Gasification as a technology is established and works. Globally there are many examples of successfully operating gasification plants. However, gasification as a technology for treating solid municipal waste (MSW) and industrial and commercial waste (C&I) is still considered to be a relatively unproven technology.
The UK has been at the forefront of developing and delivering gasification projects which use a range of technology providers and are at different scales.
A number of gasification projects are currently heading towards completion and operation. However, a number of others have fallen by the wayside for varying reasons. It is important to take the lessons from these to help make the overall sector more successful going forward. Projects that have not been successfully delivered into operation have failed for a number of reasons but we should make sure that positive lessons are taken from these projects to ensure that current and future projects have a greater chance of being delivered successfully.
One of the key critical aspects for gasification plants to work successfully is the quality and consistency of the fuel. Whilst traditional energy from waste plants can accept fuel with wide ranging quality and consistency gasification requires a more consistent quality fuel to enable them operate efficiently. A solid and robust supply chain needs to be in place that will ensure a consistent quality of fuel.
In addition the pre-treatment process at the plant needs to be designed and engineered to be robust and reliable. Failure to do this will negatively impact on the rest of the process.
The second critical aspect is the scaling up of the technology. A number of gasification processes are proven at certain sizes e.g. tonnes per hour in the gasifier but simply scaling those up will not deliver a larger gasification process.
A number of projects have sought to really push the boundaries of the scale involved in an effort to improve commercial viability. This means that the technology is being pushed to unproven levels on commercial projects which increases the risk and has been the downfall of a number of projects. Increasing commercial viability and concurrently increasing risk are not the most compatible of factors. Technical viability must be the overriding priority.
The third critical aspect is sound engineering and a solid supply chain. The process is not just about the gasification process. It is critical as already mentioned above that the pre-treatment is robust. Other key aspects include the clean-up of emissions and the generation of electricity or upgrading the gas for other uses. These need to be properly engineered and with a stable supply chain. Having suppliers go bust during construction makes it that much harder to deliver the project successfully.
Ensuring that the above are in place will increase the probability of success. Maybe the biggest lesson that we can draw from this is that it is important that we learn how to walk before we attempt to run. That way it is less likely that we will fall over!
Dr Stephen Wise, waste sector director and waste technical lead, Amec Foster Wheeler
Problems with new technology
Gasification involved heating waste at high temperatures in the absence of oxygen to produce syngas. This can then be used to power generators or be converted to use as transport fuel.
A number of attempts to get large-scale facilities going in the UK have floundered.
The failure of Air Products’ TV1 and TV2 gasification plants in Teesside in 2016 provoked a debate on the viability of schemes of this size, especially as it involved relatively recent technology.
Last year, Avonmouth Bio Power’s advanced thermal treatment 120,000-tonne facility was put on hold. Director Navyjot Dhillon acknowledged that it had always underperformed.
“Throughput of RDF has not met financial targets and the export of electricity has been significantly below expectations,” he said.