On April 30, 2021, the U.S. Department of Energy’s (DOE) 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 City Water, Light and Power’s (CWLP’s) Dallman Unit 4. DOE is allocating $47 million for this final phase to complete the 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 an additional $20 million, bringing the total cost of this phase to $67 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. In benefits to the community, PRI projects the construction and operation of the Dallman Unit 4 carbon capture facility will have a regional economic impact of $47.1 million and will generate tax revenue of $5.6 million.

“I’m extremely proud of the University of Illinois’ partnership on this initiative and grateful to the U.S. Department of Energy and the State of Illinois’ recognition of this important research,” said then-Springfield Mayor Jim Langfelder. “As a publicly-owned utility, this new construction and innovative initiative will be a boost to our local economy while the energy industry as a whole will also be watching CWLP to see how this technology performs.”

Kevin OBrien, principal investigator for the project and director of PRI’s Illinois Sustainable Technology Center (ISTC), agrees on the project’s impact. “As a large research pilot of this type, we are anticipating very high interest in the project at Dallman 4,” he said. “The success of this project would be a model and foundation for more accessible, attainable carbon capture systems at facilities around the world.”

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.

Doug Brown, CWLP Chief Utility Engineer, said the projects are very timely for the energy industry. “We are very fortunate to have the University of Illinois undertake this important project at CWLP Dallman Unit 4 and at an opportune time when the energy industry is seeking to move to a zero-carbon future,” he said. “A proven and cost-effective carbon capture solution is what plants need to be able to demonstrate and transition to if a balanced, resilient and reliable energy grid is the goal. Further, I’m pleased the University is planning spinoff projects from this work in beneficial reuse and a study into a hybrid power plant, along with energy storage research.”

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.

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 2022, CWLP generated 1,256,662 net megawatt-hours (MWH) of electricity and had system purchases of 519,394 MWH, for a total system net input of 1,776,056 MWH. This served the native energy requirement of 1,666,182 MW, as well as system wholesale sales of 109,836 MWH.

In 2022, CWLP's coal-fired Dallman Unit 4 consumed a total of 618,240 tons of coal, 100% of which was mined in Illinois. All generating units consumed 135,364 gallons of fuel oil and 139,304 dekatherms of natural gas.

During the calendar year, Dallman Unit 4 represented 99.9% of CWLP's total net generation and Interstate, Factory and Reynolds peaking units represented 0.01% of total net generation.

In 2022, CWLP's summer peak demand was 379 MW, set on Tuesday, July 5, between 3 p.m. and 4 p.m., when the outdoor temperature was 96° F and the heat index was 106° F. This represents a 16% reduction from the record peak of 451 MW set in July 2006. The overall summer of 2022 was average, with 942 cooling degree days (CDD) versus a norm of 935 CDD.

During Winter 2022/2023, CWLP's peak demand was 301 MW (8% below the record winter peak of 325, which was set on January 6, 2014). The winter 2022/2023 peak demand occurred on December 23, 2022 at 7 p.m., when the temperature was 2° F and the wind chill was -21°F. The winter 2022/2023 was below average with 2,713 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 is planned for an effective retirement date of September 1, 2022.

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, in March of 2023 the utility proposed an agreement to enter into a contract to purchase all available wind capacity from Glacier Sands Wind Power for a five-year period in an amount up to $12.8M. The Springfield City Council approved this purchase with the contract to begin for the 2023-2024 planning season and conclude in the 2027-2028 planning season with the option for one additional year.

Beginning in 2007, 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.