On June 11, 2024, the University of Illinois’ Prairie Research Institute (PRI) and U.S. Department of Energy (DOE) marked a significant milestone with a ribbon-cutting ceremony for the upcoming testing and operations of the large-scale 10 megawatt (MWe) pilot testing of the Linde-BASF advanced post-combustion CO2 capture technology at City Water, Light and Power’s (CWLP’s) Dallman 4 coal-fired power plant in Springfield.

Under the pilot project, a slipstream is being pulled from Dallman Unit 4 unit and used to evaluate the performance of a new capture technology developed by Linde / BASF. The pilot will evaluate a new large scale capture system for its performance and economics. The pilot system will process approximately 5 percent of the unit’s flue gas, from which it will demonstrate the ability to capture over 90 percent of the slipstream’s CO2 emissions (equivalent to 200 tonnes of CO2 per day).

“As someone who has researched carbon capture for over twenty years, it is gratifying to see carbon capture achieve this milestone. It is especially exciting to see how state and local support has enabled the construction of a facility that is globally recognized. It demonstrates Illinois’ leadership in carbon capture,” said Kevin OBrien, director of the Illinois Sustainable Technology Center (ISTC) and the Net-Zero Center of Excellence at the Prairie Research Institute (PRI). The $85 million project, funded by DOE, Linde/BASF and the State of Illinois, is a groundbreaking initiative to position Illinois as a leader in carbon capture research and development. The project, which began in 2018, has successfully transitioned from engineering design to construction. The construction phase of the project is due to be completed in November 2024. Thereafter, the project will achieve an operational and testing phase.

“This phase is the last step in the development process to de-risk technologies before they go to commercial operation or commercial demonstration,” said Ronald Munson, point source carbon capture technology manager, NETL, DOE. “To see the progression of the technology and to see the application of the approach the Department of Energy has adopted is really gratifying.”

The Phase III pilot, which retrofits Dallman 4, is the largest of its kind globally, promising substantial economic and environmental benefits.

“It is essential we have solutions to meet environmental goals through carbon capture to power our nation's infrastructure, power our homes and businesses, and support the operations of our manufacturers,” said City Water, Light and Power Chief Utility Engineer Doug Brown. “Just as power plants require sustainable solutions, so will manufacturers need to rely on low-carbon processes to meet these goals.”

PRI projects that the construction and operation of the Dallman Unit 4 carbon capture facility will have a baseline regional economic impact on construction and jobs of at least $47.1 million, and it will generate tax revenue of more than $5.6 million.

Springfield Mayor Misty Buscher, alongside State Senator Doris Turner, State Representative Mike Coffey, State Representative Sue Scherer, and representatives from the offices of U.S. Senator Dick Durbin and U.S. Senator Tammy Duckworth, acknowledged the collaboration and support to bring the project forward along with local jobs benefits.

“By providing Dallman 4 as host site, we are bringing a number of union jobs to our community for the construction and operation of the plant along with large opportunities for the future,” said City of Springfield Mayor Misty Buscher. “I’m thrilled that with our PRI partnership, our city and this workforce are at the forefront in such a hallmark project to help find the solutions needed to safeguard our environment for future generations.” The features and capability of this system draws international attention to the city of Springfield. Already many international researchers in carbon capture have toured the site. The facility will enable the state of Illinois to continue to be a leader in the research, development, and deployment of carbon capture. This technology provides a means to not only reduce CO2 emissions from the power generation sector, but also industrial sectors. The project marks a significant step in showcasing the economic viability of carbon capture, the impact of stimulating workforce development in the trades, and a means to educate and train workforces.

Project History

In 2021, the DOE’s National Energy Technology Laboratory (NETL) announced it was selecting the University of Illinois’ Illinois Sustainable Technology Center (ISTC) at Prairie Research Institute (PRI) to conduct large-scale pilot testing of a carbon dioxide (CO2) capture technology at CWLP’s) Dallman Unit 4. DOE has allocated $58 million for this project, which will build a 10 megawatt (MWe) Linde-BASF advanced post-combustion CO2 capture system to process the Dallman Unit 4 flue gas. The State of Illinois has committed $20 million, and Linde-BASF has committed $7 million bringing the total cost to $85 million.

PRI’s project, “Large Pilot Testing of Linde-BASF Advanced Post-Combustion CO2 Capture Technology at a Coal-Fired Power Plant,” made it through the rigorous DOE down-selection process and was selected for Phase III (construction/operation). A second project for carbon capture membrane testing was awarded to a project underway by Membrane Technology and Research Inc. in Newark, California. The Office of Fossil Energy’s National Energy Technology Laboratory (NETL) will manage the selected projects.

DOE cited the successful construction and operation of the Dallman Unit 4 test plant as a means to demonstrate economic carbon capture technology and help enable commercialization of the technology.

Other ISTC research projects are underway with CWLP in addition to the carbon capture testing at Dallman Unit 4, including utilizing CO2 as feedstock for algae; scrubber wastewater treatment technology; beneficial reuse of coal fly ash in plastics; and advancing the design of a hybrid power plant and energy storage system.

With this award for carbon capture testing at Dallman Unit 4, ISTC will move the project to the next step, “Phase III,” which is the finalized design and construction phase. Phase III, slated to begin in June 2021, includes finalizing a detailed engineering plan, acquiring equipment and modules needed for the new system. Building the 10 MWe system is slated to begin June 2022. The testing phase is anticipated to take place beginning in March 2024 with the testing to occur from March 2024 thru May 2026 for project completion.

In May 2023, DOE selected ISTC at PRI for two more projects. The first, a project to conduct an integrated capture, transport, and geological storage study of CO2 emissions at Dallman Unit 4. DOE is allocating $4.7 million for this front-end engineering design (FEED) study, which will explore the feasibility of building a 200-megawatt (MW) Linde-BASF advanced post-combustion CO2 capture system to process the Dallman Unit 4 flue gas and transferring the captured CO2 to be geologically stored in the Illinois Storage Corridor. The project design is estimated to capture two million tons of CO2 per year.

This FEED study will leverage the existing DOE-funded 10 MWe large pilot at Dallman Unit 4. DOE cited the successful construction and operation of the Dallman Unit 4 pilot plant to demonstrate economic carbon capture technology and help enable commercialization of the technology.

For the second project, DOE announced an award of $17,736,972 million to ISTC at PRI under its CO2 Transport and Storage investments to complete site characterization efforts for the Cambrian Mt. Simon Sandstone/Eau Claire Formation storage complex, for storage of CO2 from the Dallman Power Generation Plant and about 50 million metric tons of total CO2 storage capacity.

Other ISTC research projects are underway with CWLP in addition to the carbon capture testing and studies associated with Dallman Unit 4, include using CO2 as feedstock for algae; scrubber wastewater treatment technology; beneficial reuse of coal fly ash in plastics; and advancing the design of a hybrid power plant and energy storage system.

Learn more about ISTC's carbon capture projects: https://www.istc.illinois.edu/research/energy/carbon_capture/large_pilot-scale_projects/

Read the DOE Large-Scale CO2 Capture Pilot Projects announcement: https://netl.doe.gov/node/10683

Read the DOE FEED funding announcement: https://www.energy.gov/oced/carbon-capture-demonstration-projects-program-front-end-engineering-design-feed-studies

Read the DOE CO2 Transport and Storage announcement: https://netl.doe.gov/node/12542

In 2023, CWLP generated 638,484 net megawatt-hours (MWH) of electricity and had system purchases of 923,466 MWH, for a total system net input of 1,561,930 MWH. This served the native energy requirement of 1,533,958 MWh, as well as system wholesale sales of 27,973 MWh.

In 2023, CWLP's coal-fired Dallman Unit 4 consumed a total of 359,427 tons of coal, 100% of which was mined in Illinois. All generating units consumed 97,684 gallons of fuel oil and 643,288 dekatherms of natural gas.

During the calendar year, Dallman Unit 4 represented 94.1% of CWLP's total net generation and Interstate, Factory and Reynolds peaking units represented 5.9% of total net generation.

In 2023, CWLP's summer peak demand was 390 MW, set on Thursday, August 24th, between 3 p.m. and 4 p.m., when the outdoor temperature was 98° F and the heat index was 110° F. This represents a 14% reduction from the record peak of 451 MW set in July 2006. The overall summer of 2023 was slightly cooler than average, with 854 cooling degree days (CDD) versus a norm of 935 CDD.

During Winter 2023/2024, CWLP's peak demand was 291 MW (10% below the record winter peak of 325, which was set on January 6th, 2014). The winter 2023/2024 peak demand occurred on Sunday, January 14th, between 6 p.m. and 7 p.m., when the temperature was -4° F and the wind chill was -15°F. The winter 2023/2024 was warmer than average with 2,630 heating degree days (HDD) versus a norm of 3,056 HDD.

Dallman 4, a 200-MW pulverized coal power plant, is one of the cleanest coal-fired generating units in the nation. Employing a Foster Wheeler pulverized coal boiler, Dallman 4 has a maximum capacity of 210 MW. The unit is designed to burn coal with an approximate heat content of 10,500 Btu per pound.

Construction began on the plant in late 2006. The plant became operational on May 11, 2009, when—under power of natural gas—it produced 13 MW of electricity as the unit was synchronized to the grid. As testing continued, the plant began operating using coal on June 1 of that year. Systems-testing was completed on November 19, at which time the general contractor, handed over operating control of the plant to CWLP. In addition to being completed months ahead of its contract completion date, Dallman 4 came in under its projected $454.6 million budget, a feat virtually unheard of in the power industry.

KBV Springfield Power Partners served as general contractor for the construction project; Black & Veatch designed the plant, while Kiewit provided the construction; and Burns & McDonnell served as owner's engineer on behalf of CWLP.

Dallman 4 employs a number of environmental control technologies, including:

1. For NOx removal, low-NOx burners for the boiler; and a selective catalytic reduction (SCR) system

2. For removal of fine particulates, a fabric filter bag house to remove fine particulate

3. For removal of sulfur dioxide (SO2), a wet flue gas desulfurization unit (scrubber) uses limestone to trap SO2 in the flue gas before it can be emitted into the atmosphere, allowing CWLP to meet and exceed federal Clean Air Act requirements while continuing to use high-sulfur Illinois coal. The byproduct from this process, synthetic gypsum, can be used as a soil amendment and in cement making.

4. For removal of acid mist and ultra-fine particulate from the flue gas, a wet electrostatic precipitator

This equipment assists CWLP in its goal of becoming one of the most environmentally friendly primarily coal-fired electric utilities in the nation. Air emission controls aren't the only way Dallman 4 complements the utility's efforts to protect and preserve the environment. By utilizing state-of-the-art cooling towers, CWLP is able to avoid discharging high-temperature cooling water from the plant into Lake Springfield.

1. In constructing the facility:
- 644 pier foundations were drilled
- 21,500 cubic yards of concrete were poured - 7,100 tons of steel were used
2. The 8.8-million-pound Unit 4 boiler is hung from the top of the building.
3. The facility has three coal silos, each of which hold 650 tons of coal.
4. One of the unit's environmental controls, a pulse jet fabric filter baghouse, contains over 6,600 26-foot-long bags that collect fine particulate from the flue gas.
5. At 440 feet in height, the Unit 4 chimney is the second tallest structure in Springfield. (The Unit 3 chimney is the tallest; the Units 1 and 2 chimney is third tallest; and the State Capitol is fourth.) Construction of the Unit 4 chimney took 28 days, 3 hours.

The Dallman Power Station was built just to the southwest of the Lakeside Power Station in 1968 to answer the increasing electric demand of a growing city. The first Dallman generator placed online was Dallman 1, which had a maximum nameplate capacity of 78 MW. It was followed by Dallman 2, which went online in 1972 and had a nameplate rating of 78 MW. These units were retired at the close of 2020 following conclusion of an Integrated Resource Plan (IRP).

In 1978, the completion of Dallman 3, with a maximum nameplate capacity of 192 MW, more than doubled the power station's total generating capacity. This unit, which was planned to retire by September 2023 following the utility’s Integrated Resource Plan (IRP), was suspended in 2021 after a trip and subsequent damage. Following suspension, the unit was officially retired in March 2024.

The flue gas desulfurization system or scrubber for Dallman 3, for control of sulfur dioxide (SO2) emissions, was among the first installed in the nation in 1980. A $30 million upgrade to that system that was completed in the spring of 2012. As part of this upgrade, more modern system controls and efficient equipment were installed to allow the unit to continue to comply with Clean Air Act regulations. The use of scrubbing technology, which uses limestone to trap SO2 in the flue gas before it can be emitted into the atmosphere, allows CWLP to meet and exceed federal Clean Air Act requirements while continuing to use high-sulfur Illinois coal. The byproduct from this process, synthetic gypsum, can be used as a soil amendment and in cement making.

The newest CWLP power generating unit in operation is a 250 kW solar installation, representing the utility’s first owned renewable generation resource. The system was put into operation on December 13, 2018. The solar photovoltaic (PV) array, consisting of 716 panels, is projected to generate between 339,000 and 373,000 kWh per year. It is located behind Harrison Park subdivision and adjacent to the Sangamon Valley Trail and the utility’s Washington Substation at 606 Old Tippecanoe Drive.

Beyond a new generation resource, the solar installation will provide CWLP customers the opportunity to purchase solar energy for those that want to go green or for customers without the financial means or roof space to install their own solar. A solar subscription program, “mySolar,” launched in early 2019, which allows CWLP customers to purchase 100 kWh blocks of energy through their bill.

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CWLP operates three peaking generators, two that are oil-burning and one that has dual-fuel operating capabilities. These units have a combined maximum capacity of 144 MW.

As part of a commitment to diversify CWLP’s energy portfolio and scarcity of capacity and generation in MISO Zone 4, in March of 2023 the utility entered into an agreement to purchase all available accredited wind capacity from Glacier Sands Wind Power for a five-year period in an amount up to $14.4M. In March 2024 the utility amended that agreement and extended it for another 10 years for an additional $10.3M in all bringing the contract total to $24.7M and extending term to 2037-2038. The amendment reduced the cost of the remaining 4 years of the contract in the initial agreement.

Beginning in 2007, as part of its Sierra Club agreement associated with the construction of Dallman Unit 4, CWLP commenced wind power contracts with NextEra Energy Resources, LLC (formerly FPL Energy, LLC) for the purchase of 120 megawatts (MW) of capacity. This green energy was produced at the Hancock County and Crystal Lake Wind Farms, both of which are located in Northern Iowa.

The purchase of 20 MW of wind-generated energy and capacity from Hancock County commenced in July 2007 and expired in June 2017. The purchase of 100 MW of wind energy and capacity from Crystal Lake commenced in November 2008 and expired in November 2018. CWLP's total wind power capacity over the term when both contracts were in place produced enough renewable energy to supply an average of 20% of CWLP's net native energy requirements.

The Lakeside Power Station was the original generating facility constructed in the mid-1930s on the shore of the utility's then-new man-made Lake Springfield. By the mid-1960s, Lakeside consisted of eight coal-fired boilers and seven turbine-generators. Two of these—boilers 7 and 8 and turbine units 6 and 7, which had a combined maximum capacity of 76 MW—remained active in meeting intermediate customer load until mid-2009. However, age and increasingly stringent emissions control requirements took their toll on the old Lakeside plant and, rather than spending the multi-millions of dollars that would be needed to bring the old units into compliance with state and federal standards, in 2002 the utility decided to construct a new, larger, state of the art, environmentally friendly power plant and, upon its completion, cease using the Lakeside units. The Dallman 4 Power Station went online in May 2009, at which time, Lakeside units 6 and 7 became non-operational.