**Author details**

carboxylic acid and aromatic compounds, which will damage human organs like lung and liver [26]. For control of these particles' emission, an efficient gas clean-up system with conditioning unit is necessary, as well as avoiding insufficient combustion and gasification. In addition, ashes and condensate from biomass gasification also contribute to environmental problems if they are not disposed properly. Especially the toxic condensate with high content

Besides the risk of health hazards and environment, gasification is also confronted with risk of fire and explosion. Because the gasification system is normally operated at relatively high temperature and pressure, it also produces flammable gas mixture with a great portion of hydrogen gas. However, explosion is not easy to be created even air leakage into the gasification system, which could raise a partial combustion. This will only lead to lower quality and higher temperature of producer gas [1], unless there is a large amount of air which enters with

feedstock from the feeding system or massive leakage of flammable outlet gas occurs.

The development of bioenergy will need a lot of land for energy-growing crops. This requirement will clash with other applications of farmland, like food and other cash crops. The competition with food agriculture must be intensive. The food shortage is still a big global issue nowadays. According to the data of World Hunger Education Service, the world's hungry population was 925 million in 2010. Besides this, the world population is still growing by rate of 1.2%. The natural disasters and climate change also affect agriculture. These three factors will decide that the demand of the farmland in the future will expand. Thus, transferring farmland for energy crop planting in a large scale would be difficult, especially in Europe.

The bioethics report by Nuffield council points out that deployment of bioenergy should not violate the human right which is reflected in the Universal Declaration of Human Right (UDHR). In the UDHR, it states that every people can share and enjoy the protection of the moral and the any product from any scientific, literary or artistic which is owed by them. There are a lot of ethical issues referring bioenergy, like human rights, solidarity and sustainability. Biofuel production application will require land use, water supply and labor from local community. Destruction to the land and local ecosystem cannot be avoided. Also, land displaced for energy crops will not only bring food price increases; some local residents may face migration. All these could be regarded as the actions, which violate the human rights of

The commercialization of biomass gasification is still at the early stage of development and leaves a lot to be desired on the technology aspect. In particular, large-scale utilization of biomass still needs to overcome the challenge of biomass collection and transportation, due

of tar is very difficult to deal with and has higher risk of hazards.

**4.2. Social impact**

14 Gasification for Low-grade Feedstock

**4.3. Ethical issues**

citizens and non-citizens.

**5. Conclusion**

Xiang Luo1,2\*, Tao Wu1,2, Kaiqi Shi1,2, Mingxuan Song3 and Yusen Rao3

\*Address all correspondence to: xiang-luo@nottingham.edu.cn

1 A Key Laboratory of Clean Energy Conversion Technologies, The University of Nottingham Ningbo China, Ningbo, China

2 New Materials Institute, The University of Nottingham Ningbo China, Ningbo, China

3 Department of Chemical and Environmental Engineering, The University of Nottingham, Nottingham, UK
