Hydrogen

Recognising the role that hydrogen can play to help decarbonise the energy system and make a positive contribution towards net zero greenhouse gas emissions objectives, the Scottish Government has published its Hydrogen Policy Statement (2020) and Action Plan (2022).

The UK Government has published a Hydrogen Strategy which sets out the approach to developing a low carbon hydrogen sector in the UK to meet increased ambition for 10GW of low carbon hydrogen production capacity by 2030.

Classifying hydrogen production

Hydrogen production is often classified depending on the energy source. The main ones as defined in the Scottish Government Hydrogen Action Plan are:

Renewable hydrogen (also referred to as green hydrogen) – is produced using renewable electricity from the electrolysis of water, a process which splits water into its constituent parts of hydrogen and oxygen.
Low-carbon hydrogen (also referred to as blue hydrogen) – is produced in the same way as grey hydrogen below but the process is aligned with carbon capture and storage (CCS) systems which capture most of the CO2 produced, preventing it from entering the atmosphere.
Unabated hydrogen (also referred to as grey hydrogen) – is produced from the reforming of natural gas. This process produces both hydrogen and carbon dioxide.

Hydrogen production techniques

Hydrogen can be produced from a number of techniques. Hydrogen production by electrolysis and natural gas reformation are the two common production pathways in Scotland. Both have environmental impacts that can result from emissions, wastes from production, consumption of energy and water resources, as well as land disturbance for development.

Electrolysis of water

This process involves an electric current being passed through water to split the hydrogen and oxygen. The environmental impacts of the process may include:

Use and release of water. The discharged water may contain concentrated chemicals and minerals depending on the source and pre-treatment. There may also be a temperature change.
Fugitive emissions of hydrogen – although not a greenhouse gas, hydrogen is considered to have a global warming potential.
Noise from condensers, compressors.
Use of electricity.

Reforming natural gas

Methods of methane reforming can be used to manufacture syngas (a mixture of hydrogen and carbon monoxide) from natural gas (methane). Hydrogen can then be separated from the syngas. As well as those listed in the section above, the environmental impacts of the process may include:

Methane reforming requires a great deal of energy.
Solvents and other chemicals may be used which can lead to polluting by-products.
Risk of emissions of CO2 if capture and transport systems aren’t utilised or fully functioning.

What is currently happening in Scotland?

The Scottish Government Hydrogen Action Plan is assisting the development of the sector to ensure Scotland is in the best possible position with a view to achieving 5 GW of renewable and low-carbon hydrogen capacity by 2030 and 25GW by 2045, and will focus actions to support meeting the following six key challenges:

Scale up hydrogen production in Scotland.
Facilitate the development of a domestic market.
Maximise benefits of integrating hydrogen into the energy system
Strengthen research and innovation.
Establish and strengthen international partnerships and markets.
Growing and transitioning Scotland’s supply chain and workforce.

A map of existing and potential hydrogen projects in Scotland can be found on the Hydrogen Scotland webpage.

Outlined below are the key planning and regulatory requirements to develop the hydrogen sector.

Planning

Planning permission will generally be required from the relevant planning authority (local authority or Energy Consents Unit of the Scottish Government) for hydrogen projects and relevant requirements under the Town and Country Planning (Environmental Impact Assessment) (Scotland) Regulations 2017 will also apply. SEPA are statutory consultees for planning applications.

Hazardous Substances Consent regulates the presence of hazardous substances to ensure risks to people and environment are properly addressed in land use planning. It is required from the planning authority (in consultation with both HSE and SEPA) where 2 or more tonnes of hydrogen is present on a site, or where hydrogen is present in addition to certain other chemicals.

The Scottish Government has established a national Planning Improvement Hub to build capacity and resilience, and to improve consistency and efficiency in decision-making amongst planning authorities. The Hub’s initial priority will be to help planning authorities make quicker decisions on hydrogen planning applications.

Environmental Regulation

SEPA supports the Scottish Government’s net zero ambitions including the development of renewable and low carbon energy while also recognising that these developments can have an impact on the local environment through emissions to air, land and water, or globally through the releases of greenhouse gas emissions. We use our regulatory toolkit to drive more efficient energy and resource use and to ensure that the local environment is protected and improved.

As a growing technology, SEPA has a key interest in relation to the design of pollution prevention measures during the periods of construction, operation, maintenance, demolition, and restoration to ensure no deterioration of satisfactory state / site condition and therefore pre-application discussions are encouraged as early as possible.

Production of hydrogen

The production of hydrogen is a listed activity under the Pollution Prevention and Control (Scotland) Regulations 2012 (PPC) as a Part A production of inorganic chemicals activity 4.2 (a) (i).

There is no minimum threshold but there is a caveat that the production should be on an “industrial scale”. Additional guidance on capacity is available.

PPC includes any hydrogen production installations up to 12 nautical miles offshore.

There is more information and guidance about our PPC permitting regime here. A Part A permit will regulate emissions to air, water and land, and consider issues such as noise and the best use of raw material, water and energy. This permit does not cover water abstraction, the operator will need an appropriate water abstraction authorisation, more information summarised below. The operator must use the Best Available Techniques to ensure that emissions are removed or reduced.

The UK environmental regulators have published guidance on the environmental standards and best practice expected and developers should ensure they have covered all the aspects raised in the guidance when submitting an application for a permit.

Other European Brefs may be applicable

A permit must be obtained from SEPA prior to any hydrogen being produced. SEPA is statutorily allowed 4 months to determine the application as well as an additional month for public consultation of the draft determination. We publicly consult on all PPC Part A draft permits, or variations to existing permits before they are issued.

SEPA has produced a draft bespoke application form for hydrogen production by electrolysis projects which meet certain “low risk” criteria. Please contact ppcpermitting@sepa.org.uk as early as possible to discuss whether your project meets these criteria.

Combustion of hydrogen

If hydrogen is being burned as a fuel in any plant greater than 1MW net rated thermal input (RTI) it will also be regulated under conditions of a PPC permit.

If it is on the same installation as the production site or on a permitted PPC installation, conditions can be incorporated into the production permit, or the existing permit can be varied.

If the combustion activity is taking place on an installation that is not subject to a PPC permit, an application for a Part B permit must be made for any new medium combustion plant greater than 1MW (including standby plant operating <500 hours per annum). Advice on permitting requirements can be found at medium combustion plant.

Installations comprising of a combustion plant with a total RTI greater than 50MW require a Part A permit.

SEPA, along with other UK environmental regulators, has published guidance which sets out how to comply with emission limit values (ELVs) for hydrogen combustion plant greater than 1MW. It sets out ELVs for oxides of nitrogen (NOx) and carbon monoxide (CO). We are applying the principle that there should not be an increase in the amount of NOx or CO released when burning hydrogen compared with burning natural gas.

The combustion of hydrogen results in a change in the flue gas volume. Therefore, you need to use a correction factor to achieve equivalence with ELVs defined for natural gas on a mass per unit volume basis with a range of ELV correction values related to the hydrogen content of a natural gas/hydrogen blended fuel, up to a maximum of 1.37 at 100% hydrogen.

Hydrogen combustion: comply with emission limit values - GOV.UK

Water abstraction and discharge

Under the Water Environment (Controlled Activities) (Scotland) Regulations 2011 (CAR) the abstraction of water is a controlled activity and will require authorisation from SEPA. As hydrogen production may need a significant amount of water, pre-application discussions are strongly advised to ensure sufficient water is available at all times of the year – this includes periods of water scarcity.

The selection of an appropriate water supply in the early stage of a project is critical. Water resource is becoming increasingly strained and even though Scotland is considered to have a relatively abundant source of fresh water, there are an increasing number of water scarcity events and any proposal to use abstracted inland surface water should be aware that the authorisation will have a hands off flow condition (this will restrict access to water abstraction) to protect river flows from abstraction during low flows. This means there may be occasions where the authorised abstraction would have to stop. SEPA will not require an authorisation for an abstraction from the public water supply as agreement to provide this supply is obtained from Scottish Water.

Hierarchy of supply:

Treated effluent.
Seawater.
Ground/surface water.
Treated public supply should be the last option.

Minimisation and reuse within the process should be considered and highlighted in all cases. The developer should be aware of any seasonal disruptions in water supply, the impacts of climate change are likely to result in increased periods of water scarcity as well as flooding. Storage of water on site should also be considered.

Obtaining an appropriate water supply for a hydrogen project may require works that are remote from the main development site. Where possible, this should be presented and consulted upon, considering all infrastructure including water supply. Selection of supply should also take account of potential prohibition of raw water transfer between catchments to prevent spread of invasive non-native species

Most electrolysers require water of a demineralised standard, and all sources of water are likely to require some form of pre-treatment. The concentration of minerals, salts, etc during pre-treatment must be assessed and the effect of the discharge on the receiving environment considered. The discharge of concentrated effluent to the water environment needs to be authorised by SEPA. This will normally be controlled by conditions in the PPC permit. If there is no PPC permit, then the discharge needs a CAR authorisation.

The CAR Practical Guide provides information on levels of authorisation.

Please contact SEPA Water Permitting team on waterpermitting@sepa.org.uk for more advice on the abstraction and use of water for hydrogen production.

The Control of Major Accident Hazards Regulations 2015 (COMAH)

Hydrogen is a named dangerous substance under COMAH regulations. Where the COMAH qualifying quantity threshold for dangerous substances will be exceeded by the proposed development, the establishment will need to be regulated under the COMAH regime. Changes to quantities of substances stored on existing sites may result in a change of tier. The threshold quantities for COMAH are 5 tonnes (lower tier) and 50 tonnes (upper tier) Presence of other hazardous substances on site may affect these thresholds.

In either of these circumstances the operator is required to notify the Competent Authority, within a reasonable period of time (normally between 3 and 6 months) and prior to increasing the inventory stored at the establishment. Notification should be made to the competent authorities, the HSE and SEPA. Following notification, SEPA will expect the operator to submit an assessment of the environmental risks, demonstrating that All Measures Necessary have been undertaken in relation to the potential for major accidents to the environment.

To inform the assessment, it is recommended that sensitive environmental receptors within a 10km radius of the development are identified; this should include statutory and local environmental designations, as well as local agricultural uses including livestock rearing.

See Scotland’s Environment Website COMAH search tool for guidance.

Please contact SEPA’s COMAH team wasteandindustry@sepa.org.uk if the qualifying quantity threshold for dangerous substances are likely to be exceeded by the proposed development (>5 tonnes) or if changes to stored substances on an existing site alters the site’s COMAH tier