The manager for two new biomass power plants spoke with Madison County Rotarians Oct. 25 about the new facilities.
David Groves, who works for Veolia, the company that has a 20-year contract to run power facilities in Colbert and Carnesville, touted the sites as among the most efficient biomass plants in the world. He explained that the plants, owned by Georgia Renewable Power (GRP), have a heat rate of 11,500 "BTU" (British Thermal Unit), adding that 15,000 to 16,000 is more typical for biomass plants and less efficient than GRP.
“For a biomass plant that (11,500) is very efficient,” he said. “In fact, it could be the most efficient in the world.”
Groves explained that “biomass” means the use of plant or animal materials as a fuel source. He said this constitutes about five percent of the total energy portfolio of the U.S. Biomass plants are viewed as an alternative to other energy sources that are cited as a source of greenhouse gas emissions, such as coal.
Georgia Power and other energy companies are trying to expand their energy sources, with biomass being an option. GRP has a 30-year contract to provide biomass-generated electricity to Georgia Power.
“Biomass itself as compared to coal, if you have half energy in a pound of biomass compared to a pound of coal, you’re doing well,” he said. “So it doesn’t have as much energy as natural gas or things like that which means the boilers typically need to be larger so you can pull what heat you can out of it.”
The plant manager spoke of the potential for carbon neutrality through biomass.
“Trees take in carbon dioxide,” said Groves, a West Virginia native. “Whether they burn or decompose naturally, they release the same amount of CO2 into the air. While carbon neutrality is debated by certain environmental groups, the more efficient the plant, the less material it takes to make the equivalent energy.”
Groves said wet materials don’t burn efficiently. So, GRP has wood dryers.
“And these (dryers) are very innovative,” he said. “They are the first of their kind. So we’re trying to get the wood down to approximately 10 percent moisture. And we’re using the waste energy from the plant to do that. So it’s no loss to the overall process.”
Groves said both plants in Colbert and Carnesville produce about 65 megawatts of electricity, with five megawatts used in-house.
“These are considered small plants,” he said. “But a good rule of thumb in the South is 120 megawatts can power about 100,000 homes.”
Groves spoke of burn sources for the GRP facilities.
“For these plants, we’re looking at industrial residues and forestry crops and potentially some agricultural crops and residue, potentially peanut shells,” he said.
He noted that the facilities provide work for local citizens, adding that the total salary and benefit packages at the plants are about $3.3 million.
“We hire local whenever possible,” he said. “These are well-paying jobs.”
Groves said each plant “requires 42.5 tons of 10-percent moisture fuel an hour.”
“If we’re at 30-percent moisture, that requires 60 tons,” he said. “You can look at just about two semi trucks of material an hour. The target is to use as much waste/feedstock as possible. We want to use as much C&D (construction and demolition) as we can, discarded railway ties and the greenwood being treetops and things like that. That’s our overall goal.”
Groves said plant emissions are a concern of citizens and a concern for him, too. But he said the emissions are closely monitored by the federal Environmental Protection Agency (EPA) and state Environmental Protection Division (EPD).
“Each stack’s emissions are monitored 24 hours a day, seven days a week by a continuous emissions monitoring system,” he said. “We must pass an annual test audit performed by an EPA-certified company. The Madison County plant had their inaugural test two weeks ago. We knew it would pass because we could see the numbers as you’re doing it. But we got the official results and it passed overwhelmingly. It wasn’t even close.”
The emissions must be reported twice a year to the EPD. Groves said Trinity Environmental Services will prepare reports, while working with the EPD to make sure it’s in the format regulators want.
Groves acknowledged that the burning of creosote-treated railroad crossties is a concern for citizens. He said the federal government under the Obama Administration changed regulations to allow the burning of the ties.
“The CTW crossties, they’re subject to the non hazardous secondary materials rule, which in February 2016, the EPA determined this is a fuel that can be safely burned in a boiler designed to burn biomass,” he said. “That was under, for what it’s worth, the Obama EPA. The difference is when you burn a crosstie on a fire (versus in a boiler). My father would bring home crossties, cut them in thirds and throw them on the fire, because they make a good fire. But the difference is, it’s not controlled. You’re not burning it very efficiently.”
Groves said crossties burnt at extreme heat in a boiler lose their toxicity.
“When you burn it in a boiler under extreme temperature, the VOCs (volatile organic compounds), which is what everybody is concerned about, are destroyed,” he said. “And the EPA determined you can safely burn them in a biomass boiler to do that. The alternative is I guess, a landfill. I know some of them (crossties) go out to Home Depot and Lowes. But I personally feel we burn them a lot more efficiently and safely than just leaving them in a landfill to leach out or whatever. We are destroying them, the nasty stuff. There’s been a few studies where if you burn them in a boiler, because they do have a little more BTUs and burn hotter, they actually burn cleaner than normal biomass.”
Groves said the plant where he worked in North Carolina burned a lot of crossties.
“The plant I came from in North Carolina, we burned about 450 tons of CTW a day,” he said. “The crossties when they come to us are about 25 years old on average. The railroads all across the country and CSX, I believe spends about $3 million a year replacing ties. So these ties here primarily come from CSX and eventually Norfolk Southern.”
Groves said that by the time old crossties are burned, they have lost most of their creosote.
“The North Carolina Division of Air Quality which is the same as the EPD here, did a study on the ties and they determined that after 25 years, 94 percent of the creosote dissipated from the ties,” he said. “In North Carolina, they issue renewable energy credits (REC), so if you get a megawatt out of burning railroad ties, they’ll give you 94 percent of a REC. That’s considered renewable. So, that’s their official opinion on it.”
The plant manager spoke of ash at the facilities and said it is monitored through the "Toxicity Characteristic Leaching Procedure."
“When I was in Virginia I worked for Dominion Power and we actually sold the ash to local farmers,” he said. “The farmers like it. It’s good fertilizer.”
“Biomass is naturally alkaline,” he said. “They take it and they run through tests to determine if there’s any leaching of heavy metals out of the ash. Ours passed that test. It wasn’t even close to be honest with you. It’s wood ash. Heavy metal concentrations are typically very low and we do test for that.”
Groves said he is proud of the Colbert and Carnesville facilities, saying they’ll be “a source of clean, renewable energy for years to come.”
“We plan and will be good neighbors,” said Groves. “We care about the communities that literally place their trust in us. And we want to be a part of community events and be a valued partner with our neighbors. We want to keep you informed once the plants are up and running. As soon as commissioning and startup is done, probably two weeks away, we plan on having some open houses and inviting everybody.”