South Korea tests pink hydrogen with high-temperature electrolysis on nuclear power

Hydrogen from the nuclear plant — with a smart twist

South Korean energy company KHNP (Korea Hydro & Nuclear Power) plans to set up a pilot facility that produces hydrogen using nuclear energy. The twist lies in the chosen technology: solid oxide electrolysis, also known as high-temperature electrolysis (SOEC). With it, KHNP uses not only the nuclear plant's electricity, but also its heat.

What is different about this technology?

In ordinary electrolysis, water is split into hydrogen and oxygen using electricity. Solid oxide electrolysis works at high temperature and uses steam instead of cold water. Part of the energy then comes from heat, so less electricity is needed for the same amount of hydrogen.

And a nuclear plant happens to deliver exactly two things at once: electricity and heat. That combination makes the match a logical one. Solid oxide systems reach up to around 90% electrical efficiency, and with waste heat that can in theory approach 100%. For comparison: South Korea's research institute KIMM showed with its own SOEC system that the technology needs roughly 15% less electricity than conventional alkaline or PEM electrolysis.

Pink hydrogen

Hydrogen made with nuclear energy is called 'pink hydrogen'. Like green hydrogen (from sun and wind), it is a form with no direct CO2 emissions. KHNP operates almost 25 gigawatts of nuclear capacity and has been researching this route since 2022. It works with international technology partners, including the US company FuelCell Energy, which specialises in solid oxide electrolysers.

Part of a bigger ambition

The SOEC pilot fits into a broader South Korean push on nuclear hydrogen. The country is building a 10-megawatt demonstration plant that from 2027 should produce more than 4 tonnes of hydrogen a day, backed by 29 billion won (around 21 million US dollars) from the Ministry of Trade, Industry and Energy. The aim: to become less dependent on imported hydrogen and move toward climate neutrality.

Why this matters

For hydrogen mobility, it ultimately comes down to clean hydrogen that is affordable and available in large volumes. That is why we find it encouraging that countries are developing several production routes side by side. The more efficient and cheaper production becomes, the sooner hydrogen turns into an obvious choice at the pump — for passenger cars, and certainly for heavy transport.

Sources

• Hydrogen Insight — South Korean power company plans to launch nuclear hydrogen pilot using solid oxide electrolysers
• Fuel Cells Works — KHNP plans nuclear-powered hydrogen pilot using high-temperature SOEC technology (24 July 2026)
• EurekAlert! / KIMM — Korea's first 20 kW SOEC system for clean hydrogen production
• Hydrogen Industry Leaders — South Korea to launch first nuclear hydrogen production plant by 2027
• FuelCell Energy — MoU with KHNP for clean hydrogen (October 2024)