PHOTOGRAPHS
WRITTEN HISTORICAL AND DESCRIPTIVE DATA
FIELD RECORDS
HAER WI-119HAER WI-119
ROCK RIVER GENERATING STATION935 West B R Townline RoadBeloitRock CountyWisconsin
HISTORIC AMERICAN ENGINEERING RECORDNational Park Service
U.S. Department of the Interior1849 C Street NW
Washington, DC 20240-0001
HISTORIC AMERICAN ENGINEERING RECORD
ROCK RIVER GENERATING STATION
HAER No. WI-119
Location: 935 W. BR Townline Road, Beloit, Rock County, Wisconsin
The Rock River Generating Station encompasses approximately 18 acres; the following two coordinates
represent the northernmost and southernmost points of the plant and associated structures.
42.582267°, -89.027448° (north corner of plant)
42.575032°, -89.030695° (southwest end of discharge canal)
These coordinates were obtained on June 6, 2016, by plotting their location on the 1:24,000 Beloit U.S.
Geological Survey (USGS) Topographic Quadrangle Map. The accuracy of the coordinates is +/- 12
meters. The coordinates’ datum is North American Datum 1983. The Rock River Generating Station
location has no restriction on its release to the public.
Present Owner: Alliant Energy
Present Use: Vacant
Significance: The Rock River Generating Station is significant for its role in the post-World War II (postwar)
expansion of Wisconsin’s electrical utility infrastructure and is one of at least 14 coal-fired plants constructed
statewide by private utilities during this period.1 The Rock River station represents the culmination of the
seven-year construction program initiated by the Wisconsin Power and Light Company (WP&L) in 1947 and
is the largest single facility built by the company under this program. WP&L supplied electricity to much of
south-central Wisconsin during this period, including 336 communities, several important manufacturing
centers, and over 30,000 farms. The Rock River plant played a crucial role in WP&L’s ability to meet the
demands imposed by modernized agriculture and the Korean-war-era defense industry.
Historian(s): Sebastian Renfield and Christina Slattery, Mead & Hunt, Inc. Fieldwork for the project was
conducted in the summer of 2015. Project documentation was accepted by HABS/HAER in 2016.
Project Information: This documentation was completed by Mead & Hunt, Inc. at the request of Alliant
Energy, in consultation with the Wisconsin State Historic Preservation Office. Alliant Energy demolished
the property in 2016. Under the requirements of Section 106 of the National Historic Preservation Act,
this documentation was prepared as mitigation for the demolition of the National Register of Historic
Places (National Register)-eligible property. Representatives of Alliant Energy furnished original
drawings, photographs, and interviews. Project photography was produced by Dietrich Floeter.
1 This figure is derived from 2003 data listing extant Wisconsin plants with construction dates between 1945 and
1960. The total includes expansions of pre-war facilities and does not include plants constructed by individual
manufacturers or institutions to supply their own power. Energy Information Administration, U.S. Department of
Energy, “Existing Electric Generating Units in the United States, 2003,” 2003,
http://www.eia.gov/electricity/capacity/xls/existing_gen_units_2003.xls. (accessed June 8, 2016).
ROCK RIVER GENERATING STATION
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Part I. Historical Information
A. Physical History:
1. Date(s) of construction: 1952-1955. Construction began on Unit 1 in January 1952 and was
completed in 1954, along with the crib house and circulating water discharge system.2 Unit 1 was
placed into operation immediately and a temporary northwest end wall separated the two units
while Unit 2 was under construction. Unit 2 was completed and placed on line in November
1955.3
2. Architect/Engineer: Sargent & Lundy, LLC. The firm’s founder and senior partner, Frederick
Sargent, began his career as an electrical engineer in 1884 with Western Edison Light Company
in Chicago and continued to serve as a consultant to Edison throughout his life. Sargent
established a partnership with Ayres Lundy in 1891 and the firm of Sargent & Lundy went on to
design a number of important early electrical generating plants, including Chicago Edison
Company’s Harrison Street station in 1892.4 At the time of its construction, the Harrison Street
Station was the largest coal-fired plant in the United States and the first to employ condensing
engines that reduced coal consumption by half.5 The firm continued to innovate both in fossil-
fuel-based generating technology and later nuclear power, and designed the world’s first boiling
water reactor at the Argonne National Laboratory in the mid-1950s.6 By 1974 the company
advertised itself as the largest design firm in the United States.7 Sargent & Lundy continues to
design power-generating facilities and remains based in Chicago.
3. Builder/Contractor/Supplier:
Lakeside Bridge & Steel Co., Milwaukee, Wis.: structural steel fabricator/erector (Unit 1)
Worden-Allen Co., Milwaukee, Wis.: structural steel fabricator/erector (Unit 2)
Cunningham Brothers, Inc., general contractors
Allis-Chalmers, Milwaukee, Wis.: turbine-generator units
Babcock & Wilcox, New York, NY: cyclone furnaces
Rex Chain Belt Company, Milwaukee, Wis.: coal handling conveyors and equipment
Janesville Brick and Fuel Yards, Janesville, Wis.: Brick for walls and stack lining
Westphal & Co., Janesville, Wis.: electrical wiring
2 Wisconsin Power and Light Company, Annual Report, 1954 ([Madison, Wis.]: Wisconsin Power and Light
Company, 1955), 3, 10.
3 Wisconsin Power and Light Company, Annual Report, 1955 ([Madison, Wis.]: Wisconsin Power and Light
Company, 1956), 7.
4 “In Memoriam,” General Electric Review 22, no. 8 (August 1919): 631; “Power Development in Chicago,”
Electrical World 76, no. 13 (September 24, 1920): 620.
5 Sargent & Lundy, LLC, “Company History,” 2015, http://www.sargentlundy.com/about/company-history.html
(accessed June 9, 2016).
6 Sargent & Lundy, LLC, “Company History.”
7 “Advertisement,” Reading Eagle, June 2, 1974.
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Western Architectural Iron Company, Chicago, Ill.: steel stairs and galleries
Midwest Piping Company, Inc., St. Louis, Missouri: Pipe fabrication and erection
R&I Equipment, Greensburg, Penn.: substation
Fairbanks, Morse & Co.: cool water pumping system
Ingersoll-Rand, New York, NY: boiler feed pumps, soot blower and instrument air compressors.8
4. Original plans and construction: Plans for the Rock River Generating Station were prepared
successively by Sargent & Lundy, LLC over a period of several years while the plant was under
construction. The earliest plans for the structural aspects of the facility are dated January 1952,
and additional plans were prepared through 1953. Artists’ renderings and photographs of the
newly completed facility (see Figures 1 through 3) show the plant looking much as it did at the
time it was retired. The view facing south shows the stepped massing of the crib house, turbine
block, and boiler block, and the meeting/locker room area protruding slightly beyond the wall
plane on the southwest elevation. Transformers flanked the crib house and the original
substation was located north of the plant in the same location as the current substation. Paired
smokestacks rose above the roofline of the boiler block, and the uppermost two stories of the
boiler block were lit by bands of metal windows, now obscured by the addition of the electrostatic
precipitators. The complex also included two small brick buildings with flat roofs that served as
the deep well house and blower house, both located west of the plant. Several small storage
sheds were erected in the paved yard on the west side of the main plant. All three buildings are
prefabricated metal buildings with low arch-truss roofs.
Historic photographs from the 1950s and 1970s (see Figures 2 through 4) show a coal yard to the
west of the plant; coal was supplied by a rail spur from the west with thawing pits adjacent to the
rails for use in winter. Coal was moved along a conveyor to the crusher house, shown in plans
from 1952 as a four-story concrete building with metal siding on the upper three stories and a
small one-story control room and locker room wing on the south. Crushed coal was then carried
by a second conveyor from the crusher house to the upper level of the south corner of the boiler
block. A sluice pipe carrying fly ash (the waste product from coal combustion) ran southwest
from the plant along the river bank to a series of settlement ponds and a road ran parallel to the
pipe.
5. Alterations and additions: Following completion of the plant and associated structures
(including the coal yard facility, circulating water discharge system, substation, storage sheds,
and ash settlement ponds) several small additions were also added to the exterior of the plant
beginning in the 1970s, including the one-story shed roof maintenance office and storeroom on
the northwest facade and the one-story laboratory wing at the north corner of the northeast
facade.9
8 “Advertisement,” Janesville Daily Gazette, May 18, 1954, sec. 2, 2–3, 5–7, 9–10, 12–13.
9 Karl Wedel, interview with Mead & Hunt, Inc., July 13, 2015.
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Additional changes were made to the plant’s operating equipment as part of periodic
maintenance or to meet new environmental standards. Electrostatic precipitators were added to
the east side of each smokestack in 1971 to comply with emission requirements. Plans dated
1974 also indicate that portions of the coal bunker walls were replaced with new stainless steel
plates and the gunite lining was sandblasted and replaced. The chemical addition building and
adjacent pump house were constructed in 1976, and the interior water treatment equipment was
replaced in the 1990s. Gas burners were added to the furnaces in 1999, enabling the plant to
produce power using either gas or coal, although operation ceased entirely in 2008.10 Aerial
imagery indicates that the coal yard, crusher house, blower house, exterior coal conveyor system,
and settlement ponds were gradually removed between 2013 and 2015.
B. Historical Context: The birth of Wisconsin’s electric power generating industry occurred in 1882,
when the state’s first electric power station (only the second nationally) began producing hydroelectric
power for a paper manufacturer in Appleton, Wisconsin. By the mid-1880s various companies sold
electrical equipment and central generating stations were established in Wisconsin communities such as
Waupaca, Green Bay, Stevens Point, Kenosha, Beloit, Janesville, and Oshkosh.11 In Beloit, a central
station using waterpower was established as early as 1887, and by 1898 this evolved into the Beloit
Electric Company; eight years later it became part of the Beloit, Water, Gas and Electric Company. In
nearby Janesville, several small early plants were merged in 1899 to become the Janesville Electric
Company, which, operating on water power, became the most successful utility in the state.12
While much of Wisconsin’s early electrical infrastructure relied on hydroelectric power, the steam turbine,
introduced in 1903, represented a substantial technological improvement at a time when the industry was
also rapidly expanding. By 1904 full-time electric service was available in over two dozen communities,
including Madison, Janesville, Beloit, Racine, Kenosha, Burlington, and Milwaukee.13 Three years later,
193 communities had service, with 59 of these full time, and by 1917, 370 communities in the state had
service.14 As the United States entered World War I, the demand for electricity increased and 19
companies across the state served the modern system. Seven of these were locally owned, including the
Janesville Electric Company and the Beloit Water, Gas and Electric Company.15
A major innovation in coal-fired power generation occurred just before World War I when the Milwaukee
Electric Railway and Light Company (TMER&L) began to experiment with pulverized coal as a substitute
for conventional-sized stoker coal. By 1919 its Oneida Street Plant was completely converted to
pulverized fuel. Pulverized fuel was a great technological achievement but also an economic
10 Wedel, interview with Mead & Hunt, Inc.
11 Forrest McDonald, Let There Be Light: The Electric Utility Industry in Wisconsin, 1881-1955 (Madison, Wis.:
American History Research Center, 1957), 16–17.
12 McDonald, Let There Be Light: The Electric Utility Industry in Wisconsin, 1881-1955, 78–79, 81.
13 McDonald, Let There Be Light: The Electric Utility Industry in Wisconsin, 1881-1955, 92, 96.
14 McDonald, Let There Be Light: The Electric Utility Industry in Wisconsin, 1881-1955, 99, 172.
15 McDonald, Let There Be Light: The Electric Utility Industry in Wisconsin, 1881-1955, 177, 182.
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achievement as it only required one-third or one-quarter of coal per kilowatt-hour.16 In the decades that
followed, newer and more efficient coal-fired power plants eclipsed hydroelectric facilities as the primary
source of power generation in Wisconsin.
At this same time, WP&L grew out of the acquisition of two large hydroelectric facilities—the Kilbourn and
Prairie du Sac Dams—and the acquisition, merger, and consolidation of a number of small companies,
including the Janesville Electric Company and Beloit Water, Gas and Electric. The company planned an
interconnected system serving power to cities in the central part of the state from Wisconsin Rapids to the
north, the Illinois border to the south, Lake Michigan to the east, and the Mississippi River to the west.
Only five cities in this area had a population over 10,000, including Janesville and Beloit (Milwaukee was
outside the company’s service area) and these cities served as a nucleus for the system. In contrast with
the 36 million kilowatt-hours supplied in 1919 by more than 80 unconnected plants, by 1930 WP&L alone
delivered more than 290 million kilowatt-hours annually along a 1,455-mile network of transmission lines,
serving 92,700 customers in 302 communities.17
During the Great Depression, WP&L faced a reduction in profits as the majority of its income was from
residential, farm, and non-industrial clients.18 With the onset of World War II, the needs of the defense
industry increased demand for electricity. In 1941 the United States War Department established the
Badger Ordnance Plant at a site near Baraboo due in part to its proximity to WP&L’s Prairie Du Sac
facility, and by 1944 WP&L’s annual production reached 500 million kilowatt-hours compared to 300
million kilowatt-hours in 1940.19 Within WP&L’s service area, as was typical elsewhere in Wisconsin,
hydroelectric facilities continued to supply the majority of electricity in the early decades of the twentieth
century. By the late 1940s, however, steam plants generated at least 70 percent of the total electricity
produced by WP&L facilities.20
During this period utility companies were regional; Madison was served by its own city-based company,
and the successor to TMER&L, the Wisconsin Electric Power Company (WEPCo), served most of the
urban and suburban areas in the southeastern part of the state. Wisconsin Public Service Corporation
(WPSCo) operated in Green Bay and several northern counties, and Northern States Power Company
served much of northern Wisconsin. WP&L’s service area consisted of what it referred to as the “heart” of
Wisconsin, namely the central portion of the state from the Illinois border to southern Langlade County,
along with Fond du Lac, Sheboygan, and the surrounding areas. While not faced with the demands of
the rapidly expanding greater Milwaukee area, WP&L supplied power to nearly a quarter-million
customers by the late 1940s, and its territory included much of the state’s agricultural land, as well as
16 McDonald, Let There Be Light: The Electric Utility Industry in Wisconsin, 1881-1955, 203, 210–211.
17 McDonald, Let There Be Light: The Electric Utility Industry in Wisconsin, 1881-1955, 230–231, 240.
18 McDonald, Let There Be Light: The Electric Utility Industry in Wisconsin, 1881-1955, 334.
19 “$65,000,000 Powder Plant to Be Built Near Merrimac - Construction Approved By War Department
Wednesday,” Sauk County News, October 30, 1941; McDonald, Let There Be Light: The Electric Utility Industry in
Wisconsin, 1881-1955, 386–387.
20 Wisconsin Power and Light Company, 1950 Annual Report ([Madison, Wis.]: Wisconsin Power and Light
Company, 1951), 5.
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important industrial pockets such as Janesville, Beloit, and the Badger Ordnance Works.21 By the end of
1949, 92 percent of the farms within its service area were connected to the company’s lines, making it the
state’s largest supplier of electricity to farms.22
The postwar years saw the expansion of utility infrastructure throughout the state in response to
skyrocketing electrical consumption for residential and industrial use. Wartime restrictions on
construction were lifted, enabling utility companies to begin the herculean task of catching up to demand
and planning for future growth.23 Rural electrification programs continued to add thousands of new
customers each year and the outbreak of the Korean War created further demand for electricity as the
nation’s defense industries increased production. As the number of customers increased, so too did their
average consumption as new home appliances and farm machinery became available. Between 1945
and 1950 average per capita power consumption increased by over 50 percent among WP&L’s
residential customers.24 To meet demand, Wisconsin electrical utility companies planned to add
approximately 565,000 kilowatts of generating capacity between 1951 and 1954.25 WEPCo invested
millions of dollars in expansion of its Port Washington facility and construction of a new plant at Oak
Creek, while WPSCo expanded its J.P. Pulliam steam plant in Green Bay.26
WP&L laid out a seven-year plan to double its generating capacity between 1947 and 1955, which it
planned to achieve mainly by expanding its steam generating facilities. Initially budgeted at $42 million,
the program funds were increased to $68 million by 1950 due to record-breaking service demands. The
plan called for the expansion of two existing stations and the construction of a third new facility. Designed
before the war but not completed until 1946, the Blackhawk plant in Beloit was expanded in 1948 with the
addition of a second 25,000-kilowatt unit.27 The Edgewater station in Sheboygan, constructed in 1931
and expanded before the war, received an additional 60,000-kilowatt unit in 1950.28 The new $9 million
unit at Edgewater began operating in 1951, and the turbine generator was the first of its kind in the world
to use a supercharged hydrogen cooling system that reduced generator size.29 The furnaces also
incorporated cyclone burners, which maximized fuel consumption by using a whirling drum to burn
crushed coal rather than pulverized coal, the first use of this technology in Wisconsin.30 The Rock River
21 Wisconsin Power and Light Company, 1949 Annual Report (Madison, Wis.: Wisconsin Power and Light
Company, 1950), 14–15.
22 Wisconsin Power and Light Company, 1949 Annual Report, 10, 12, 19.
23 Wisconsin Power and Light Company, 1949 Annual Report, 10.
24 Wisconsin Power and Light Company, 1950 Annual Report, 18.
25 “Cotton Reports on Capacity Outlook,” Utilitarian 28, no. 6 (November 1951): 10.
26 “News Items,” Utilitarian 27, no. 8 (January 1951): 6.
27 Wisconsin Power and Light Company, 1948 Annual Report (Madison, Wis.: Wisconsin Power and Light
Company, 1949), 12.
28 Wisconsin Power and Light Company, 1949 Annual Report, 5.
29 “World’s First ‘Supercharged’ Generator at Edgewater,” Power Engineering, January 1952, 104; Wisconsin
Power and Light Company, 1951 Annual Report ([Madison, Wis.]: Wisconsin Power and Light Company, 1952), 6.
30 “Power Plant Showing Set,” Milwaukee Journal, April 29, 1952.
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site, located between Janesville and Beloit, was selected in 1951 for the construction of the new facility
that was to be the culmination of the largest construction program in the company’s history. The new
plant incorporated the technological advances deployed at the Edgewater facility, and was the third
example of a supercharged hydrogen-cooled generator in the nation.31 The two generating units were
constructed sequentially to provide a total capacity of 120,000 kilowatts at an estimated cost of $24
million.32 Although WP&L initially considered a location on the Mississippi River, the company selected
the Rock River site instead, owing largely to the fact that the majority of the power produced would be
consumed locally by manufacturing operations in Janesville and Beloit and by dairy farms in the
surrounding agricultural area.33
The groundbreaking ceremony occurred on January 29, 1951, and work began on Unit 1, the more
southerly of the two generating units. The turbine and boiler blocks were constructed with temporary
northwest walls to enable operation of the first unit while the second was under construction, and the crib
house and water discharge systems were completed in the first phase. The first generating unit was
dedicated in January 1954, and over 15,000 WP&L customers toured the Rock River plant during the
five-day open house in May of that year.34 The second Rock River unit was placed in service in
November 1955, bringing the company’s seven-year plan to completion. Although the plant was initially
intended to house two 60,000-kilowatt turbines, WP&L ultimately elected to install 75,000-kilowatt units
instead. WP&L’s construction program had succeeded in increasing total generating capacity from
129,000 kilowatts in 1945 to 382,000 kilowatts in 1955, of which the Rock River plant constituted a
substantial portion. For the first time since before World War II, the company had a comfortable
production margin above peak demand.35
The plant continued to operate until 2008, and during the final decade of operation, modifications to the
burners enabled the furnaces to burn coal, natural gas, and shredded tires. A 30,000-kilowatt natural
gas-fired facility constructed immediately to the east of the original Rock River plant in 1967 continued to
generate electricity to meet peak demands, and the 1954 facility remained on standby until May 2009,
when WP&L announced plans to close the plant permanently.36
31 “Hydrogen Cools Generator Rotor,” Janesville Daily Gazette, May 18, 1954, sec. 2, 2.
32 Wisconsin Power and Light Company, Annual Report, 1952 ([Madison, Wis.]: Wisconsin Power and Light
Company, 1953), 11.
33 “$11,500,000 Generating Plant to Be Built in ’52,” Janesville Daily Gazette, December 31, 1951.
34 Wisconsin Power and Light Company, Annual Report, 1954, 3, 10.
35 Wisconsin Power and Light Company, Annual Report, 1955, 7.
36 “Retirement of Dam Will Benefit City,” Janesville Daily Gazette, August 2, 1968, 17.
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Part II. Structural/Design/Equipment Information
A. General Statement:
1. Character: The Rock River Generating Station is an excellent intact example of a mid-century,
coal-fired power plant. The plant displays character defining features of the property type,
including the large open turbine room, multi-story boiler block, smokestacks, and water circulation
system. The interior retains its coal conveyor and storage systems, boilers, original turbines,
control room, and other specialized spaces. The building reflects mid-century stylistic trends as
applied to an industrial building, such as wide bands of horizontally divided windows, low flat
parapets with plain coping, and glazed tile interior walls and flooring. The Rock River station
displays an unusually high degree of integrity compared to other similar generating stations
constructed in Wisconsin the 1950s, many of which have been dwarfed by modern additions and
expansions in recent decades.
The Rock River Generating Station exemplifies the typical coal-fired plant constructed during this
time period and shares most of its design features with other examples constructed in the late
1940s and 1950s, such as the Blackhawk, Edgewater, J.P. Pulliam, and Oak Creek facilities.
The form of the building is dictated by its function, and the various wings are proportioned to
accommodate the equipment housed within. Examples of the property type are generally L-
shaped in cross section, and consist of two rectangular blocks joined along their long sides. The
shorter block houses a turbine hall, consisting of a large, high-ceilinged, open room, often with
tiled walls and floors, which contained the turbine units, surrounded by a crane rail to facilitate
servicing of the equipment. The taller block contains the multi-story boilers and coal bunkers, as
well as the furnaces and coal handling equipment. Smokestacks are located adjacent to each of
the furnace/boiler units. Plants were typically sited adjacent to a lake or river, which provided
fresh water used as a coolant. In addition to the main generating building, each plant also
included facilities for coal delivery and storage. Facilities located on navigable rivers or lakes
could accept delivery via barge, while others such as the Rock River plant were supplied by rail
spurs.37 The Rock River plant displays all of these characteristic features, although it now lacks
the coal storage yard and exterior conveyors mounted on trestles that once moved coal from the
storage area to the upper level of the building.
2. Condition of fabric: The Rock River Generating Station retains good integrity. Aside from the
addition of several small, one-story sheds and the installation of electrostatic precipitators on the
smokestacks, replacement windows are the only other exterior alterations to the main building
and most have been replaced in-kind or with units that preserve the original configuration. While
some individual components were replaced over the facility’s 54 years in operation, the plant
retains its interior equipment, floorplan, and many historic finishes, and continues to convey its
historic function. The complex also retains the rail spur, large open yard, and circulating water
discharge system, as well as numerous historic-period outbuildings. The land to the west of the
37 M.K. Drewry, “Oak Creek Power Plant,” Mechanical Engineering 77, no. 1 (January 1955): 17.
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plant that contained the coal storage pit, sluice pipe, and ash settlement ponds has undergone
remediation and these areas are now vacant. The remediation of the ash settlement ponds,
removal of the coal yard and conveyor system, and the addition of electrostatic precipitators and
small shed additions to the main building are comparatively minor alterations that do not affect its
ability to convey its historic significance.
B. Description of Exterior:
1. Overall dimensions: The main power plant consists of a taller block that houses the multi-
story coal bunker and boiler system and a shorter block extending from the northeast facade
containing the turbine room and condensers. The boiler block is approximately 128’ tall, 168’
wide, and 95’ deep, and the turbine block is 68’-4 ½” tall, 233’-6” wide, and 60’-0” deep.
A smaller, two-story crib house/office wing extends approximately 53’ on the northeast facade of
the turbine block, and the forebay crib and screenhouse, located beneath the northeast facade of
the crib house, consist of an open, concrete-lined water containment structure with three concrete
bays in the base of the crib house, separated by concrete piers. Steel grid catwalks provide
access from a ladder on the northwest side and a small crane is located immediately adjacent.
A one-story water treatment room projects approximately 23’ from the southwest facade of the
boiler block and two large cylindrical storage tanks rest on the roof. The turbine block projects
approximately 66’ beyond the wall plane of the boiler block on the northwest facade to enclose a
delivery bay where a rail spur enters the turbine block, enabling heavy equipment to be hoisted to
and from the turbine floor.
2. Foundations: The plant rests on a reinforced-concrete foundation that varies from 5’-6” to 10’-
0” in depth. Foundations are deeper directly beneath heavy elements such as boilers and
condensers, and an additional foundation cradle supports each of the turbine/generator units.
Each cradle consists of a 26’-1 ½” by 66’-0” by 28’-6” reinforced-concrete frame that rests on the
basement slab and extends upward to the turbine floor, partially enclosing the condenser units
beneath each turbine.
3. Walls: The walls are clad in buff-colored brick with slight variations in shade, laid 12 ½” thick in
a five-course common bond. The central bays on both the northwest and southeast sides of the
boiler block project several inches beyond the wall plane on either side, but the walls are
otherwise unadorned.
4. Structural system, framing: The plant structure is supported by a load-bearing frame of steel
I-beams. Column bases rest in pockets in the concrete foundation slab, and framing connections
and splices are riveted using angles and gusset plates. Vertical columns are typically 14” wide-
flange members, while horizontal bracing varies depending on the weight of the equipment
above. Most bracing is 16” or 18” deep, while the main turbine floor and fan floor are supported
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by 24” beams and each boiler unit is suspended between a pair of plate girders 5’-3” in depth.
Roof framing consists of 16” wide-flange I-beam rafters and purlins.
5. Chimneys/stacks: A pair of 12’-0”-diameter steel stacks extend approximately 115’ above the
roofline of the boiler block. Electrostatic precipitators surround the lower portion of each stack
and extend downward along the northeast facade of the boiler block.
6. Openings:
a. Doorways and doors: Plain protruding concrete door surrounds are found on the original
main entrance on the northwest facade of the crib house/office wing, as well as entrances at the
southwest and southeast ends of the boiler block, providing access to the meeting and locker
rooms along the southeast side of the boiler block. Remaining original doors are metal with
horizontally divided, three-light glazing in the upper half. An oversized garage bay door is located
at the turbine block’s northwest corner, providing access to the delivery bay at the turbine room’s
northwest end.
b. Windows and shutters: Windows throughout the building are horizontally divided, four-light,
metal awning sash with precast concrete sills and are arranged in groups or continuous bands on
various facades. Windows on the second through fifth floors of the southwest facade of the boiler
block are arranged in bands comprised of six groups of four. The meeting/locker room area of
the boiler block features window bands that wrap around the south corner; lower-story windows
have been painted to make them opaque, and the upper-story window band has two-light
replacement units with aluminum sash. Approximately half of the window openings retain their
original steel sash, and most replacement units are aluminum sash that replicate the appearance
of the originals.
7. Roof:
a. Shape, truss type, covering: Each of the various blocks of the plant has a concrete slab roof
covered in asphaltic membrane. Roof slabs are supported by I-beams and sloped slightly to
drain rainwater into 4” pipes. The wall plane extends above the roof slab to form a 3’-0” high
parapet with a precast concrete coping covered with metal. Numerous pipes project above the
roof of the boiler block to vent heat and exhaust from machinery other than the main stacks. The
roof is accessible for maintenance and observation of the electrostatic precipitators.
C. Description of interior:
1. Floor plans and stairways: The interior spaces of the plant consist of a basement/ground
floor at grade, a main floor directly above, and a series of five steel grid deck levels that enable
workers to reach machinery and equipment in the upper portion of the boiler block (see plans
included in the field notes that accompany this documentation). A sixth level at the top of the
boiler block contains the fan floor and the coal conveyor area, connected by metal catwalks on
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either side of the boilers. A central elevator between the two boilers provides access to all levels
of the building, and a metal stairway with steel grid treads is located directly adjacent. Additional
stairways provide access between the basement and main floors of the turbine block, and to
upper and lower floors within smaller spaces such as the offices, locker rooms, and water
treatment room.
2. Flooring: With the exception of linoleum tile in non-industrial office spaces, flooring throughout
the plant is utilitarian in nature and features heavy-duty construction. The basement and main
levels have concrete floors, as does the fan floor and conveyor level. The concrete slabs have
finished surfaces in most areas, although the turbine hall has ceramic tile flooring. The majority
of the boiler block is open, and steel grate galleries and catwalks provide access to machinery at
various levels. Metal grating floors are rated for 200 pounds per square foot live load, while most
concrete floors are rated for 350 pounds per square foot.
3. Wall and ceiling finish: The face brick used in the exterior walls is visible on the inside of the
plant, and is used for many of the dividing walls. The main floor of the turbine hall has ceramic
tile wainscoting. The locker room areas have terrazzo floors and white tile walls. Walls in the
office spaces and control room are a combination of plaster, tile, and knotty pine paneling. Most
ceilings are open and expose the underside of the roof system above, although the offices and
control room have drop ceilings with suspended acoustical tile.
4. Openings:
a. Doorways and doors: Most interior doors are hollow metal fire-resistant doors with plain
knobs, mounted in pressed metal frames. Doors to offices, control rooms, and similar spaces are
partially glazed, and original doors feature the three horizontal lights found on exterior doors as
well.
b. Windows: Windows on most exterior walls allow natural light into the working spaces of the
plant. Windows on the boiler block and turbine hall that are not within easy reach of a walkway
have interior bars and levers to allow operation from the floor below.
c. Mechanical equipment:
(i) Lighting: Most light fixtures in the working spaces of the boiler and turbine blocks are
suspended bay lights with aluminum reflectors and incandescent bulbs. Office spaces and the
control room have fluorescent lights.
(ii) Plumbing: Pumps for both the circulating and service water are located in a pit in the lower
level of the crib house. Restrooms and showers are located in the locker room area on the main
floor.
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d. Cranes: An overhead traveling crane is mounted on rails along the northeast and southwest
walls of the turbine room, enabling workers to hoist machinery and service the turbines. A
smaller crane arm is located outside the crib house, adjacent to the forebay.
e. Conveyor and coal storage: Although the exterior coal conveyor has been removed, the
interior conveyor belt remains on the conveyor floor at the top of the boiler block and spans much
of the length of the 168’-0” space. Coal arrived at the south end of the building and was moved
northwest along the conveyor and distributed into the coal hopper below. The hopper is built of
steel and lined with gunite; inspection hatches are located in the floor adjacent to the conveyor,
and several manholes provide access to the hopper interior via steel ladders.
D. Machines: The plant’s two coal-fired boilers were each rated at 969.6 mmBTU per hour and produced
steam to power the turbines.38 Electrical power was generated by two 75,000-kilowatt, 12,500-volt
turbines built ca. 1954 by Allis-Chalmers in Milwaukee, Wisconsin. The turbines produced three-phase,
60-cycle alternating electrical current. As of 1956, the first full year in which both generating units were
operational, the plant had a net generating capacity of 849.3 million kilowatt-hours.39
E. Site layout: The plant and associated complex are located on W. BR Townline Road on the west bank
of the Rock River and are separated from the road by a deep setback. A paved, tree-lined driveway
accessed from a security gate on the south side of the road leads to the complex, which consists of the
plant and associated structures and outbuildings, including storage sheds, a deep well house, and
chemical addition building. The circulating water discharge system is comprised of a pipe running
southwest from the plant beneath the Rock River and a canal that parallels the east bank and rejoins the
river downstream from the plant. A paved yard is located on the west side of the main plant and a short
spur from the Chicago, Milwaukee, St. Paul & Pacific Railroad enters the property from the west and runs
along the northwest side of the complex. A large, grassy open space is located at the southwest of the
complex where the coal yard and ash settlement ponds have been obliterated.
38 One million British Thermal Units (mmBTU) is a standard unit of measurement that can refer to either the
amount of heat energy contained in fuel or the ability of a system (in this case, the boiler unit) to produce heat.
39 U.S. Federal Power Commission, Steam-Electric Plant Construction Cost and Annual Production Expenses,
Ninth Annual Supplement. (Washington: U.S. Government Printing Office, 1956), 132.
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Part III. Operations and Process
A. Operations: The Rock River Generating Station produced electrical current using coal-fired
combustion, following a process typical of most mid-twentieth century facilities. The process consisted of
a coal transport and storage system, furnaces and boilers to produce heat and steam, generators to
convert the motive power of the turbine into electricity, and a substation and transformer to transmit the
electricity to the power grid. Additional elements in the process included a variety of pumps,
compressors, fans, pipes, and ducting to move air and water, control their temperature and purity, and
convey waste ash and heat away from the plant.
B. Technology: Coal arrived by railcar via a spur that enters the site from the southwest and included
thawing pits for winter use. After the cars were unloaded, the coal was stored in the large yard southwest
of the main plant. Prior to use as fuel, coal from the storage yard was processed through the crusher
house, where larger chunks were broken down into smaller pieces less than 2” in diameter. A conveyor
belt mounted on a trestle moved crushed coal to the uppermost level of the plant, entering the conveyor
floor at the south corner of the building. The crushed coal was stored in interior bunkers before being fed
into the cyclone burners, where it was consumed to heat water in the boilers. The stacks carried the
heated flue gas away from the plant after fly ash (tiny particles of ash from coal combustion) was
removed. A sluice pipe carried the fly ash, mixed with water, to the settlement ponds located west of the
plant.
The boilers used the heat of the coal combustion to produce steam, which was then used to power the
turbines. Steam moved from the high-pressure environment of the boiler to the low-pressure environment
of the condenser, turning the turbine blades as it traveled from one to the other. The rotation of the
turbine blades spun the shaft of the generator, producing electricity. Condensate from the exhausted
steam was then purified and pumped back into the boiler to be reused. The water purification room
located at the southwest end of the plant contained the chemicals and equipment used for this purpose.
In order to provide the necessary low temperatures in the condenser, a constant supply of cold water
must be circulated through tubes in the condenser shell. The Rock River plant drew cooling water from
the river nearby, which entered via a forebay on the west bank. The water passed into the screen house,
where debris and aquatic life were filtered out, before being pumped into the condenser tubes. The cool
water passed through the tubes in the walls of the condenser, where it absorbed some of the heat
transferred from the condensing steam beneath the turbine, and then exited the condenser. This warmed
water then left the plant and had to be cooled before being returned to the river. The water entered a
pipe on the west bank, controlled by a sluice gate, that traveled beneath the river bed and discharged into
a canal on the east side. Water flowed through the canal to cool and then re-entered the river a short
distance downstream.
In order to avoid metal-on-metal contact between the turbine shaft and bearings, a thin film of oil must be
maintained at all bearing points. The oil house, located near the east corner of the plant, supplied oil to
both of the turbines via pipes that entered the plant on the southeast elevation.
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C. Workers: In the plant’s first year of operation, 49 employees worked at the facility, and throughout the
1950s and 1960s the total workforce numbered approximately 55, growing to 60 in the early 1970s.40
D. End Product: The Rock River Generating Station produced electrical power for a large area of south-
central Wisconsin, located in Federal Power Commission Power Supply Area 13. High-voltage electricity
was provided to the power grid and carried by transmission lines throughout WP&L’s service area, where
the voltage was stepped down for use by residential, commercial, and industrial customers.
40 U.S. Federal Power Commission, Steam-Electric Plant Construction Cost and Annual Production Expenses,
Eighth Annual Supplement. (Washington: U.S. Government Printing Office, 1955), 129; U.S. Federal Power
Commission, Steam-Electric Plant Construction Cost and Annual Production Expenses, Thirteenth Annual
Supplement. (Washington: U.S. Government Printing Office, 1960), 153; U.S. Federal Power Commission, Steam-
Electric Plant Construction Cost and Annual Production Expenses, Twenty-Seventh Annual Supplement.
(Washington: U.S. Government Printing Office, 1974), 168.
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Part IV. Sources
A. Primary Sources:
Sargent & Lundy, LLC. “Rock River Generating Station.” Scale varies. 1952-1974. Original plans for
construction and subsequent alterations in the collection of Alliant Energy.
U.S. Federal Power Commission. Steam-Electric Plant Construction Cost and Annual Production
Expenses, Eighth Annual Supplement. Washington: U.S. Government Printing Office, 1955.
———. Steam-Electric Plant Construction Cost and Annual Production Expenses, Ninth Annual
Supplement. Washington: U.S. Government Printing Office, 1956.
———. Steam-Electric Plant Construction Cost and Annual Production Expenses, Thirteenth Annual
Supplement. Washington: U.S. Government Printing Office, 1960.
———. Steam-Electric Plant Construction Cost and Annual Production Expenses, Twenty-Seventh
Annual Supplement. Washington: U.S. Government Printing Office, 1974.
Wedel, Karl. Interview with Mead & Hunt, Inc., July 13, 2015.
Wisconsin Power and Light Company. 1948 Annual Report. Madison, Wis.: Wisconsin Power and Light
Company, 1949.
———. 1949 Annual Report. Madison, Wis.: Wisconsin Power and Light Company, 1950.
———. 1950 Annual Report. [Madison, Wis.]: Wisconsin Power and Light Company, 1951.
———. 1951 Annual Report. [Madison, Wis.]: Wisconsin Power and Light Company, 1952.
———. Annual Report, 1952. [Madison, Wis.]: Wisconsin Power and Light Company, 1953.
———. Annual Report, 1954. [Madison, Wis.]: Wisconsin Power and Light Company, 1955.
———. Annual Report, 1955. [Madison, Wis.]: Wisconsin Power and Light Company, 1956.
B. Secondary Sources:
“$11,500,000 Generating Plant to Be Built in ’52.” Janesville Daily Gazette. December 31, 1951.
“$65,000,000 Powder Plant to Be Built Near Merrimac - Construction Approved By War Department
Wednesday.” Sauk County News, October 30, 1941.
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“Advertisement.” Janesville Daily Gazette, May 18, 1954, sec. 2.
“Advertisement.” Reading Eagle, June 2, 1974.
Content, Thomas. “Beloit Power Plant to Shut down by Year-End.” Milwaukee Journal Sentinel, May 26,
2009. http://www.jsonline.com/blogs/business/46127242.html (accessed August 15, 2016).
“Cotton Reports on Capacity Outlook.” Utilitarian 28, no. 6 (November 1951): 10, 12.
Drewry, M.K. “Oak Creek Power Plant.” Mechanical Engineering 77, no. 1 (January 1955): 12–18.
Energy Information Administration, U.S. Department of Energy. “Existing Electric Generating Units in the
United States, 2003,” 2003. http://www.eia.gov/electricity/capacity/ (accessed June 8, 2016).
“Hydrogen Cools Generator Rotor.” Janesville Daily Gazette, May 18, 1954, sec. 2.
“In Memoriam.” General Electric Review 22, no. 8 (August 1919): 631.
McDonald, Forrest. Let There Be Light: The Electric Utility Industry in Wisconsin, 1881-1955. Madison,
Wis.: American History Research Center, 1957.
“News Items.” Utilitarian 27, no. 8 (January 1951): 5–7.
“Power Development in Chicago.” Electrical World 76, no. 13 (September 24, 1920): 620–22.
“Power Plant Showing Set.” Milwaukee Journal, April 29, 1952.
“Retirement of Dam Will Benefit City.” Janesville Daily Gazette, August 2, 1968.
Sargent & Lundy, LLC. “Company History.” 2015. http://www.sargentlundy.com/about/company-history/
(accessed August 16, 2016).
“World’s First ‘Supercharged’ Generator at Edgewater.” Power Engineering, January 1952, 104.
C. Likely Sources Not Yet Investigated: Additional contract documents in the collection of Alliant
Energy may yield more information on the various firms that erected the plant, provided structural steel,
and furnished machinery.
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Figure 1. Artist's rendering of future Rock River plant as seen from the north, 1952.
Wisconsin Power and Light Company, 1952 Annual Report (Madison, Wis.: Wisconsin Power and Light
Company, 1953).
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Figure 2. Rock River plant after completion of first unit, view facing west, 1953.
Wisconsin Power and Light Company, 1953 Annual Report (Madison, Wis.: Wisconsin Power and Light
Company, 1954).
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Figure 3. Completed plant, 1954.
Wisconsin Power and Light Company, 1954 Annual Report (Madison, Wis.: Wisconsin Power and Light
Company, 1955).
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