Feb-2024

Addressing the energy trilemma through advanced gasification

Advanced gasification technology is revolutionising the waste-to-energy sector, playing a crucial role in the circular economy and decarbonisation.

Amna Bezanty
KEW Technology

Article Summary

The UK and much of the world are trapped in an energy ‘trilemma’ as we grapple with the affordability, security, and sustainability of our energy. Similarly, waste and what we do with it has been and continues to be a massive problem. Whether in developing countries without any waste management infrastructure or in developed economies driven by consumerism, circular economies must be created to reduce the amount of waste ending up in the environment and damaging our land and seas.

The current waste hierarchy begins with reduction. We all know we have to create less waste. Then, there is reuse and recycling. Travel down the pyramid, and we hit the well-known solutions of how we traditionally deal with waste – recovery (via incineration) backed up by disposal (via landfill). We need to divert waste going to landfill and incineration.

In many countries, landfilling is still the predominant solution. In general, organic waste, such as food scraps and yard waste, tends to generate more methane as it decomposes anaerobically (without oxygen) in landfills. According to estimates by the Intergovernmental Panel on Climate Change (IPCC), the conversion factor for methane emissions from municipal solid waste (MSW) in landfill is around one tonne of methane per tonne of waste. This is significantly detrimental to the environment and global warming as methane is a potent greenhouse gas, with much higher warming potential than carbon dioxide over a short time frame.

The next best alternative is incineration. For many decades, this has been the primary way many countries treat waste.
However, what if another way could fundamentally change waste management systems by decarbonising waste before it hits incineration and landfill?

While incineration is preferable to landfill, we need to consider the following factors:
ΠLandfilling must be phased out.
    Grid electricity is becoming more sustainable through wind, solar and other renewable sources.
Ž Electricity from waste incineration is carbon intensive in comparison to renewable electricity generation sources.
    Waste is potentially more valuable as a feedstock for energy solutions in harder-to-decarbonise sectors.

KEW’s innovative pressurised advanced gasification process, a form of advanced conversion technology (ACT), sits above incineration and landfill and can play a vital role in decarbonisation across multiple sectors. By taking any form of waste (including non-recyclable and low-grade biomass), the technology converts it into fuel and different advanced molecules for use across hard-to-abate sectors such as energy-intensive industries, off-grid energy, transport, and chemicals (see Figure 1).

Technology benefits
One significant challenge in ACT is the creation of tar, which is extremely problematic. Tars can be detrimental to downstream equipment, such as engines and turbines or fuels/chemical synthesis catalysts, and require additional processing or cleaning to ensure the gas meets quality standards for various applications. Managing and minimising tar content is critical to optimising the efficiency and reliability of waste gasification technologies. 

KEW’s proprietary technology has overcome this challenge, which means it can focus on addressing hard-to-abate sectors by facilitating the production of renewable molecules like dimethyl ether (DME) as a low-carbon liquefied petroleum gas (LPG) and diesel substitute, hydrogen, methanol, and sustainable aviation fuel (SAF) without tar-related hindrances.

To date, other gasifiers have been able to gasify waste to a dirty and inconsistent composition of syngas, typically with high levels of tar remaining in the gas stream. This inability to crack and reform ‘dirty syngas’ has resulted in numerous operating failures in the market due to poor run time and availability. The other challenge is achieving the consistency of syngas composition, specifically the 1-1 ratio between H2 and CO that is critical for progressing from syngas to high-value molecules through a catalyst.

KEW’s proprietary Equilibrium Approach Reformer, which utilises high pressure and temperature for the syngas reformation process, enables it to achieve both tar-free syngas at robust availability levels, as well as a clean, consistent syngas for the production of molecules regardless of the waste feedstocks.

Moreover, the technology extends beyond generating syngas as a natural gas substitute or sustainable chemical feedstock. It integrates with other technologies to upgrade syngas into valuable, sustainable energy products, including renewable and recycled carbon DME, hydrogen, methanol, heat, and other fuels and chemicals. This capability empowers industrial, commercial, and residential energy consumers to achieve and surpass net-zero ambitions, particularly in sectors with limited alternatives, when electrification is not applicable.

The technology is also carbon capture ready – an essential feature in achieving negative emissions. KEW utilises pre-combustion carbon capture, providing a highly cost-effective pathway to achieving negative carbon outcomes.

Cost-effective modular solution
There are other ‘competitors’ using gasification, particularly in the US and Canada, but their focus is on large-scale projects on a massive scale. KEW’s pressurised technology works for multiple industries because it is modular, flexible, cost-effective and can scale up via its modularity (see Figure 2). By integrating into communities or existing industrial processes, it can not only revolutionise sustainable energy production from waste processing but also significantly reduce installation and energy costs. The sweet spot is smaller- to medium-scale project deployment from approximately 5-100 MWth energy output from 20,000-400,000 tonnes per annum of waste (which varies depending on the specification and moisture content).

Minimal CO2 emissions
For waste majors collecting rubbish, the technology allows them to start with converting their ‘dirtiest’/more challenging waste (high CV plastics and fines) that is difficult and expensive to incinerate into a stable, clean gas with lower carbon emissions.