Utilization of biomass either as a renewable energy source or for the generation of biogenic materials has received considerable interest during the past years. In the case of rice husk (RH) and rice straw (RS) with high silica contents in the fuel ash, these approaches can be combined to produce high-grade biogenic silica with purities >98 wt % from combustion residues. The overall process can be considered nearly neutral in terms of CO₂ emission and global warming, but it can also address disposal challenges of rice husk and rice straw. For the resulting biogenic silica, several advanced application opportunities exist, e.g., as adsorbents, catalysts, drug delivery systems, etc. This article provides a comprehensive literature review on rice husk and rice straw combustion as well as applied strategies for raw material pre-treatment and/or post-treatment of resulting ashes to obtain high quality biogenic silica. Purity of up to 97.2 wt % SiO₂ can be reached by combustion of untreated material. With appropriate fuel pre-treatment and ash post-treatment, biogenic silica with purity up to 99.7 wt % can be achieved. Studies were performed almost exclusively at a laboratory scale.

Full reduction of greenhouse gas emissions involves transforming the industrial process heat supply. The status and future perspectives of biomass for industrial heat mainly based on the German example are reviewed, and a more differentiated consideration by a newly introduced method is attempted. The article focuses on temperature levels above 200 °C combined with an individual examination of most energy‐consuming industrial subsectors according to the feasibility of biomass utilization. Numerous studies conclude that biomass use will shift substantially from residential to industrial heat. Results indicate that biomass could play a bigger role especially for cement and clinker production, but they indicate also a significant need for further research and development to take final conclusions.

As one of the renewable resources, biomass is in demand for the transformation of the energy system to achieve climate protection targets. At the same time, the availability of biomass is limited. In this paper, the energy system optimisation model BenOpt is used to determine the optimal use of the limited biomass under different frame conditions (scenario settings) in the future German energy system. Previous energy system studies have summarised available biomass and biomass conversion technologies in a very general way, with little differentiation between biomass types, conversion technology options with their technical parameters, and their applications. In this paper, 20 different groups of biogenic residual and waste materials; 15 types of energy crops grown on limited agricultural land; other biomasses such as algae, paludiculture, and log wood; 111 different bioenergy technologies; and a total of 265 renewable and fossil energy technology options for meeting sector‐specific energy needs are considered. With this focused and differentiated presentation of biomass and biomass conversion technologies in the energy system, the study is a novelty and fills a research gap. In summary, to achieve the climate protection targets, biomass is most cost‐effective in sectors where direct electrification is not possible or only possible on high costs: in high‐temperature industrial applications and in the aviation and shipping sector. In addition, biomass especially biogas is also the cost‐optimal option used in electricity flexibilisation to cover the residual load. In this study, the political decision on the future role on energy crops and thus the availability of biomass has the greatest influence on the results. Depending on whether a sole use of residues and waste biomass or a maximum availability of residues, waste and cultivated biomass is assumed; the bioenergy used comprises a total of approx. 660 PJ to approx. 1,830 PJ.