Ultimo Power Station facts for kids

The Ultimo Power Station, also known as the Ultimo Powerhouse, was a big building in Ultimo, a suburb of Sydney, Australia. It was built to make electricity. This power station started working in 1899. It was the first large power station in Sydney. Its main job was to power the electric tram network. Before this, a smaller power setup was used in Regent Street from 1882. Some experimental electric trams had also run since 1890.

How the Power Station Made Electricity

The Ultimo Power Station used different kinds of machines to make electricity. At first, it had American-made steam engines. These engines were connected to special machines called generators. These early generators made direct current (DC) electricity. Later, the station got British-made turbo-alternators. These machines made alternating current (AC). Most of the AC power was 6,600 volts at 25 cycles per second.

Early Power: Direct Current

The first machines at Ultimo were four large steam engines. They were made by E.P. Allis & Co. Each engine was very powerful, making 1250 horsepower. They spun at 100 rpm. These engines were connected to generators made by General Electric. Each generator could make about 850 kW of power. This was 550 volts of direct current.

The power station used 14 large boilers to make steam for these engines. These boilers were made in Sydney. They each made enough steam for 300 horsepower. The steam pressure was 140 psi. Workers had to feed coal into these boilers by hand. Only 12 boilers were needed to run the station at full power. The other two were kept as spares. The first generators were taken out in 1915 and 1916. However, some of the boilers stayed for a while.

Switching to Alternating Current

The tram line on George Street had problems with power dropping. To fix this, the power station started using alternators in 1902. The first three alternators were 1500 kW machines. They made 6.6 kV of power. Each alternator was run by a large steam engine. These engines were very powerful, making 2500 horsepower. The alternators made three-phase alternating current at 25 Hz.

When these new machines were added, some of the old boilers were removed. Then, eight new boilers were installed. These new boilers made steam at 160 psi. As the station grew, 24 more boilers were added by 1904. This meant there were 32 new boilers in total. The power station had planned to add more steam engine-alternator sets. But they decided to use newer, more efficient turbo-alternators instead.

Even More Power: Turbines Arrive

The first turbo-alternator started working at Ultimo Power Station in 1905. It was made by C.A. Parsons & Company in England. This steam turbine was very powerful, making 3000 horsepower. It spun very fast, at 1500 rpm. It drove an alternator that made 1875 kW of power. To power this new machine, 16 more boilers were added in 1905. This brought the total number of boilers to 48.

Two more turbo-alternators were added in 1909. They were also made by C.A. Parsons & Company. Each of these could make 5000 kW of power. They made three-phase alternating current at 25 Hz. More boilers were added in 1910 and 1913 to support these new machines. Some of the older boilers were removed to make space for coal storage.

In 1911 and 1913, two more 5 MW turbo-alternators were installed. These machines replaced some of the older vertical generators. In 1912, a very powerful 7.5 MW turbo-alternator was brought to Ultimo. It was originally meant for the White Bay Power Station. It was later moved there in 1918. Another 8.7 MW set was installed in 1914.

Later, in 1919, two more alternators were added. When the direct current (DC) section closed in 1920, more modern turbo-alternators were installed. These were 2.4 MW machines. They made 50 Hz alternating current. However, in 1921, it was decided that Ultimo would only make 25 Hz power. So, the smaller 50 Hz turbo generators were removed by 1928.

Modernizing the Power Station

In 1929, work began to replace 58 small boilers with six much larger ones. These new boilers worked at a higher pressure of 350 psi. They were the first in New South Wales to burn coal that had been ground into a fine powder. The smoke from these boilers went up the two tall brick chimneys built in 1902. Along with the new boilers, two new 20 MW turbo-alternators were installed. This work was finished in 1931.

In 1941, two more large boilers were added. These boilers were very efficient. In 1942, a third 20 MW turbo-alternator was started. In 1948, two older 5000 kW turbo-alternators were removed. In 1949, a single 18.75 MW machine took their place. This machine had come from the White Bay Power Station. This brought Ultimo's total power output to its highest level, 79.5 MW. Around 1948-1949, the boilers were changed so they could burn furnace oil. This was because there wasn't enough coal.

Control of the Ultimo Power Station changed in 1953. It moved from the Department of Railways to the new Electricity Commission of New South Wales.

The Sydney Power Grid

The Sydney railway and tramway power grid was a network of power stations. It included Ultimo and White Bay Power Stations. They were connected by a 6600 V power line. This network supplied electricity to railway and tramway stations.

After the first direct current (DC) setup, Ultimo Power Station made three-phase alternating current (AC). This was 6600 V at 25 cycles per second. Special machines called rotary converters changed this AC power into 600 V DC for the trams. When the heavy rail lines started using 1500 V DC power in 1926, they also used large rotary converters.

In 1939, a special machine was installed at White Bay. It could change 25 Hz power to 50 Hz power. This meant that power from the railway power stations could be sent to the general Sydney power grid if needed. Over time, electric trams were removed from Sydney. This meant less power was needed from the 25 Hz grid. In 1959, it was decided to stop making 25 Hz power completely.

Closing Down the Power Station

The Sydney tram network closed down in 1961. Because of this, the Ultimo Power Station was closed in 1963. The building was later reused. It became the Powerhouse Museum. You can find more details about its history there.

Engineering Heritage Award

The Ultimo Power Station received a special award. It was given a Historic Engineering Marker by Engineers Australia. This is part of their program to recognize important engineering sites.