German renewable energy company Baywa re and solar developer Suntrace GmbH have completed construction on a 30 MW/15.4 MWh solar-plus-storage plant at the Fekola gold mine owned by Canadian gold mining company B2Gold in Mali.

Baywa re explained that the mine operates 24 hours a day and that the solar plant will replace three out of six heavy fuel oil generators while reducing the production of the remaining three generators during the daytime. “The 15.4 MWh battery storage compensates energy generation fluctuations and assures a reliable operation, which allows up to 75% of the electricity demand of the gold mine to be covered by renewable energy during the daytime,” it said in a statement.

The two companies claim the $38 million plant will enable saving around 13.1 million liters of heavy fuel oil per year.

“Integrating such a large amount of solar into a small, isolated grid safely and reliably has been a major technical challenge and required the use of battery storage as well as a tailor-made control system,” said Baywa re project manager Thorsten Althaus. “This was conceptualized in the early stages of the project and we ensured that our vision was implemented accordingly by the suppliers.”

Finnish marine and energy solutions provider Wärtsilä supplied a storage system based on its GEMS software platform for power monitoring and optimization, for the project. The company said the payback time for similar projects is typically short, as fuel costs for extremely remote locations can be excessive.

Suntrace and Baywa re were selected to handle project planning and construction duties in October 2019.

This is the second solar-plus-storage project being built at a Malian mine. In October, British oil provider Vivo Energy said it was developing a project at the Nampala gold mine owned and operated by Canada-based mining company Robex Resources in the country, under a power purchase agreement.