A Wisconsin county plans to use landfill emissions for its combined heat and power projects—and aims to save money in the bargain.

By Dan Rafter

Jim Morris doesn’t mind that Wisconsin’s Winnebago County is in the minority when it comes to tapping into its landfill gas. Doing so, he says, will provide a host of benefits to his county government.

By using gas emissions from landfill waste for a pair of combined heat and power (CHP) projects, the county stands to save money and gain control over volatile energy prices, all while doing good for the environment.

Winnebago County is far from alone in relying on landfill gases as a source of power. The EPA estimates that more than 400 offices, municipal buildings, and commercial sites run on landfill gas emissions, using a source of energy that would otherwise be burned off and wasted. But of this number, only a tiny percent are CHP projects, where engines transform a single source of landfill gas emissions into both electric power and thermal heat. The EPA’s Landfill Methane Outreach Program (LMOP) estimates that, as of early November 2006, only 14 CHP projects across the country had been powered by landfill gas emissions.

Winnebago County is not just part of this smaller group; it’s at its forefront. At the end of 2006, the county completed a CHP project fueled by landfill gas. Waste heat recovered from a Jenbacher JMC 320 engine generator will provide heat to the sheriff’s station in Oshkosh, WI. The electricity will be sold directly to the Wisconsin Public Service Corp. A similar project has been proposed for the nearby State Correctional Facility, and county officials estimate that, if it is approved, it will be up and running sometime in 2007. The county is considering one more CHP project at the Winnebago County Highway Building, where direct-use landfill gas is already being tapped to power the building’s heating boilers.

To Morris, the decision to tap into the county’s two landfills for heat and power made economic sense.

“Our landfill gas supply was rising. We needed to decide how to use it efficiently,” says Morris, landfill gas electric generation manager for Winnebago County Gas Recovery. “Waste-heat recovery seemed like a good idea. We figured out the rough costs of doing this, and we liked what we saw."

The move gives Winnebago County some control over volatile energy costs. Depending on the price of natural gas at any given time, Morris says, the county can save anywhere from $50 to $100,000 a year in energy bills.

This is key. Environmental officials agree that CHP projects powered by landfill gas emissions will become more popular as long as government officials and commercial property owners realize the financial benefits of such projects. Morris gave such a wide range of possible savings to illustrate just how notoriously volatile energy costs can be, high one year, low the next. Not only do CHP projects save money for property owners, they make it easier for property owners to accurately control and budget for their yearly energy costs; no longer are owners subject to the whims of natural gas and energy price fluctuations.

A Growing Market?
Government officials hope that others will follow the path set by municipalities such as Winnebago County.

The EPA considers CHP to be a far more environmentally friendly option than are electric- or thermal-only power systems. CHP systems typically require only three-quarters of the primary energy needed by heat and power systems that operate separately, according to the federal agency.

Chris Voell, program manager for LMOP, says that the concept of harnessing landfill gas emissions to provide heat and electricity is not new. Remember those gas lines at service stations in the 1970s? The first landfill gas emissions projects came online during this time in response to the energy crisis.

Scientists and government officials searched for new renewable energy technologies that would offer alternatives to fossil fuels. Landfill gas—plentiful and easy to harness—was a natural choice.

Voell says that today landfill gas emissions power more than 400 projects in the United States, with anywhere from 25 to 50 new projects starting each year.

CHP projects powered by landfill gas emissions, though, are far less common, with only 14 now in operation, according to the EPA.

Voell, though, expects to see more of these projects in the coming years as commercial property owners and government officials grow increasingly frustrated with high and volatile energy prices.

“As the price of anything goes up, we look at these new technologies, and they begin making more economic sense,” Voell says. “When natural gas prices rise, that has certainly driven the field. We are seeing electricity prices start to creep up, too. That helps generate interest in these projects. When energy prices, as a broad term, start to rise, people look for new options.”
The vast majority of projects using landfill gas emissions involve the production of electricity. The 14 CHP projects account for a smaller subset of this group.

Direct-use projects account for the second most popular use of landfill gas emissions. In these projects, landfill gas is piped offsite where it then replaces the use of natural gas, coal, oil, or other fossil fuels. Most commonly, direct-use projects provide fuel for industrial clients that rely on boilers. Property owners, of course, must first retrofit these boilers to accept landfill gas instead of natural gas.

Landfill gas emissions are also powering about 10 alternative-fuel projects across the country, Voell says.

Financial Benefits
CHP projects powered by landfill gas emissions provide additional financial advantages for property owners. These projects use internal combustion engines or turbines located at landfills that pipe gas offsite to an end user’s facility. Engines located at these facilities generate electricity and heat. Depending on the size of the electricity program at the end user’s site, property owners can sell any excess electricity the CHP system generates back to their utility, earning extra income in the process.

Thanks to this benefit—and to the fact that landfill gas projects can be considered eco-friendly—Voell says he doesn’t expect any slowdown in the pace of new landfill gas emission projects even if the prices of natural gas and other energy sources dip.

“It’s not just the price of energy that people are concerned about—it’s the volatility of those prices,” Voell says. “It’s about not being able to budget for energy prices from year to year.”

The “green” movement is another driver. More consumers are requesting that the companies with which they do business seek out environmentally friendly ways to power their buildings and factories. Projects that use landfill gases are a natural fit with the eco-friendly movement.

“Certainly, we are seeing more people request green power,” Voell says. “There is a demand out there for electricity that is generated by things other than fossil fuel sources. This is helping to drive landfill-gas projects forward. The increased awareness by the general public and corporations to environmental sensitivity is helping.”

Tapping Landfill Gas in Winnebago County
Winnebago County officials have never been afraid to tap into their landfills for energy. During the last 12 years, the county has invested about $10 million on a gas collection system and electrical power generation at its two landfills: the Snell Road landfill (closed in 1990), which holds about 5 million tons of waste, and the Sunnyview Landfill (slated to close in 2017), which currently holds about 1.3 million tons of waste. The county has operated a Jenbacher Power plant with three 1-MW units since 2000 at the Snell Road facility.

The revenues that this plant generates—coming from a combination of the sale of excess electricity and monies received from the alternative energy tax credit—easily offset the costs required to control gas emissions. These revenues also help reduce the overall operating expenses of the landfills.

This year, county officials decided to get even more use out of their landfill gas, pumping gas from the Sunnyview landfill to a newly built sheriff’s station on the east side of the landfill. With the assistance of Butler, WI–based Inland Energy Services, which provided Winnebago County with service parts and maintenance, the county installed a 1-MW Jenbacher JMC 320 cogeneration unit in the sheriff’s station to create hot water for the heating system in the building. Because this is a CHP project, the unit also generates electricity that is sold directly to the local electric utility.

The county is saving money in two ways here. First, it is selling electricity from this system to the public utility grid. Secondly, the CHP project has boosted the total efficiency of the power plant from 38% to more than 87%.
It is this financial benefit that makes landfill gas CHP projects so desirable, says Jon Going, sales director with Inland Energy Services. The fact that there aren’t a greater number of similar projects across the country has nothing to do with either their effectiveness or their economic benefits, Going says, and everything to do with that old real estate axiom: Location is everything.

“These CHP projects are rare in the landfill industry not because they don’t make sense or that they’re not good projects. They’re rare for the main reason that typically a customer is not located right near a landfill that can utilize the heat,” Going says. “That is the main reason why these projects are still so rare.”

That wasn’t a problem with the sheriff’s station in Winnebago County. And it won’t be a problem, either, for the second CHP project the county plans to tackle. In late 2007, Winnebago officials plan to move one of the 1-MW engines at the Snell Road landfill site to the new state prison in Oshkosh.
The waste heat from the generator system will provide hot water for the prison. All that is required is for county officials to install and refit one current Jenbacher cogeneration unit so that it can recover waste heat.

Providing Clean Gas
Landfill gas, of course, isn’t usable until it is transformed into a clean fuel source. Fortunately, cleaning the landfill gas at Winnebago County—and making it usable for CHP projects—is a relatively simple process.

Saturated gas is first pre-cooled and sent to an evaporator that chills it to about 35°F. This temperature drop causes condensation, removing the liquids. The gas is then reheated to 80°F and a dew point of 40°F.
The county does have to deal with siloxanes, chemical compounds of silicone, oxygen, and usually carbon and hydrogen. But instead of installing a comprehensive and costly gas-cleaning system, Winnebago County has chosen to increase the maintenance intervals at the plants, a more cost-effective solution.

County officials are pleased enough with their CHP projects that they may use landfill gas emissions in the future to provide heat and power to the county’s highway department building.

“This is an extremely efficient use of our landfill gas,” Morris says. “And the county is glad to hear that we are saving money in heating and energy costs.”

Landfill gas emission projects, including CHP projects similar to the ones at Winnebago County, should continue their steady rise in number, pleasing an even greater number of government and commercial customers.

LMOP has identified 600 additional landfills that are good candidates to host such a program. Good candidates generally have at least 1 million tons of waste in the ground and are either still open or have been closed fewer than five years.

In all, landfill gas emission projects generate about 9 billion kWh of power every year.

Additional Projects
One of the more high-profile CHP projects is currently under way at SC Johnson, the manufacturer of such well-known consumer cleaning products as Windex, Pledge, and Glade.

In 2005, the company installed a second CHP turbine at its facility in Waxdale, SC. Together, the two turbines—both powered by waste methane extracted from landfills—provide 6,400 kW of electricity and 19,000 pounds of steam per hour.

The turbines together provide enough energy to operate the entire Waxdale site. They also provide half of all the steam needed, depending on the season. The turbines remove 52,000 tons of greenhouse gases each year. According to SC Johnson press materials, that’s equal to taking 5,200 automobiles off the road or returning 149 railroad cars full of coal to the ground.

“We’re doing this because it’s right for [SC Johnson], right for our community and right for the environment,” says Scott Johnson, vice president of global environmental and safety actions for SC Johnson, in a written statement.
BMW Manufacturing Co., based in Spartanburg, SC, also operates a high-profile CHP project powered by landfill gas emissions. BMW transforms methane gas produced at the nearby Palmetto Landfill into both heat and electricity for its manufacturing plant.

The project removes the equivalent of 61,000 automobiles from US highways each year, and generates enough power annually to heat 15,000 homes. Energy provided by recycled methane gas supplies BMW Manufacturing with 53% of its energy needs, according to the company.

Construction crews built a 9.5-mile pipeline from the Palmetto Landfill to the manufacturing plant. This makes the project unique: BMW’s landfill project is the only one that cogenerates electricity and hot water to be used at an industrial location remote from the landfill.

The landfill gas-to-energy project reduces carbon dioxide emissions equal to driving 116 million miles a year or more than 4,300 times around the earth.

Based in Chesterton, IN, Dan Rafter is a frequent contributor to Forester publications.

DE - March/April 2007