Small Town, Big Green Footprint
A city administrator’s obsession with the power of landfill gas
Wednesday, August 31, 2011
By Jeanne Bojarski, Marilyn Mattione, Ted Christensen
In May 2006, the Noble Hill Landfill Renewable Energy Center fired up in Springfield, MO, generating 3.2 MW of power from landfill gas. The city administrator of the much smaller town of Lamar, MO, had taken note of the project. Now, when Lynn Calton looked at the flare burning methane at Prairie View Landfill in southwest Missouri he could think of only one thing: “Dollar bills going up in the air.”
By the time the Springfield plant came online, Calton had already taken steps towards capturing those dollars. Ultimately, the clean energy generated from waste methane gas would more than halve the city’s electric bill—and provide significant environmental benefits by replacing 3.2 MW of “dirty” energy generation (equal to consuming 357,833 barrels of oil).
Lamar is a member of the Missouri Joint Municipal Electric Utility Commission, a co-op that pools power generation resources for communities across the state. Calton had heard about the “green” Combined Heat and Power (CHP) plants the Energy Services Division of Shafer, Kline & Warren Inc. (SKW) had delivered for other commission members.
The city of Lamar retained SKW to evaluate the technical and economic feasibility of a landfill gas-to-energy project at Prairie View Landfill, the second largest in the state. In a good year, the facility receives 2,300 tons of waste per day. “We love trash,” Calton says.
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Photo: City of Lamar, MO
Schematic for the Lamar green power project |
The study was delivered in April 2006, verifying gas composition and estimating the quantities that could be recovered over the next 50 years. The investment in the plant could be paid off by the energy generated, and still save on the city’s overall energy costs. In 2007, SKW was contracted to work out the engineering details.
“They [SKW] showed us we could be green and generate green at the same time,” says Calton. “They found ways to reduce capital costs in order to make it happen.”
Project Overview
In 2009, SKW was awarded the contract for project implementation. The design is mindful of capital expenditure. The two 1.6-MW generators match initial gas availability, providing maximum power production at the lowest cost. Housing the plant in a prefabricated metal building versus block building saved $200,000. Integrating the existing flare to work with the gas-treatment skid saved $55,000 versus installing a new flare as is typical.
To produce usable fuel, raw methane from the landfill is filtered, compressed, and cooled on a treatment skid. SKW programmed a low-cost controller to totally automate the process.
The project team designed the plant to economically accommodate expansion to a planned 8 MW of generation capacity as landfill gas production rises. The city will be able to add three generators and more than double capacity at half the cost of Phase I. SKW also designed the 69-kV substation with switchgear safeguards and the new transmission line that carries the electricity to the city-owned distribution substation.
To keep operating costs low, the Lamar plant was equipped with a supervisory control and data acquisition (SCADA) system that controls the plant automatically. Operations can be monitored (and controlled, if needed) from a remote workstation in Lamar. In addition, the control system automatically optimizes energy production based on gas availability, increasing profitability. The project captures 1300 standard cubic feet of landfill gas per minute and generates 3.2 MW, enough to power approximately 2,300 Lamar homes. There are currently 2,200 homes in the city.
Getting It Right the First time
Landfill gas-to-energy plants are nothing new. There are at least 519 operational projects in 46 states producing 13 billion kWh of electricity a year. However, this project boasts features that are, if not unique, unusual:
- The project was financed solely by the city of Lamar, with no subsidies or grants.
- The city also owns the plant electrical substation and transmission line to its main substation, which was necessary for the economic viability of a self-financed project.
- SKW’s design re-engineered the existing flare system to feed gas to the treatment skid, a first in landfill-gas collection technology. In addition, the provision of a control system that allows the facility to operate unmanned contributes to low, long-term operating costs.
Project Structure
The city of Lamar owns and operates its own electric utility, including the distribution system, several substations, and the electric generation facilities. So it was not a stretch for this enterprising town of 2,200 homes (along with several large industrial concerns) to build its own landfill power plant.
The facilities were financed by a city bond issue approved by the city council. The city also received a $500,000 federal loan.
The landfill owner, Allied Waste Services (now Republic Services), agreed to lease land for the plant to the city for $1 a year. The city pays the landfill 1 cent per kilowatt of electricity generated for the gas.
The Missouri Joint Municipal Electric Utility Commission’s Public Energy Pool, or MoPEP, plays a significant role, since it is a wholesaler that can buy and sell energy in bulk. Previously, Lamar purchased the energy the city utility did not produce itself through MoPEP. Now, MoPEP “buys” its energy at cost and “sells” it back at the same price. MoPEP also guaranteed the city’s loan.
Single-Source Project Design and Management
SKW evaluated, designed and provided professional services for the entire project, reducing its complexity and cost. The project team drew from a deep pool of experience in power generation facilities and controls. In addition, team members made field trips to the Springfield, Jefferson City, and Columbia Landfill Gas-to-Energy Plant installations in Missouri to familiarize themselves with current best practices. Below is a list of the services provided.
The SCADA system, which automatically controls the plant and allows for remote monitoring (and control override, if necessary) was supplied on a turnkey basis.
- Evaluation
- Engineering/economic study
- Design
- Building and access road (drainage,
utilities, etc.)
- Power plant and piping
- Flare conversion
- Methane treatment skid
- Substation, power line, grid tie-in
- Unmanned control system (turnkey)
- Additional Services
- Air permit preparation/coordination
- Equipment specification/procurement
- Coordination with electric utility
- Coordination with landfill owner
- Preparation of construction bid packages
- Construction oversight
- Commissioning
Flare Retrofit
Contributing to the project’s economic viability was the landfill’s existing gas collection and flare system operating successfully at the time of the initial evaluation. That meant the gas had already been routed to a central location.
The project team brainstormed a way to optimally utilize this existing system. The team members applied their process piping experience to design an in-line modification that routes the collected gas to a treatment skid.
This unique innovation saved $55,000 over purchase and installation of a purpose-built system.
Project Dedication
The project came online in June 2010. On October 13, the city of Lamar and Allied/Republic held an open house to show off and dedicate the project.
The event generated local, regional, and national TV and newspaper attention similar to that generated by the press conference held by the city of Lamar about project progress the year before. The Associated Press again picked up the story, and so did NPR and international power engineering and renewable energy websites and publications.
Environmental and Economic Benefits Achieved
The project captures 1,300 standard cubic feet of landfill gas per minute, providing green energy to approximately 2,300 Lamar homes. The two 1.6-MW generators were selected to match gas availability, providing maximum generation capacity at the lowest cost.
The annual reduction of greenhouse gases attributable to this project is approximately the same as the annual greenhouse gas emission from nearly 28,181 passenger vehicles, the carbon dioxide emissions from more than 357,833 barrels of oil consumed, or the carbon sequestered by more than 34,970 acres of pine or fir forest.
The cost of the 3.2-MW plant along with the substation and transmission line is about the same as Springfield’s 3.2-MW plant alone—and Lamar’s was built five years later.
Lamar’s cost of energy is now about half the wholesale price.
The city receives capacity credits for owning and operating the landfill gas plant.
The plant’s energy generation—and its planned expansion—ensure that the cost of electricity in Lamar will stay low, encouraging population growth and economic development.
The plant is designed to economically accommodate future expansion to a planned 8 MW of generation capacity. The city will be able to add three generators and more than double capacity at half the cost of Phase I. In addition to the benefits for Lamar, 34 other Missouri cities are realizing energy savings due to this clean baseload energy project.
Author's Bio: Jeanne Bojarski is in technical communications at SKW. |
Author's Bio: Marilyn Mattione is project manager at SKW. |
Author's Bio: Ted Christensen Sr. is a project manager at SKW. |
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