Landfills Close the Loop–Repurposing Landfill Gas for the Trash Business
Landfill owners are joining the growing alternative fuel movement by using compressed natural gas to run their heavy-duty trucks.
Generation of alternative gas is one more LFG application a few big players like Republic Services and Waste Management have added to their portfolio rather than to simply flare it and release it into the atmosphere.
But it’s not as simple as collecting LFG, funneling it into the trucks and running them. Technology to clean it is expensive; there are infrastructure issues to work out; and while for now CNG is cheaper than diesel, markets fluctuate.
Landfill Gas vs. Natural Gas“Landfill gas is not the same as natural gas, which contains more methane and burns cleaner. To make CNG from it, you have to reduce the carbon dioxide content and raise the percentage of methane,” says Anne Germain, director of waste and recycling technology for the National Waste and Recycling Association (NWRA).
But quality requirements for CNG are not as stringent as for pipeline quality gas; CNG trucks can burn about 85 percent methane; pipeline is in the upper 90s.
“So now you are looking at a project that’s more feasible than converting to pipeline quality, which could spur growth of CNG as an alternative fuel,” says Germain.
Republic collects and delivers more than 100 billion cubic feet of its LFG to various markets every year, mainly to generate electricity, though they also produce renewable natural gas (RNG), a pipeline gas product that’s a very clean CNG. About 800 of Republic’s heavy-duty route trucks in California run on RNG. The company works with partners that clean the LFG to make the fuel and put it into the nationwide grid of natural gas pipelines. It also taps into the grid, pulls the gas and then transports it to the fleets’ locations.
“The reasons [we invest in RNG] are many: resource extraction, revenue enhancement, cost reduction, fleet emission reductions and community partnering, to name a few,” says Pete Keller, Republic’s vice president of recycling and sustainability.
Landfill gas-to-energy projects also complement Republic’s Blue Planet sustainability initiative.
“We have specific sustainability goals related to renewable energy and fleet emissions, and growing our portfolio of these … projects allows us to meet those goals,” says Keller.
Relatively, few waste management companies are capitalizing on the concept to date as it costs to build infrastructure for fueling stations, and there is capital expense to clean the gas. Plus, the end product must be competitive with diesel prices. It’s competitive today but with prices dropping, it’s getting marginal, says Germain.
Building economies of scale is a major, expensive project.
“Taking low-hanging fruit [establishing on a small scale] is not a lot of effort. But going for greater volumes ramps up cost, which is a consideration,” says Germain.
But, she said, “If you can add [monetary] value for environmental benefits, and we have seen this with the carbon tax on fossil fuels, it may be worthwhile to pursue.”
Current government incentives to switch to alternative fuels might make it doable even if the raw economics don’t work.
If You Build It, Will They Come?Before they make the investment in alternative fuel, companies need to scope out demand, whether it’s to fuel their own vehicles or whether they negotiate long-term contracts with multiple haulers or municipalities.
“If you don’t have that volume, you wasted a lot of money, so there needs to be discussions to ensure a sufficient number of trucks outfitted to use the fuel … this can’t be done in a vacuum,” says Germain.
But supply should be no issue. LFG generation varies across the country with wet areas producing more, though after a few years, landfills generally generate enough gas to run every vehicle that comes to their landfill. Some in the industry estimate it could be done on as little as one-third of the gas they produce, according to Germain.
Meanwhile, there are between 100,000 to 130,000 refuse and recycling trucks on the road almost daily, says Chaz Miller director of policy and advocacy for NWRA.
“We would like to see landfills fueling every vehicle bringing waste to it,” says Germain. “If it happens, we celebrate. If it doesn’t, our member companies will continue looking at other opportunities for landfill gas. The idea is to get beneficial use from it.”