Entry no.22 - The Power Plant, Dresden GS
The Dresden GS(Generating Station) is a major coal-fired power plant owned and operated by the PRPA(Pretoria Regional Power Authority) a publicly owned electrical utility company which owns and operates a total of 11 power plants in and around the Pretoria Metropolitan Area. Dresden GS is by far the largest of PRPA's power plants with a total nameplate capacity of 2,240MW. When operating at peck capacity the plant produces almost 50% of Pretoria's electric supply, enough power for 1.2 million people. The plant is located on the East side of the Dresden Port District.
Phase One
Prior to the plants construction most of the electricity supplied to Pretoria came from 3 medium sized hydroelectric stations and an antiquated coal power plant all of which were located in the Central Pretoria. Together these 4 plants - Holyrood(Coal) GS - 335MW, Noirwater1 - 294MW, Noirwater2 - 190MW & Evermore1 - 118MW), along with a couple of other small stations produced a little over 1,000MW. This was more than enough for the region's 400,000 residents back in the mid 1940's. However at the start of the 50's the city entered into a prolonged period of growth and expansion. With its population and economy expanding by nearly 8% per yearly it quickly became evident that power demand would outstrip supply in matter of years. A site was quickly selected on the south side of Cisco Bay and 18 hectares of land near Dresden's booming port was earmarked for the thermal-electric plant that would meet Pretoria's seemingly insatiable growing power demands.
Construction began in May 1951 and quickly became a project of superlatives: The stations first boilers were the largest ever installed in the nation; the 380,000 kilowatt Parsons G2-5A generators were the largest available and the stations power transformers were the largest in the world. Each of the boilers was paired with a brick-line smokestack, both towering 465ft(142m) over the surround landscape which made them the tallest structures in Dresden at the time. A new hydro interconnection was built consisting of the Hardack, Tauon & Muon hydro corridors and the Hillsboro & Enforce transmission substation through which electricity was directed around Cisco Bay to Central Pretoria. The total cost of this project was $148 million.
The station was formerly commissioned and put into service on Aug 13, 1954. Almost instantly regional capacity nearly doubled from 1,050MW to 1,810MW. It was much needed since by then the power situation had become so desperate that the government had to implement rolling blackouts two months beforehand. Though these only effected the outlying(and less affluent) areas of the growing metropolis.
Dresden Generation Station, circa Jan 1955
But Dresden GS's story does not end here.
Phase Two
Regional growth would continued unabated over the next 10 years. By 1960 it was clear that additional units would be needed. A study concluded that year indicated the plant would reach maximum capacity within 10 years and another 1,000 MW of electricity would be needed within 25 years. This time the government did not wait around and quickly authorized the PRPA to building additional generation capacity. And so in early 1962 construction on phase two of the station began. Part of Cisco Bay, directly west of Units 1&2 was backfilled and Unit's 3 & 4 were built on the new landfill. The coal stockpile was moved to the west side of the plant and expanded. A new much larger docking facility was also built. Coal imports would increase by 125% from an average of 400 tons per day to 900. The amount delivered by ships would increase from 40% to over 90%.
In Aug 1965 Units 3 & 4 were completed and placed online. Two Parsons G5-9S generators with a capacity of 500,000 kilowatt's, once again the largest available at that time were installed. And the Hardack, Tauon & Muon hydro corridors were all expanded with a second set of electric pylons. The new boilers were of a far more efficient design and were each paired with a 600 foot tall(183m) smokestack. The two new stacks again assumed the title of Dresden's tallest structure until the KIRO TV tower(609ft/186m) was build on Mount Tokiko in 1971.
Dresden Generation Station, circa 1975
After the completion of units 3 & 4 total nameplate capacity of the plant rose from 760MW to an impressive 1,760MW. Phase two had a total cost of $226 million and when completed made Dresden GS the world's largest power plant, a title it would hold on to for the next 15 years(1965-79).
Modernization Project
By the late 1980's the original units of the plant were approaching the 40 year mark and nearing the end or their life expectancy. These units were operating at less then 30% thermal efficiency and were under powered for their size. The station was a major source of pollution and smog in the Pretoria air shed. With the oldest units dating back to the 1950s, the plant was ranked 3rd on the national list of dirtiest power plants in terms of sulphur dioxide emissions per megawatt-hour of electrical energy produced. Overall it was by far the largest generator of sulfur dioxide, nitrogen oxides and other particulates in the entire region.
Dresden GS's old Unit 1 & 2, only used for peak load purposes by the late 80's.
In 1989 after after Baycole GS and the new transcontinental hydro corridor were built, phase one of the plant containing the Units 1 & 2 underwent a 1.6 billion dollar modernization program. The original boilers, turbines and generators were all replaced in the 6-year long project. Low NOx burners and electrostatic precipitators where also added at the time. Two new Dynamic Electric T-1000 generators, each producing 620,000 kilowatts, were installed increasing the total generating capacity by 27% to 2,240MW. The two boilers were marred to a single new 1,001-foot tall(305m) superstack built to vent pollution high above the local air shed. The original brick line stacks were taken out of service, however they were not demolished because they were connected to the buildings superstructure.The super stack greatly reduced local pollution levels because not only did it replace the two shorter stacks of Unit's 1 & 2 but Unit's 3 & 4 with its shorter stacks would transition into more of a peak load role. The superstack is currently the tallest in the region, being a single foot taller then the ICON smelters "Big White" just across the Bay.
Units 1 & 2 today
The superstack took 6 months to complete and contains nearly 25,000 tons of concrete. It is currently the the 8th tallest smokestack on planet Azura and the tallest structure in the city of Dresden/the South Shore borough, overtaking the 839ft (256m) tall WBNS TV tower built in 1985. Dresden GS is connected to the PRPA's(Pretoria Regional Power Authority) operations center via direct microwave link. The transmitter/receiver is located on the 280m level of the superstack. Direct links to both Hillsboro TS & Enforce TS are also located on there.
Tip of the stack
In the shadow of giants
Rising above it all
Cooling Systems
Two 270ft tall cooling towers were added to the east side of the plant as part of the upgrade to units 1 & 2, dramatically reducing the plants thermal pollution.
All of the waste heat generated by the plant was at one time released into Cisco Bay. This water is used in large condensers to cool the used steam back to its liquid form. Prior to the construction of the cooling tower the plant withdrew more than 50 million gallons of water per hour for cooling needs at peak load. Today Units 1 & 2 operate using a new closed loop system. Units 3 & 4 continue to use the once-through system. Withdrawal levels have been reduced to 30 million gallons of water per hour at peak load when all units are in operation. However Units 3 & 4 only operate on a peak load basis, usually between the hours of 6am and 8pm for an average of 14 hours per day, while the newly replaced Units 1 & 2 are used for base load purposes. The closed loop system of Units 1 & 2 withdraw only a fraction of the amount of water they used to, approx. 1 million gallons per hour. This means that the plants actual average hourly withdrawal rate is much lower coming in at around 18 million gallons per hour.
The intake and outlet structures
Coal Supply
Western coal is delivered to Dresden via ocean going 100,000-ton freighters. Shipments of coal regularly arrive at the Dresden GS docking facility
The plant coal pile is relatively small for a plant of this size with a maximum capacity of 0.75 megatons. This is nonetheless sufficient to provide for about 40 days of operation at maximum load
Coal is feed into the plant by a series of conveyor belts either directly off anchored bulk carriers next to the pier or from the coal stockpile
Typical mix of the coal batch is 90% western 10% eastern. Eastern coal has a higher energy content but has greater emissions so its use is limited. Eastern coal is delivered by rail on unit trains to an unloading facility on the "coal spur" which branches off GWR's mainline Almera sub
Connections to power grid
The plant is connected to the power grid by 4 double circuit 250 kV transmission lines, also owned and regulated by the PRPA. Two lines travel eastward merging with a third from the nearby Bunsen Burner Waste to Energy plant to form the Hardack hydro corridor. Most of Dresden GS's power flows on this interconnection towards the Middle East and Central districts. Two other 250kV lines travel southward on the Zelfor hydro corridor providing power to the South Shore borough and creating an interconnection with other power plants located south of Pretoria.
The Switchyard at Dresden GS, looking east
The Switchyard looking west, obscured by the mist from the cooling towers
Overview of the Plant Today
Units 1 & 2
Units 3 & 4
Currently Dresden GS is currently the third largest coal-fired plant in the nation and the 16th largest electric plant overall on planet Azura.
This complex is one of my 3 favorite creations that I've made in SC4. Hope you enjoyed checking it out 
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