Hydrogen Economy

In this context, hydrogen economy encompasses hydrogen's production through to end-uses in ways that substantively contribute to phasing-out fossil fuels and limiting climate change.

Most hydrogen produced today is gray hydrogen, made from natural gas through steam methane reforming (SMR) which accounted for 1.8% of global greenhouse gas emissions in 2021. Low-carbon hydrogen, which is made using SMR with carbon capture and storage (blue hydrogen), or through electrolysis of water using renewable power (green hydrogen), accounted for under 1% of production. Virtually all of the 100 million tonnes of hydrogen produced each year is used in oil refining (43% in 2021) and industry (57%), principally in the manufacture of ammonia for fertilizers, and methanol.^{: 18, 22, 29}

In its contribution to limiting global warming to 1.5 °C, it is broadly envisaged that the future hydrogen economy replaces gray hydrogen with blue and predominantly green hydrogen, produced in greater total volumes, to provide for an expanded set of end-uses. These are likely to be in heavy industry (e.g. high temperature processes alongside electricity, feedstock for production of green ammonia and organic chemicals, as alternative to coal-derived coke for steelmaking), long-haul transport (e.g. shipping, aviation and to a lesser extent heavy goods vehicles), and long-term energy storage. Other applications, such as light duty vehicles and heating in buildings, are no longer part of the future hydrogen economy, primarily for economic and environmental reasons. These reasons include the difficulty of developing long-term storage, pipelines, and engine equipment, safety concerns since hydrogen is highly explosive, and the inefficiency of hydrogen compared to direct use of electricity.

As of 2023^[update] there are no real alternatives to hydrogen for ammonia production for fertilizer, hydrogenation, hydrocracking, and hydrodesulfurization. The extent to which hydrogen will be used to decarbonise chemical feedstock, long haul aviation and shipping, and long-term energy storage is likely to be influenced by the evolving production costs of low- and zero-carbon hydrogen. Estimates of future costs face numerous uncertainties – such as the introduction of carbon taxes, geography and geopolitics of energy, energy prices, technology choices, and their raw material requirements – but it is likely that green or white (underground) hydrogen will see the greatest reductions in production cost over time.

Origins

The concept of the hydrogen economy, though not the term, was by geneticist J.B.S. Haldane in 1923, who, anticipating the exhaustion of Britain's coal reserves for power generation, proposed a network of wind turbines to produce hydrogen for long-term energy storage through electrolysis, to help address renewable power's variable output. The term itself was coined by John Bockris during a talk he gave in 1970 at General Motors (GM) Technical Center. Bockris viewed it as an economy in which hydrogen, underpinned by nuclear and solar power, would help address growing concern about fossil fuel depletion and environmental pollution, by serving as energy carrier for end-uses in which electrification was not suitable.

A hydrogen economy was proposed by the University of Michigan to solve some of the negative effects of using hydrocarbon fuels where the carbon is released to the atmosphere (as carbon dioxide, carbon monoxide, unburnt hydrocarbons, etc.). Modern interest in the hydrogen economy can generally be traced to a 1970 technical report by Lawrence W. Jones of the University of Michigan, in which he echoed Bockris' dual rationale of addressing energy security and environmental challenges. Unlike Haldane and Bockris, Jones only focused on nuclear power as the energy source for electrolysis, and principally on the use of hydrogen in transport, where he regarded aviation and heavy goods transport as the top priorities.

Later evolution

 

A spike in attention for the hydrogen economy concept during the 2000s was repeatedly described as hype by some critics and proponents of alternative technologies, and investors lost money in the bubble. Interest in the energy carrier resurged in the 2010s, notably with the forming of the World Hydrogen Council in 2017. Several manufacturers released hydrogen fuel cell cars commercially, with manufacturers such as Toyota, Hyundai, and industry groups in China having planned to increase numbers of the cars into the hundreds of thousands over the next decade.

The global scope for hydrogen's role in cars is shrinking relative to earlier expectations. By the end of 2022, 70,200 hydrogen vehicles had been sold worldwide, compared with 26 million plug-in electric vehicles.

Early 2020s takes on the hydrogen economy share earlier perspectives' emphasis on the complementarity of electricity and hydrogen, and the use of electrolysis as the mainstay of hydrogen production. They focus on the need to limit global warming to 1.5 °C and prioritize the production, transportation and use of green hydrogen for heavy industry (e.g. high-temperature processes alongside electricity, feedstock for production of green ammonia and organic chemicals, as alternative to coal-derived coke for steelmaking), long-haul transport (e.g. shipping, aviation and to a lesser extent heavy goods vehicles), and long-term energy storage.

Hydrogen production globally was valued at over US$155 billion in 2022 and is expected to grow over 9% annually through 2030.

In 2021, 94 million tonnes (Mt) of molecular hydrogen (H₂) was produced. Of this total, approximately one sixth was as a by-product of petrochemical industry processes. Most hydrogen comes from dedicated production facilities, over 99% of which is from fossil fuels, mainly via steam reforming of natural gas (70%) and coal gasification (30%, almost all of which in China). Less than 1% of dedicated hydrogen production is low carbon: steam fossil fuel reforming with carbon capture and storage, green hydrogen produced using electrolysis, and hydrogen produced from biomass. CO₂ emissions from 2021 production, at 915 MtCO₂, amounted to 2.5% of energy-related CO₂ emissions and 1.8% of global greenhouse gas emissions.

Virtually all hydrogen produced for the current market is used in oil refining (40 MtH₂ in 2021) and industry (54 MtH2).^: 18, 22 In oil refining, hydrogen is used, in a process known as hydrocracking, to convert heavy petroleum sources into lighter fractions suitable for use as fuels. Industrial uses mainly comprise ammonia production to make fertilisers (34 MtH₂ in 2021), methanol production (15 MtH₂) and the manufacture of direct reduced iron (5 MtH₂).^: 29

 

 

Hydrogen can be deployed as a fuel in two distinct ways: in fuel cells which produce electricity, and via combustion to generate heat. When hydrogen is consumed in fuel cells, the only emission at the point of use is water vapour. Combustion of hydrogen can lead to the thermal formation of harmful nitrogen oxides emissions.

Industry

In the context of limiting global warming, low-carbon hydrogen (particularly green hydrogen) is likely to play an important role in decarbonising industry. Hydrogen fuel can produce the intense heat required for industrial production of steel, cement, glass, and chemicals, thus contributing to the decarbonisation of industry alongside other technologies, such as electric arc furnaces for steelmaking. However, it is likely to play a larger role in providing industrial feedstock for cleaner production of ammonia and organic chemicals. For example, in steelmaking, hydrogen could function as a clean energy carrier and also as a low-carbon catalyst replacing coal-derived coke.

The imperative to use low-carbon hydrogen to reduce greenhouse gas emissions has the potential to reshape the geography of industrial activities, as locations with appropriate hydrogen production potential in different regions will interact in new ways with logistics infrastructure, raw material availability, human and technological capital.

Transport

Much of the interest in the hydrogen economy concept is focused on hydrogen vehicles, particularly planes. Hydrogen vehicles produce significantly less local air pollution than conventional vehicles. By 2050, the energy requirement for transportation might be between 20% and 30% fulfilled by hydrogen and synthetic fuels.

Hydrogen used to decarbonise transportation is likely to find its largest applications in shipping, aviation and to a lesser extent heavy goods vehicles, through the use of hydrogen-derived synthetic fuels such as ammonia and methanol, and fuel cell technology. Hydrogen has been used in fuel cell buses for many years. It is also used as a fuel for spacecraft propulsion.

In the International Energy Agency's 2022 Net Zero Emissions Scenario (NZE), hydrogen is forecast to account for 2% of rail energy demand in 2050, while 90% of rail travel is expected to be electrified by then (up from 45% today). Hydrogen's role in rail would likely be focused on lines that prove difficult or costly to electrify. The NZE foresees hydrogen meeting approximately 30% of heavy truck energy demand in 2050, mainly for long-distance heavy freight (with battery electric power accounting for around 60%).

Although hydrogen can be used in adapted internal combustion engines, fuel cells, being electrochemical, have an efficiency advantage over heat engines. Fuel cells are more expensive to produce than common internal combustion engines but also require higher purity hydrogen fuel than internal combustion engines.

In the light road vehicle segment including passenger cars, by the end of 2022, 70,200 fuel cell electric vehicles had been sold worldwide, compared with 26 million plug-in electric vehicles. With the rapid rise of electric vehicles and associated battery technology and infrastructure, hydrogen's role in cars is minuscule.

Energy system balancing and storage

Green hydrogen, from electrolysis of water, has the potential to address the variability of renewable energy output. Producing green hydrogen can both reduce the need for renewable power curtailment during periods of high renewables output and be stored long-term to provide for power generation during periods of low output.

Ammonia

An alternative to gaseous hydrogen as an energy carrier is to bond it with nitrogen from the air to produce ammonia, which can be easily liquefied, transported, and used (directly or indirectly) as a clean and renewable fuel. Among disadvantages of ammonia as an energy carrier are its high toxicity, energy efficiency of NH₃ production from N₂ and H₂, and poisoning of PEM Fuel Cells by traces of non-decomposed NH₃ after NH₃ to N₂ conversion.

Buildings

Numerous industry groups (gas networks, gas boiler manufacturers) across the natural gas supply chain are promoting hydrogen combustion boilers for space and water heating, and hydrogen appliances for cooking, to reduce energy-related CO₂ emissions from residential and commercial buildings. The proposition is that current end-users of piped natural gas can await the conversion of and supply of hydrogen to existing natural gas grids, and then swap heating and cooking appliances, and that there is no need for consumers to do anything now.

A review of 32 studies on the question of hydrogen for heating buildings, independent of commercial interests, found that the economics and climate benefits of hydrogen for heating and cooking generally compare very poorly with the deployment of district heating networks, electrification of heating (principally through heat pumps) and cooking, the use of solar thermal, waste heat and the installation of energy efficiency measures to reduce energy demand for heat. Due to inefficiencies in hydrogen production, using blue hydrogen to replace natural gas for heating could require three times as much methane, while using green hydrogen would need two to three times as much electricity as heat pumps. Hybrid heat pumps, which combine the use of an electric heat pump with a hydrogen boiler, may play a role in residential heating in areas where upgrading networks to meet peak electrical demand would otherwise be costly.

The widespread use of hydrogen for heating buildings would entail higher energy system costs, higher heating costs and higher environmental impacts than the alternatives, although a niche role may be appropriate in specific contexts and geographies. If deployed, using hydrogen in buildings would drive up the cost of hydrogen for harder-to-decarbonise applications in industry and transport.

Bio-SNG

As of 2019^[update] although technically possible production of syngas from hydrogen and carbon-dioxide from bio-energy with carbon capture and storage (BECCS) via the Sabatier reaction is limited by the amount of sustainable bioenergy available: therefore any bio-SNG made may be reserved for production of aviation biofuel.

 

A hydrogen infrastructure is the infrastructure of hydrogen pipeline transport, points of hydrogen production and hydrogen stations (sometimes clustered as a hydrogen highway) for distribution as well as the sale of hydrogen fuel, and thus a crucial prerequisite before a successful commercialization of automotive fuel cell technology.

 

The hydrogen infrastructure would consist mainly of industrial hydrogen pipeline transport and hydrogen-equipped filling stations like those found on a hydrogen highway. Hydrogen stations which were not situated near a hydrogen pipeline would get supply via hydrogen tanks, compressed hydrogen tube trailers, liquid hydrogen trailers, liquid hydrogen tank trucks or dedicated onsite production.

Pipelines are the cheapest way to move hydrogen over long distances compared to other options. Hydrogen gas piping is routine in large oil-refineries, because hydrogen is used to hydrocrack fuels from crude oil.

Hydrogen embrittlement (a reduction in the ductility of a metal due to absorbed hydrogen) is not a problem for hydrogen gas pipelines. Hydrogen embrittlement only happens with 'diffusible' hydrogen, i.e. atoms or ions. Hydrogen gas, however, is molecular (H₂), and there is a very significant energy barrier to splitting it into atoms.

The IEA recommends existing industrial ports be used for production and existing natural gas pipelines for transport: also international co-operation and shipping.

South Korea and Japan, which as of 2019 lack international electrical interconnectors, are investing in the hydrogen economy. In March 2020, the Fukushima Hydrogen Energy Research Field was opened in Japan, claiming to be the world's largest hydrogen production facility. The site occupies 180,000 m² (1,900,000 sq ft) of land, much of which is occupied by a solar array; power from the grid is also used for electrolysis of water to produce hydrogen fuel.

 

Production

Storage

 

Several methods exist for storing hydrogen. These include mechanical approaches such as using high pressures and low temperatures, or employing chemical compounds that release H₂ upon demand. While large amounts of hydrogen are produced by various industries, it is mostly consumed at the site of production, notably for the synthesis of ammonia. For many years hydrogen has been stored as compressed gas or cryogenic liquid, and transported as such in cylinders, tubes, and cryogenic tanks for use in industry or as propellant in space programs. The overarching challenge is the very low boiling point of H₂: it boils around 20.268 K (−252.882 °C or −423.188 °F). Achieving such low temperatures requires expending significant energy.

Although molecular hydrogen has very high energy density on a mass basis, partly because of its low molecular weight, as a gas at ambient conditions it has very low energy density by volume. If it is to be used as fuel stored on board a vehicle, pure hydrogen gas must be stored in an energy-dense form to provide sufficient driving range. Because hydrogen is the smallest molecule, it easily escapes from containers. Considering leakages, transport and production costs, hydrogen could have a Global Warming Potential (GWP100) of 11.6. Methane, for comparison, has a GWP of 34.

More widespread use of hydrogen in economies entails the need for investment and costs in its production, storage, distribution and use. Estimates of hydrogen's cost are therefore complex and need to make assumptions about the cost of energy inputs (typically gas and electricity), production plant and method (e.g. green or blue hydrogen), technologies used (e.g. alkaline or proton exchange membrane electrolysers), storage and distribution methods, and how different cost elements might change over time.^: 49–65 These factors are incorporated into calculations of the levelized costs of hydrogen (LCOH). The following table shows a range of estimates of the levelized costs of gray, blue, and green hydrogen, expressed in terms of US$ per kg of H₂ (where data provided in other currencies or units, the average exchange rate to US dollars in the given year are used, and 1 kg of H₂ is assumed to have a calorific value of 33.3kWh).

The range of cost estimates for commercially available hydrogen production methods is broad, As of 2022, gray hydrogen is cheapest to produce without a tax on its CO₂ emissions, followed by blue and green hydrogen. Blue hydrogen production costs are not anticipated to fall substantially by 2050,^: 28 can be expected to fluctuate with natural gas prices and could face carbon taxes for uncaptured emissions.^: 79 The cost of electrolysers fell by 60% from 2010 to 2022, before rising slightly due to an increasing cost of capital. Their cost is projected to fall significantly to 2030 and 2050,^: 26 driving down the cost of green hydrogen alongside the falling cost of renewable power generation.^: 28 It is cheapest to produce green hydrogen with surplus renewable power that would otherwise be curtailed, which favours electrolysers capable of responding to low and variable power levels.^: 5

A 2022 Goldman Sachs analysis anticipates that globally green hydrogen will achieve cost parity with grey hydrogen by 2030, earlier if a global carbon tax is placed on gray hydrogen. In terms of cost per unit of energy, blue and gray hydrogen will always cost more than the fossil fuels used in its production, while green hydrogen will always cost more than the renewable electricity used to make it.

Subsidies for clean hydrogen production are much higher in the US and EU than in India.

 

The distribution of hydrogen for the purpose of transportation is being tested around the world, particularly in the US (California, Massachusetts), Canada, Japan, the EU (Portugal, Norway, Denmark, Germany), and Iceland.

An indicator of the presence of large natural gas infrastructures already in place in countries and in use by citizens is the number of natural gas vehicles present in the country. The countries with the largest amount of natural gas vehicles are (in order of magnitude): Iran, China, Pakistan, Argentina, India, Brasil, Italy, Colombia, Thailand, Uzbekistan, Bolivia, Armenia, Bangladesh, Egypt, Peru, Ukraine, United States. Natural gas vehicles can also be converted to run on hydrogen.

Also, in a few private homes, fuel cell micro-CHP plants can be found, which can operate on hydrogen, or other fuels as natural gas or LPG.

Australia

Western Australia's Department of Planning and Infrastructure operated three Daimler Chrysler Citaro fuel cell buses as part of its Sustainable Transport Energy for Perth Fuel Cells Bus Trial in Perth. The buses were operated by Path Transit on regular Transperth public bus routes. The trial began in September 2004 and concluded in September 2007. The buses' fuel cells used a proton exchange membrane system and were supplied with raw hydrogen from a BP refinery in Kwinana, south of Perth. The hydrogen was a byproduct of the refinery's industrial process. The buses were refueled at a station in the northern Perth suburb of Malaga.

In October 2021, Queensland Premier Annastacia Palaszczuk and Andrew Forrest announced that Queensland will be home to the world's largest hydrogen plant.

In Australia, the Australian Renewable Energy Agency (ARENA) has invested $55 million in 28 hydrogen projects, from early stage research and development to early stage trials and deployments. The agency's stated goal is to produce hydrogen by electrolysis for $2 per kilogram, announced by Minister for Energy and Emissions Angus Taylor in a 2021 Low Emissions Technology Statement.

European Union

Countries in the EU which have a relatively large natural gas pipeline system already in place include Belgium, Germany, France, and the Netherlands. In 2020, The EU launched its European Clean Hydrogen Alliance (ECHA).

France

Green hydrogen has become more common in France. A €150 million Green Hydrogen Plan was established in 2019, and it calls for building the infrastructure necessary to create, store, and distribute hydrogen as well as using the fuel to power local transportation systems like buses and trains. Corridor H2, a similar initiative, will create a network of hydrogen distribution facilities in Occitania along the route between the Mediterranean and the North Sea. The Corridor H2 project will get a €40 million loan from the EIB.

Germany

German car manufacturer BMW has been working with hydrogen for years.^[quantify].

Iceland

Iceland has committed to becoming the world's first hydrogen economy by the year 2050. Iceland is in a unique position. Presently,^[when?] it imports all the petroleum products necessary to power its automobiles and fishing fleet. Iceland has large geothermal resources, so much that the local price of electricity actually is lower than the price of the hydrocarbons that could be used to produce that electricity.

Iceland already converts its surplus electricity into exportable goods and hydrocarbon replacements. In 2002, it produced 2,000 tons of hydrogen gas by electrolysis, primarily for the production of ammonia (NH₃) for fertilizer. Ammonia is produced, transported, and used throughout the world, and 90% of the cost of ammonia is the cost of the energy to produce it.

Neither industry directly replaces hydrocarbons. Reykjavík, Iceland, had a small pilot fleet of city buses running on compressed hydrogen, and research on powering the nation's fishing fleet with hydrogen is under way (for example by companies as Icelandic New Energy). For more practical purposes, Iceland might process imported oil with hydrogen to extend it, rather than to replace it altogether.

The Reykjavík buses are part of a larger program, HyFLEET:CUTE, operating hydrogen fueled buses in eight European cities. HyFLEET:CUTE buses were also operated in Beijing, China and Perth, Australia (see below). A pilot project demonstrating a hydrogen economy is operational on the Norwegian island of Utsira. The installation combines wind power and hydrogen power. In periods when there is surplus wind energy, the excess power is used for generating hydrogen by electrolysis. The hydrogen is stored, and is available for power generation in periods when there is little wind.^{[citation needed]}

India

India is said to adopt hydrogen and H-CNG, due to several reasons, amongst which the fact that a national rollout of natural gas networks is already taking place and natural gas is already a major vehicle fuel. In addition, India suffers from extreme air pollution in urban areas. According to some estimates, nearly 80% of India's hydrogen is projected to be green, driven by cost declines and new production technologies.

Currently however, hydrogen energy is just at the Research, Development and Demonstration (RD&D) stage. As a result, the number of hydrogen stations may still be low, although much more are expected to be introduced soon.

Saudi Arabia

Saudi Arabia as a part of the NEOM project, is looking to produce roughly 1.2 million tonnes of green ammonia a year, beginning production in 2025.

Turkey

The Turkish Ministry of Energy and Natural Resources and the United Nations Industrial Development Organization created the International Centre for Hydrogen Energy Technologies (UNIDO-ICHET) in Istanbul in 2004 and it ran to 2012. In 2023 the ministry published a Hydrogen Technologies Strategy and Roadmap.

United Kingdom

The UK started a fuel cell pilot program in January 2004, the program ran two Fuel cell buses on route 25 in London until December 2005, and switched to route RV1 until January 2007. The Hydrogen Expedition is currently working to create a hydrogen fuel cell-powered ship and using it to circumnavigate the globe, as a way to demonstrate the capability of hydrogen fuel cells. In August 2021 the UK Government claimed it was the first to have a Hydrogen Strategy and produced a document.

In August 2021, Chris Jackson quit as chair of the UK Hydrogen and Fuel Cell Association, a leading hydrogen industry association, claiming that UK and Norwegian oil companies had intentionally inflated their cost projections for blue hydrogen in order to maximize future technology support payments by the UK government.

United States

Several domestic U.S. automobile companies have developed vehicles using hydrogen, such as GM and Toyota. However, as of February 2020, infrastructure for hydrogen was underdeveloped except in some parts of California. The United States have their own hydrogen policy.^{[citation needed]} A joint venture between NREL and Xcel Energy is combining wind power and hydrogen power in the same way in Colorado. Hydro in Newfoundland and Labrador are converting the current wind-diesel Power System on the remote island of Ramea into a Wind-Hydrogen Hybrid Power Systems facility.

A similar pilot project on Stuart Island uses solar power, instead of wind power, to generate electricity. When excess electricity is available after the batteries are fully charged, hydrogen is generated by electrolysis and stored for later production of electricity by fuel cell. The US also have a large natural gas pipeline system already in place.