# Technology-Economy-Policy: Biochar in the Low-Carbon Energy Transition--A Review
## 6 Economy: Application of Biochar
### Application of Biochar in the Renewable Energy Sector
#### 6.1.6 Biochar-Based Composites  
Replacing cement with biochar supports both waste management and carbon sequestration. However, optimizing the dosage of biochar in the mix can increase the compressive strength, toughness, and durability of biochar-cement composites. Biochar at a concentration of 0.5-2% can be used as a filler in biochar-cement composites to increase mechanical performance [200]. [PERSON] et al. observed that replacing sand with 20% of biochar increased flexural strength by 26% and reduced bulk density to 10% [194]. The addition of biochar improved mechanical properties such as tensile strength, flexural strength, and functional performance, such as the electrical conductivity and rolling resistance of biochar-polymer composites. The addition of biochar in epoxy resin increases its use for surface coating, laminating electronic circuit boards, and further use in the automotive and aerospace industries [201]. Carbon black is a filler used in rubber composites, which can be replaced by biochar prepared from waste biomass [202]. Biochar from coconut shells showed five times the tensile modulus of rubber composites compared to natural rubber [203]. Biochar has a stable porous honeycomb structure, contains no flammable  
Figure 4: Diagram of the effect of biochar as an additive to cement [134]. volatiles, exhibits high thermal resistance, and can be used as a fireproof material [45]. Concrete and asphalt mixtures are present in pavement materials that can adsorb and retain solar energy and reflect the urban heat island effect, releasing stored energy. Asphal pavement generates volatile organic compounds that pose a health risk to construction workers. Adding biochar into concrete can increase the water sorption capacity by mitigating the heat island effect [204]. [PERSON] et al. showed that a temperature of about 6 \({}^{\circ}\)C can be lowered for 18 h by using biochar in pavement production [205]. Biochar can reduce the emissions of volatile organic compounds by 50% [206]. Cement composites with biochar reduced thermal conductivity by 25% [207]. The addition of 2% of biochar showed lower thermal conductivity and significantly increased the acoustic performance of biochar-cement composites. Biochar can be used in chip boards to adsorb VOCs, and can improve indoor air quality and interior finishes. The use of 3D printing in the development of construction materials can reduce waste by up to 30-60%, labor input by up to 50-80%, and production time by up to 50-70% [208]. The addition of biochar with a negative carbon footprint in 3D-printed concrete reduces the density of the concrete and increases its durability [45]. Despite the promising potential of biochar in the low-carbon energy transition, several challenges hinder its widespread implementation. A key limitation is the technological maturity of biochar production, which remains inconsistent and costs on a large scale. One of the primary issues is the lack of standardized processes, leading to variability in biochar quality depending on the feedstock and pyrolysis conditions. Additionally, although biochar production is often considered carbon neutral, the energy-intensive nature of the pyrolysis process can offset some of its environmental benefits, especially in smaller-scale operations. The scalability of biochar production systems remains another challenge, with many existing technologies being too small scale or inefficient for industrial adoption. To overcome these obstacles, further research is needed to improve the efficiency of production processes, reduce costs, and enhance the overall quality and functionality of biochar [209]. LCA as a Tool for Calculating the Actual Production Efficiency and Environmental Impact of a Product  
The scientific literature has reported abundantly on the environmental benefits of biocarbon in many industries [210; 211; 212; 213].