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Being a developing economy, Pakistan is facing a severe energy crisis that limits its economic development. Pakistan relies heavily on energy resources like natural gas, oil, hydropower, nuclear, coal and liquefied petroleum gas (LPG) which contribute as 48.3, 32.1, 11.3, 7.6, and 0.6% of the primary energy supply, respectively. Because of the rapidly growing population and economy, Pakistan's energy needs are huge; to accomplish these energy necessities, Pakistan is continually spending $7-9 billion on the import of fossil fuels. To resolve the serious issues of energy availability, the Alternative Energy Development Board (AEDB) of Pakistan is currently exploring the development of renewable energy technologies in Pakistan that will be beneficial for the developing economy so that Pakistan might be able to minimize the growing energy crisis. Out of all the renewable energy resources, biomass is considered the best and most easily accessible source of energy with its unique environmentally friendly nature, constant supply, wider availability, and ease of integration into existing infrastructure. Despite the presence of an abundance of biomass energy resources, there is still a need for work on the use of these sources to produce energy. This literature review explores the availability of biomass resources in Pakistan and their potential for addressing rapidly growing energy demand in the country, which can assist in the stabilization of a Pakistan's energy demand for challenged economic development.

Addressing the contemporary waste management is seeing a shift towards energy production while managing waste sustainably. Consequently, waste treatment through gasification is slowly taking over the waste incineration with multiple benefits, including simultaneous waste management and energy production while reducing landfill volumes and displacing conventional fossil fuels. Only in the UK, there are around 14 commercial plants built to operate on gasification technology. These include fixed bed and fluidized bed gasification reactors. Ultra-clean tar free gasification of waste is now the best available technique and has experienced a significant shift from two-stage gasification and combustion towards a one-stage system for gasification and syngas cleaning. Nowadays in gasification sector, more companies are developing commercial plants with tar cracking and syngas cleaning. Moreover, gasification can be a practical scheme when applying ultraclean syngas for a gas turbine with heat recovery by steam cycle for district heating and cooling (DHC) systems. This chapter aims to examine the recent trends in gasificationbased waste-to-energy technologies. Furthermore, types of gasification technologies, their challenges and future perspectives in various applications are highlighted in detail.

The paper and pulp industry is the sixth largest consumer of energy in the U.K. Furthermore, the industry produces a significant amount of fibrous sludge and reject waste material, containing high amounts of useful energy. Currently the majority of these waste fractions are disposed of by landfill, land-spread, or incineration. These disposal methods not only present environmental problems but are also very costly. This review explores how paper industry wastes can be valorized into useful energy vectors via advanced thermal conversion routes, thus providing not only a solution for waste disposal but also a means of producing useful sustainable energy at paper mill sites. The scope of this work explores the application of advanced thermal conversion methods (gasification and pyrolysis) for the conversion of secondary fiber paper mill wastes into energy vectors. The order of the paper follows a specific structure. Initially, a detailed description is given concerning which wastes are generated from secondary fiber paper mills. This is followed by a brief review of the state of the art in waste management and energy systems currently used by paper mills. Then, a review on advanced thermal conversion pathways as a solution to the dual issue of waste management and energy generation for secondary fiber paper mills is given, including details regarding the feasibility of integrating them into the current mill infrastructure. Finally, a discussion of the challenges associated with the proposed conversion pathways is given.

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