Fusion Energy Viability | 07 Apr 2026

Source: TH 

Why in News?  

A recent study published in Nature Energy warns that current cost projections for nuclear fusion are overly optimistic, raising concerns about inefficient allocation of clean energy investments. 

• Experts caution that such unrealistic projections may divert funds from more viable climate solutions and suggest exploring alternative reactor designs, fuels and smaller configurations to improve cost reduction and scalability. 

What is Fusion? 

• About: Fusion is the process where two small, light atoms (like hydrogen isotopes)  come together to form a bigger, heavier atom, releasing vast amounts of energy. This is the energy process that powers the Sun and stars. 
  • For example, in the Sun, hydrogen nuclei fuse to form helium and release energy in the form of light and heat. 
• Energy Release: The fusion of nuclei releases energy because the fused product has less mass than the sum of the individual atoms. This "lost" mass, known as the mass defect, is converted into energy according to Einstein's theory of special relativity (E=mc²). 

• Conditions for Fusion: 
  • High Temperature: Around 100 million°C. 
  • High Pressure: Forces atoms nuclei close enough to fuse. 
  • Plasma: The material is in a high-energy state where atoms are broken into ions and electrons. 
• Tokamaks: A tokamak is a fusion reactor that uses magnetic fields to confine and control plasma within a doughnut-shaped vessel. Its effectiveness is measured by how long it can hold the plasma without dissipation.  
  • Longer confinement times bring reactors closer to achieving continuous and reliable fusion reactions. 
• Q Value (Energy Gain Factor): The Q value measures the efficiency of a fusion reactor. 
  • It is the ratio of output energy to input energy. A Q value > 1 means the reactor produces more energy than it consumes. 
• Fusion vs Fission: Fission is the process used in nuclear reactors. In fission, a heavy nucleus (like uranium) splits into smaller nuclei, releasing energy.  
  • Fusion, on the other hand, combines lighter nuclei to release energy. Fusion produces much less radioactive waste than fission, making it a more attractive option for clean energy. 

Challenges to Economic Viability of Nuclear Fusion 

• Fusion power plants are large-scale and capital-intensive, requiring very high energy output to sustain internal operations like cooling and heating. 
• The technology is highly complex and often more intricate than nuclear fission, with interdependent designs that limit standardisation and scalability. 
• Fusion plants require site-specific customisation due to factors like seismic risks, water availability and regulatory conditions, reducing the scope for mass production. 
• These constraints result in low cost-reduction potential, requiring massive scaling for modest gains and limiting competitiveness with solar and advanced fission technologies.