South Australia is continuing to dive into the renewable energy market in a serious way. After announcing that a new battery facility will be backing up a wind farm in the state by the end of the year, they are going to add 150 megawatts of capacity in the form of a solar thermal power plant. This is no small feat. In fact, it would be the biggest of its kind in the world when completed.
The new Aurora solar power plant would be located in Port Augusta in South Australia. They’re hoping to break ground next year with a completion year set for 2020. According to Science Alert, the new power plant will generate “650 construction jobs for local workers” and “provide all the electricity needs for the state government.” It will be developed with a $110 million loan from the government with 25 MW used for other purposes.
Interestingly, solar thermal power plants operate a bit differently than solar photovoltaic, or solar electric. These methods collect and concentrate sunlight to produce a high temperature that creates electricity. Basically, this is done by using mirrors that reflect the sunlight on a receiver. Many benefits of this process exist, such as operating when the sun is down because of stored energy, and it’s much more efficient than its PV counterpart.
If it’s more efficient, why is it not used more frequently or in more households? First, there is the rapid decline of photovoltaic cell cost to consider, and beyond that, it’s sadly not as convenient. In older homes, for example, bigger tanks would need to be used and the installation costs could be anywhere from $8,000 to $10,000. While solar thermal is more efficient than PV, issues such as overheating and freezing could prevent them being usable in extreme climates.
However, for its purpose to generate power for the government, that’s not a bad option to consider. The new thermal plant will use molten salt to heat up water, which would then spin turbines to generate electricity. This is similar to Google’s parent company, Alphabet, using salt and antifreeze to store energy. There will be separate tanks that would hold cold and hot thermal energy, and it would be combined to create usable electricity.
Reactions among local energy experts in Australia suggest that people are really excited to see what the facility can accomplish. Samantha Hepburn, Research Director at Deakin University in Melbourne, said that it will be interesting to monitor how it goes considering the “large plant requires both land as well as access to transmission lines.”
Matthew Stocks, Research Fellow at The Australian National University, notes that the product can only store heat. That means if there’s excess energy available, it cannot efficiently use it to store electrical power, unlike, for instance, batteries and pumped hydro. He points out that, for the time being, we don’t know which version is ultimately better.
Solar thermal technology has rarely been talked about on the road to renewable energy, and it doesn't sound like it's currently a feasible option to many, considering how cheap it is compared to PV. However, it'll be interesting to see how it compares to Tesla's battery backup facility at the Hornsdale Wind Farm. At the least, it should be a great compliment and it's still much cheaper and environmentally friendly than opting for a coal-fired power plant.