Frequently Asked Questions
About the Technology and Processes
What is MSW?
Municipal Solid Waste (MSW) covers all rubbish or refuse collected from the kerbside for disposal by local authorities. It includes food waste, plastic, paper, cardboard, garden waste, metal and glass. Many of these materials are increasingly sorted either before or after collection for recycling, but there is inevitably some part that cannot be recycled economically and is sent for disposal by landfill, incineration or waste-to-energy facilities.
What is C&I?
Commercial and Industrial waste comes from business premises rather than homes but is otherwise very similar in composition to MSW.
What is carbon based waste?
This includes paper and cardboard, textiles, plastics and organic material such as food, wood and other plant material.
Is MSW the same as RDF?
Refuse Derived Fuel’ is a description sometimes used to describe types of waste that can be incinerated to provide energy or generate heat.
Isn’t it better to recycle waste rather than burning it to produce energy?
This method of waste management works hand in hand with recycling. Recycling is a good solution for certain types of waste, those where there are already established collection, sorting and handling facilities and a steady market for the recovered materials. So yes, reduce, re-use and recycle as much as possible, but whatever waste is left over can now be recycled as energy in a highly efficient way.
How will fuel feedstock of waste be obtained?
Given the need for clean, segregated, carbon based feedstock we intend to enter into partnerships with waste logistics companies. Full economic appraisal of feedstock gate fees against the local market conditions will also be undertaken.
What is a gate fee?
A gate fee is the amount charged by a landfill site for every tonne taken there for disposal. It has two parts: the landfill tax and the operator’s disposal charge. By diverting waste from landfill AKS will benefit from the latter charge.
How will your process affect the environment?
What is gasification, and what is gasification with plasma?
High temperature Gasification is an existing technology similar to an incineration process except that it limits the amount of oxygen (air) in the burning process. This causes the waste to breakdown into its component gases – a mixture of hydrogen, carbon monoxide, carbon dioxide and a small percentage of other gases and tar. Plasma is an extremely high temperature source (at 5,500+°C) and eliminates all of the tar and several of the other toxic gases plus reducing the residue to an inert vitrified slag.
How robust is the gasifier technology?
Gasifier and starved air processes are well established around the world. In the UK these have not become commonplace due to low levels of landfill gate fees but as the latter escalate due to annual increases in taxes more facilities are being proposed.
What is vitrified slag?
It is the metal and mineral residues that are not turned to gas during gasification, forming an inert, non-leaching, glassy material. It has potential to be used as an aggregate in road building.
Why is your process better than incineration?
Our process eliminates the issues of air pollution and waste ash. It will also produce at least twice as much electricity for the National Grid for every tonne of MSW processed.
Does the system reduce CO2 emissions?
Our process efficiently converts the carbon in the waste to CO2, and maximises the energy that can be recovered from disposing of MSW. Waste is also diverted from landfill, where it produces methane when breaking down. The electricity generated for the National Grid actually saves coal, gas or oil being burnt in conventional power stations. This means the process will make a positive contribution to reducing the amount of CO2 generated by the UK. Once hydrogen fuel cells are used in combination with high temperature gasification CO2 can be captured at the stage where syngas is converted to hydrogen – combined with storage this process gives potential for carbon neutral or even carbon negative electricity.
What about waste ash?
Incineration can produce 25% ash for every tonne of MSW burnt and this has to be treated and buried. Because our process uses vey high temperatures, the amount of waste is much smaller [potentially less than 1% to landfill, The co-product of vitrified slag is so inert it can be used in construction as a substitute for aggregate.
What is the overall Carbon Dioxide footprint profile?
As a result of the substantive improvement in fuel to energy conversion efficiency in the AKS process we are totally confident that the CO2 output per tonne of throughput will be dramatically lower than conventional systems. Until a final version is running on an industrial scale, however, we cannot speculate on the absolute level of reduction, but in combination with fuel cells and carbon capture & storage (CCS), carbon neutral or even negative electricity is possible depending on the proportion of renewables in the feedstock.
What is the energy balance of the plant?
Our calculations suggest that each plant processing 50,000 tonnes of prepared MSW per year would supply the National Grid with a nett of 48k MWh per year from the Stage 1 ICE phase & 79k MWh per year from the Stage 2 fuel cells.
Where will you build your plants?
Existing landfill sites are an obvious place, as they are already receiving waste and the transport infrastructure exists. The plants can also be placed alongside existing incinerators, eventually taking over from them. Otherwise they can be built on other industrial or brownfield sites.
- The AKS process will have a positive effect on the environment in a number of ways:
- Existing landfill waste streams can be diverted in order to produce clean electricity.
- With less landfill, the future emission of undesirable greenhouse gases such as methane can be much reduced from that source.
- It is potentially a more efficient form of electricity generation in terms of reducing carbon emissions when compared to existing fossil fuel, most renewable or other waste-to-electricity models such as incineration.
- In contrast to incineration, the high temperature gasification process emits fewer pollutant gases, and no fly ash or waste ash. Harmful emissions, such as dioxins, are destroyed by process itself.
- A co-product of the process is inert vitrified slag, which can be used as road-building aggregates, reducing demand for gravel extraction.
- The facilities can be built on existing landfill sites, reducing the likelihood of opposition to their construction, and can utilise existing infrastructure such as roads built for waste transport.