignment, regulatory frameworks, and financing barriers persist, hampering the full realization of renewable energy potential.