Britain's rubbish regret
As modern consumer societies have developed, humans have been presented with a beguiling problem: what to do with all the waste generated by our modern lifestyle.
Initial solutions favored an "out of sight, out of mind" approach: Governments buried trash underground - or sent it out to sea, sometimes resulting in catastrophic environmental damage.
But what if the trash could really be made to disappear? Burning rubbish seems to present an ideal solution. Not only does it make the garbage go away, it could also generate heat and electricity - while releasing less greenhouse gas emissions than burning fossil fuels.
With this in mind, the United Kingdom has wholeheartedly embraced incineration technology in recent years. Since 2010, the country has more than doubled its capacity for burning residual waste - that is, waste that has not been recycled - up from 6.3 to 13.5 million tons of capacity. An additional 7.9 million tons of capacity has already been contracted to be built in the coming years.
But with the rise of renewables, such energy is looking less attractive. Building out incinerator capacity is making recycling goals hard to meet - and could lead to the absurd situation of having to import waste to feed to industrial burners.
Mystery black bags
According to a new report from the environmental consultancy Eunomia, all of this incinerator-building will make it impossible for the UK to meet its planned recycling targets. That's because incineration capacity offers a perverse incentive to stop recycling.
According to the "waste hierarchy" guiding government policy, only waste that cannot be recycled should be incinerated.
But what can and cannot be recycled is sometimes subjective, Eunomia's Harriet Parke, one of the authors of the report, told DW.
"Residual waste is the rubbish that's put into the black bags instead of being separately collected," she explained. "But a lot of what's in there is recyclable, it's just not being sorted properly. At the moment it's all just being burnt in incinerators."
Except that if all of the companies building incinerators were to recoup their investment, that would mean they want as much "black bag" rubbish as possible. Which, again, offers a perverse disincentive for recycling.
The Eunomia report concludes that if all of the planned incinerators were built, the UK will only reach a 57 percent recycling rate by 2030. That is far below the 70 percent target about to be adopted under European Union law - a target the UK government has signaled it will keep, even after Brexit.
Industry counters that increased incineration capacity does not lead to reduced recycling.
Ella Stengler, managing director of the Confederation of European Waste-to-Energy Plants, says there is no evidence to suggest incineration inhibits recycling. "The competition is not between waste-to-energy and recycling - it is between waste-to-energy and landfilling," she told DW. "Those countries that do not have sufficient waste-to-energy capacity ship the waste abroad, or landfill it."
Parke says the incineration boom is a result of unclear government policy. The UK has not set any recycling goals beyond its 2020 target of 50 percent - which has created market incentives for companies to build incinerators.
According to the report, the UK is going to end up with more capacity than it has rubbish to burn by 2021, because there will be ever less black bag rubbish as recycling rates improve. That gap will reach 3.4 million tons by 2030.
To keep the incinerators operational, the UK would have to either reduce recycling rates or import rubbish to burn from other countries. And given that these plants have 20-year lifespans, building incineration facilities now locks in that approach for some time to come.
A UK government spokesperson told DW that the country is examining a range of policy options while still seeking to boost recycling rates.
"We recognize the need for a mix of infrastructure - and this will form part of a renewed strategy on waste and resources that looks ahead to opportunities outside the EU," he said.
Reduced climate benefit
The UK is not alone in its enthusiasm for incineration. It is a phenomenon across northern Europe - and some of Britain's neighbors are far ahead in the incineration game.
Sweden already burns 50 percent of the waste it generates, and imports 700,000 tons of waste per year from other countries to fuel its incinerators. The Netherlands and Denmark also now have more incineration capacity than waste.
The incineration boom is partly the result of a belief that these facilities could provide a cleaner way to generate energy than fossil fuels, producing less carbon emissions and thus reducing climate change.
Under the EU legal framework, some of the electricity generated from waste is deemed to be a "renewable energy source" and is therefore eligible for tax credits and counting toward national renewable goals. The facilities can also generate heating for cities - burning waste for energy seems to close the loop as a circular economy should.
But as countries' power sources have become cleaner, the comparative benefit of burning trash has become less clear-cut. Although trash is far less carbon-intensive to burn than coal or even oil, when compared to gas, the difference is less stark. And of course, renewables such as solar or wind power are far cleaner.
"As we're increasing our use of renewables, we're now offsetting a much less carbon intense energy mix, and therefore the benefits of burning waste to create energy are far less," Parke said.
So whatever small climate benefit was once present no longer outweighs the negative effect on recycling rates.
Incineration can also release harmful pollutants into the air such as dioxin, furan and bottom ash - although modern plants have become much better at scrubbing or filtering out these emissions.
Stengler acknowledges that burning waste is more carbon-intensive than renewables, largely because the waste often contains fossil fuel products such as plastics. But she points out that if these elements go into landfill, that results in significant emissions of methane - a potent greenhouse gas - which are avoided in the incineration process.
"We estimate that the energy produced from the residual biodegradable waste, which is considered carbon-neutral, is about 50 percent renewable energy," she says.
Don't be like the neighbors
Eunomia is advising the UK government to quickly set mandatory recycling targets for after 2020 - ahead of EU law - so that investors will pull out of planned incinerator construction.
If not, the UK could end up with the same overcapacity as its northern European neighbors, where the consultancy says recycling is being stifled and creating an environmentally harmful "rubbish trade" across borders.
The UK currently has capacity to burn 71 percent of its residual waste. In Germany, this figure is 91 percent. Sweden's capacity is 162 percent of its waste generation - while in the Netherlands, it's 143 percent.
"These countries are experiencing what we're trying to prevent happening in the UK in the future," she says. "They have too much [incineration] infrastructure in comparison to the amount of waste."