story by Michael Tilley. Photos from the Fort Smith Department of Sanitation. Graphic from the U.S. Environmental Protection Agency.
It’s time to update the rule book with this revision to an old rule. “Garbage In, Gas out”
A lot of gas.
More than 450 U.S. landfills are finding that the pressure of putrefaction is profitable; that the noxious and the nasty can be worth a nickel or two. Or millions.
That’s the case at the 1,000-plus acre Fort Smith Sanitary Landfill, where an almost 3-year old investment in a methane gas capturing system (photo above) produces about 1.3 million cubic feet of gas a day. The production generates more than $100,000 a month in sales for Los Angeles-based Cambrian Energy, according to Baridi Nkokheli (pronounced, Bah-read-e No-Ko-Kaylee), director of the Fort Smith Department of Sanitation.
Prior to a $6 million equipment upgrade in 2005 by Cambrian and South-Tex Treaters, less than 20 percent of Fort Smith’s landfill gas was sold, and even then, it was “low-grade” gas useful only to MacSteel for use in its blast furnaces and for heating systems at Owens Corning.
Landfill gas sold between October 1998 and February 2006 provided the landfill with $177,114, or less than $1,990 a month.
“When I came on board, I wanted to get this gas up to pipeline quality so we could expand our users and make more money,” Nkokheli said.
The investment by Cambrian created the pipeline quality gas sought by Nkokheli. In March 2007, Cambrian began selling the gas to Fort Smith-based Arkansas Oklahoma Gas Corp.
The revenue stream is much better. Between March 2007 and September 2008, the landfill has collected $272,398 from its share of the sale proceeds and property rental, or just short of $15,100 a month.
Cambrian estimates the landfill could produce up to 3 million cubic feet of methane a day. To capture that potential, Cambrian drilled 11 new wells and re-drilled 10 existing wells (see schematic at left of a landfill well). There are about 67 wells on the landfill, Nkokheli said.
Fort Smith didn’t spend a dime on the investment. Cambrian energy pays rent on the land they use, and pays the sanitation department 6.5 percent of total revenue.
The financial return to the sanitation department has an added bonus in that the department is operated under an “enterprise fund” arrangement. This means the department essentially operates as a business — its revenue must cover its expenses.
“The revenue through this (gas sales) reduces any pressure we might have to raise sanitation rates to cover our costs,” Nkokheli explained. “And I think we’ll see that amount (methane sales revenue) increase.”
THE 300-YEAR PROJECT
The Fort Smith landfill is the only Arkansas operation selling methane gas to a utility. The landfill in North Little Rock uses its methane to generate electricity to power operations at the landfill, Nkokheli said.
How long could the city sell methane?
“Potentially forever,” Nkokheli said.
The formal estimate is about 300 years.
“That might as well be forever, the way I see it. It’s way past my lifetime,” Nkokheli said with a laugh.
The Fort Smith landfill sits on 1,012 acres and has a disposal capacity of more than 72 million cubic yards of waste and required soil cover material. It has an estimated operational life of 65-plus years.
The landfill takes waste from six Arkansas counties and in portions of two Oklahoma counties. An average of more than 400 vehicles bring more than 1,000 tons of trash to the landfill each day, according to the department’s Web site.
BEER AND PLASMA
Nkokheli and Cambrian aren’t unique in their arrangement.
The federal Environmental Protection Agency estimated in a June 2008 report that landfills were the second largest human-made source of methane in the United States in 2006, accounting for 22.6 percent generated.
At least 450 operational projects in 43 states supply 11 billion kilowatt hours of electricity and 77 billion cubic feet of landfill gas to direct-use applications annually, according to EPA data. This energy powers more than 870,000 homes and heats about 534,000 homes annually.
And there is beer to be made from landfill gas. Anheuser-Busch is working with the McCarty Road Landfill in Houston to power its Houston brewery. The gas is expected to power six steam-producing boilers at the brewery. Combined with other renewable energy efforts, Anheuser-Busch believes that about one in every seven of its U.S. beers will be brewed using renewable energy by the end of 2009, according to an EPA report.
Nkokheli isn’t happy to rest on his gaseous laurels. He is investigating a “plasma arc” process that heats solid waste — up to 6,000 degrees — that then powers an electricity-generating turbine. The plasma arc, by burning material that would otherwise be placed in the landfill, reduces solid waste volume by as much as 80 percent.
“If that works for us, it could add many years to this (life of the landfill),” Nkokheli said.
The electricity from a plasma arc system also could be sold to a utility, providing yet more non-sanitation revenue for the department.
Nkokheli values the surprise of citizens who first learn of the methane gas operation almost as much as he does the gas revenue.
“The benefits to the city and community are cleaner air and cost savings,” he said. “During tours of the Fort Smith landfill, citizens and visitors are surprised to learn that the Fort Smith landfill provides gas to homes and business that is used for heating and cooking meals.”
Night operations at the methane plant at the Fort Smith Sanitary Landfill.