Taking care of our waste : are waste-to-energy plants compatible with waste reduction policies?
34% of municipal solid waste in the European Union are still landfilled. Those landfills are the third largest source of methane in the EU, behind industry and agriculture, thus contributing to global warming.
Waste incineration plant, Malmö. Source : wikimedia commons
Waste-to-energy is the process of generating energy from waste. The most common way is to create heat through the combustion of waste ; it is a form of energy recovery.
These plants burn waste in a furnace, producing heat, that in turn boils water, thus activating a turbine that creates electricity. The recent plants are working in cogeneration, so the remaining heat that is not converted into electricity is used for heating. Constructing such modern cogeneration plants requires an important investment, especially when they have an efficient flue-gas cleaning system to reduce their hazardous atmospheric emissions, so there must be a market for the heat produced. For that matter, waste-to-energy plants are good for injecting into the grid as district heating.
They are a good way of producing energy while taking care of waste efficiently. It can also be considered a local energy source, as they don’t require the import of fossil fuels and each country generates trash proportionally to the population.
Waste reduction and recycling are best and cost-effective
Usually, a waste-to-energy plant signs a contract with the city that supplies it with trash. But this can create a conflict as those plants require a lot of waste to be efficient, thus reducing the incentive to recycle more and waste less as they want to increase the energy production and lower costs.
In addition, it is more expensive to collect and sort out waste for material recycling than just collect it as residual waste and send it to energy recovery.
For example, plastic can be a good fuel for energy plants, as it creates a lot of energy when burned. But it is better to recycle it into other plastics or something else, also because it is hard to filter-out toxics from plastic combustion.
After combustion, it is easy to collect the metals left, and recycle them. The non-hazardous residue left, called bottom-ash is often used in the construction industry, for example to build roads.
Some European countries show the good example
But it is not incompatible with such plants.
Countries like Germany or Sweden, that recycle the most also incinerate residual waste for energy recovery: the two should go hand in hand. For example, in Sweden, about 50% of household waste is material recycled, most of the rest is used in waste-to-energy plants and only about 5% are landfilled. The best strategy is to promote material recycling before energy recovery: removing hazardous waste (such as batteries, light bulbs, etc) and valuable material that can be recycled (metal, paper) and then only use the rest for energy recovery.
Some countries continue to approve, finance and build waste-to-energy plants even though their capacity exceeds domestic waste volumes. The reason for that is that it remains profitable to use such plants, even if it means importing waste from another country. It is the case in Sweden, Germany, Netherlands and Denmark.
Even though some people argue that in the long run, it can be counter-productive with waste-reduction policies as it is not encouraging to reduce waste, in the current situation, a lot of waste is still produced, so these facilities are a good way to deal with waste while producing energy.
There is a need to reduce the volume of waste produced.