Bioenergy

Waste-Based Energy, Present and Future

There is little doubt that the renewable energy sector will continue to grow in the United States due to concerns over the use of foreign energy supplies and the need to reduce carbon emissions.

Every day, Americans throw out a collective 1.4 billion pounds of waste: 4.6 pounds of municipal solid waste (MSW) per person adding up to more than 250 million tons of waste generated annually. Managing this staggering amount of material in a cost-effective and environmentally sustainable manner is a challenge, but also an opportunity to recover valuable resources.

MSW is a rich source of domestic energy potential. Columbia University researchers estimate the energy content of the nation’s MSW is equivalent to continuously generating 82,000 megawatts of electricity. This is a theoretical number, of course; every system has limited conversion efficiencies and an increasing amount of the waste stream is being diverted (quite appropriately) for recycling. Nevertheless, the immense scale of the resource is undeniable.

In many ways, we are already taking advantage of this resource. Mature and scalable technology to recover energy from non-recyclable materials takes two forms: waste-to-energy and landfill gas-to-energy (LFGTE) facilities. Currently, the country’s 86 waste-to-energy facilities have 2,700 megawatts of generation capacity, more than the entire domestic solar industry. Similarly, the hundreds of landfills across the country with LFGTE facilities have a collective capacity of 1,600 megawatts.

Waste-based energy has a number of advantages over other sources of renewable power: unlike intermittent sources of energy, it can generate consistent base load power and directly offset the need for fossil fuel resources. These proven technologies can provide not only electricity but also methane for heating and industrial use (LFGTE) and steam for municipal and industrial use (waste-to-energy). And these facilities take advantage of existing collection and transmission infrastructure largely in place, reducing the need for costly and logistically complex changes to our energy infrastructure.

Waste-based energy is also clean. The U.S. Environmental Protection Agency has stated that waste-to-energy plants produce electricity with “less environmental impact than almost any other source of electricity.” Studies have determined that we can avoid nearly one ton of carbon dioxide emissions for every ton of trash processed by a waste-to-energy plant rather than discarded conventionally. And far from incinerators of past generations, modern waste-to-energy plants control emissions with state of the art air emission technology to protect air quality.

Importantly, using waste-to-energy does not compete with recycling. We know this from direct experience: in the communities we serve across the country, those with waste-to-energy facilities tend to have higher rates of recycling because the facility is one part of a comprehensive program that also emphasizes recycling. Notably, waste-to-energy plants also recover more than 700,000 tons of metals on site annually.

With less than 20% of waste going to waste-to-energy facilities and over 500 additional landfills identified as promising candidates for LFGTE, there is clearly room for growth. Capturing more of the resources in the waste stream will rely on expanding proven technologies and developing newer waste based technologies at the commercial scale.

Some of these promising new technologies include a variety of biochemical and thermo chemical approaches. Gasification, in which waste is superheated in the absence of oxygen to create flexible syngas, has the potential for processing divergent waste streams.  Organic waste in anaerobic digesters, where microbes consume food and yard waste to generate methane-rich biogas, can generate electricity.  Organic waste can also serve as feedstock for waste-to-fuels technologies that transform the carbon-containing components in waste to marketable transportation fuels. In many instances, these technologies have shown promise at small scales and need further investment and pilot-scale development for real-world operational data.

The international community has embraced waste-based energy, and European countries benefit from broad deployment of these technologies. With the United States looking to reduce carbon emissions, expand renewable energy sources and stimulate domestic manufacturing, waste-based energy is a market-ready solution that can provide an important component to our country’s long-term environmental and economic sustainability—while also connecting every American to the production of renewable energy.

Carl Rush is the Senior Vice President of Organic Growth for Waste Management. Over the years, Carl has overseen the development of several business opportunities, including the conversion of landfill gas into liquefied natural gas (LNG) for the fleet; investment in waste gasification technologies for energy and fuel production; development of new organics composting and energy generation technology and innovative approaches to recycling.