This graphic shows how seasonal waste can be used to generate power. | Graphic by BCS for the Energy Department
This Halloween, think of turning seasonal municipal solid waste (MSW) to energy as a very important “trick” that can have a positive environmental impact. Usually, these seasonal items including hay, pumpkins, candy, and leaves, are thrown away and sent to landfills. From there, the MSW decomposes and eventually turns into methane—a harmful greenhouse gas that plays a part in climate change, with more than 20 times the warming effect of carbon dioxide (CO2).
However, when MSW is used to harness bioenergy—rather than simply being thrown away—the end result benefits the environment and helps our nation become less dependent on carbon-based fuel. Harnessing the potential of bioenergy allows the United States to generate its own supply of clean energy that reduces greenhouse gas emissions. It also limits stress on landfills and could ultimately create jobs for manufacturing, installing, and maintaining energy systems.
So how does this process work? Similar to composting, one method of converting waste to energy is called anaerobic digestion. This is a natural process where microorganisms are used to break down organic waste materials in an air-sealed tank, which is heated up to accelerate processing.
This allows the waste material to decompose quickly and produce biogas that can be captured and directed through a turbine to ultimately generate electricity. This electricity can power homes and run vehicles, and the heat that results from the process can be used onsite to reheat the digester.
Pumpkins and hay are indeed capable of producing bioenergy, but everyday MSW—such as packaging, newspapers, and food—can also be used to generate clean, renewable energy. The United States generates nearly 250 million tons of trash annually, so the potential to convert waste to energy extends beyond the Halloween season.
The Energy Department’s Bioenergy Technologies Office is working to expand waste-to-energy opportunities in the United States especially related to anaerobic digestion at landfills. This will help grow America’s network of distributed power and biofuel production sites.
Check out our Energy Basics site for more information on how bioenergy works.