Engineering Excursions: Hydropower and Smelters

Two weeks of rigorous studying and one exam later, it was time for our five-day excursion around the island. I can confidently say that this trip is something everyone was looking forward to since the first day. Groggy yet eager with excitement, everyone tumbled out of the hostel early Monday morning. Our larger bags were loaded into the attached unit behind the bus, while we all piled inside. The whole week had already been planned out with the best Tasmania had to offer, as well as accommodations for each night. Although the whole week was a mix between engineering site visits and cultural landmarks, I’ll be focusing on only the site visits in this post. Don’t worry, I’ll definitely write about everything else in another post!

Our first destination was a site visit to the Tarraleah Power Station. This was the moment I had been waiting for. Not knowing much about what Mechanical Engineering was, I was interested to see how it translated to the real world. This visit did exactly that, showing me one of the many concentrations in this field, which was power and energy. For those of you that were like me, not knowing much about this type of renewable energy: hydropower is the use of high-pressure water (carried down by pipes or canals) to spin turbines at a power station in order to generate electricity. Rotational energy from the spinning turbines is then converted into electrical energy that can be sent to the grid. Seeing all of this for the first time absolutely blew my mind. But most importantly, I loved that I had gained new insight into applications of engineering. This power station used a Pelton wheel for their turbine which consisted of two buckets that the water was split into. The power station had 6 turbines running at all times, constantly outputting water at extremely high velocities into the connected river. Even with so much water and energy being generated, I found out that this is one of the smaller hydropower stations too!

The following week, we visited Tasmania’s other power station at Gordon Dam. After about a 2.5 hour bus ride away, we reached the Gordon Dam. We first went inside the main power station and were shown around the machinery. This power station only had three turbines; however at maximum capacity they can produce 10x the power of Tarraleah! The technology for the turbines that was used here was the Francis wheel. Additionally, the reservoir at the Gordon Dam was a lot larger. We were taken to the top of the dam itself at the end of the tour at the power station. For a few moments, everyone stood still in awe. Below us a 130 meter drop across the curved surface of the dam. The view was mesmerizing but terrifying at the same time. Although we weren’t able to see the exit point of the water at this dam, I could only imagine how fast the water would be coming out. Renewable energy is something that is so interesting to me, and it was terrific to see it in person. Just like Tarraleah, this visit had only added to my knowledge about what mechanical engineers did.

We also visited the Bell Bay Aluminium smelter near the end of our excursion. Personally, I was incredibly excited for this because I knew that a smelter created metal, which meant that they worked with chemical elements! Specifically in this case, they worked with aluminum. Right off the bat I noticed that they pronounced and spelled aluminum differently. They added in an extra “i”. During the introductory presentation that was given, all of us quickly could pick out this difference. We were taken across the whole campus of the smelter to see the steps of the smelting process. To make it simple, the smelter would receive powdered alumina which would then combine with a carbon form to create molten alumina after undergoing a reduction process. As the day went on, we were taken to the building that held the cells of molten aluminum. Right before our eyes, we got to see how anodes were put in and removed from the cells. Hot, dripping anode material was falling everywhere, burning a bright red color. You could feel the heat on your skin as the overhead machine carried the anodes from one side of the building to the other. The anodes are what help the aluminum undergo the electrolysis process, each the size of a beach cooler, weighing about 550 kilograms. Once enough molten aluminum was created in each cell, a crucible with a nozzle would go in and suck everything out. You could easily see that this crucible, the size of a large hot tub, would begin steaming once there was a decent amount of molten metal inside of it.

From here, the metal was either taken to another plant where they use the liquid metal itself to create pastes or powders, or it was taken to the casting room at the smelter. We were repeatedly warned to not touch any aluminum due to its deceiving state. Hot aluminum and cold aluminum look exactly the same. We didn’t want any casualties on this trip! One of the last things we did was see how the casting process was performed: tall beams, T-blocks, and rectangular blocks of aluminum were being made. We each even got to take home our own sample of some of the aluminum that was made that day. The engineers at Bell Bay kept telling us that we were incredibly lucky to have visited on a day where the casting room and campus as a whole was buzzing with excitement. I was incredibly grateful for this trip because it reaffirmed me that I loved what chemical engineers did. The fact that they were working with different elements that were undergoing reduction had me on my tip toes. It was just unbelievable to me that they could take white powder and turn it into solid aluminum at such a large scale. To this day, this was my favorite site visit.

An overhead picture from the metal staircase of Gordon Dam. The reservoir can be seen on the right hand side, showing how the dam is anchored to land on both sides.