Low quality carbon resource is hydrocarbons containing moisture and ashes at high density, which is disposed as waste. Those materials have not been considered as the energy resources for a long time, because of low heating value and difficulty in use. However, it is very important to use those hydrocarbons as the alternative fossil fuels in the aspect of environment and energy security in Japan. There are so many problems and issues in utilization of low quality carbon materials. Therefore, this article explains the present situation and current challenges in the utilization of low quality carbon fuels and introduces new energy utilization techniques of those materials, especially in sludge treatment and utilization.

Biomass (bioenergy) has features of carbon neutrality, long distance transportable and stackable hydrocarbon, and multi-uses such as food, feedstock, and energy. Carbon neutrality is originally the term that explains net CO₂ emissions of sustainable biomass uses, but it becomes the concept of the goal of the whole energy systems. Biomass can realize not only the carbon neutrality but also the carbon negative emissions when the captured carbon in the biomass is not discharged. In this document, it is explained that biomass uses in Japan in this century is affected by feed-in-tariff and other policies. Then, biomass uses in Japan to head toward low emissions energy systems is discussed.