78 IEEE power & energy magazine 1540-7977/08/$25.00©2008 IEEE march/april 2008

Thomas J. Blalock and Craig A. Woodworth

IIN 1950, A NEW TREATY BETWEENthe United States and Canada greatlyincreased the amount of water thatcould be diverted for power generationpurposes. Remedial work and a controlstructure made it possible to retain themajesty of Niagara Falls in spite of thisincreased water diversion. Also in1950, construction began on Sir AdamBeck Station No. 2 (adjacent to theexisting Station No. 1) in Canada.When completed in 1953, the new sta-tion had three times the generatingcapacity of the first station, and all ofits generation was at 60 Hz.

Meanwhile, in the United States,construction of the Niagara Power Pro-ject by the Power Authority of the Stateof New York (now known as the NewYork Power Authority) was delayeduntil 1957 due to political considera-tions. This huge facility (named theRobert Moses Plant after New York’smaster builder of public works and thechairman of the power authority) islocated at Lewiston, New York, acrossthe Niagara River from the Sir AdamBeck stations. The largest ever built inthe Niagara region, the plant originallycontained 13 60-Hz turbine-generatorsthat were rated at 150 MW each. Later,these units were all rebuilt to 193.5-MW capacity, or over 2,500 MW total.Water was supplied via two tunnelsfrom a location on the Niagara Riverabove the falls. This project alsoincluded the Lewiston Reservoir andthe pumped-storage Lewiston Pump

Generating Plant that contained 12 gen-erating units of 20-MW capacity each.When operating as synchronous motorsto pump water back into the reservoir,each of these units can develop 37,500hp. During periods of low load, as wellas during summer night hours when thewater diversion can be increased,power from the main Robert MosesPlant is used to refill the reservoir.Then during the daytime peak demandperiod, the reservoir water drives boththe Lewiston Pump Plant and theRobert Moses Plant generators.

To acquire the land necessary forthis massive project, Robert Moses wasperfectly content to dispossess theTuscarora Indians who inhabited theland, just as he often had done with res-idents of New York City who happenedto be in the way of his public worksprojects there (such as the controversialCross Bronx Expressway).

Power SystemInterconnectionsInterconnections among some of theNiagara Falls power plants were madeat an early date. The Rankine Stationwas connected with the Adams Stationsvia 12-kV cables run beneath the road-way of a bridge that spanned the gorgebelow Niagara Falls and to the CataractPower & Conduit Company (thewholesale electric power provider inBuffalo) via 22-kV overhead lines thatcrossed the Niagara River at Buffalo.The Rankine Station was also connect-ed to the Electrical Development Com-pany station by means of underground

cables. These interconnections enabledthe Cataract Power & Conduit Compa-ny to purchase power from both theRankine and the Electrical Develop-ment stations in Canada. In addition,Cataract Power also had an intercon-nection with the Niagara, Lockport,and Ontario Power Company that, inturn, purchased 25-Hz power from theOntario Power plant in Canada andmaintained a 60-kV transmission lineto Syracuse, New York.

In 1916, with increasing load anda limited supply of power from Nia-gara Falls, the Buffalo General Elec-tric Company (successor to theCataract Power & Conduit Compa-ny) began construction of a steamgenerating station located on theNiagara River north of Buffalo. Thiswas originally known as the RiverStation and contained three 20-MW,

hist

ory

25-Hz at Niagara Fallsend of an era on the Niagara Frontier, part 2

Digital Object Identifier 10.1109/MPE.2007.915180

Part 1 of this article, published in

the January/February 2008 issue

of IEEE Power & Energy Maga-

zine, summarized early hydro-

electric developments at Niagara

Falls and the establishment of

25-Hz power in most of western

New York State. Here we contin-

ue this story through the second

half of the 20th century and up

to the eventual demise of 25-Hz

power on 12 October 2006.

—Carl Sulzberger

Associate Editor, History

march/april 2008 IEEE power & energy magazine 79

25-Hz turbo-generator units. In 1926,the plant was renamed the HuntleyStation in honor of Charles R. Hunt-ley, the late president of the BuffaloGeneral Electric Company. By 1930,seven 25-Hz generators having acombined capacity of 305 MW hadbeen installed and were in operation.Figure 1 shows the Huntley Station.

In spite of the extensive develop-ment of 25-Hz hydroelectric genera-tion at Niagara Falls, as described inpart 1 of this article, surrounding areasin New York State began to develop60-Hz power systems during the early20th century. In 1930, two 80-MW,60-Hz units were added at HuntleyStation to enable the beginning of aconversion of 100 MW of 25-Hz loadto 60 Hz. By the mid-1950s, more 60-Hz additions at Huntley had increasedits capacity to 785 MW, making it thelargest steam generating station in theworld except for the ConsolidatedEdison Company’s Hudson AvenueStation in New York City. However,Huntley had a higher load factor thanthe Hudson Avenue Station and, as aresult, generated more kilowatthourson an annual basis.

Frequency ChangersPrior to 1924, the Niagara, Lockport,and Ontario Power Company had inoperation several synchronous fre-quency changers (two synchronousmachines coupled together) due to theneed to interconnect the 25-Hz powersystem in western New York State withthe growing 60-Hz systems in sur-rounding areas. In 1924, this companyinstalled two 6-MW “variable-ratio”frequency changers at Altmar, NewYork, and, just one year later, installeda third such machine at Jamestown,New York. These machines operatedon the principle of the “Scherbius”drive system that recently had beendeveloped for the accurate speed con-trol of large ac motors driving steelrolling mills. This concept had beendeveloped by Arthur Scherbius ofSwitzerland and was marketed in theUnited States mainly by the GeneralElectric Company. The use of the

Scherbius scheme allowed for slightchanges in the speed of the frequencychanger sets to accommodate minorvariations in frequency on both the 25-and 60-Hz systems.

Then, in 1927, two 20-MW variable-ratio-type frequency changers wereinstalled at the town of Lockport, NewYork. These were not actually Scher-bius machines but used a speed controlsystem that differed somewhat in itsoperating details. Consequently, thisstyle of frequency changer eventuallybecame known in the industry as the“Lockport type.” Thus, Lockportbecame a center of distribution for boththe 25- and 60-Hz power systems inwestern New York State.

During 1930, the Buffalo GeneralElectric Company installed a 20-MWScherbius frequency changer at theHuntley Generating Station. Thismachine actually remained in opera-tion into the 1990s. The reason forthis long operating life was that theformer Bethlehem Steel plant in near-by Lackawanna, New York, had a 20-MW, 25-Hz steam turbo-generatorfacility in place that operated onwaste gas from the plant’s coke ovens.Bethlehem Steel wanted to continueto make use of that gas (actual steel-

making at the plant had ceased by thistime) by selling electric power to theNiagara Mohawk Power Corporation.To do that, however, the Huntley fre-quency changer had to be used to con-vert this power to 60 Hz; BethlehemSteel paid to have this machine reha-bilitated for that purpose.

During the 1950s, two more fre-quency changers were installed byNiagara Mohawk at Gardenville,southeast of Buffalo. These were not,however, variable-ratio machines.They had been purchased from theConsolidated Edison Company ofNew York City, and each set consist-ed of a 42,000-hp, 60-Hz synchro-nous motor coupled to a 30-MW,25-Hz generator. The latter machineswere equipped with mechanicalframe-shifting devices to enable thepower flow through the sets to becontrolled by adjusting the phaseangles of the machines.

Thus, during a portion of the 20thcentury, five large frequency changerswere in operation in western New YorkState: two at Lockport, two at Gar-denville, and one at Huntley Station.

At one time, there had been in usetwo frequency changers at the Trans-former House associated with the

figure 1. The Charles R. Huntley Steam Generating Station with the 25-Hz sec-tion on the right and the 60-Hz section on the left, 12 May 1953. (Photo cour-tesy of the Niagara Mohawk Power Corp. archives.)

80 IEEE power & energy magazine march/april 2008

Edward Dean Adams Stations in NiagaraFalls. These machines had been installedby a local chemical company to be ableto purchase 60-Hz “Schoellkopf replace-ment power” from the New York PowerAuthority and convert it to 25 Hz for oldmotors still being used in its plant. Bythe year 2003, these two machines aswell as the two frequency changers atLockport had been removed, and boththe Gardenville and Huntley Stationmachines had been taken out of service.

Later DevelopmentsIn 1919, power generation in NewYork State was comprised of thefollowing:

67% 25 Hz24% 60 Hz5% 40 Hz*4% direct current (dc)

*40 Hz was an unusual frequencyintroduced by General Electric in the1890s.

An editorial article in a 1923 issueof Electrical World stated that “NiagaraFalls could never be expected to changefrom 25 cycles to 60 cycles.” This opin-ion was based on the large amount ofindustry in the area at the time thatoperated on 25-Hz power. In 1945,however, a lengthy article in ElectricalNews & Engineering described indetail the problems to be overcome inchanging southern Ontario from 25- to60-Hz power distribution.

The Edward Dean Adams Stations(see Figure 2), which had beenplaced in reserve by 1924, werereturned to service at the beginningof World War II when the increaseddemand for electric power resulted inan increase in the permissible waterdiversion. The Adams Stations andthe rehabilitated portion of Schoel-lkopf Station 3A operated at highload factors until 30 September 1961when they were shut down and theirwater allotment transferred to theRobert Moses Plant.

The Adams Stations themselveswere demolished in the mid-1960s,but a small advertisement in theMarch/April 1999 issue of Preserva-tion magazine, published by theNational Trust for Historic Preserva-tion, offered for sale the former Trans-former House at that location for“adaptive re-use.” The asking pricewas US$3 million, and the buildingwas described as still having in placeits 10-ton overhead crane.

On the Canadian side of the river,the Toronto Power Station (see Figure3) was shut down in 1974, and theOntario Power Station (see Figures 4and 5) was shut down in 1997. TheRankine Station remained in serviceuntil December 2005 (on an occasionalbasis only), and plans are now in placeto convert it into an operating museum.So ended 124 years of hydroelectricgeneration in the immediate vicinity ofNiagara Falls (see Figure 6).

The 60-Hz peak load in the Buffa-lo area did not exceed the 25-Hz peakload until 1952, and the last 25-Hzrotary converter (Edison system)substation in Buffalo was not shut

figure 3. The Electrical Development Company generating station, later theToronto Power Station, circa 1998. (Photo courtesy of Margaret Dunn, NiagaraFalls—A Pictorial Journey.)

figure 2. The Edward Dean Adams Stations of the Niagara Falls Power Compa-ny with Station 1 on the left and Station 2 on the right of the canal, circa 1927.(Photo courtesy of the Niagara Mohawk Power Corp. archives.)

down until 1956. One factor in thelongevity of 25-Hz service in the cityof Buffalo was that elevators couldnot be converted to 60-Hz operationunless they were brought completelyup to then-applicable building codes.Thus, it was less expensive to pay aminimum monthly charge to retainthe 25-Hz service and just leave theelevators alone.

By 1994, Niagara Mohawk was nolonger generating any 25-Hz powereven though the company still had a7-MW demand. That demand was sup-plied by power purchased from theRankine and Sir Adam Beck plants inCanada, and from the Bethlehem Steelplant in Lackawanna (as describedabove). In fact, the Gardenville fre-quency changers were, by this time,normally operating to convert 25-Hzpower into 60-Hz power because therewas surplus 25-Hz power availablefrom Canada. In Canada, seven of thenine Sir Adam Beck No. 1 generatorshave been converted to 60 Hz. Theother two 25-Hz generators and a fre-quency changer serve the remainingtwo 25-Hz customers that have a maxi-mum load of 31 MW when the steelplant in Hamilton, Ontario, is operat-ing. It is anticipated but not mandatedthat the 25-Hz system in theNiagara/Hamilton area will be decom-missioned at the end of 2009.

EpilogueThe beginning of the end of 25-Hzpower in the western New York Statearea was the 1947 decision of theNiagara Mohawk Power Corporationpredecessor to accept no additional25-Hz customers and not to increasethe 25-Hz service to existing cus-tomers wherever 60-Hz power wasavailable. Later, the almost completedestruction of the Schoellkopf plantsin the 1956 rockslide led to anincrease in the cost of supplying 25-Hz power. The completion of theRobert Moses Plant in 1961 providedreplacement power for Schoellkopfcustomers, but it was 60-Hz power.

In 1963, Niagara Mohawk petitionedthe Public Service Commission of New

York State to terminate all 25-Hz serviceby as early as 1965. That terminationwas not destined to occur, however, untilOctober 2006.

Over the years, the 25-Hz loaddecreased as customers modernizedor, as was the case with the westernNew York State steel industry, wentout of business. The number of 25-Hzcustomers (all in the Buffalo area)had dwindled from 73 in 1994 to only46 in 1998 when a tariff approved bythe Public Service Commission ofNew York provided for the elimina-

tion of 25-Hz power service by 31December 2007 and required a con-tribution from affected customers ifany necessary repairs to the 25-Hzsystem exceeded US$25,000.

In 2002, an incentive program wasapproved that provided for a limitedmatching grant to retrofit equipmentfor 60-Hz operation. Over time, trans-mission and subtransmission circuits,substations, and feeders were retired tostreamline the 25-Hz system andreduce losses. In 2004, the last remain-ing connection (at Harper Substation in

march/april 2008 IEEE power & energy magazine 81

figure 4. Ontario Power Company powerhouse at the waterline in theNiagara Gorge downstream from the falls, March 1997. Ice in the gorgeduring the winter caused operating problems over the years. (Photo courtesy ofCraig Woodworth.)

figure 5. The 187.5 rpm, 12-kV, 25-Hz generators at the Ontario PowerCompany powerhouse, May 1995. (Photo courtesy of Craig Woodworth.)

Niagara Falls) from the Rankine Sta-tion was eliminated. Subsequently, theonly available 25-Hz power was fromthe Sir Adam Beck Station No. 1. By12 October 2006, there were only five25-Hz customers remaining, includingthe former Hotel Statler in Buffalo (forelevators) and a General Mills plant.The repair of the transmission conduc-tors that were downed on that date andinterrupted the 25-Hz service wouldhave required contributions from theremaining few customers; they electednot to contribute. Thus ended the era of25-Hz power service on the Americanside of the Niagara Frontier.

For Further ReadingG.W. Davenport, The Niagara FallsElectrical Handbook. Syracuse, NY:Mason, 1904.

W.E. McIntyre, “Niagara Fallshydro-electric industry,” Ph.D. disserta-tion, Clark Univ., Worcester, MA,1951.

R.B. Belfield, “The Niagara fron-tier,” Ph.D. dissertation, Univ.Pennsylvania, Philadelphia, 1981.

T.J. Blalock, “The frequency chang-er era,” IEEE Power & Energy Mag.,vol. 1, no. 5, pp. 72–79, Sept.–Oct.2003.

E.D. Adams, Niagara Power. NewYork: Niagara Falls Power Co., 1927.

E.S. Bundy, A. Van Niekerk, andW.H. Rogers, “A 40,000-kW variable-ratio frequency converter installation,”AIEE Trans., vol. 49, pt. 1, pp.245–256, Jan. 1930.

C.A. Scarlott, “Power generation atNiagara Falls,” Electric J., vol. 27, no.11, pp. 669–675, Nov. 1930.

E.M. Haacke, “Problem presented byproposal to change over SouthernOntario’s power to 60-cycles,” Elect.News Eng., vol. 54, no. 22, pp. 44–47 and71–77, Nov. 15, 1945.

M. Dunn, Niagara Falls—A Pictori-al Journey. Niagara Falls, ON: MargaretDunn, 1998.

figure 6. The location of the hydroelectric powerhouses in the immediate vicinity of Niagara Falls.(Drawing adapted from E.D. Adams, Niagara Power, vol. II, p.136; courtesy of Craig Woodworth.)

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InternationalBoundary

Niagara FallsNew York, USA

Niagara FallsOntario, Canada

3A

3B

3C

Niagara River

Edward Dean AdamsStations

12

TailraceTunnel

Hydraulic Canal

Am

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anFa

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Hor

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21

Fore

bay

Hydraulic Power/Schoellkopf Stations

OntarioPower Co.

Canadian NiagaraPower Co.

(Rankine Station)

GoatIsland

Tailr

ace

Tunn

els

ElectricalDevelopment Co.(Toronto Power)

Inta

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82 IEEE power & energy magazine