Tea plantation biomass wastes, such as tea plantation pruning, shade trees, and woody weeds have not been utilized. The waste can be used as renewable energy in the form of wood pellets. The problem is the feasibility of biomass waste to be used as material for making wood pellets as energy. This paper aims to analyze the potential of tea plantation biomass waste as wood pellet material to meet energy needs. The research was conducted in a tea plantation owned by the Tea and Kina Research Center (PPTK). Quantification of biomass waste potential per unit area was conducted in the plantation using direct measurement method. Proximate analysis of each wood pellet variant of biomass waste was conducted to match the quality of Indonesian Wood Pellet Standard. The biomass waste potential in PPTK is 14,281 tons per year which can produce 8,186 tons of wood pellets per year. This potential can meet the needs of wood pellet consumption from the tea production process at PPTK which is around 1.8 tons / day for the tea processing process of 13 tons/day. Based on proximate analysis, the wood pellets produced have a calorific value of 4425 cal/gram, density of 1.35 grams/cm3, fixed carbon content of 85.2%, and volatile matter of 3.72%. These results confirm that the wood pellets comply with the National Wood Pellet Standard (SNI 8021:2014). This can be a model for the application of the Green Circular Economy concept in the plantation sector. Keywords: Biomass pellets; Green circular economy; Renewable energy; Tea plantation waste; Wood pellets

Clay 3D printing is an emerging field within additive manufacturing that presents significant opportunities for both structural and artistic applications. Driven by the increasing interest in this technology, there is a growing demand for optimized printing protocols tailored to clay, a readily available and versatile material. This study investigates the optimal processing parameters for kaolin clay composites and assesses the influence of clay-to-water ratios on the physical and mechanical properties of printed specimens. Experimental results demonstrate that higher clay content enhances the dimensional stability and structural integrity of printed components. The optimal formulation was determined to be 60% clay and 40% water, which produced the highest mechanical performance: the flexural strength of sintered specimens reached 1.3125 MPa and the compressive strength attained a maximum of 6.14 MPa. Shrinkage analysis indicated that specimens with greater water content experienced increased volumetric shrinkage, with reductions of up to 10% in linear dimensions and 14% in mass during drying and sintering. These findings highlight the critical relationship between material composition and final part performance in clay 3D printing and provide guidance for optimizing material formulations to enhance the mechanical robustness of printed clay composite structures for diverse applications.

The high availability of biomass waste in the agricultural sector as an energy source promises sustainable energy for drying agriculture product. The low efficiency of air heating of biomass burners due to their separate design from the heat exchanger. This study aims to analyse the effect of various types of biomass pellets on the performance of a mobile vertical burner according to the air heating system efficiency and carbon emission production. This experiment used biomass waste from tea plantations as raw material for the pellets. There are three variations of biomass pellets used in this study: black pellet (A), mixed pellet (B), and white pellet (C). An analysis for the efficiency of the air heating system is conducted at six different heating process levels. The analysis showed that the mobile vertical burner machine can provide up to 1,028 CFM with a temperature of 89.9°C. The highest air heating efficiency is achieved using black pellet [80.6%], followed by mixed pellet [75.2%], and white pellet [71.4%]. Carbon monoxide gas emission production from this machine ranges from 33,6-114,8 ppm. These results indicate that black pellets have the potential to improve air heating efficiency with low gas emission production.

The decrease in sugar productivity was due to insufficient process of the sugar production process such as the low efficiency of boiler machine input energy. This study aims to analyze the potential use of Bagasse Briquetting Fuel (BBF) made from sugarcane milling waste at PT Madubaru as an attempt to obtain the optimal efficiency of boiler machine. Analysis of the effect of the adhesive concentration on the BBF quality was carried out to determine the optimal composition of the use of adhesive materials. Economic analysis was also conducted to determine the economic potential of BBF development. The analysis revealed that the BBF from Sugarcane milling waste has Calorific Value of 17,367-19,497 KJ/kg and density of 0.740-0.915 g/cm3. BBF with an adhesive variation of 1.25% is the BBF with the highest efficiency because it meets the needs of boiler fuel with the least amount of 100.8 tons/day for the operation of 1 boiler machine. The development of BBF from sugarcane milling waste has a selling value of Rp1.390.5,-/kg much lower than the existing biomass fuels found in the market. Keywords: Bagasse briquetting fuel; Boiler machine; Energy efficiency; Renewable energy; Sugarcane milling waste.