How Chile’s 1GWh Solar Battery Upgrade Signals the Next Energy Shift

Why a 1GWh Battery in the Atacama Desert Matters

70% of Chile’s electricity came from renewables in 2024. Five years earlier it was 47%. That kind of growth isn’t just impressive – it breaks the old rules of how power systems work.

Here’s the thing about rapid renewable growth: at some point, generation isn’t the problem anymore – timing is. You can have all the solar panels you want, but if they all peak at midday and crash at sunset, you end up curtailing cheap green power and firing up fossil plants at night.

That’s the context behind Acciona Energía’s decision to retrofit a 200MW/1,000MWh battery energy storage system (BESS) to its Malgarida solar complex in Chile’s Atacama Desert. It’s not just another project announcement. It’s a clear signal of where green technology – and smart energy investment – is heading in 2026 and beyond.

For anyone working in clean energy, sustainability strategy, or green technology investment, Malgarida is a live case study of how solar-plus-storage and intelligent control are reshaping power systems, especially in markets that are racing ahead on renewables.

---

Inside the Malgarida Solar-Plus-Storage Retrofit

Acciona Energía’s Malgarida complex is a 238MWp solar PV plant spread across 535 hectares in the Atacama Desert, one of the sunniest regions on the planet. Commissioned in mid-2021 with around US$170 million invested, it was already a solid utility-scale solar asset.

Now it’s being upgraded with:

• 200MW / 1,000MWh BESS
• 5-hour duration storage
• Co-location at the existing Malgarida PV site

That 5‑hour duration isn’t arbitrary. In Chile, this has quickly become the standard profile for large-scale batteries, because it matches a key use case:

Store excess solar at midday, then discharge over the evening peak and into the night.

From a system view, that means:

• Less curtailment during solar peaks
• Smoother ramping when the sun drops
• Reduced need for gas or diesel plants to cover the evening
• Better use of transmission capacity that was previously overloaded at noon

From a project owner’s view, it means a second revenue stack layered on top of PV:

• Arbitrage: buying (charging) when prices are low, selling (discharging) when they’re high
• Capacity: providing dependable evening energy
• Ancillary services: frequency and voltage support

I’ve seen a lot of solar projects stay “just PV” for years. Malgarida shows why that’s leaving money on the table in high-renewables markets.

---

Chile: When Too Much Clean Energy Becomes a Problem

Chile is the textbook example of what happens after you successfully scale renewables.

• Renewables supplied 70% of electricity in 2024, up from 47% in 2019.
• The country has aggressively built out solar in the Atacama and wind across several regions.

That growth has created a new challenge: curtailment.

At the Energy Storage Summit Latin America 2025 in Santiago, the Chilean renewable association ACERA highlighted a striking number:

3.2TWh of solar and wind was curtailed in August 2025 alone.

That’s not a rounding error. It’s an industrial-scale waste of clean energy, capital and potential revenue. In practical terms, curtailment means:

• Solar farms operating below their capability because the grid can’t take their output
• Lost return on investment for developers and financiers
• Increased system costs, as fossil backup remains necessary for non-solar hours

Batteries directly attack that problem. A 5‑hour BESS turns “too much solar at noon” into “firm power at 8pm”.

Chile’s energy minister has already said the country will overshoot its 2GW-by-2030 storage target by early 2026, and is on track to exceed its 6GW-by-2050 target by about 2GW within the next two years. That’s an extraordinary acceleration.

Acciona’s Malgarida retrofit slots into a broader build-out that includes:

• AES Andes: two hybrid projects with 2.2GWh of BESS
• Grenergy:
  • Oasis de Atacama – 2GW solar + 11GWh storage
  • Central Oasis – 1.1GW solar + 3.8GWh storage (first phase underway with 340MW PV / 960MWh BESS)

The pattern is obvious: green technology in Chile has moved from “add solar” to “add storage everywhere”.

---

Why Retrofitting Batteries to Existing Solar Makes Sense

Most companies get this wrong. They treat batteries as something you only add to new projects. In high-renewables markets, that mindset is already outdated.

Retrofitting storage to existing solar plants, like Acciona is doing at Malgarida, can be a smarter, lower-risk move. Here’s why it works so well.

1. You Monetise Energy You’re Already Producing

If your solar farm is facing curtailment, you’re literally giving away energy. Adding a BESS lets you:

• Capture that “wasted” production during curtailment windows
• Shift it into higher-priced hours
• Turn a grid constraint into a revenue opportunity

This is especially powerful where curtailment is structural, not temporary – like Chile’s northern regions.

2. You Reuse Grid Connections and Site Infrastructure

Securing new grid connections is often the hardest and slowest part of a new project. Retrofitting skips most of that pain:

• The site is already permitted and grid-connected
• Land rights, community engagement and environmental studies are in place
• Access roads and basic infrastructure exist

That can dramatically cut timelines and soft costs, while also reducing project risk for lenders.

3. You Future-Proof Your Asset in a Changing Market

Power markets evolve. Static solar assets don’t. A PV plant that made sense in 2021 might look less attractive by 2027 if:

• Daytime prices have collapsed from solar saturation
• Evening peaks are consistently expensive
• New market products reward flexibility and capacity, not just raw MWh

Adding storage changes the profile of your asset from a “price taker” to a flexibility provider. You’re now positioned to:

• Bid into capacity markets or firm supply contracts
• Provide ancillary services
• Reduce imbalance and profile risk on long-term PPAs

Acciona isn’t just installing batteries; it’s repositioning Malgarida to stay competitive in a storage-heavy, AI-optimized grid.

---

How AI and Software Turn Solar-Plus-Storage into Real Green Technology

Hardware alone doesn’t deliver the full value. What makes projects like Malgarida truly powerful green technology assets is the software and AI layer controlling how they behave.

In practice, that means:

Intelligent Dispatch and Forecasting

AI models can combine:

• Solar generation forecasts
• Demand forecasts
• Real-time and forward price curves
• Grid constraints and congestion data

…to decide when to charge, when to discharge, and when to stay idle. Over thousands of operating hours, the difference between basic rules and intelligent dispatch can easily mean a 10–30% swing in project revenue.

Curtailment Prediction

In markets like Chile, where curtailment is frequent and somewhat predictable, AI can:

• Learn patterns of when and where curtailment is likely
• Pre‑charge the battery ahead of anticipated restrictions
• Adjust contractual positions to minimise penalties or missed opportunities

The result is a plant that isn’t just reacting; it’s anticipating.

Multi-Asset, Multi-Market Optimization

Acciona has three battery projects in Chile totaling 1.5GWh at its solar plants, on top of 922MW of operating renewables in the country. Coordinating multiple sites is a software problem, not a hardware one.

An AI-driven optimizer can:

• Treat all assets as a virtual power plant
• Decide which BESS charges or discharges first
• Allocate capacity to different revenue streams (energy, capacity, services)
• Respect local constraints while maximizing portfolio value

This is where green technology earns its name: the system isn’t just low-carbon; it’s intelligent.

---

What This Means for Developers, Utilities and Corporate Buyers

Malgarida isn’t an isolated story. It’s a template. If you’re planning, owning, or buying clean energy, there are clear lessons.

For Developers and IPPs

You should be asking three blunt questions about every solar asset, existing or planned:

1. Is curtailment already happening, or likely within 3–5 years?
   If yes, a retrofit feasibility study isn’t optional – it’s urgent.
2. Can a 4–6 hour BESS materially improve your revenue stack?
   Model arbitrage, capacity, ancillary services and reduced merchant risk, not just “PV plus a small battery”.
3. Do you have (or partner for) strong dispatch and optimization software?
   The value gap between “dumb storage” and “smart storage” widens every year.

For Utilities and System Operators

Projects like Malgarida support your main headaches:

• Flexibility to integrate higher shares of variable renewables
• Local congestion relief without always building new lines
• Enhanced system resilience with fast-responding assets

Regulation that rewards duration, location, and flexibility – not only capacity – will bring more Malgarida-style retrofits into the market.

For Corporate Offtakers and Large Energy Users

If you’re signing long-term PPAs today, you should be pushing for:

• Solar-plus-storage contracts, not solar-only
• Guarantees of evening or 24/7 availability, backed by BESS
• Clear visibility on how assets are optimized across markets

In Chile and in other fast-moving markets, “plain solar at a flat price” is beginning to look dated compared to hybrid, firmed, intelligently managed green power.

---

Where Green Technology Is Heading Next

The reality is simple: renewables growth without storage growth breaks the grid. Chile hit that wall early because it moved faster than most. Now it’s showing how to climb over it.

Acciona Energía’s 1GWh battery retrofit at Malgarida captures the core shift in green technology:

• From just building clean generation to orchestrating clean, flexible systems
• From static assets to software-driven portfolios
• From exporting surplus daytime solar to delivering reliable clean power on demand

As more countries push toward 60–80% renewables, Chile’s experience – and projects like Malgarida – are going to look less like an outlier and more like a roadmap.

If you’re planning your own energy strategy for 2026 and beyond, the question isn’t whether solar-plus-storage will matter. It’s whether your assets and contracts are ready to operate in a world where batteries, AI, and green technology define how power systems actually work.