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Audrey Nesbitt
Guest
Solar and batteries got cheaper. Fuel got riskier. Hormuz just closed the gap between them.
Picture the meeting a few years ago. A green technology founder stands at the front of an industrial boardroom, laptop open, eager to show how solar power and batteries could cut the company's fuel use, reduce exhaust from its generators and help save the planet. Before the first slide, an executive hears green technology and thinks: This is going to be expensive.
For years, "green" entered industrial boardrooms with a heavy price tag attached. Now fuel is sending its own bill. The Hormuz shock reaches far beyond mining, but mines give us something useful to look at: companies that invested in sustainable technology before that bill got bigger.
What an Industrial Solar and Battery System Actually Does
B2Gold's Fekola mine in Mali is too far from an accessible electricity grid to rely on one. When the mine opened, its power came from heavy fuel oil generators. As production grew, B2Gold added more engines. Then it added solar generation and batteries to operate alongside them.
The interesting part is what happens when the sun comes up. The solar plant begins supplying electricity, and the mine can run fewer thermal engines. B2Gold says that during peak solar hours, it needed only two or three engines running. In 2024, the hybrid system saved approximately 13 million litres of heavy fuel oil and avoided an estimated 38,000 tonnes of greenhouse gas emissions. Those are reported results from a working mine, not savings taken from a sales presentation. B2Gold describes the plant's operation and results here.
The system has since grown to 52 megawatts of solar capacity and approximately 28 megawatt-hours of battery storage, an expansion B2Gold estimated could reduce annual heavy fuel oil consumption by around 20 million litres. According to B2Gold's most recent responsible mining report, the expanded facility supplied about 23% of the site's electricity in 2025. That electricity share and the 2024 fuel savings above are reported performance; the 20 million litre figure is an estimate for what the expansion will deliver going forward.
The batteries do not magically make an off-grid mine independent of fuel. Their value lies in helping solar generation work within a power system that still includes engines. The engineering achievement is getting those sources to serve an operation that needs electricity continuously while running the fuel-powered part less often.
The Price of the Technology Has Changed Too
The old "green is expensive" reaction also misses what happened to the equipment market. According to the International Renewable Energy Agency, the cost of utility-scale battery storage fell to $192 per kilowatt-hour in 2024, a 93% decline from 2010. Solar has moved the same direction: IRENA's 2024 renewable power generation costs report puts the global average cost of utility-scale solar at $0.043 per kilowatt-hour in 2024, a 90% decline since 2010 and now cheaper than the least-cost fossil fuel alternative. Those are industry-wide figures, not quotes for installing solar and storage at a remote mine. Site construction, controls, transport and integration still have to be priced. But a judgment formed years ago about what this equipment costs deserves a fresh estimate.
The other side of the comparison is moving as well. Suppose a system displaces 20 million litres of fuel a year, as B2Gold estimates for its expanded plant. Every $0.10 per litre increase in the delivered price of that displaced fuel adds $2 million annually to the value of using less of it. At $0.25, the difference is $5 million.
This is an illustration, not Fekola's reported return. It leaves out the cost of building and operating the plant, its actual annual fuel savings and the mine's remaining life. What it shows is why a proposal can look different when both the technology price and the fuel forecast are updated.
What Hormuz Has Put on the Bill
Fuel exposure was a real issue before the current war. The disruption around the Strait of Hormuz has made it much harder to treat as a distant scenario.
In its September 2026 oil market report, the International Energy Agency said Gulf exports of diesel and gasoil averaged just over a quarter of their prewar level in August, while flows through the strait remained severely constrained. Those products are different from the heavy fuel oil used at Fekola; their prices cannot be inserted into Fekola's business case. But the figures show how quickly a fuel's availability can change when shipping and refining are disrupted.
Gold Fields has reported the effect on its own costs. In May 2026, the company said diesel prices across its operations had risen approximately 30% to 70% since February, alongside increases in freight and LNG costs. Assuming oil at $100 a barrel, it estimated a combined impact of $40 to $50 per ounce across its portfolio, according to MiningWeekly's coverage of the disclosure. That does not establish a return for any renewable project at Gold Fields. It establishes that the fuel and logistics assumptions in an operating plan can change enough to matter.
A Mine Plan Is Also an Energy Plan
A company considering new power technology still has hard questions to answer. How much fuel will it actually displace? What will the batteries do when solar output changes? How many engines must stay available? Will the savings last long enough to recover the capital cost?
Those questions are especially useful before a mine or restart plan is fixed. Mario Stifano, CEO of Galantas Gold Corporation, describes how his company is considering energy at its Andacollo project in Chile:
The economics still have to work. Mine life, capital requirements and grid reliability all affect whether a sustainable technology investment makes sense. Electrification can also move a company's exposure from diesel to an unreliable or fossil-fuel-dependent grid.
But the calculation deserves current inputs. Fekola shows what a hybrid system has already delivered, what its expansion now supplies and what further fuel reduction B2Gold expects. Battery costs have changed. Fuel costs have changed. An executive can still run the founder's proposal through that math and reject it. What won't hold up much longer is rejecting it on the strength of a reflex formed when both of those prices were different.
Disclosure: The author provides consulting services to Galantas Gold Corporation, whose CEO is quoted in this article.