BioCycle October 2008, Vol. 49, No. 10, p. 47
Solid waste authority in Ohio opens facility that converts landfill gas to compressed natural gas for use in fleet vehicles and medium duty trucks.
Nora Goldstein

IN mid-September, the Solid Waste Authority of Columbus, Ohio (SWACO) cut the ribbon on Phase I of its Green Energy Center that will convert landfill gas to compressed natural gas (CNG) for use in CNG-powered cars and medium duty trucks. The facility will produce enough CNG annually to replace almost 250,000 gallons of gasoline, plus additional natural gas sufficient to generate electricity for its own operations.

The first phase of the Green Energy Center is a public-private partnership between SWACO and FirmGreen Fuels, LLC. The facility collects and cleans raw landfill gas – primarily composed of methane and carbon dioxide, using CO2 Wash®, a patented technology developed in Ohio by Acrion Technologies.
“What started four years ago as a vision has now become reality. By making use of waste gases generated from SWACO’s landfill, we will produce renewable transportation fuels and skilled jobs for Ohio,” says Steve Wilburn, founder and CEO of FirmGreen, Inc.
SWACO is working to establish a consortium of local governments, school districts and private companies that are interested in adding CNG vehicles to their fleets. The CNG is available at a gasoline gallon equivalent rate of less than $3.00 – and much less if pumped directly from the Green Energy Center. “We will have plenty of fuel beyond what we could ever realistically use ourselves,” says Ron Mills, SWACO’s Executive Director. “This is the very first application of the Acrion technology anywhere in the world. We felt confident enough that it would work that we were willing to invest in the installation of a modest sized facility to demonstrate that it would perform as advertised to produce the quality of fuel needed. We plan to convert many of our vehicles and light-duty pickups to run on CNG within the next 18 months, and hope to see it used in our heavy-duty trucks as soon as possible.”
PROJECT BACKGROUND
SWACO operates a 142-acre municipal solid waste landfill to service the Columbus, Ohio metro region. The Franklin County landfill, which opened in 1985 and receives about 3,500 tons/day of MSW, has about 200 acres of expansion capacity. Because of the size of its landfill, SWACO was required to install a landfill gas collection system and a flare. Recognizing that the flare releases carbon monoxide and NOX into the atmosphere – and that the landfill gas itself contains methane and CO2, which have resource value – SWACO decided to explore options available to utilize the resources.
The more traditional landfill gas to electric system was a challenge because of access to the grid, as well as the low price paid by the utility for the electricity. While researching alternatives, SWACO learned about the Acrion CO2 wash system, which was operating on a pilot basis at the Burlington County (New Jersey) Resource Recovery Complex. SWACO’s previous executive director, Mike Long, toured the installation in Burlington County and ultimately decided to create a partnership with FirmGreen to install a CO2 wash system at the SWACO landfill (see “Fueling Up On Landfill Gas,” May 2007).
Acrion’s CO2 Wash technology removes hydrogen sulfides, VOCs and siloxanes out of raw landfill gas. Carbon dioxide, recovered from the landfill gas and converted to liquid form, is used to wash out the impurities. The CO2 Wash product, a contaminant-free mix of roughly 70 percent methane and 30 percent CO2, can be used to generate electricity. Further separation of CO2 produces methane suitable for pipeline injection or vehicle fuel.
Groundbreaking on the Green Energy Center was held in June 2005. Elements of the center are being developed in phases. Phase I was financed and developed by SWACO. Capital costs were about $4.5 million. Phase II is being developed (and will be owned) solely by FirmGreen. At full build-out of Phase II, FirmGreen will process 4,000 MMBtu/day of landfill gas using the CO2 Wash technology. With CO2 production, yields are expected to equal about 25,900 diesel gallons (DGE)/day as CNG and 132 tons/day of CO2.
“This amount of CNG production can displace the use of 9.1 million gallons of diesel fuel or 10.3 million gallons of gasoline annually,” notes Rhonda Howard, Communications Director of FirmGreen, which is based in Newport Beach, California. “Our ability to produce a fuel that meets natural gas pipeline specifications as well as vehicle and truck engine specifications (ASTM) provides us marketing flexibility.”
There is currently a 30-year supply of gas in SWACO’s Franklin County Landfill. Phase I of the Green Energy Center will tap approximately 8 percent of that supply. “We are relying on FirmGreen to take the balance of the gas – 92 percent – that is available,” says Mills. “Groundbreaking and construction of Phase II of the Center could happen in a matter of months.”
CNG VEHICLE AND TRUCK ENGINES
With the CNG production facility up and running at the Green Energy Center, the next step is supply fuel to vehicles and trucks equipped with CNG engines. At this point in time, however, the number of vehicles equipped with those engines is limited. “It is the proverbial chicken-and-egg situation,” says Mills. “One reason we don’t have more trucks and vehicles with CNG engines is the lack of access to CNG. There are light-duty passenger vehicles and pickup trucks, as well as light-duty construction equipment, being converted to run on CNG. I don’t think it will be that long before we start seeing more production of CNG-powered vehicles as it is not a big challenge from an engine perspective. But right now, people committed to driving a CNG vehicle either have to purchase that vehicle in a state where dealerships are licensed by auto manufacturers to sell CNG light-duty vehicles, or buy a conventional vehicle and have it converted to a CNG engine. Either option means the consumer will be paying anywhere from 30 to 50 percent more to get it equipped. That is an important barrier in the marketplace right now and one that elected officials are paying attention to.”
That cost may be a barrier for individual consumers, however the price differential when considering a higher cost pickup truck or a school bus becomes less significant, he adds. “Because the starting sticker price is higher, retrofitting those vehicles with a CNG engine is a smaller portion of the total cost. For example, a pickup truck with a gasoline engine may be $50,000; with a CNG engine, it could cost $70,000, which is a smaller differential when considering the lower cost fuel.”
School districts that are getting hit with budget-breaking costs for diesel fuel this year also are good candidates for CNG-powered buses. “Again, there may be a 20 percent difference in the sticker price, but if a school district can realize significant savings by using a lower cost fuel, the payback on the investment becomes very practical,” says Mills.
While school districts near the Green Energy Center have access to CNG, much wider infrastructure is needed to truly make this conversion to an alternative fuel feasible. “Our primary barrier remains infrastructure – how to deliver the fuel to fleets,” says Rhonda Howard. The access issue makes waste collection trucks an ideal candidate for an engine conversion – if they are using a disposal facility that captures and converts landfill gas to CNG. “If a fueling station is at the landfill, haulers can drop off the trash, go to the fuel station, and go back out on their routes,” she adds.
Howard notes that the CO2 Wash technology can work with biogas produced by anaerobic digesters, but it may not be an ideal application. “The real advantages of the CO2 wash is its ability to effectively screen out all kinds of contaminants, such as are found in landfill gas,” she says. “Other technologies are designed to clean out one contaminant, but not another. In addition, the wash system uses CO2 as the solvent. As trash decomposes, it continuously generates CO2 with the methane, so our solvent is continuously available. And because we aren’t bringing any solvents to the site, the permitting process is simplified, reducing the time it takes to get a project going.”
Recently, Ron Mills spent two days in Washington, D.C., meeting Congressional representatives from Ohio to tell them about the Green Energy Center and discuss the role that the federal government can play in providing incentives to promote development of the infrastructure needed to make this kind of fuel practical nationwide. “If enough people are buying the vehicles that use this fuel, more cars will be produced that can run on the fuel and the price differential will keep going down,” says Mills. “We also discussed how there need to be numerous outlets for this fuel around the country. The federal government can help get this jump started.”
Mills estimates that there are at least 100 MSW landfills in the U.S. that are the size of SWACO’s Franklin County landfill. “Our landfill alone has the potential to replace 3 million gasoline gallon equivalents per year,” which he says is a conservative estimate. “If the other landfills of our size installed a system like ours, it could be significant in a national strategy for energy independence.”