Reference
Gulf hydrogen glossary
The terms that carry the most weight in sector material, defined plainly. Several are defined here specifically because they are routinely conflated: a bid tariff is not a levelised cost, a solar megawatt is not an electrolyser megawatt, and ammonia is not an aviation fuel.
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6 entries
Molecules and products
- Green hydrogen
- Hydrogen produced by splitting water in an electrolyser powered by renewable electricity. The term is a market convention, not a legal definition: what counts as green depends on which certification scheme you are being measured against.
- Blue hydrogen
- Hydrogen produced from natural gas with carbon capture. The UAE strategy treats it as a stepping stone: 0.4 Mt/yr of the 2031 target is blue.
Source: UAE National Hydrogen Strategy · ise.fraunhofer.de
- Low-carbon hydrogen
- The colour-neutral term the UAE strategy itself uses. It covers green, blue and pink hydrogen together and is measured by carbon intensity rather than by production route.
- Pink hydrogen
- Hydrogen from nuclear-powered electrolysis. It appears in the UAE strategy at 0.0075 Mt/yr by 2031 — about half a percent of the total target.
- Green ammonia
- Ammonia synthesised from green hydrogen and nitrogen. It liquefies at about −33 °C using conventional refrigeration and moves on an existing global fleet, which is why most Gulf export plans are ammonia plans.
- SAF
- Sustainable aviation fuel: a drop-in liquid jet fuel. Ammonia is not a substitute for it and has no certified pathway for turbine aircraft — a distinction sector material frequently blurs.
9 entries
Technology and physics
- GH₂
- Standard technical notation for gaseous hydrogen, paired with LH₂ for liquid hydrogen. It appears in that sense in NASA's Safety Standard for Hydrogen and Hydrogen Systems (NSS 1740.16, 1997), republished by the US Department of Energy, and across the hydrogen safety literature. Since around 2020 the same three characters have also circulated as a contraction of green hydrogen. The abbreviation is not exclusive to the hydrogen field at all: it is also a human gene symbol (growth hormone 2), a Formula One car, a Panasonic camera and a highway on Guam.
Source: H2tools (Hydrogen Safety Panel) / NASA NSS 1740.16 · h2tools.org
- Electrolyser
- The device that splits water into hydrogen and oxygen. Rated in megawatts of electrical input, which is why a solar farm's megawatt rating must never be read as electrolyser capacity.
- Alkaline electrolysis
- The oldest and cheapest commercial electrolyser chemistry, well suited to steady operation and less tolerant of the rapid load swings that a solar-only supply produces.
- PEM electrolysis
- Proton exchange membrane electrolysis. More expensive per kilowatt than alkaline but follows a variable renewable load far better, which matters where the power source is solar.
- SOEC
- Solid oxide electrolysis. Operates at high temperature and reaches higher electrical efficiency where waste heat is available, but is the least commercially mature of the three.
- CCUS
- Carbon capture, utilisation and storage. In the Emirates the operating capacity is 0.8 Mt CO₂/yr at Al Reyadah, with a further 3.0 Mt/yr under construction at Habshan and Hail & Ghasha.
Source: ADNOC · adnoc.ae
- Hydrogen DRI
- Direct reduced iron made with hydrogen instead of natural gas, the main route to lower-carbon primary steel. Masdar and EMSTEEL ran a pilot in Abu Dhabi in 2024; the 100 MW scale-up was cancelled in August 2026.
Source: MEED · guest.meed.com
- Boil-off
- The fraction of a cryogenic cargo lost to evaporation each day. For liquid hydrogen in shipping and storage it is 0.05–0.25% per day, roughly an order of magnitude below the 1–3% figure that circulates widely.
Source: IRENA · irena.org
- LHV and HHV
- Lower and higher heating value. Hydrogen carries 33.3 kWh/kg on an LHV basis and 39.4 kWh/kg on an HHV basis. Gravimetric energy density does not change with pressure or phase.
Source: IDEALHY · idealhy.eu
5 entries
Economics and project finance
- LCOH
- Levelised cost of hydrogen: the price per kilogram at which a project recovers its capital, fuel and operating costs over its life. It is not the same as a market price and not the same as an awarded tariff.
- Bid tariff
- The price a project company agreed to be paid in a competitive tender. Gulf solar records are bid tariffs. They are real, but they reflect state land, a state offtaker and sovereign-risk debt, so they sit below the underlying cost of capital.
- FID
- Final investment decision: the point at which sponsors commit capital. Before FID a project is an intention. Most of the announced hydrogen capacity in the Gulf has never reached it.
- Offtake agreement
- A binding commitment by a buyer to purchase the output. Offtake, not capacity, is what makes a hydrogen project financeable; across roughly 80 Middle Eastern green hydrogen projects, three have one.
Source: Mitsui MGSSI · mitsui.com
- Mt/yr
- Million tonnes per annum, the unit the UAE strategy states its targets in. Also written mtpa. One million tonnes of hydrogen is roughly the output of 8–10 GW of electrolysis running at Gulf solar load factors.
3 entries
Regulation and certification
- RFNBO
- Renewable fuel of non-biological origin: the European Union's legal category for hydrogen that counts toward its renewable targets. Qualifying requires additionality, temporal correlation and geographic correlation between the electricity and the hydrogen.
Source: EU Delegated Regulation 2023/1184 · eur-lex.europa.eu
- CBAM
- The EU's Carbon Border Adjustment Mechanism, which prices the embedded carbon of certain imports. Hydrogen and fertilisers are in scope, so it governs what a Gulf exporter can sell into Europe and at what effective cost.
- ISO 19870
- The international standard for quantifying the greenhouse gas footprint of hydrogen production and delivery. Masdar's green steel pilot certified its hydrogen against it.
Source: Masdar · masdar.ae
2 entries
Policy and institutions
- Hydrogen oasis
- The UAE strategy's term for a cluster that co-locates hydrogen production with its end use, to generate demand and share development costs. Two are planned by 2031 and five by 2050. No location has been officially designated.
Source: Ministry of Energy and Infrastructure · moei.gov.ae
- PWPA
- Power and water purchase agreement, the contract through which Abu Dhabi's EWEC procures generation. Any large electrolyser in the emirate depends on one for its electricity.