Many mines and lithium projects in the Puna generate their own power. Some have a high-voltage line or natural gas within reach. Those that do not burn diesel, and every liter that feeds the gensets travels hundreds of kilometers, part of it on gravel roads, to sites at 3,500–4,000 meters.
That makes energy one of the few operating costs a site can attack directly. The question operators, EPCs and lenders keep asking is the same: how much diesel can solar and batteries really replace, and how fast does it pay back?
The liter that matters is the one delivered to site
The pump price is the wrong input. What a remote site pays is the pump price plus freight, handling, storage and losses on the last mile. On a gravel road at altitude, that gap is material, and it moves with every logistics disruption.
This is the single number that most changes the business case. If you only adjust one input in any model, adjust this one.
What a real hybrid site looks like
Mina Lindero, in Salta at roughly 3,800 meters, became the first hybrid mine in the Argentine Puna: a 6 MWp solar array plus 12 MWh of battery storage running alongside the existing diesel gensets. The operator estimates a cut in annual fuel consumption of around 40%. Larger lithium projects in the region are planning much bigger off-grid solar installations.
That 40% is a useful anchor, because it shows what a first hybridization step can look like: solar covers a large share of daytime load, the battery shifts part of the surplus into the evening, and diesel still carries the night.
Running the numbers
We built a free Off-grid Mining Energy Payback Calculator to reproduce that logic with a daily energy balance. Using a Lindero-scale setup (6 MWp + 12 MWh) and our own assumptions for the parts that are not public (a 4 MW average site load, USD 1.30/L delivered diesel, USD 1.10/Wp installed PV and USD 380/kWh installed BESS):
| Configuration | Diesel displaced | Simple payback |
|---|---|---|
| Solar only (6 MWp) | ~30% | ~1.7 years |
| Solar + 12 MWh battery | ~38% | ~2.2 years |
| The battery alone (marginal) | +8 points | ~4.2 years |
Three things stand out.
1. The model lands close to the operator's estimate. About 38% displaced versus the roughly 40% estimated at Lindero. The 4 MW load is our assumption and it moves the result, so this is a plausibility check, not a validation. A daily energy balance is enough to size the first conversation.
2. Solar pays back fast; the battery is the harder sell. Without storage, about a quarter of solar output is curtailed because gensets cannot drop below their minimum loading and nothing else can absorb the midday surplus. The battery recovers that energy, but on its own it pays back in roughly four years, about two and a half times as long as the array. That is the line item procurement will push back on.
3. Diesel price drives everything. At USD 0.91/L delivered (30% lower), payback stretches to about 3.1 years. At USD 1.69/L (30% higher), it drops to about 1.7 years. A site that does not know its true delivered cost per liter cannot defend either number.
Where these projects actually go wrong
The engineering is largely solved. Local EPCs have already built and operated hybrid systems in the Puna, and global battery suppliers are setting up in Argentina.
The weak point is measurement. After commissioning, someone has to prove that the system delivers what the business case promised, and that proof lives in scattered places: fuel delivery logs, genset run hours, inverter and battery data, maintenance records, and ESG reports built by hand at quarter end. When those sources do not reconcile, the savings become a debate instead of a number, and that weakens the case for the next phase or the next site.
The same applies upstream. Lenders and impact funds financing these assets want standardized, verifiable data on generation, fuel avoided and emissions, not a spreadsheet assembled for each report.
What the model does not cover
The calculator uses annual averages, so it is optimistic for very high solar fractions; cloudy weeks and winter matter. It does not model battery or panel degradation, altitude derating of gensets, taxes, financing structure (EPC versus PPA) or RIGI incentives. Treat it as a way to frame the conversation, not to sign a contract.
Try it with your site's numbers
Replace the defaults with your own load, delivered diesel price and supplier quotes in the Off-grid Mining Energy Payback Calculator. If the result is interesting but you are not sure your fuel and generation data would hold up to scrutiny, that is the conversation we have with operators and EPCs.
Sources: EconoJournal — Lindero, the first hybrid mine in the Argentine Puna · Global Solar Atlas · US EPA GHG Emission Factors Hub. Calculator figures are model estimates based on the assumptions stated above, not published data from any operator.