In a sustainable world, waste would be reduced from the outset and composted, recycled, or reused. The current reality, however, is that cities and land-scarce countries face a dilemma about what to do with their trash. Waste-to-energy is a transitional strategy for a world that wastes too much and needs to reduce its emissions.
Incineration, gasification, and pyrolysis are means of releasing the energy contained in trash. Some of the heavy metals and toxic compounds latent within it are emitted into the air, some are scrubbed out, and some remain in residual ash. With these outcomes, why bother at all? Waste-to-energy plants create energy that might otherwise be sourced from coal- or gas-fired power plants. Their impact on greenhouse gases is positive when compared to landfills that produce methane emissions as organic wastes decompose.
At Project Drawdown, we consider waste-to-energy a regrets solution. It has a positive impact on emissions, but social and environmental costs are harmful and high. It can help move us away from fossil fuels in the near-term, but is not part of a clean energy future. Even when incineration facilities are state-of-the-art (and many are not), they are not truly clean and toxin-free.
Technical summaries for each solution will be available May 1, 2017.