On 22 December 2020, the Scottish Government issued its Hydrogen Policy Statement. This covers all the ways in which hydrogen is to be used as an alternative to carbon-based fuels. The full document can be viewed here.

Here are the key rail-related elements of the statement:

Having successfully demonstrated the technical viability of hydrogen in a range of transport applications, our focus is turning to scaling-up the potential for hydrogen by linking together opportunities across sectors and transport modes and building Scotland's potential for innovation and supply chain growth.

In line with the sustainable travel hierarchy, our priority is managing or reducing demand for travel, and supporting active travel and public transport.

Although often viewed as competing technologies, battery electric and hydrogen systems are in fact complementary and could both become cornerstone technologies for the electrification of transport.

The Scottish Government, Transport Scotland and our enterprise agency partners are already supporting a range of initiatives and projects to build out Scotland's capabilities, with zero emission mobility now a key enterprise theme, and a priority inward investment theme.

Example initiatives and action include:

• launching the Hydrogen Accelerator programme based at the University of St. Andrews. This links academic, public and commercial interests in the development and deployment of hydrogen technologies and provides expert advice and support to the design, development and implementation of transport initiatives across Scotland.
• funding the development of a hydrogen fuel cell rail vehicle to assess the potential for wider use on Scotland's railways.

Scotland's Rail Services Decarbonisation Action Plan recognises that although, initially, hydrogen fuelled trains are expected to have higher capital and operating costs than diesel trains, the growth and maturity of the market will drive down costs. Recent market engagement with rolling stock manufacturers suggests hydrogen fleets to replace diesel-powered trains are seen as a realistic and affordable option for Scotland in the second half of this decade. Those hydrogen fleets may be used to provide a transitional solution on parts of the network prior to the implementation of electrification infrastructure as well as providing a permanent solution on more remote, less intensively used sections of the network where full scale electrification is either not economic nor desirable for environmental reasons.

The Zero Emissions Train project is an exciting hydrogen-focussed initiative currently being developed by Transport Scotland and Scottish Enterprise in response to the Scottish Government's Programme for Government commitment that; "Where we cannot electrify or it is inappropriate to do so, we will invest in battery powered trains and work with developers of hydrogen fuel cell trains to accelerate their development and deployment through practical trials in Scotland."

The project will convert a withdrawn ScotRail Class 314 electric train over to utilising hydrogen fuel cell (FC) traction. The project aims to demonstrate this technology by operating the train on closed rail network by autumn 2021. The project has six key objectives:

• prove we have the capability to modify an existing item of rolling stock to use hydrogen FC, batteries, control equipment, etc.;
• work with the regulatory bodies to develop the necessary standards and controls for the use of hydrogen FC power on passenger rolling stock;
• inform rail policy on the application of such technology on the Scottish passenger rail network in advance of the decarbonisation target of 2035 for Scotland's passenger rail services;
• demonstrate to Scotland's rail community through practical application the operation of hydrogen FC passenger rolling stock;
• provide the supply chain with the opportunity to develop their skills and knowledge of the application of hydrogen FC technology on passenger rolling stock and hydrogen supply and refuelling infrastructure; and
• provide educational institutions with the opportunity for research and practical application of hydrogen FC technology within the rail industry.