Gasification

Waste to energy: Lessons from Japan

The objections to gasification have not changed since the technology was invented: too expensive, too maintenance-intensive, not efficient enough in comparison with conventional incineration. Only Japan has been able to do better. Why is this?

Gasification plant in Kitakyushu City: Japan’s extremely restrictive landfill policy is a major driver for gasification, while the technology’s disadvantages are less important than they are elsewhere.

Gasification is considered to be the most widespread alternative to the conventional waste incineration processes of grate and fluidised bed. However, it has not yet been implemented on a large scale. According to the World Bank, the market share of alternative technologies such as gasification is no more than 2%, even in high-income countries. In low-income countries, these technologies are in reality non-existent.

There is one major exception, however: Japan. In the early 2000s, gasification and the less commonly used pyrolysis processes together had a market share of over 50% in the waste-to-energy sector. While this has now fallen to an estimated 25- 30%, Japan’s waste industry would still be inconceivable without gasification plants.

Japan’s preference for gasification is a result of its geography. Large parts of the island nation are so densely populated that there is extremely limited scope for building landfill sites, where the residual waste from thermal recycling could be disposed of. In addition to a very strict separation and recycling regime, gasification is therefore a key lever in Japan’s waste management strategy in order to minimise the use of landfill.

Advantages of Gasification

Nobuhiro Tanigaki is Senior Manager at Nippon Steel Engineering, the market leader in Japan, which has built more than 50 gasification plants. He explains the advantages using the example of the company’s Direct Melting System (DMS), one benefit of which is that significantly less residue is produced than with conventional incineration. “The final landfill amount from grate in Japan is approximately 15%, while the final landfill from our Direct Melting System is only 3%. It contains only the Air Pollution Control residue, whereas the landfill from conventional grate technology contains bottom ash and APC residue. As the landfill costs of bottom ash and APC residue are almost the same, the gap is the benefit. In addition, DMS co-gasification of other waste that is difficult to treat, such as rejects from recycling centres, incombustibles or reclamation waste, would help to minimise the final landfill as well.”

In Japan, which has the highest average landfill costs in the world, this is a very strong argument. The prohibitive landfill costs are the decisive factor for the Japanese waste industry. While an average of around 25% of household waste is still sent to landfill in the EU, the corresponding figure in Japan is 10%. This waste consists solely of residual material from incineration or gasification. In Europe, the 10% landfill target set out in the Circular Economy Package is not expected to be achieved until 2035. However, the importance of waste-to-energy recycling in Japan becomes even clearer when the total amount of waste is considered, not just household waste. According to figures from the Japanese Ministry of the Environment, just 1.1% of the entire volume of waste generated in Japan was landfilled in 2015.

Restrictive policy

While the extremely restrictive landfill policy is a major driver for gasification, some of the technology’s disadvantages are less important in Japan than they are elsewhere. This is primarily due to the specific legislation governing the Japanese waste management system.

For example, municipalities in Japan not only have to draw up a long-term waste management plan for at least the next 20 years, they are also required to treat and/or recycle their own waste in their area. If necessary, small municipalities can also form associations, but waste transport over longer distances is generally prohibited. In addition, as waste to energy is one of the waste management schemes, the redundancy of the plant is in the interest of the municipalities. This encourages demand for relatively

small units that process relatively small quantities and for which there are also sufficient maintenance slots available as a result of lower utilisation levels – all factors that favour gasification technologies. According to estimates, the plants only operate for around 280 to 300 days a year.

And gasification has an additional advantage: in Japan, the bottom ash produced during incineration cannot be used directly, for example in road construction, but must undergo additional treatment beforehand, such as melting or calcination. In gasification, in which no bottom ash is produced, this problem does not arise in the first place.

Waiting for the breakthrough

For Nobuhiro Tanigaki, one thing is therefore clear: “Under the legal framework we have in Japan, conventional grate incineration may not be the best solution for municipalities. Moreover, if the technology can process as wide a range of waste as possible in the same plant, in a process known as co-gasification, it changes the waste management boundary conditions and is advantageous for municipalities,” says Tanigaki. That, too, speaks in favour of this form of gasification.

At present, however, Japan’s experiences cannot easily be transferred to other countries – because no matter how well the technology fits into the Japanese system, in other countries it is regarded as exotic. And justifiably so in the view of Peter Quicker, Professor of Technology of Fuels at RWTH Aachen University. “Gasification technologies have reportedly been on the verge of a breakthrough in the waste industry for decades, according primarily to the providers of these technologies. Amazing and ostensibly new concepts have been extolled time and again, but none of these concepts has yet been viable and at the same time affordable. That’s why there are no plants of this kind in Europe.”

>> Read the full interview with Peter Quicker here: “You can even make diamonds out of residual Waste”

What the Japanese example also shows is that the technical aspect is one factor that determines the success or failure of a technology. The political and legal framework is another. This is why the likes of Amedeo Vaccani and Suejean Asato from Zurich-based management consultancy A. Vaccani & Partners believe that gasification should remain on the radar of European providers too. In a market assessment, they judge that: “It is conceivable that one or another new syngas technology may actually reach market maturity and achieve a good level of competitiveness. As a result, European plant manufacturers using traditional processes are likely to find themselves being compared with alternative processes more often in future.”