Seven gas-driven compressor stations are to give way to one that runs on electricity, and Wärtsilä has been chosen to supply the power. On 22 October the company announced an order for five Wärtsilä 31SG gas engine generator sets, a 59 MW extension of a power plant at Moomba in South Australia. Wärtsilä describes the customer only as one of Australia's major oil and gas producers.
One Compressor Station Instead Of Seven
The project modernizes ageing gas field infrastructure around Moomba. Instead of keeping compression at seven separate gas-driven stations, the producer will replace them with a single centralized electric-driven station. The engines in the plant extension supply the electricity for it and run on gas from the local Moomba fields.
The order was booked in the third quarter of 2026 and the engines are due to be delivered in mid-2027. Wärtsilä will also give advisory support to the project. It does not state a contract value or the date the plant is to start. Kari Punnonen, Wärtsilä Energy's business director for Australasia, says the 31SG has high efficiency and suits applications where the cost of producing gas is a priority, and that its flexibility may open the way to sustainable fuels later on.
Power For A Process, Not For A Grid
Five units for 59 MW is roughly 12 MW per engine if the load is shared evenly. That is a simple division, and the release does not say how the plant is arranged or whether any engine is held in reserve. It is the question an operator asks first about a plant of this kind. A grid-connected plant that loses an engine has the network to lean on. A plant that feeds one compressor station has only itself, and the gas flow depends on it.
Field gas is also not pipeline gas, and its composition can differ from one field to the next and over the years. The release only says the engines run on local gas, so how much treatment it needs before it reaches the engines is not known. Anyone planning such a plant should ask that question early. Efficiency, the reason Wärtsilä gives for the selection, has a plain meaning on the plant side as well: every unit of fuel that does not become electricity leaves as heat, through the exhaust and the cooling circuits, and the site has to get rid of it to the surrounding air.
It is the second Australian engine order from Wärtsilä in three weeks; the first was the 300 MW plant for grid balancing. The two projects have little in common beyond the maker: one serves a grid, the other a gas field. For more on engine-driven power plants in general, see our application pages.
Sources: Wärtsilä
