Countries worldwide must dramatically reduce their emissions to achieve the goal of limiting temperature increases in line with the Paris Agreement. Involving developing countries in global actions on emission reduction will greatly enhance the effectiveness of global warming mitigation. This study investigated the feasibility of establishing a wind farm at four onshore and three offshore sites in Indonesia. Installing wind turbines with the highest hub height, largest rotor diameter, and lowest cut-in and rated wind speed in an identified area off Wetar Island presented the highest time-based availability and a capacity factor of 46%, as well as the highest power-based availability at 76%. The levelized cost of electricity at 0.082 USD/kWh was comparable to that of power generated from fossil fuels, which ranges from 0.07 to 0.15 USD/kWh in Indonesia. Increasing the feed-in-tariff for wind power from the current 0.08 USD/kWh would provide sufficient incentive for investment. Moving subsidies from fossil fuels toward renewables would facilitate the transition to low-carbon renewables without increasing the financial burden on the country.

Methane (CH4)/air lean combustion can be enhanced by increasing the concentration of the oxidizer, like oxygen (O2) enrichment, or adding a strong oxidant to the reactant. Hydrogen peroxide (H2O2) is a strong oxidizer that yields O2, steam, and appreciable heat after decomposition. This study numerically investigated and compared the effects of H2O2 and O2-enriched conditions on the adiabatic flame temperature, laminar burning velocity, flame thickness, and heat release rates of CH4/air combustion using the San Diego mechanism. The result showed that in fuel-lean conditions, the adiabatic flame temperature changed from H2O2 addition > O2-enriched scenario to O2-enriched scenario > H2O2 addition with increasing α. This transition temperature was not affected by the equivalence ratio. Adding H2O2 enhanced the laminar burning velocity of the CH4/air lean combustion more than the O2-enriched scenario. The thermal and chemical effects are quantified in various H2O2 additions, and it is found that the chemical effect has a noticeable contribution to the laminar burning velocity compared with the thermal effect, especially in higher H2O2 addition. Further, the laminar burning velocity had a quasi-linear correlation with (OH)max in the flame. The maximum heat release rate was observed at lower temperatures for H2O2 addition and higher temperatures for the O2-enriched scenario. The flame thickness was significantly reduced upon adding H2O2. Finally, the dominant reaction to the heat release rate changed from the reaction of CH3 + O ↔ CH2O + H in the CH4/air or O2-enriched scenario to the reaction of H2O2 + OH ↔ H2O + HO2 in the H2O2 addition scenario.

Sewage sludge is a usual waste from urban areas that can be utilized in many renewable energy sources. In this study, we examine the sewage sludge utilization using pyrolysis process to produce pyrolytic oil using Taguchi methods, combustion characteristic of sludge pyrolytic oil (SPO) blend with heavy fuel oil (HFO), and co-gasification of sewage sludge with CO2/steam as the gasification medium using Taguchi methods. The best-operating conditions for the pyrolysis of sewage sludge are a heating rate of 10oC/min, temperature of 450oC, the residence time of 60 min, and N2 flow rate of 700 mL/min. Under these conditions, the obtained pyrolytic oil yield is very close to the result from the Taguchi method calculation. In the combustion characteristic of sludge pyrolytic oil (SPO) blend with heavy fuel oil (HFO), a higher SPO in the fuel blend enhances the occurrence of micro-explosion and reduces the size of the residual. Higher SPO content in the fuel blend increases the combustion rate and increases the ignition delay due to moisture evaporation. In the co-gasification of sewage sludge and palm kernel shell optimization using Taguchi method, the best operational condition for maximum H2/ CO syngas ratio reaches at the gasification temperature of 900 C, a blending ratio of 30%, a CO2/(CO2+H2O) ratio of 70%, and a catalyst addition of 20% bed material mass. The best operating condition for maximum concentration of H2 reach with gasification temperature of 800 C, a blending ratio of 40%, a CO2/(CO2+H2O) ratio of 70%, and a 15% catalyst addition of bed material mass. The CO2/(CO2+H2O) ratio is the most important parameter among both case.