Fusion2Grid: The Most Compact Path to Fusion Energy | Manuel García Muñoz

This article has been translated using artificial intelligence

Fusion energy has long promised an energy revolution -a clean, safe, and virtually limitless power source that could replace fossil fuels without emissions or long-lived waste. Yet, its commercial arrival has always seemed decades away.

At the Future Trends Forum in Madrid, hosted by Fundación Innovación Bankinter, more than 20 international experts gathered to explore how to accelerate that future. The outcome is the report “Fusion Energy: a Revolution in Progress”, which outlines five key pillars to scale and fast-track fusion as a climate, economic, and tech driver.

As part of our mission to bring innovation—and in this case, fusion energy—closer to society, we continue the Fusion Forward series. After Carlos Alejandre’s roadmap for Europe’s fusion industry and Gianfranco Federici’s deep dive into the key technological challenges, we now highlight a bold, concrete proposal that could speed up fusion’s arrival.

At the Forum, Manuel García Muñoz, professor at the University of Seville and director of the Plasma Science and Fusion Technology lab, presented a disruptive approach: a compact, efficient, and pragmatic path to fusion energy.

While global megaprojects aim for 2050, García Muñoz argues that—by advancing key technologies in parallel—fusion could be connected to the grid within the next decade. His proposal, developed entirely in Spain, offers strong industrial potential and is already being tested.

Relying on well-established technologies and a highly pragmatic design, García Muñoz’s strategy envisions smaller, faster, and more affordable fusion reactors. His message is clear: there’s another way to get there—more agile, more compact, and closer to industrial reality.

If you’d like to watch Manuel García Muñoz’s talk, you can do so here:

Manuel García Muñoz: “The High Field Spherical Tokamak Path” #FusionForward

Fusion2Grid: Spain’s Bet on Practical, Grid-Connected Fusion

In a landscape long dominated by massive international efforts like ITER and DEMO -projects defined by their monumental scale and timelines stretching over decades- Manuel García Muñoz’s proposal stands out for its conceptual simplicity and pragmatic ambition.

Fusion2Grid is not meant to replace these flagship projects but to complement them: a parallel track aimed at building an operational fusion plant within the next decade—compact in size, cost-effective, and technically feasible.

The strategy builds on three proven technologies, each validated independently by the scientific community, but never combined in this way before:

• Spherical tokamaks, which allow for greater efficiency in a smaller volume.
• High-temperature superconductors (HTS), essential to reduce costs and boost magnetic field strength in tighter spaces.
• Negative triangularity, a novel plasma geometry that enhances performance and extends reactor lifespan.

These core concepts are explored in detail in the following sections.

But Fusion2Grid is more than a theoretical proposal. It anchors a research strategy developed at the Plasma Science and Fusion Technology Lab at the University of Seville, and has already attracted interest from international institutions and research centers.

The core idea: deliver fusion energy directly to the grid with a design 20 times smaller than ITER, but with meaningful power output and clear potential for industrial scale-up.

“We’re not saying fusion is easy. But we are saying there’s another viable path—if we tackle design, materials, and cooling challenges as one integrated system,” García Muñoz explained.

Fusion2Grid is designed to be a fast, non-speculative route to fusion. It starts from engineering, not just physics—and focuses on making fusion a useful, grid-ready technology within a realistic timeframe.

Spherical Tokamaks: Compact Design, High Power

A cornerstone of the Fusion2Grid strategy is the use of spherical tokamaks—a variant of the traditional design that offers major advantages in the pursuit of more compact and efficient fusion reactors.

While conventional tokamaks—such as ITER—use large toroidal geometries with high construction and operational costs, the spherical tokamak drastically reduces the required volume. According to García Muñoz’s calculations, at equal magnetic field strength, a spherical tokamak could be up to 20 times smaller than ITER, with direct implications for cost and construction time.

More Pressure in Less Space

The key appeal of spherical tokamaks is their ability to sustain up to 40% higher plasma pressure than conventional designs. This higher pressure translates into better energy output in smaller devices—a crucial factor for scaling down fusion infrastructure without compromising performance.

“In terms of stability, the spherical tokamak is more robust than a conventional tokamak. That difference is baked into the plasma physics equations,” says García Muñoz.

Advantages Over Conventional Designs

Traditional tokamaks do offer one key advantage: large surface areas for distributing the escaping plasma heat. However, they come with two major drawbacks:

• Extremely high capital investment, due to their size and system complexity.
• Long construction timelines, which clash with the urgency of the energy transition.

In contrast, spherical tokamaks offer:

• Compactness, reducing volume and cost.
• Efficiency, making better use of the magnetic field and sustaining higher plasma pressure.

Challenges to Overcome

Still, downsizing introduces significant technical challenges. García Muñoz highlights two critical limitations:

• Power exhaust management: In spherical tokamaks, the power density at the points where plasma strikes the walls is much higher. This puts extreme pressure on the divertor—the part of the reactor that absorbs heat and particles.
• Limited space in the central stack: This core region must house the central solenoid, neutron shielding, and tritium breeding systems (which surround the plasma and generate fresh tritium from lithium). In a spherical design, this space is tighter, making integration a major engineering challenge.

A Promising but Demanding Path

Despite these difficulties, the Fusion2Grid strategy makes a strong case: spherical tokamaks offer a promising path toward more economically and temporally viable fusion plants.

The challenge is to pair compactness with innovation, pushing the engineering envelope. This is where high-temperature superconductors (HTS) and negative triangularity come into play—two concepts García Muñoz sees as potential game changers in the next phase of fusion development.

Negative Triangularity: A Potential Game Changer for Fusion

While spherical tokamaks offer a promising route to more compact and efficient fusion reactors, they also introduce engineering challenges that can’t be ignored—namely, extreme heat concentration in the divertor and limited space in the central stack. For Manuel García Muñoz, the key to overcoming these issues may lie in an unconventional but increasingly promising approach: negative triangularity.

What is Negative Triangularity?

In a tokamak, the cross-section of the plasma can take on different shapes. Traditionally, designs use positive triangularity, where the plasma elongates outward, toward the edge of the torus. Negative triangularity flips that shape inward—creating a reversed, concave profile.

Though first explored in the 1980s, the concept was set aside for decades. But recent experiments at facilities like DIII-D (USA) and JET (UK) have reignited interest, showing clear improvements in plasma performance and heat distribution.

Key Advantages

García Muñoz highlights several critical benefits of negative triangularity—especially for compact, spherical designs:

• Improved plasma stability: Fluctuations are reduced, enhancing core performance.
• ELM-free operation: It eliminates Edge Localized Modes—instabilities that damage reactor walls.
• Better heat management: The divertor wetted area increases, spreading thermal loads more evenly—mitigating one of the biggest bottlenecks in compact tokamaks.
• Extended reactor lifespan: With less plasma-wall interaction, material erosion is minimized, increasing operational longevity.

“Negative triangularity could truly be a game changer for spherical tokamaks,” García Muñoz says. “It allows us to better manage thermal loads and unlock new design possibilities that were previously out of reach.”

SMART: Sevilla’s Testbed for Compact Fusion

The Fusion2Grid strategy is not limited to simulations or conceptual designs. At the Plasma Science and Fusion Technology Lab at the University of Seville, Manuel García Muñoz and his team have already launched a pioneering device in Europe: the SMART (SMART (SMall Aspect Ratio Tokamak).

SMART was created with a clear mission: to validate, under real-world conditions, the technologies that will power the compact Fusion2Grid reactor. Specifically:

• Negative triangularity as a stable, high-performance plasma configuration.
• High-temperature superconducting (HTS) coils, which enable stronger magnetic fields in tighter spaces.
• Integration of a high-field spherical tokamak, designed to reach fusion-relevant temperatures in a much smaller device.

A Validation Lab

SMART has already achieved plasmas with negative triangularity, directly comparing their behavior to positive triangularity configurations. The results are clear:

• Lower fluctuation levels in the plasma core.
• Wider heat distribution in the divertor, lowering the risk of material damage.

As García Muñoz emphasizes, this experimental evidence is essential to move from theory to practice—and to prove that compact designs are not only viable, but also scalable.

A Future-Ready Design

SMART is also designed as a test platform for HTS coils, allowing researchers to trial superconducting technologies in a real tokamak environment. This is a critical step to ensure that materials and configurations meet the demanding stability and reliability standards of a commercial reactor.

“SMART is a proof of concept on the path to a compact reactor,” García Muñoz explains. “It’s not the end goal—it’s the tool to validate that this technology stack is the future of fusion.”

Putting Spain on the Fusion Map

With SMART, Seville becomes a key node in the global fusion community. Beyond its scientific contributions, the lab positions Spain at the forefront of a strategic sector—opening industrial opportunities and strengthening the country’s role in reshaping the future energy system.

Looking Ahead: Fusion as a Reality Within the Next Decade

Manuel García Muñoz’s intervention at the Future Trends Forum – Fusion Forward leaves one message loud and clear: fusion energy doesn’t have to remain a promise for the mid-century. If we combine proven technologies—spherical tokamaks, high-temperature superconductors, and negative triangularity—and develop them in parallel, fusion could be connected to the grid in less than ten years.

With the SMART Tokamak already operating in Seville as a proof of concept, Spain is positioning itself as a bold and innovative player in the global fusion landscape—offering homegrown solutions with real potential. This contribution brings not only scientific prestige, but also opens strategic industrial opportunities in a sector poised to redefine the energy future.

“I’m optimistic,” García Muñoz concludes. “If we push these key technologies forward in parallel, fusion doesn’t have to be a dream for 2050—it can become a reality within the next decade.”

This article is part of our broader analysis from the Future Trends Forum. The full report, “Fusion Energy: A Revolution in Progress”, brings together insights from over 20 international experts and defines the five critical pillars to scale fusion as a driver of climate, economic, and technological transformation.

Download the full report and explore how we can start building tomorrow’s energy system—today.