Getting the Most From LFG

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Landfill gas as a renewable energy resource gained in stature with some high-profile projects in 2012. With installations at Coca-Cola and the University of Iowa Research Park launching to major fanfare, the industry is seeing recognition of its environmental benefits and sustainability. But looking beyond the obvious is the fact that both projects are great examples of using trigeneration, to provide electricity, heat, and cooling, to gain ultrahigh efficiency from the gas.

Such high-efficiency strategies as trigeneration and cogeneration are important factors in the economics of landfill gas projects, according to Joel Zylstra, chief operations officer for Granger Energy Services, Lansing, MI. Granger has 13 landfill-gas-to-energy (LFGTE) projects in six states, and has found success with two basic strategies. “We have landfill gas pumped through pipelines to get the gas to industrial customers where they can use it directly,” says Zylstra, “and lately we’ve been moving to a hybrid model at some of our compression facilities, where these have been upgraded with electrical generators so we can generate our own electricity for processing the gas. We call that a hybrid, and it’s a good trend for us. The Lanchester landfill was our first hybrid plant, and we’re using what we need, then exporting the remainder under a net metering program. That’s a trend in Pennsylvania, and they have a net metering program that works well for that kind of application, so we’re taking full advantage of it.”

Permits, Pipes, and Progress
If you ask Zylstra about the biggest challenge for landfill gas projects his answer can be summed up in one word: permitting. With that said, the Lanchester Landfill in Narvon, PA, could be a textbook example of how to overcome permit obstacles and create a beneficial alliance between state and county governments and the private sector. The project’s heavy paperwork was necessary because Granger wanted to transport gas to multiple customers, so before the company could begin the pipeline, it had to work with the state of Pennsylvania to overcome outdated regulations that categorized Granger as a natural-gas utility.

“These kinds of projects with a pipeline are more complex because we passed through a lot of different principalities in Pennsylvania and we had to work through all of them to get permits and easements and right of ways,” recalls Zylstra. The negotiations took months, but ultimately relieved Granger from being classified as a utility. Moreover, as the first multicustomer landfill-gas pipeline in Pennsylvania, the precedent defined the regulatory approval process for future landfill gas projects.

In December of 2004, three manufacturers, Dart Container Corp., Advanced Food Products, and L&S Sweeteners, tapped into a 12.77-mile pipeline that transports 3,500 cubic feet per minute (CFM) of landfill gas. In 2008, after another round of permits and easements and right of ways, the pipeline from the Lanchester Landfill joined with a pipeline from neighboring Conestoga Landfill and a fourth customer, New Holland Concrete, boosted its sustainability profile by using landfill gas. Today, three additional companies, Tyson Foods, Case New Holland, and H.R. Ewell also use landfill gas from the joint pipeline.

A Sweet Deal for Cogeneration
In late 2012, Granger launched a new project with L&S Sweeteners to install 2.2 MW of electricity at its location. “They wanted to continue to buy gas to generate steam and at the same time create electricity rather than take it from traditional sources,” Zylstra explains. “It’s a trend we’re starting to see where customers are electing to install onsite electrical generation. Dart Containers is another one that installed two, 5 MW turbines, and they have heat recovery. Historically, we sold the majority of our gas to Dart, and they used it to generate heat. But over the last year-and-a-half, they’ve installed the turbines so they’re producing electricity and using the heat from the turbines to produce steam in a true cogeneration operation with landfill gas, and it’s a fairly recent development in Pennsylvania.”

Granger may soon find future demand for its landfill gas as a resource for natural-gas-fueled vehicles. Pennsylvania’s Department of Environmental Protection recently held a natural-gas vehicle seminar to promote Act 13, which supports a development program to distribute up to $20 million in grants over the next three years to help pay for the incremental purchase and conversion costs of heavy-duty natural-gas vehicles operating in fleets.

Over the years, the Lanchester/Conestoga project has racked up a number of awards, including the Governor’s Award for Environmental Excellence and the EPA’s Landfill Methane Outreach Program’s Project of the Year. The Solid Waste Association of North America (SWANA) awarded Granger the Landfill Gas Utilization Silver Award in 2006. Bob Watts is a member of SWANA, where he has taught landfill management courses, and he will be speaking at the SWANA 2013 Annual Landfill Gas Symposium. He bases much of his experience on his role as Lanchester’s vice director, LFGM Technical Division, and executive director, Chester County Solid Waste Authority, PA. And he notes that Lanchester certainly qualifies as a landfill that can add to a manager’s experience.

The gas collection system at Lanchester is extensive, with about 170 gas extraction wells, leachate cleanouts, and toe-drain collectors. Gas is collected via a vacuum, and Watts says that a good gas technician has to use science, but also, the process is something of a balancing act that requires a level of experience to understand the landfill’s history and how it reacts. “Each well has an individual measurement with a valve,” Watts explains, “and the important thing is to remove all the gas that’s produced, but you don’t want to pull too hard with the vacuum because you could be pulling atmosphere down into the landfill, and the anaerobic process doesn’t like oxygen. So it’s monitored to keep the anaerobic activity within its proper temperature range because these wells heat up as the biology happens.”

Once the gas is compressed, filtered, and dewatered, it’s divided between Granger’s onsite facility and the pipeline that connects the gas customers. The onsite facility uses the gas in two Caterpillar 3520C engines to generate 3.2 MW of electricity. Though it may seem as if such hardware could complicate day-to-day management, Watts observes that an LFGTE project can be beneficial to management and operations overhead.

“Overall it has simplified my management of the landfill,” says Watts. “We have to do something with the gas, and without a project like this we would need a full-time person to maintain the gas and operate a flare. But since Granger does the maintenance, they have two-and-a-half full-time employees on our property to maintain their operations, and they also are responsible for the two flares, so overall it reduces my headaches.”

Gas-tronomical Holidays
The fact that Lanchester still flares excess gas would seem to contradict the philosophy of sustainability, but Watts explains that with landfills, size matters. “The majority of the gas is going to the end-users but those are manufactures that don’t operate seven days a week. Then we have six holidays a year and weekends so even with the two engines taking 1,000 cubic feet per minute (cfm) the system puts out 9,000 cfm. The landfill doesn’t know it’s a holiday when end-users are shut down for something like a four-day Thanksgiving weekend, so there can be a lot of excess gas.”

There should be many more holidays to come for Lanchester. The site grows by 300,000 tons per year, and that’s despite the county’s admirable recycling rate that has peaked as high as 50%. Under current projections, its life expectancy should run to at least 2025.

The long life expectancy allows gas suppliers and gas consumers to benefit from long-term contracts, according to Joel Zylstra. He notes that Granger’s contracts are typically at least 10 years or more. “They can go way out there,” says Zylstra, “and the majority of our gas contracts are linked to natural-gas prices. So it’s a great time for industrial customers because natural prices are so low and we discount off of those prices. That is a factor in the cogeneration facility at Dart, and a driving force for the generation facility at L&S Sweeteners.”

Microturbines Rescue Declining Gas Resources
Even with so many positive benefits to landfill gas to energy projects, things can go wrong, and such was the case in Santa Clara, CA, where declining landfill gas output caused the retirement of a 2.5-MW generator. Normally, that wouldn’t seem to be a major issue, but to complicate matters the landfill continued to produce enough gas to require flaring to meet environmental requirements. However, the flare needed a boost of natural gas because the landfill’s gas methane concentration fell below adequate levels. Yet as often happens, a bad situation became an opportunity for an innovative solution.

In this case, the solution came from Ameresco Inc., in Framingham, MA. As an independent provider of comprehensive energy efficiency and renewable energy services for facilities, Ameresco had a way to return the Santa Clara landfill to productivity, and designed a system using three FlexEnergy MT250 microturbines to generate electricity purchased by Silicon Valley Power. As expected, due to lower gas flows, the output from the new system is lower-750 kW, rather than the original 2.5 MW.  This innovative resolution to capture and productively utilize the waning LFG supply versus flaring received SWANA’s Silver Excellence Award in Landfill Gas Utilization.

“The award is important because it’s industry-specific and it’s nice to be recognized by your industry peers as accomplishing something special,” says Michael Bakas, Ameresco’s senior vice president, Renewable Energy. The LFGTE market has been the source of many accomplishments for Ameresco, such as the recent launch of a 2.2 MW LFGTE project at Butte County’s Neal Road landfill, from which a portion of the revenues from the sale of that power will be returned to the county for the duration of the 20-year contract.

Ameresco is not a stranger to innovative approaches to maximize project efficiencies and benefits for its clients. Bakas notes that by leveraging different efficient approaches for the landfill gas project, this can reduce the financial challenges faced by many projects due to the remote location of landfills. One design approach Ameresco has successfully employed on many projects is cogeneration. “Generally, most landfills are not located near large end users who have a consistent need for both electric and thermal loads, but there are exceptions. In the case of our BMW project, we process and then transport the gas in a 10-mile pipeline that we designed, own, and operate. It was capital intensive to move the gas a great distance that had a tremendous impact on the project economics. In order for the economics to be beneficial to our customer, Ameresco needed to sell a high volume of gas to amortize the cost over many units of gas. In the end, the price for the fuel to the client was competitive to their then current energy supply. BMW, in their own press release, states that they save about $7 million a year. Assuming such savings over the next 20 years, this extrapolates to about $140 million in total savings. That is impressive, to say the least.”

The BMW project uses gas from the Palmetto Landfill at its South Carolina automotive plant to fuel four gas turbine cogeneration units (11 MW capacity) and the plant also recovers 72 MMBtu per hour of hot water. In mid-2011, BMW Manufacturing began researching the economic and technical feasibility of converting landfill gas into hydrogen for use in the company’s fleet of material handling equipment.

A Captive Audience for Efficiency
As part of Ameresco’s comprehensive energy efficiency and renewable energy solutions, the company offers ESPC (energy-saving performance contract) services that allow customers to renew facilities and reduce energy costs without the need for upfront capital expenditures. In the case of the Algoa Correction Center in Jefferson City, MO, Ameresco had a rare opportunity to boost the sustainability aspect of Algoa’s ESPC project and leverage project efficiencies by adding a landfill-gas-fueled cogeneration installation next to the correction center.

“We were awarded an energy efficiency contract for their prison, and our local energy efficiency team suggested the site for locating a cogeneration plant that we were already developing for Columbia Water and Light,” recalls Bakas. “By locating the plant at the prison, about 4 miles from the landfill, the correctional facilities benefit from the thermal energy created by the cogeneration plant as part of the landfill gas to energy project. First, the State of Missouri reduced their overall energy requirements by having Ameresco replace their inefficient equipment through the ESPC contract at these facilities. As an innovative way to capture additional savings for the project, we then provided them a very cost-competitive [renewable] thermal supply for their reduced load from our plant. This allowed the facilities to lock in the energy savings for 20 years.”

The project starts with gas from a landfill owned by Republic Services. It’s transported through a 4-mile pipeline to the cogeneration plant owned and operated by Ameresco at the Jefferson City Correction Center (JCCC), where three GE Jenbacher engines generate 3.2 MW of electricity. Columbia Water & Light has a 20-year power purchase agreement for the electric energy produced from the plant. A steam piping system transports excess steam from JCCC to Algoa for heat and returns used steam condensate back to the plant for reuse.

With flexible solutions such as those at Santa Clara, BMW Manufacturing, Jefferson City and others, Bakas believes that the landfill-gas-to-energy marketplace will continue to grow, despite the challenges that the industry has faced in recent years with falling energy prices and less MSW being generated in certain regions of the country, which in essence reduces the gas generated at these sites in the long run. “Even in this environment, we are proud our team has been able to consistently develop innovative solutions and bring projects online through effectively leveraging all the products and services we offer,” says Bakas.

Trash-to-Fuel Energy Plants
In fact, history may well be rewriting itself with a recent announcement from Sweden, where officials have contracted an export agreement with Norway to supplement Sweden’s dwindling supply of garbage. With a recycling rate above 90%, the country is running out of fuel for its waste-to-energy incineration system. Could that happen anytime soon in North America? If we use the latest figures from the EPA, it doesn’t seem likely. The agency’s 2009 statistics say that Americans generated about 243 million tons of trash, or 4.34 pounds per person per day. In Canada, it’s a lower overall volume, but the daily stats are close to the same. It’s worth noting that the highest gas output comes from foodwaste, which typically accounts for about 13% to 30% of MSW content, depending on the locale.

That percentage of food and other organics becomes important when factored into the rise of MSW costs and a nationwide anti-landfill sentiment that has spurred rapid growth of large-scale waste-to-energy (WTE) plants across the US and Canada. According to Pike Research, in Boulder, CO, worldwide revenues from WTE systems are expected to grow from $3.7 billion to $13.6 billion, by 2016. It’s beginning to look like landfills could soon be competing for high-energy organic waste.

The impact could be considerable in light of the growing trend of using biogas to create liquefied natural gas. For example, one of North America’s largest MSW treatment and haulers, Waste Management, recently commissioned its thousandth natural-gas truck. The company is the largest owner and operator of natural-gas-burning, heavy-duty trucks in North America, and one-third of its fleet runs on LNG derived from organic waste delivered and processed at the Altamont Landfill, located in Livermore, CA. The company also has 17 CNG and LNG fueling stations at its facilities, and more under development. Waste Management has many landfill biogas energy projects that sell electricity back to the grid.

These projects are attractive because they can help to meet a state’s renewable energy portfolio standards, as is the case in Moncks Corner, SC, where the South Carolina Public Service Authority, an electric and water utility recently agreed to a 20-year power purchase agreement with W2E-Organic Power, Columbia, SC, to construct a 1.6-MW generation plant fueled by biogas from foodwaste, grease, food processing waste and wastewater sludge.

Ultimately, the landfill gas to energy industry has both opportunities and challenges ahead. But for the short term, the opportunities still have the edge, and new technologies will also have a positive impact.

 

Coca-Cola Puts Its Brand on Landfill Gas
In 2012, Coca-Cola and Mas Energy claimed the accomplishment of launching the first US trigeneration project fueled by landfill gas. The new 6.525 MW power system provides electricity, steam, and chilled water to the Coca-Cola syrup plant in Atlanta, GA. The landfill gas is transported by a 6-mile pipeline from Republic Services’ Hickory Ridge Landfill in neighboring Conley, GA, and fulfills the role of prime fuel source for energy at Coca-Cola’s facility. For backup, the plant can blend or run solely on natural gas. With the launch, the EPA’s Green Power Partnership recognized the Coca-Cola Co. as the third-largest onsite green power generator in the US.

The plant uses three GE Jenbacher J616 reciprocating gensets, rated at 2.175 MW each, for a total output of 6.525 MW. Engine exhaust produces a maximum of 3,500 pounds per hour each of steam at 125 psig, with steam output totaling 10,500 pounds per hour. The steam’s primary job is to power a 1,065-ton chiller, but it can also offset steam production from the facility boilers. Georgia Power consumes any excess power from the gensets.

Triple Score for University of Iowa’s Trigen Plant
The University of Iowa gets high marks in sustainable power, energy efficiency, and a hands-on lab for the university’s engineering school, with its new 2.8-MW trigeneration. Located at University of Iowa Research Park’s (UIRP), two Jenbacher 1.4-MW 420 Series generators share peak-shaving duties to reduce demand during hours of electricity surcharges from the utility. Gas is supplied from the Iowa City Landfill, and travels via a 6-mile pipeline. For backup, the plant can blend or run solely on natural gas.

Absorption chillers reuse waste heat to chill water for cooling UIRP campus buildings and heat recovery units have bypass dampers that control campus heating requirements.

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