It is ironic that as our nation searches for sustainable energy solutions, an energy source passes through our hands unnoticed every day. It's domestic, renewable, low carbon, doesn't require building pipelines and we have a lot of it. While it's not as catchy as wind turbines or solar panels, it's worth a second look: garbage.
Or in government speak, "municipal solid waste."
Americans create a lot of waste. We have less than 5 percent of the world's population but generate 20 percent of the world's trash. Although we currently bury the vast majority of it in landfills, there are better options: We can take these waste streams and convert them into useful energy, convenient fuels or valuable materials.
Researchers at Columbia University found that our nation's everyday garbage could power at least 16 million homes every year - maybe more, depending on the process. Instead of burying it and taking up precious landfill space, let's put that energy to work for something useful. The garbage we regularly place at the curb could provide a key to a more energy-efficient America.
A recent study I led at the University of Texas at Austin helps illustrate this opportunity. Working with the private sector, we diverted a stream of municipal solid waste (after the recyclables had been removed) and converted it into fuel pellets. We used this engineered fuel to help power a Texas cement kiln (kilns are notoriously energy-intensive) in a blend with conventional energy sources, such as coal and petroleum coke.
Our research confirmed that this type of engineered solid fuel is suitable for powering kilns and other commercial operations. And it can produce more energy per pound than some forms of coal. We also found that if only 5 percent of the undesirable materials from recycling facilities - the stuff that doesn't have a decent market value or can't be economically recycled with today's technologies - were converted to solid fuel, we could power about 700,000 American homes.
Compared with traditional energy sources, the reduction in carbon emissions would be equivalent to removing 1 million cars from the road. And we also found significant reductions in sulfur emissions.
Most policymakers and energy experts agree that we need a comprehensive "all of the above" strategy to truly strengthen America's energy security. Engineered fuels from waste streams should be part of that strategy. The potential is too great to waste, so to speak.
And solid fuels represent only one of many promising methods to recover energy from waste. Other novel technologies transform nonrecycled plastics into a synthetic crude oil that can be used to create liquid fuels and raw materials. Another technology converts waste into synthetic gas, a versatile energy source.
The bottom line: With today's technologies, the untapped potential of our nation's solid waste is too vast to continue burying it in landfills.
This opportunity is big enough to warrant attention by policymakers. Four shifts in existing public policy would go a long way toward realizing this potential:
. Broadening definitions of "renewable energy" and "clean energy" to include forms of energy recovered from solid waste would help kick-start this industry.
. Updating policies so that engineered fuels aren't burdened with regulations meant for wastes headed for landfill is crucial.
. Streamlining environmental permitting of energy recovery facilities and making sure that energy recovery counts toward fulfillment of mandated recycling and diversion goals are both important steps that can be taken by policymakers at the state level.
. Sourcing energy from solid waste streams should be included in government renewable energy portfolios.
These shifts in public policy don't require large expenditures, multinational pipelines or drilling offshore. But they would swiftly open up a new source of domestic, abundant and renewable energy while setting our nation on a course to stop wasting our waste.
Fortunately, lawmakers are coming together to press for a comprehensive national energy strategy that includes recovering energy from waste. At a June forum of leaders in the energy recovery field, we were joined by Sen. Ron Wyden (D-Ore.) and Rep. Bill Cassidy (R-La.), who made a nonpartisan, compelling case for including energy recovery in a national energy strategy. And I'm proud to say that Sen. John Cornyn (R) from my home state of Texas has been a strong supporter of energy recovery.
David Scott, a forward-thinking energy expert, says "waste is what's left when you run out of imagination." If we put our imagination to work, in the not too distant future, we'll look back at our long history of landfilling and ask ourselves: "What were we thinking?"
Michael Webber is associate director of the Center for International Energy and Environmental Policy and assistant professor of mechanical engineering at the University of Texas.
Former Sen. Scott Brown, R-Mass., candidate for U.S. Senate in New Hampshire, holds his hand over his heart during the singing of the national anthem as he waits to take the stage for his town hall campaign rally with Sen. John McCain at the Pinkerton Academy in Derry, N.H., on Monday, Aug. 18, 2014.