Waste-to-energy proves a viable alternative for non-recycled plastics

Originally commissioned by the ACC to look at what can be done with non-recycled plastics that would be beneficial, the study estimated that if all the non-recycled plastics discarded in the U.S. annually were diverted in modern waste-to-energy facilities, they could produce 52 million megawatt hours of electricity, or enough to power 5.2 million households per year.

"There's a movement in terms of recycling and reuse to look at alternatives to what to do with non-recycled plastics and waste," explained Marco Castaldi of the Department of Earth and Environmental Engineering at Columbia University and Associate Director of EEC, in a telephone conference. "About 85% of those plastics that don't get recycled go to landfills."

Castaldi noted that Europe is much more advanced than the U.S. in waste-to-energy technology and in building the facilities necessary to divert municipal solid waste (MSW) from landfills and create useful energy.

According to the Confederation of European Waste-to-Energy Plants about 40% of MSW across the EU27 is still land-filled, although landfill gases (methane) contribute significantly to global warming. "The Member States who have most successfully reduced dependence on landfills have done this by combining recycling, geological treatment (e.g. composting and anaerobic digestion) and waste-to-energy," according to information from the Confederation's web site.

Castaldi noted that the same is true for the U.S.; those communities that have a waste-to-energy facility also do a high amount of recycling. "We want to make sure waste-to-energy is compatible with recycling," he said. "Those communities with waste to energy typically provide more recycling."  

There are currently only 87 waste-to-energy facilities in the U.S., but thousands of communities can benefit from this technology. Castaldi noted that the infrastructure is there to collect the waste in most cities, and many already have waste-to-energy plants, with many of those going through expansions. "Instead of sending MSW to landfills and burying that energy, we can send it to a waste-to-energy facility," he said. "We hope this study provides greater awareness of the need for more waste-to-energy facilities."

"We have to think of all possible alternatives when it comes to energy, not just solar and wind but also the untapped resource in waste - particularly plastics - that is valuable energy," Castaldi said, adding that the direct calculation of the amount of energy in plastic as it equates to coal is 1 lb. of plastic produces the same amount of energy as 1.25 lbs. of coal. "Alternative energy means including waste-to-energy in the mix, as the inherent energy is significant in the plastic waste."

Steve Russell, vice president of plastics for the American Chemistry Council, said, "Even after use, plastics continue to be a valuable resource. Whenever possible, plastics should be recycled, but when plastics aren't recycled, there is still a tremendous opportunity to recover this abundant energy source to power our homes, vehicles and businesses."

The other comparison that Castaldi draws is that for every 1 ton of plastic material, there is about 125 million barrels of oil that can be saved that is currently being used for energy purposes. "There's a large amount of energy that can be harnessed, and the tried and true way is through existing waste-to-energy facilities and how that can reduce the dependency on fossil fuel." 

But can you make money with it?

In addressing cost effectiveness, Castaldi said that the economics of waste-to-energy with plastics make sense in that it is generating the same type of energy but without having to buy coal and natural gas. "With the waste-to-energy facility, the amount the consumer would pay is about the same," he said. "In Europe the price the consumer pays is a lot less than buying fossil fuel for energy or heat."

Burning plastic is a direct replacement for burning fossil fuel, however Castaldi noted that non-recycled plastics and MSW are not sent to coal-fired facilities but rather to special-built ones to handle waste-to-energy. "All the non-recycled plastics are burned with all the other types of municipal waste - there's a certain amount that already gets into that stream and that stream can increase with plastics," Castaldi said. "The combustor is very similar to (that in a) coal-fired facility, but with some slight differences, and overall the emissions are lower from a waste-to-energy facility than from a coal-fired facility. We have data on that. Additionally, no humans have to sort the waste; it all goes right into the facility."  

The full study, "Energy and Economic Value of Non-Recycled Plastics (NRP) and Municipal Solid Wastes (MSW) that are Currently Landfilled in the Fifty States", can be found by going to the website of the American Chemistry Council.