Waste to energy
Could WTE help solve our energy needs?
Could WTE help solve our energy needs, firm up energy supply and reduce energy prices, while providing the added benefit of dealing with waste?
We explore some of the often-asked questions around Waste to Energy and how it can become a part of the energy transition solution.
What is Waste To Energy?
‘Waste to Energy’ (WTE) or Energy from Waste (EfW) is the recovery of gas, heat and electricity from waste materials such as agricultural and food processing residues, green, garden and food waste, and municipal solid waste.
What are the advantages of WTE?
Waste stores chemical energy, just as coal, oil and gas do, and so electricity and heat can be generated continuously, but unlike fossil fuels energy from biomass does not increase CO₂ in the atmosphere. (Incinerating plastic which is made from oil, does increase CO₂ in the atmosphere).
The obvious benefit is the removal of tons of organic waste which would normally go to landfill. The flow on effect with the reduction in managing the waste would also see a large decrease in costs from managing this waste.
Waste, unlike fossil fuels is free, or may have a negative cost.
Waste is available everywhere, so there is no need to transport waste long distances to a power station.
Electricity and heat can be generated locally, close to both the source of the energy and the energy users. This reduces the need to build new electricity transmission lines and converting waste to energy also helps to overcome the problem of what to do with the waste, as burying waste in large landfills is increasingly difficult and risky due to toxic gases, groundwater contamination where you will also see soil quality degradation.
How is WTE low cost?
Low cost or even negative cost energy source, unlike coal, gas and diesel.
Behind the meter generation eliminates network charges which account for two-thirds to three-quarters of electricity bills.
Why is the global renewable energy community not already using Waste to generate electricity, 24/7?
Despite all the intrinsic benefits and advantages of WTE, adoption has been slow.
Here are some possible reasons, and ways of addressing the issues that have been raised.
why is your WTE plant built as a modular size and How does this make a difference?
Many WTE proposals are based on very large power stations. These may appear attractive in a spreadsheet because the construction and operational overheads are spread over a higher energy output. There might also be some ‘pathway dependent thinking’, basing the WTE power stations on large coal-fired power stations.
With small modular WTE systems, efficiency is achieved through production volume rather than physical scale.
The need to transport waste and electricity are both reduced, and heat can be used in the region on a local scale.
Large scale brings large problems. A large WTE facility needs a lot of waste, which necessitates transporting low value waste longer distances that in turn, increase costs, increases the risk of environmental impact, and increases truck movements in the vicinity. Communities are less likely to accept a WTE facility that deals with the waste from other areas than one which just deals with waste from their own community.
Large facilities don’t blend into their surroundings, and so aesthetically are more likely to be resisted by communities.
The alternative to large WTE facilities is small, modular WTE plants which only use the waste from a local area or just a single factory.
Capricorn Powers small modular WTE power plant (Barton Heat Engine) is built primarily for this niche.
Would this process remove our 6.9 million tonnes of organic municipal waste from landfill altogether? (ABS 11/2020)
Some of the organic waste is now going to landfills, but we only know stories of individual councils and organisations sending organic waste to landfills, but don’t have data on the tonnes at individual sources and landfills, or aggregate data for states nationally.
Waste conversion generally comes with polluting the environment.
For WTE to benefit the environment and to be accepted, the conversion process must be to the highest standards, so the exhaust stream is very clean and meets community expectations. Low tech, low temperature combustion results in unacceptable emission of dioxins, furans, and PFAs.
The Barton Engine can use high temperature, long residency time pyrolysis and incineration that destroys these pollutants.
is all waste appropriate for energy generation?
A valid WTE concern is that the material used could have higher value than using it for the conversion to energy. However, there is plenty of material being wasted and sent to the landfill, and there will be more than enough material for energy generation even after all the material with higher potential value is removed.
These higher value uses include food processing byproducts to other food products, food waste to fertiliser and soil conditioner, paper, cardboard and some plastics for recycling.
How does WTE resolve the renewable energy transition gaps that are being seen with current intermittent solar and wind farms?
Energy sources have built-in storage, so enable 24/7 electricity generation, filling the time or temporal gap with wind and solar, without the need for batteries.
Providing baseload renewable electricity enables adding more (intermittent) solar and wind to the grid.
Utilising additional types of energy sources increases the total supply of renewable electricity and importantly right now, the transition to 100% renewable energy much more quickly.
Waste to energy power plants are an integrated part of the circular economy.
