Wasting to Produce Energy

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If you knew that waste could be used to produce energy, would you waste more? Maybe not, but isn’t it exciting to know that urban waste could be converted to energy / electricity? And yes, it is a quickly maturing industry in today’s context. With an ever-increasing global demand for energy, innovative technologies are emerging to cope with it, and they seem to address this issue with a cleaner and greener approach with every cycle of evolution.

Waste to Energy (WtE)

Waste is of different types depending on its source – residential, industrial, medical, and agricultural. And due to its heterogenous nature, it is cumbersome to separate and sort them into individual waste type for recycling / recovery of materials, such as, metals. Readily separable waste items could be handled in a Material Recovery Facility (MRF), whereas the remaining residue that is complex and uneconomical to separate are left for energy recovery. WtE is the process of recovering energy (electricity / heat) from waste and there are various ways to do just that. The two main technologies employ thermal and biological methods, namely, gasification, pyrolysis, and incineration. However, to make the process efficient, segregation of the waste is an essential aspect. (Link)

Gasification of waste is preferred over incineration because it provides a syngas product that can be used in many ways as opposed to hot combustion gases. It provides syngas of uniform quality from a heterogeneous and complex residual waste. Gasification is the only option that can provide multimodal products such as heat, power, cooling, gas and liquid fuels as well as chemicals. Gasification also enables efficient power production with an excellent ability for integration with existing power production equipment such as, steam cycle, gas turbines, and gas engines. (Link)

Fig. 1: Landfill compactor in action (Image courtesy: Link)

How much is wasted
Even as early as 2006, the global Municipal Solid Waste (MSW) amounted to more than 12 billion tonnes, most of which was disposed of in open fields or water bodies. Landfills not only waste the land they occupy, but pollute the surrounding soil and groundwater with toxic releases. And when trash decomposes, methane gas is released into the atmosphere polluting the air as well. Thereby, WtE has gained prominence in recent times because of its obvious contribution to meet the energy demands of the world, and also for its contribution to using wastes that could otherwise end up in landfills and water bodies, thereby reducing pollution. (Link)

Annually, around 130 million tonnes of MSW are combusted in over 600 WtE facilities worldwide, producing electricity and steam for district heating networks. It is remarkable that the global annual MSW used by WtE facilities has grown by 16 million tonnes since 1995. Over the last 5 years, WtE has contributed 4 – 8% of Europe’s energy production, and 10 – 15% of domestic heat. While emerging technologies do contribute to growing interest in WtE, it is also the scarcity of landfill sites and the increasing volume of waste, which seem to drive countries to invest in WtE. (Link)

Currently, European countries are the champions of the WtE movement. They are followed by the Asia Pacific region and North America respectively. Even as early as 2007, there were more than 600 WtE plants in 35 different countries, including large countries such as China and small ones such as Bermuda. Countries in the Asia Pacific region are engaging more rapidly with WtE than the rest of the world, with major contributions coming from China, Japan, and India. As of 2008, the United States processed 14 percent of its trash in WtE plants, while Denmark, processed more than any other country – 54 percent of its waste materials. (Link)

Emerging waste-to-energy technologies, such as Dendro Liquid Energy (DLE), which is four times more efficient than conventional methods, in terms of electricity generation, with additional benefits of zero emission discharge and effluent hazard at plant sites, are expected to create significant opportunities for the market players, over the coming years. The WtE market is expected to register a CAGR of 7.35% during the forecast period of 2021 – 2026, reaching a market size of USD 69.94 billion by 2026, up from USD 43.66 billion in 2019. The COVID-19 pandemic affected the market negatively in the form of supply chain disruptions and delays in project implementation. However, the market is expected to recover soon, owing to increasing devotion by countries to promote waste treatment and energy recovery. The spent arrow cannot be recovered, but pretty much anything else can be converted to useful energy.

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