Harvesting Green Energy through Energy Recovery from Waste: Technology Review & Singapore Assessment

Meaning

Energy recovery from waste refers to the process of converting non-recyclable waste materials into usable forms of energy such as electricity, heat, or fuel. Instead of discarding waste in landfills, technologies like incineration, anaerobic digestion, and gasification extract energy while reducing waste volume.

Introduction

The growing demand for sustainable energy and limited landfill space has pushed many countries to explore energy recovery from waste as part of their waste management strategies. Singapore, a small island nation with scarce land resources, has been a pioneer in this field. By integrating waste-to-energy (WTE) plants with advanced resource recovery systems, Singapore not only reduces its dependence on fossil fuels but also extends the lifespan of its only landfill, Semakau. This makes energy-from-waste an essential part of both its Zero Waste Masterplan and low-carbon future.

Advantages

1. Renewable energy source – Converts waste into continuous power and heat.

2. Landfill reduction – Minimises the volume of waste sent to landfills.

3. Carbon benefits – Displaces fossil-fuel use and cuts methane emissions from landfills.

4. Resource recovery – Metals and ash by-products can be reused in construction (e.g., Singapore’s NEWSand).

5. Energy security – Provides a steady local energy supply, reducing import dependency

Disadvantages

1. High capital costs – WTE plants require expensive infrastructure and maintenance.

2. Air emissions – Risk of pollutants if not well controlled, though modern plants use strict flue-gas cleaning.

3. Energy efficiency – Incineration yields less energy compared to direct renewable sources like solar or wind.

4. Feedstock dependency – Requires continuous waste generation; may discourage reduction and recycling if not managed carefully.

5. Ash disposal – Incineration produces ash requiring safe handling and landfilling.

In-depth Discussion

Singapore exemplifies how energy recovery from waste can be integrated into national planning. The country operates four large-scale WTE plants—TuasOne, Keppel Seghers, Tuas South, and Senoko—that incinerate waste to produce electricity while reducing its volume by up to 90%. Since land is limited, this system ensures that Semakau Landfill receives only ash and non-incinerable materials.

The upcoming Tuas Nexus project marks a leap forward. It combines the Integrated Waste Management Facility (IWMF) with the Tuas Water Reclamation Plant (WRP) to create energy synergies. Food waste will be co-digested with sewage sludge to produce biogas, which will be harnessed for electricity. This integrated model could boost energy recovery efficiency by up to 40% compared to traditional sludge digestion.

Singapore also addresses the challenge of incineration ash through NEWSand, an initiative to turn incinerated bottom ash into construction material, reducing reliance on imported sand while extending landfill lifespan. However, despite technological advances, challenges remain. Domestic recycling rates are still low (about 11% in 2024), which means much recyclable material ends up incinerated. Furthermore, while WTE reduces landfill use, it cannot replace upstream waste minimisation and circular economy practices.

Summary

Energy recovery from waste is the process of converting non-recyclable waste into usable energy, helping reduce landfill reliance and contribute to clean energy generation. Singapore has emerged as a leader by adopting WTE incineration plants, developing NEWSand, and building the Tuas Nexus to integrate waste and water treatment. The system offers strong advantages such as renewable energy, reduced landfill pressure, and carbon savings, but also faces drawbacks like high costs, emissions management, and limited efficiency. Overall, energy recovery is not a stand-alone solution but a critical part of Singapore’s broader strategy to achieve sustainability, circularity, and energy resilience.