National Physical Laboratory

Hydrogen Purity Analysis


Hydrogen is set to become a crucial part of the UK's future energy matrix as the Government strives to meet challenging targets for reducing greenhouse emissions. One application of hydrogen is to power fuel cell vehicles - these vehicles are emission-free at the point of use, and fossil fuel usage is eliminated if the hydrogen is generated from renewable energy sources. According to a recent report written by UK H2Mobility, in the UK we should expect 1.6 million fuel cell vehicles on the road and 1,100 hydrogen refuelling stations in operation.

Various studies have been performed that have specifically investigated the effects of hydrogen impurities on fuel cell lifetime and, more recently, the international standard ISO 14687-2 has been published, which provides a list of the maximum levels of impurities that can be present in hydrogen used to power proton exchange membrane (PEM) fuel cell vehicles. In 2014, European Directive 2014/94/EU was written which states that fuel cell hydrogen provided by all hydrogen refuelling stations in Europe must comply with this ISO standard (or the relevant new EN standard) from the end of 2017 onwards.

What we can do

Our hydrogen purity laboratory can provide the following services:

  • Purity analysis of hydrogen (with UKAS accreditation)
  • Provision of custom Primary Reference Gas Standards (with UKAS accreditation)
  • Proficiency testing scheme

To find out more about the services that our hydrogen purity laboratory can provide, please click here

Senior research scientists developing a new gas analysis method in the hydrogen purity laboratory
Senior research scientists developing a new gas analysis method in the hydrogen purity laboratory


Hydrogen purity analysis

NPL is a key player in the field of hydrogen purity for fuel cell vehicles. Our goal has been to provide traceable methods for accurately determining the levels of impurities in fuel cell hydrogen to support the growth of the hydrogen economy. As an expert in the field, NPL has written the first concise review paper on analytical methods for performing purity analysis of fuel cell hydrogen (click here).

NPL gas bottles

Methods currently exist for performing measurement of all impurities listed in ISO 14687-2, except for total halogenated compounds (where the maximum limit is 50 ppb). There is no established method that can achieve this measurement (read more about this in NPL's paper by clicking here). NPL is currently developing new analytical methods using gas chromatography techniques for measuring:

  • The key individual halogenated compounds in fuel cell hydrogen
  • Total halogenated compounds (as specified in ISO 14687-2)

In addition to developing analytical methods, NPL is also producing the primary reference gas standards (such as low level formaldehyde in hydrogen) that will allow these hydrogen purity measurements to be traceable to national standards.

Overcoming hydrogen fuel's chicken-and-egg conundrum is a question of purityEngine Technology International

Industry opinion: hydrogen fuel purity testingAutomotive Testing Technology International

Online hydrogen purity analyser

NPL is working with Cascade Technologies to develop online hydrogen purity analysers that can monitor the key impurities in fuel cell hydrogen directly at the hydrogen refuelling station. They are currently developing three online analysers; each analyser is designed to monitor the key impurities for three different hydrogen processes (including steam methane reforming and electrolysis). Cascade Technologies use innovative Quantum Cascade Laser technology to develop their analysers. This work is part of an Innovate UK project and includes collaboration with ITM Power, BOC and the University of St Andrews.

NPL's hydrogen impurity enrichment device

NPL has developed a device for concentrating the impurities in a sample of hydrogen before performing purity analysis. This can allow lower amount fractions to be measured using routine techniques, which can simplify and speed up purity analysis. The device operates by tracking a known amount of tracer gas during the enrichment process and this can allow high enrichment factors that are quantified with high accuracy.

NPL's hydrogen impurity enrichment device
H2FC European Infrastructure logo

This device has been validated in the laboratory and the next step will be to roll it out as a commercial product to allow gas analysis laboratories to perform fast, low cost and high accuracy hydrogen purity measurements using their existing analysers.

Please click here for NPL's paper on the hydrogen impurity enrichment device.


Island Hydrogen

In addition to providing quality assurance of fuel cell hydrogen, we are keen to use our expertise and capabilities to support projects that aim to progress hydrogen technologies. The Island Hydrogen project (funded by Innovate UK in collaboration with ITM Power) aims to power the Isle of Wight using only renewable sources, using hydrogen as an energy buffer to store surplus energy generated by solar, wind, tidal and geothermal power.

A result of this project was the delivery of the UK's first renewable hydrogen refuelling station (where hydrogen is produced using an electrolyser powered by a wind turbine).


  • Hydrogen London
  • ISO TC 197 – Hydrogen technologies
  • ISO TC 158 – Analysis of gases
  • CEN/TC 268/WG 5 – Specific hydrogen technologies applications
  • CEN-CENELEC Sector Forum 'Energy Management'
  • BSI/PVE/3/8 - Gas containers - Hydrogen technologies

Contact us

Research work:

Dr Arul Murugan
T: +44 20 8943 6382

Measurement services:

We work with Innovate UK logo

Gas Metrology Customer Enquiries
T: +44 20 8943 8715

Last Updated: 31 May 2016
Created: 28 Nov 2013


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