Sevier Building Organics-to-Energy Plant in Tennessee

Sevier Solid Waste Inc. (SSWI) is building a waste-to-energy (WTE) plant in Pigeon Forge, Tenn., at a cost of $2.25 million.

The facility will convert composted material into thermal energy while also producing a high-carbon biochar. The new biomass gasification plant will be capable of converting more than 30 tons of organics daily.

PHG Energy will build the plant for the Pigeon Forge-based Sevier, according to its news release. The companies expect the plant to open in mid-2016.

SSWI operates a waste composting plant that processes more than 100,000 tons annually from Sevierville, Gatlinburg, Pigeon Forge and the Great Smokey Mountains National Park. The plant processes all their municipal solid waste (MSW), with 60 percent of it made into compost.

The new operation will reduce the carbon footprint of the facility by more than 450 tons of carbon dioxide emissions each year, according to calculations by the U.S. Environmental Protection Agency (EPA).

“This new installation will help us reduce the amount of compost we need to transport by converting it into a biochar material, creating a new revenue stream for us,” said Tom Leonard, director of SSWI. “The energy from the gasification system will be used in a thermal oxidizer promoting odor control in the buildings and will allow us to defer other upgrades. This represents a significant savings from our current disposal and operating costs.”

Sevier is receiving a $250,000 Clean Energy Tennessee Grant through the Tennessee Department of Environment and Conservation (TDEC).

The Nashville-based PHG Energy will provide the gasifier, thermal oxidizer, material handling equipment and build the facility. The project will feature PHGE’s second installation of its large-frame gasifier, possibly the world’s largest downdraft unit and capable of more than 60 tons per day throughput.

PHGE’s gasification plants use a thermo-chemical process that cleanly converts biomass to a combustible fuel gas. About 90 percent of the biomass that is gasified in the PHGE system becomes fuel gas, and the remaining residue is the charcoal-like biochar. SSWI will sell the biochar from the Pigeon Forge plant to a local industrial user as a renewable source of fuel in place of coal.

The WTE market has seen a resurgence this year, as the first ground-up large-scale project in 20 years opened in June. The Solid Waste Authority of Palm Beach County WTE facility in West Palm Beach, Fla. is now the largest such facility in the country. Smaller scale developments have occurred as well, with Blue Sphere Corp., an Israeli-based company active in the fields of organic waste to energy, beginning construction on its first two U.S. projects this year. It broke ground on a $19-million 3.2-megawatt WTE facility in Johnston, R.I., and on a $27-million, 5.2-megawatt facility in Charlotte, where it maintains its U.S. headquarters.

Both facilities use organic waste as a fuel, which generates smaller amounts of electricity than most of the large incinerators that are burning bulk quantities of MSW.

But as governments get more aggressive about waste recycling and diversion goals, WTE comes more into play. In Chaz Miller’s March Circular File column for Waste360, he spoke about states like Florida that include WTE in their recycling goal. ”Waste to energy is a valuable technology for managing waste, but it is one and done,” Miller said. “It is not recycling.”