“HOFF and HON:” Gold mine passes key test, shifts to 100 pct renewables and back again

Pacific Energy has marked an important milestone at the hybrid energy system it is building to power a gold mine in remote Western Australia, after the project’s solar farm successfully supplied the entire mine load for 40 minutes.

The mine in question is AngloGold Ashanti Australia’s Tropicana, where Pacific Energy is adding 24MW of solar, 24MW of wind and a 13MW battery energy storage system to the existing power system at the site, around 330km northeast of Kalgoorlie.

Once complete, the added renewables and storage capacity will take the microgrid to a total of 115MW, making it the largest hybrid investment in Pacific Energy’s portfolio, and “the largest islanded hybrid power system in Australia.”

For the mine’s owners, Anglogold Ashanti and Regis Resources, the addition of the extra solar and wind will cut diesel and gas consumption at the mine by 96% and 50% respectively.

Pacific Energy says the 40 minute period of running the mine on solar only was achieved during the system’s first round of “hydrocarbons off” (HOFF) testing – a critical milestone in the development of the hybrid microgrid.

“During a low-load shutdown period, our 24MW solar farm supplied the entire mine load for 40 minutes. This allowed us to test out the transition from HOFF to HON (hydrocarbons on) and back into HOFF,” the company said in a LinkedIn post on Friday.

“This important milestone demonstrates our system’s capability to be 100% renewables powered for extended periods and, importantly, ensures reliability as we take the next steps to bring our wind turbines online,” the post says.

“Seamlessly transitioning to HOFF during operations can be a complex process. Our industry-leading HOFF track record and integration technologies have enabled us to achieve this great outcome at Tropicana, which is helping us to build on this important capability.”

Perth-based Pacific Energy, which in April completed a new $350 million debt facility, has built 93 power stations totaling more than 1.1 GW of capacity and has more than 900MW under contract over a range of generation sources including solar, wind, battery, diesel, and gas.

Among these projects are four hybrid solar, battery, and gas systems with a combined capacity of 82MW which were completed in September at four goldmines operated by West Australian gold producer Westgold – Tuckabianna, Bluebird, Fortnum, and Big Bell.