Developing a Green Path Power Expansion Plan in Indonesia by Applying a Multiobjective Optimization Modeling Technique

This paper aims to apply a multiobjective optimization modeling technique to a power expansion problem evaluating two objectives functions: minimizing the power generating cost and minimizing ${\mathrm{CO}}_2$ emissions, between which there is a tradeoff. A convex curve is obtained representing the relationship between the generating cost ($\mathrm{Rp}/\mathrm{kWh}$) and ${\mathrm{CO}}_2$ emissions (ton). This represents a bad-luck curve where there is an increasing marginal cost to reduce 1 t of ${\mathrm{CO}}_2$ emissions. This is because most of the less-carbon-intensive power plants consume oil, which has the highest fuel cost. Instead of simply minimizing ${\mathrm{CO}}_2$ emissions, this paper argues that Indonesia needs to pursue technology to switch from steam coal subcritical technology to supercritical and ultra-supercritical technology to reduce ${\mathrm{CO}}_2$ emissions. It is further found that the generating cost will increase by less than 1.6% and yearly ${\mathrm{CO}}_2$ emissions can be reduced by about 6.9% by adopting supercritical technology. This implies that adopting ultra-supercritical technology can cut ${\mathrm{CO}}_2$ emissions by more than half. A squeezing effect is also found by adopting more-advanced steam coal technology. Thus, promoting renewable energy and gas utilization also should be enhanced. The green path power system allows both ${\mathrm{CO}}_2$ emissions and the generating cost to increase gradually, but with lower ${\mathrm{CO}}_2$ emissions than by minimizing the generating cost alone. It is thereby proposed that the current feed-in tariff for renewable energy also needs to be supported with an emissions reduction target.