UNECE workshop hears nuclear has key role in hydrogen production

In a breakout session on hydrogen production during UNECE's workshop on Attaining Carbon Neutrality: The Role of Hydrogen, Lee presented an overview of the production of clean hydrogen from nuclear energy. More than 200 participants attended the online discussion that explored the production, transport, storage and use of hydrogen as a zero-carbon energy medium.

Lee noted that nuclear energy can generate low-carbon hydrogen via a number of different ways. These include: low-temperature water electrolysis using nuclear electricity; steam electrolysis using nuclear-generated electricity and heat; and thermochemical processes using nuclear heat. He said another process - steam reforming of methane - is not low-carbon, but the use of nuclear heat to provide the thermal energy needed would reduce natural gas consumption by about 30%.

Technology developments

Technology for the production of hydrogen using nuclear energy is at different stages of development around the world, Lee said. He gave several of examples, such as the H2atScale initiative in the USA to fund a number of projects to advance flexible operation of light water reactors with integrated hydrogen production systems.

Exelon Corporation has agreed to host a 1 MW electrolyser at one of its nuclear power plants, which could be operating by 2023. The US Department of Energy's Idaho National Laboratory is also working with Xcel Energy to demonstrate high-temperature steam electrolysis technology using heat and electricity from one of Xcel's nuclear plants.

A demonstration high-temperature gas-cooled reactor - the HTR-PM - is currently under construction at Shidaowan, in China's Shandong province, and is expected to begin operating by the end of this year. This technology - with a design temperature of up to 750 degrees Celsius - can provide heat for high-temperature steam electrolysis or for thermochemical hydrogen production.

Japan has a High Temperature Test Reactor (HTTR), with a design output of 950 degrees C, focused on investigating hydrogen co-generation production. In 2019 it demonstrated the iodine-sulphur thermochemical process over 150 hours of operation. The intention, Lee said, is to connect the hydrogen process to the HTTR directly.

Elsewhere, Poland is also investigating the use of high-temperature gas reactors primarily for the production of heat and hydrogen for industrial applications to replace coal-fired boilers for processing production. In the UK, there has been a study into using the existing Heysham nuclear power plant to generate hydrogen. Also, EDF has issued an expression of interest to seek partners to develop its hydrogen demonstration project as part of the proposed Sizewell C Energy Hub.

Production costs

"The extent of deployment of low-carbon hydrogen will be dependent on the economics and business model," Lee said. "Some of the main drivers for hydrogen costs are the capacity factor of the energy supply, the capital costs and the efficiency of the electronics and the capital costs of the electrolyser."

He noted a 2020 study by Lucid Catalyst which showed that using current conventional nuclear new build in the EU or the USA, even with high capital costs, can produce hydrogen at around USD3 per kilogram. And in the Asian market, where large reactors are being built in China, these can deliver clean hydrogen for less than USD2 per kilogram.

"We know that for long-term operation of existing nuclear power plants we have the lowest generation costs of low-carbon electricity and its high capacity factor is well placed to produce low-carbon hydrogen," Lee said.

The Lucid Catalyst study also looked at using new advanced modular reactors and with new manufacturing-based methods like modular construction, it could deliver hydrogen on large scale for around USD1 per kilogram.

"Our colleagues at the International Atomic Energy Agency have studied a range of nuclear reactors with different hydrogen production concepts, and in-depth study shows that for a high-temperature reactor coupled with a sulphur-iodine thermal couple cycles system, hydrogen production costs are estimated into the range of USD1.6-2.4 per kilogram of hydrogen."

Policy changed needed

Appropriate policies are needed to ensure that nuclear energy can play its role as part of the mix for low-carbon hydrogen production, Lee said. "Hydrogen produced with nuclear energy should be classed as green, and the classification should be technology-neutral and based on the carbon intensity of the source."

Support should also be given to support the markets and services of current large reactors into integrated low-carbon systems and sector coupling with renewables for hydrogen production, electricity and heat generation. Support must also be given to research and development of advanced modular reactors for efficient production of hydrogen.

"All low-carbon technologies have to be considered on their own merits to produce clean hydrogen," Lee said. "Nuclear is a proven low-carbon source of electricity and heat."

Francisco de la Flor, chairman of UNECE's Group of Experts on Gas, moderated a workshop session on the transportation and storage of hydrogen. He said: "We agreed today that all options for hydrogen production should be discussed from a level playing field perspective."

"For many years, UNECE has developed regulations and standards for the transport and storage of hydrogen and other compressed and liquified gases," said Dmitry Mariyasin, deputy executive secretary of UNECE. "However, hydrogen is not just another danger to be contained. It could be our secret weapon to achieving carbon neutrality."