Gasification is often considered the most environmentally-friendly method for converting waste into energy, because it emits less CO2 and other pollutants when compared with incineration. This makes it a sustainable option for both waste management and energy production.
For several reasons, gasification also offers an attractive return on investment for energy infrastructure owners and other partners. Yet the industry suffers from several damaging myths that could hinder adoption. This article challenges those myths, and explores the many often-misunderstood benefits of gasification.
Myth 1: “Gasification is the same as incineration”
FALSE – gasification is very different to incineration.
There’s a lot of confusion around this topic.
Perhaps because gasification and incineration are both waste to energy technologies.
This is dangerous, however, because the environmental impact, efficiency and outputs of these two processes are very different.
Incineration is a process that applies oxygen and high temperatures to waste, converting it into heat, ash, and flue gas. The flue gas must be cleaned of polluting gases and particles before being released into the atmosphere. In some cases, the heat produced can be used to generate electrical power.
Gasification also applies heat to waste – in this case specifically organic or fossil fuel-based carbonaceous materials. In other words, for gasification to work, the feedstock used in the process must contain carbon.
But there are two big differences. Firstly, gasification does not burn the waste as incineration does. Secondly, the process produces a substance called synthesis gas (syngas). In itself, this gas can be used as a fuel. It can also be converted into other forms which can also be used for energy production, biofuels, hydrogen, and synthetic natural gas (SNG). As a byproduct the gasification process can also generate biochar for use as natural fertilizers.
Myth 2: “Gasification is not environmentally-friendly”
FALSE – gasification is the most environmentally-friendly waste to energy technology.
Depending on the application, it is also considered to be a source of renewable energy.
The reason for this myth is two-fold.
The first is this confusion between incineration and gasification mentioned above.
Gasification produces an average of 70% less greenhouse gases than incineration per generated MW. It produces no fly ash or toxic compounds, making it safer. And while incineration is not considered a renewable energy source, syngas produced from gasification is considered a renewable energy if it has been produced from organic “biomass” waste.
The incineration process does produce greenhouse gases, including CO2. The ash it produces includes fly ash, which contains toxins such as sulphur dioxide, hydrogen fluoride, nitrogen oxide, silicon dioxide and more. Fly ash may also contain mercury, arsenic, ammonia, cadmium, cobalt, lead and chromium – all poisonous.
The second reason comes down to the idea that syngas cannot be classed as renewable. This is due to a misunderstanding plaguing the use of biomass as an energy source, because many large coal plants in Europe have been importing biomass from the US to convert into power.
But coal plants use combustion to convert biomass into energy – not gasification. So not only are they contributing to potential deforestation and increasing CO2 emissions due to importing high volumes of biomass from North America, but their conversion process also generates higher greenhouse gas emissions than gasification.
Biomass gasification is a viable source of renewable energy, so long as gasification plants process local sources of biomass waste. One example of this is the 6MWe capacity advanced gasification plant located in Movialsa, Spain.
This plant takes waste olive pomace – a byproduct of local olive oil production – and converts it into syngas, which is then fed through Jenbacher engines to be converted into electricity that powers the plant and is sold to the national electricity grid.
Because the waste is local, the carbon footprint is negligible. The energy produced is 100% renewable, and much of it is even used onsite.
Myth 3: “Gasification has never been proven to work at a commercial scale”
FALSE – this myth has come about to the failures of certain high-profile gasification projects.
As this 2018 news story claims, gasification “has been characterised as an area of technology ‘synonymous with bankruptcies, failures and broken promises’”.
It goes on to mention the high-profile abandonment of a gasification project in the Tees Valley area of the UK.
The industry news site Let’s Recycle also goes into detail on the Tees Valley project, and follows up with a long list of similar setbacks for the industry in the UK.
In seeking to answer the question in this article of whether large-scale gasification is truly viable, the writer Tom Goulding concludes: “The jury is still out, but proof of its success could be just around the corner.”
Gasification does work at commercial scale — if the process is designed, implemented and managed correctly. Any waste to energy projects should consider the feedstock being used and the application of the syngas produced.
To return to the example of the gasification plant in Movialsa, the plant was conceived to convert local waste into heat and electrical energy. It was designed and built with that specific purpose in mind.
More to the point, the plant in question has a capacity of 6MWe. It has operated without problems for the last 9 years, with more than 125,000 cumulative engine operating hours.
Additionally, to qualify for the preferential electricity tariff when selling to the national grid, annual audits have to be performed on the gasification facility by an independent verification company.
Not only are the operations verified externally to a high standard, but the world-leading engine producer Jenbacher has offered an extremely complementary testimonial about the quality and the stability of the syngas generated at the plant.
Myth 4: “Gasification can’t convert RDF / MSW into energy”
FALSE – gasification can be very effective at converting refuse-derived fuel (RDF) – also known as municipal solid waste (MSW) – into energy.
Again, this myth comes about as a result of the high-profile failures mentioned above, all of which were designed to process RDF. Leaving some people with the misguided notion that gasification won’t work for this application.
However, we know this is wrong. The universities of Lorraine, France, and Extremadura, Spain, have test facilities based on our advanced gasification technology. As a result of R&D carried out at these locations, we have test results from over 50 different kinds of feedstocks, including municipal and industrial waste.
Before joining EQTEC in 2010, our CTO Yoel Aleman ran the operations of an RDF (mainly plastics) gasification company with an 8.5 MW facility and 11 Jenbacher engines.
Further, this news story relates EQTEC’s progress in building a gasification plant in Billingham, County Durham:
“The plant will use Eqtec’s proprietary gasification technology to convert municipal waste into gas that can be used for heat or electricity.
“Located at Haverton Hill… the plant will process an estimated 200,000 tonnes of waste per year, with a capacity of up to 25 MW.”
The technology has been proven to work. And it’s only a matter of time before the Billingham plant is likely to prove its effectiveness on converting RDF to energy at commercial scale.
Myth 5: “Gasification can only work with a narrow range of feedstocks or waste”
FALSE – We have tested over 50 kinds of feedstock with our advanced gasification technology.
It is true that gasification works more efficiently when a plant is dedicated to one or two kinds of feedstock.
However, as mentioned about, R&D carried out in conjunction with universities in France and Spain has proven that more than 50 different feedstocks can be converted into energy using this process – and in multiple different waste categories, including:
- Refuse derived fuel (RDF) from municipal solid waste (MSW)
- Solid recovered fuel (SRF) from commercial & industrial waste (C&I)
- Agri-industrial waste
And more besides.
Myth 6: “The applications for gasification are limited”
FALSE – the syngas produced from gasification can be used as fuel. It can also be converted into multiple other uses.
Syngas can be used for:
- Heat/steam for use in on-site industrial process applications
- It can also be converted to a synthetic biogas via a methanation process. The biogas can then be injected directly into the gas grid.
- Applying a Fischer-Tropsch gas-to-liquids module to our syngas will convert it to biofuel, which can be used for:
- Substituting diesel or petrol in road, rail, air and marine transport vehicles
- Energy production – because biofuels can be stored in fuel cells and used for
backup power generation
- As a lubricant
Syngas also contains hydrogen, which can be separated and purified for use as a clean energy generator in its own right.
The syngas we produce from wood waste contains 42% hydrogen, on average. And this process is 100% green.
Finally, the gasification process can generate the byproduct biochar, which in turn is used to:
- Improve water quality
- Reduce soil emissions of greenhouse gases
- Reduce nutrient leaching
- Reduce soil acidity
- Reduce irrigation and fertiliser requirements
Myth 7: “Gasification plants are expensive and difficult to build”
FALSE – While large plants have frequently proven to be expensive failures, smaller-scale modular plants require no subsidies and offer a double-digit return on investment.
To quote from a recent research note published by Arden Equity Research:
The benefits of this approach compared with large, so-called ‘stick-build’ plants are “reduced installation time and cost, greater construction schedule certainty, repeatability, scalability and small footprint,” the notes says, adding:
Why advanced gasification is the best waste to energy technology
Waste to energy projects have got a bad rap in recent years, due mainly to the growth in incineration. But, as we’ve seen, advanced gasification offers lower greenhouse gas emissions, greater efficiency, and the ability to process more than 50 different kinds of waste into dozens of clean energy solutions.
When properly designed and installed using a modular approach, the financial risks are greatly reduced and offer an unlevered, unsubsidised IRR of 12-14%.
So, in a world of rising waste levels and the need for more sustainable energy production, isn’t it time we busted these damaging myths that are holding gasification back?