• Pioneering new
    grid-scale hydrogen
    storage technology

    The potential to transform the
    transition to net zero

Utilises the exceptional but until now largely overlooked hydrogen storage properties of depleted uranium (DU)

The development of HyDUS (Hydrogen Depleted Uranium Storage) is a collaborative project involving EDF UK (lead partner), the University of Bristol, Urenco and UKAEA.

HyDUS’s grid-scale storage is designed to meet three key objectives.

To help balance fluctuations in the supply of energy from renewables such as wind and solar. Large-scale storage is vital to ensure power from renewables is dependable and available on demand.

To help decarbonise the national grid.

To provide high purity hydrogen to heavy industries finding it hard to decarbonise.

Hydrogen’s green energy potential

When burned,
hydrogen emits no
greenhouse gases

Hydrogen is
relatively easy
to manufacture

It is the most
abundant element
in the universe

H2 storage challenges

Hydrogen is widely considered to be a prime candidate to replace natural gas (methane/CH), on which the UK has depended for years for heat and electricity. But before this can happen, the tricky issue of H2 storage needs to be resolved.

Physical storage of hydrogen is inefficient.

Storage as a compressed gas at pressures of up to 900 times atmospheric is volumetrically inefficient and carries safety implications.

Storage as a liquid requires costly and constant cryogenic cooling to minus 253°C.

Without effective, efficient grid-scale storage, hydrogen’s huge potential will never happen.

The HyDUS solution

The HyDUS system makes innovative use of depleted uranium, an unlikely material to feature in the shift to green energy but one that has unexpected and quite remarkable hydrogen storage properties.

DU is a waste by-product of the nuclear industry. It has been around for decades – and in all this time no significant commercial uses have been found for it.

DU as a material had been largely ignored until research by the HyDUS team explored whether it could play any part in the transition from fossil fuels.

The results of our investigations were unexpected. They also revealed that DU is plentiful and readily available in the UK thanks for years of stockpiling.

The process underpinning HyDUS

Across the periodic table are many different metallic elements that will react with hydrogen and store it as a chemical compound known as a hydride (or metallic hydride).

The most efficient hydride-forming metal is palladium – but with a price higher than gold, it’s not a candidate for large-scale hydrogen storage.

Depleted uranium is the next most efficient and as such is the focus of our team’s work.

DU reacts with hydrogen and stores it as uranium trihydride (UH3), which contains three hydrogen atoms for every one uranium atom. At an ambient temperature and pressure it can chemically store H2 at over twice the density of pure liquid hydrogen, which is a remarkable characteristic.

Uranium trihydride (UH3)


the storage density of
pure liquid hydrogen

Simple release mechanism

To release the hydrogen from the hydride, all you have to do is heat it. At temperatures above 250°C, the hydride starts to thermally decompose, releasing the hydrogen as a gas and leaving the uranium as metal again.

The beauty of this process is that the hydride can be formed and unformed time after time, making it ideal for grid-scale hydrogen storage with the bonus that the that the material is already available in large quantities because it has been stockpiled as industrial waste.

HyDUS can convert electricity to hydrogen via electrolysis and store it for future use, which can be directly as hydrogen or converted back to electricity via a fuel cell when required.

The next step: the world’s first pilot-scale DU hydrogen storage demonstrator

Whilst the hydrogen storage credentials of depleted uranium have been rigorously tested in the laboratory, there is now a need to demonstrate the concept at a larger scale.

To this end, the HyDUS team has embarked on the world’s first pilot-scale demonstrator of bulk hydrogen storage using depleted uranium. This is scheduled for completion by 2024.

90 Whitfield Street
Created by HTP Digital
90 Whitfield Street
Created by HTP Digital