Delivering advanced system integration, dispatch, and optimisation in a hybrid microgrid

QMM operates a large-scale mining operation near Fort Dauphin, in Madagascar, owned by Rio Tinto and the Government of Madagascar. The site is powered by an islanded microgrid supplying both mining operations and the surrounding community. The site’s power system was established in 2008 with an EPC delivery of a Wärtsilä power plant, alongside an Operations & Maintenance agreement. In 2023, the mine took a significant step in its decarbonisation journey with the addition of 8 MW of solar PV and an 8.25 MW / MWh BESS, followed by further expansions.

Today, the site operates one of the most advanced captive hybrid microgrids in the mining sector, featuring a 20 MW Wärtsilä engine power plant, 14 MW of solar PV, 16 MW of wind power (partially commissioned at the time of writing with 8MW installed) and 16 MWh of energy storage capacity.

With the first critical step of installing renewable assets in place, focus shifted to ensuring the full potential of the investments could be realised. Initially, there was a lack of visibility and coordination across assets, and the renewable energy and storage use was not optimised, forcing the engine power plant to operate at low, less efficient loads and remain online unnecessarily. This revealed an important insight: while adding renewable and storage capacity to the microgrid created a strong base the system required coordinated, system-level control to drive the expected performance.

In 2024, QMM enlisted Wärtsilä’s Decarbonisation Services to improve overall system efficiency and deliver on Rio Tinto’s carbon reduction objectives. This expanded Wärtsilä’s role from operating and maintaining the engine power plant to optimising the entire energy ecosystem, including the energy storage, Solar PV and expanding wind capacity.

Wärtsilä addressed this challenge by deploying its GEMS Energy Management System . This solution utilises load and renewable forecasts and transforms the site into a fully coordinated microgrid, dispatching Wärtsilä engines, BESS, and renewable generation as a single integrated system. This enables real-time optimisation across all assets, improving efficiency, flexibility, and renewable integration. GEMS further strengthens stable grid operation with its secondary control, building on the stability and reliability provided by the engine power plant.

The implementation of GEMS transformed the operational profile of the site through smarter dispatch decisions. Instead of relying on engines for baseload generation, the system now uses them flexibly to balance and maximise variable renewable utilisation. Furthermore, because GEMS is delivered under an ongoing service agreement, its performance is continuously monitored and improved as needed.

This shift enabled QMM to unlock the full potential of their clean energy investment showcasing measurable performance improvements, including increased renewable energy penetration, a 4% decrease in engine fuel intensity, significant fuel savings and emissions reductions, higher average engine loading, and a substantial decrease in engine running hours.

The QMM project demonstrates that the delivery of effective hybrid power solutions in isolated industrial systems depends on advanced integration and optimisation, not just the addition of assets.

Who	QIT Madagascar Minerals (QMM)
What	Decarbonisation Services agreement
Where	Madagascar

This is what we achieved

7 900

tonnes estimated annual CO₂ reduction from renewables and GEMS optimisation

570

tonnes annualised fuel savings by optimising engine loading

-20%

reduction in engine running hours through GEMS optimisation

Notes: 1) Fuel saved is calculated by comparing engines’ fuel intensity (kg/MWh) for the periods before and after GEMS installation, and annualising the result. 2)“Before GEMS installation” period includes May – July 2025 including 14 MW Solar PV, 16 MW/MWh BESS and 1.7MWp of Wind. “After GEMS installation” period includes August 2025 – February 2026 (excluding December) with 4MW of additional Wind capacity being progressively installed.

“-
The reliability and efficiency of the power plant are critical to our operations. The agreement allows us to take advantage of Wärtsilä’s competence in power system optimisation and use renewables in the most efficient way, supporting Rio Tinto’s decarbonisation objectives

- Jean-Francois Richer, Director Integrated Operational Services at QMM

“-
By taking energy optimisation to a new level, this project further strengthens our long-lasting partnership with QMM. Its successful deployment required close coordination among multiple stakeholders to address asset integration and interoperability challenges. Ultimately, our technologies enable meaningful cost savings, while delivering reliable and sustainable power supply to the mine.

- Christoffer Ek, Director Decarbonisation services, Wärtsilä Energy

How we did it

Challenge

Increasing renewable energy utilisation
Lowering engine running hours, fuel consumption and costs
Reducing emissions
Ensuring uninterrupted power supply and maintaining grid stability

Solution

Wärtsilä and QMM expanded the engine power plant Operation and Maintenance agreement into a Decarbonisation Agreement, introducing advanced system integration & optimisation capabilities via Wärtsilä’s GEMS Energy Management System acting as microgrid controller.
GEMS integrates and dispatches all assets as a single coordinated system, rather than isolated components.
The implementation of GEMS transformed the operational profile of the site through its forecasting capabilities and smarter dispatch decisions.

Benefit

Renewable energy penetration increased from ~15% to ~30% through minimising curtailment. This coincided with the installation of just ~4 MWp of additional wind capacity.
Increased operational efficiency: average engine load increased from 66% to 73% and engine running hours reduced by ~20%. The optimised loading will save ~570 tonnes of fuel annually. This reduction is equivalent to approximately 390 passenger cars taken off the road for one year, or the annual electricity emissions of 230 households
Overall, CO₂ emissions reduced by approximately 7 900 tonnes, or the annual electricity emissions of 1,700 households

Questions? Contact us

The main details

Customer	QIT Madagascar Minerals S.A. (QMM)
Type	GEMS for islanded grids as microgrid controller, integrating and dispatching Wärtsilä engines and 3^rd party BESS, solar PV and wind power. Engine Operations & Maintenance agreement
Where	Large-scale mining operation near Fort Dauphin, in Madagascar.
Scope	Decarbonisation services
Delivery	Ongoing delivery