Hydrogen: planning and consenting guidance

Annex A – Green & Blue Hydrogen

Blue Hydrogen – Site Requirements & Characteristics Resources & Feedstocks – the essential resource for Blue Hydrogen is natural gas (or biogas) – along with a water supply and access to the electricity network (or other heat sources). A means of storing or utilising the CO2 produced through Blue Hydrogen production must also be in place. Land Area – The land area required can vary significantly depending on the scale of operations and associated enabling infrastructure required, including whether hydrogen is stored on site. Given the scale of investment and infrastructure required for Carbon Capture Storage & Utilisation, Blue Hydrogen production is more likely to be developed at relatively large scales. Preferable sites will be those that are developable with few technical constraints, and for which there is planning policy support for energy and/or industrial land use. Off-take and distribution – Given the requirement for intake of natural gas, and ‘off-take’ of both hydrogen and CO2, Blue Hydrogen production may often be located around existing gas distribution infrastructure and/or in proximity to industrial users that can utilise hydrogen and CO2. However, subject to scale of operation and technological viability, it may be appropriate to compress hydrogen on site and transport elsewhere for storage or utilisation. Where produced at large-scale for export, coastal locations may be preferable to enable integration with off-shore pipelines or port infrastructure for shipping of hydrogen (including as ammonia or LOHC). Site Plant & Infrastructure - The specific plant and technology on site will depend on how natural gas is reformed to extract hydrogen – which can include Steam Methane Reforming (SMR), Autothermal Reforming (ATR), Gas Heated Reforming (GHR) and Partial Oxidation (POX) – all involve treatment of natural gas to extract hydrogen and the capture of carbon dioxide emissions for storage or utilisation. Key elements of plant and infrastructure for SMR include:

• Methane feedstock – typically piped to site and often purified through an initial ‘de-sulphurisation’ process
• Steam Methane Reformers (or other gas reformation) – where methane is reacted with steam at high temperatures / pressures in the presence of a catalyst, producing hydrogen, carbon monoxide and carbon dioxide (known as syngas)
• Shift Conversion – A secondary process where Carbon Monoxide is further reacted with Stream to produce more hydrogen and carbon dioxide.
• Carbon Capture – Carbon dioxide produced during reformation and shift conversion is extracted, often using chemical absorption methods (amine-based or hot potassium carbonate solvents). The carbon is then transported (typically via pipeline or shipping) either for utilisation in chemical / industrial processes or to a storage site, typically underground.
• Hydrogen Purification: - The resultant gas mixture is further treated and separated through pressure swing adsorption or membrane separation, to remove any remaining waste gases and provide purified hydrogen.

In addition to the above core plant for hydrogen production, facilities will in most cases include buildings (control room, office, staff welfare) and site access infrastructure (internal roads and circulation, parking, loading bays, re-fuelling areas) appropriate to the scale and nature of the site. As noted above, Blue Hydrogen will in many cases be co-located to existing gas distribution infrastructure (pipelines) and/or industrial facilities that will be the end-user of hydrogen.

Green Hydrogen – Site Requirements & Characteristics Resources & Feedstock – the essential resources for Green Hydrogen are renewable energy and a supply of water – both fundamental to the electrolysis process. This will often mean siting production in close proximity to these resources in order to enable direct and secure utility connections, though the specific means of accessing water and renewable energy will vary by site. For larger-scale production, coastal locations may be preferable to take advantage of renewable energy from off-shore wind and access to sea-water for de-salination, as well as integration with off-shore pipelines or ports for shipping of hydrogen (and derivatives) Land Area- the land area required can vary significantly depending on the scale of operations and associated enabling infrastructure required, including whether hydrogen is stored on site. Electrolysers are a modular and scalable technology, meaning that green hydrogen can be developed from very small to very large scales. Preferable sites will be those that are developable with few technical constraints, and for which there is planning policy support for renewable energy and/or industrial land use. The potential for offshore green hydrogen production that is directly connected to offshore wind sites also has potential application in Scotland. It is yet to be deployed but would likely involve electrolyser and other plant directly integrated to offshore wind (or separate) platforms with hydrogen transported to land via a dedicated pipeline. Subject to further technical and commercial feasibility this may emerge as an alternative mode of green hydrogen production. Off-take and distribution – Green Hydrogen can be distributed through a variety of means, including via compressed tube-trailer (road / rail) shipping (as ammonia, liquefied hydrogen, or other LOHC), and via pipeline. The means of distribution will depend on the on the scale of production and end-user requirements / market demand. Site Plant & Infrastructure – the specific configuration of plant and technology will vary by site, but as core components would include:

• Electrolyser – the primary component of green hydrogen production – electrolysers produce hydrogen through separating hydrogen and oxygen molecules of water with an electrical current. Depending on the scale of production, these can be ‘stacked’.
• Power Source – direct cable link to renewable energy (on or off-site), in many cases including a transformer / sub-station on site.
• Water Supply & Treatment – specialist plant to purify (de-mineralise / de-ionise) water prior to utilisation in electrolysis, as well as means of treating and disposing (or re-using) effluent waste water from the production process. This may include water tanks.
• Balance of Plant – Additional plant technology for cooling of the electrolysis process, and separation, compression, and storage of hydrogen prior to utilisation or distribution from site.

In addition to the above core plant for hydrogen production, facilities will in most cases include buildings (control room, office, staff welfare) and site access infrastructure (internal roads and circulation, parking, loading bays, re-fuelling areas) appropriate to the scale and nature of the site.