9 MAY, 2022
By Christopher Gannatti Gannatti
Electricity, in many ways, powers the world. Even as I type these words, there is a dependence on electricity to ensure that they show up on your. But how is electricity generated? There are many ways, but the common thread tends to be something needs to rotate, and as long as there is energy to keep the rotation going, there can be electricity. A common approach is that some process (nuclear power, natural gas, coal) is used to heat water into steam and then the steam is used to rotate a turbine.
One of the biggest debates of the day regards how to value the different trade-offs between the different ways of rotating these turbines. Wind has no carbon emissions, but it doesn’t blow all the time. Nuclear generates heat with no carbon emissions, but it leaves radioactive materials. Fusion power has gotten some headlines of late and would generate no carbon and no radioactive wastes, but in most cases it still requires more energy to be operated than it gives off for power generation.
As yet, no energy source is perfect.
While the idea of heating water to steam and rotating a turbine is the same as many other approaches, a waste-to-energy plant will use municipal solid waste as the fuel which would then heat the water to generate the steam. It is estimated that in the United States, for every 100 pounds of municipal solid waste, about 85 pounds can be burned as fuel that could generate energy. One of the primary benefits of this approach would be that 2,000 pounds of ‘garbage’ would be reduced to ash that would likely weigh between 300 and 600 pounds. The volume of the waste could be reduced by about 87%.
An important step for a waste-to-energy plant would be how the exhaust fumes would be dealt with. There could be different pollutants generated from the burning of municipal solid waste, but technologies do exist to filter the exhaust fumes. It is also the case that technologies do exist that could aid in reducing or removing the carbon emissions. Taking these technologies from ‘existing’ to being ‘widely deployed’ is a critical step on the journey if waste-to-energy plants will achieve wide adoption and limited controversy.
Data from the EU indicates that about 2.4% of the total energy supply in 2018 came from waste-to-energy plants. The average European is responsible for roughly 500 kilograms of municipal solid waste per year. There have been changes in legislation that have led to less use of landfills and more incineration of municipal solid waste. In 1995, roughly 32 million tonnes were incinerated, and this figure more than doubled to 70 million tonnes by 2018.
Energy generation from the burning of waste was the highest in Germany, but the United Kingdom, France, Italy and the Netherlands were also participating.
What is worse: burning waste to generate electricity and releasing carbon dioxide, or not burning waste but then needing to place the waste within a landfill? It is not a simple question.
The EU is seeking to become carbon-neutral by roughly 2050. The desire to phase out the burning of coal, oil and natural gas has been fairly clear. Whether or not there is also a phase out of waste-to-energy in relation to this could depend on whether there is a belief that there is less carbon emission from burning the waste than by letting it sit in an landfill.
It is also the case that the by products of incineration are not useless—they can be used in building construction. Waste-to-energy plants can operate 365 days per year, and they can help balance solar power and wind power, which we know do not generate power at all times. Currently, 18 million European citizens receive electricity and 15 million receive heat from these plants.
In 2019, EU-based incinerators emitted 52 million tonnes of carbon dioxide. It is possible that, over time, the carbon dioxide could be collected and used. In the Netherlands, a waste-to-energy facility in Duiven is supplying a local horticultural greenhouse with carbon dioxide to promote plant growth. One cannot say that all carbon dioxide is even close to being collected today, but the concept is quite interesting.
A brief look at power generation through the waste-to-energy process envisages a microcosm of the broader issues around climate change. A perfect solution—unlimited energy without any emissions or other wastes—is not yet accessible. As a society, we must choose how we value the other trade-offs. Waste-to-energy has drawbacks, but it also has positive elements—for example limiting the space needed in landfills. We look forward to continuing to see how the waste-to-energy space evolves and if the carbon dioxide being produced can be more effectively captured for actual, economic use.