**5. Conclusions**

Across Southeast Asia, there is a vital need to deploy HELE technologies, rather than employing less-efficient subcritical technology. Deployment of HELE technologies is progressing in Southeast Asia, but the overall rate of deployment falls short of achieving the 2DS. ASEAN should therefore make increased efforts to eliminate generation from subcritical plants and increase generation from HELE plants to meet the 2Ds targets. In this study, it is revealed that the pollution control scenario (i.e., implementation of a carbon pricing policy) surpasses the other scenarios in displacing subcritical plants sooner to pave the way for HELE technologies.

The study also reveals that:


The conclusion is that HELE plants are economically competitive against the subcritical plants, and in the short run, the Southeast Asian economies should focus on devising and implementing carbon pricing to support quicker deployment of HELE and displacement of subcritical technologies. Ultimately, in the long-run, a strong carbon price signal will be needed with strict emission standards to enable HELE transition.

While this study focuses specifically on ASEAN countries, its broader lessons are applicable for global deployment of HELE coal plants.

**Author Contributions:** Conceptualization, H.A.; Methodology, H.A., H.P. and S.R.W.; Software, H.P. and H.A.; Validation, H.A., H.P. and B.S.; Formal Analysis, H.A., H.P., S.R.W. and B.S.; Investigation, H.A.; Resources, H.A., H.P. and B.S.; Data Curation, H.A. and H.P.; Writing—Original Draft Preparation, H.A.; Writing—Review & Editing, H.A., H.P., S.R.W. and B.S.; Visualization, H.A. and H.P.; Supervision, H.A.; Project Administration, H.A. and H.P.; Funding Acquisition, H.A. and H.P. All authors have read and agreed to the published version of the manuscript.

**Funding:** Financial support from ERIA, and UON Singapore (UONS) (under Grant number UONS\_SR G\_1602) is gratefully acknowledged.

**Data Availability Statement:** New data generated is shared through this article. All other sources of data are cited throughout the paper.

**Conflicts of Interest:** The authors declare no conflict of interest.

## **Abbreviations**


