Hydrogen

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Despite being the most abundant element in the universe, practically no hydrogen occurs naturally on Earth as an element (H
2
) rather than part of chemical compounds. Hydrogen can be used as a fuel, where it is regarded as an energy carrier rather than being a source like fossil fuels. Its combustion produces no CO
2
and - depending on how it is used - potentially only water as a waste product.

Generating hydrogen, however, may involve significant carbon emissions (such as generation from natural gas) or conversion from electricity which involves inefficiencies in conversion.

Hydrogen can be stored but it is hard to achieve high energy density. It can be compressed to high pressures and stored in heavy vessels for use in road and rail vehicles, or liquefied at very low temperatures for higher density storage, such as in fuel for space rocket engines. Keeping liquid hydrogen liquefied for any length of time requires power for refrigeration equipment. Hydrogen has the smallest atoms and molecules of all elements and it is very prone to leaking from any containment systems.

Hydrogen can be used as a feedstock for various chemical processes, including the production of Ammonia which is more easily stored and transported, and which can be used either to re-generate Hydrogen, or as a fuel itself, as well as being used for production of horticultural fertilisers.

Overview

A 2006 article by Jeff Wise in Popular Mechanics, "[The Truth About Hydrogen The Truth About Hydrogen]" discusses some of the potential and problems with Hydrogen.

Naturally occurring

Discovery of a large accumulation of natural hydrogen in Bourakebougou (Mali) Alain Prinzhofer, Cheick Sidy Tahara Cissé, Aliou BoubacarDiallo; International Journal of Hydrogen Energy; 18 October 2018

  • A natural hydrogen shallow gas field has been documented in Mali.
  • Several exploratory wells allow to assess a renewable hydrogen accumulation.
  • Hydrogen generation occurs in deeper formations, and accumulated migrating upward.
  • We evidence other potential areas of natural hydrogen accumulations.

Abstract

Recent exploratory wells in Mali (Bourabougou field) targeting natural hydrogen were a success and provide a new understanding of a first test well exploited by PETROMA (Bougou-1), and a comprehension of continental hydrogen functioning systems. Based on extensive gas data of a pioneer well and preliminary geochemical data obtained from a dozen exploratory wells in the vicinity, it is possible to confirm the presence of an extensive hydrogen field featuring at least five stacked reservoir intervals containing significant hydrogen that cover an estimated area well superior to 8 km in diameter. Results underline the potential economic interest of future natural hydrogen exploitation in continental onshore areas. A “hydrogen system” is presented with a kitchen of generation in the cratonic basement. The relatively pure hydrogen reservoirs are associated with traces of methane, nitrogen and helium. The geological stratigraphic accumulation of hydrogen is linked to the presence of multi overlaid doleritic sills and aquifers that seem to play a role to disable upward gas migration and leakage. The occurrence of a mixture of gas and water acting with an artesian activity confirms the presence of over-pressured fluids. This results in a geyser-type eruptive diphasic surface fluid in many of the wells. The “gas lift” system and the presence of traces of highly unstable carbon monoxide is linked to a recent hydrogen gas charge to reservoirs from underground aquifers, erupting with associated water. The Mali wells underscore the non-fossil source of hydrogen gas and presents features of a sustainable energy. The current estimate of its exploitation price is much cheaper than manufactured hydrogen, either from fossil fuels or from electrolysis.

Generation

Apparatus for demonstrating electrolysis

Pathways to hydrogen as an energy carrier THORSTEINN I. SIGFUSSON; Philosophical Transactions of the Royal Society; 1 Feb 2007

When hydrogen is used as an alternative energy carrier, it is very important to understand the pathway from the primary energy source to the final use of the carrier. This involves, for example, the understanding of greenhouse gas emissions associated with the production of hydrogen and throughout the lifecycle of a given utilization pathway as well as various energy or exergy1 efficiencies and aspects involved. This paper which is based on a talk given at the Royal Society in London assesses and reviews the various production pathways for hydrogen with emphasis on emissions, energy use and energy efficiency. The paper also views some aspects of the breaking of the water molecule and examines some new emerging physical evidence which could pave the way to a new and more feasible pathway.

A special attention will be given to the use of the renewable energy pathway. As an example of a hydrogen society that could be based on renewable primary energy, the paper describes the hydrogen society experiments in Iceland as well as unconventional hydrogen obtained from geothermal gases. In the light of our experience, attempts will be made to shed light upon drivers as well as obstacles in the development of a hydrogen society.

The Hebrides electricity to hydrogen project uses excess electricity produced from an existing biogas plant to produce Hydrogen by Alkaline Water Electrolysis.

Converting natural gas to hydrogen without any carbon emissions JOHN TIMMER; Ars Technica; 17 Nov 2017

two new papers out this week suggest we could use natural gas without burning it. They detail efficient methods of converting methane to hydrogen in ways that let us capture much or all of the carbon left over. The hydrogen could then be burned or converted to electricity in a fuel cell—including mobile fuel cells that power cars. The supply obtained from methane could also be integrated with hydrogen from other sources.

Option 1: proton conduction solid proton-conducting electrolyte

Option 2: reactions in liquid metal

Options for producing low-carbon hydrogen at scale by The Royal Society issued Jan 2018 [pdf]

Executive summary

Hydrogen has the potential to play a significant role in tackling climate change and poor air quality. It is not a cure all and should be seen as one of the possible pathways to a low carbon energy future. There are barriers to the realisation of a hydrogen-based economy including: production at scale, infrastructure investments, bulk storage, distribution and safety considerations. There is also the issue of how to create a simultaneous demand and supply for hydrogen technologies. This report sets out the best available evidence as to how hydrogen could be produced at a scale useful to power vehicles, heat homes and be used by industry. In doing so it aims to inform those making decisions in areas such as research and innovation funding and the provision of physical infrastructure. By framing the uncertainties around the future uses of hydrogen, it also aims to inform wider discussion on pathways to a low carbon economy

The briefing gives an indication of the production technologies, the readiness of each technology, the scale of cost for each and provides insights on the likely source of hydrogen at scale in coming decades. Four groups of hydrogen production technologies are examined here in order of technology readiness.

The first group of technologies has at its heart a process known as steam methane reforming, which has been used to produce hydrogen from fossil fuels for decades. The process uses natural gas and steam to produce hydrogen. The technology is well understood and is operated on an industrial scale around the world. Carbon capture and storage will be essential if this method is to be used to produce low-carbon hydrogen. Emerging thermal methods include microwaving hydrocarbons and the conversion of fossil fuels in the ground to avoid carbon dioxide emissions. Biomass gasification with carbon capture also provides a possible route to reduced carbon emissions.

Electrolysis comprises the second group of technologies. This process separates hydrogen from water using electricity in an electrolysis cell. Electrolysis produces pure hydrogen which is ideal for fuel cell electric vehicles. It has a high efficiency though many current facilities are small. This technology shows great potential to be scaled up and used as a way of converting excess electrical energy produced by renewables into hydrogen, which enables energy storage flexibility. Economic viability relies in part on the availability of sources of low carbon, low cost electricity.

The third group is biological methods whose key features are lower operating temperatures and relatively simple technology. These primarily relate to a variation of anaerobic digestion that uses microbes to convert biomass to hydrogen instead of methane, together with emerging biotechnologies that allow a greater hydrogen yield from the original biomass. These microbial processes are being developed at both laboratory scale and at demonstration level and have potential to make a small but valuable contribution to the hydrogen economy. In addition, current research indicates that there is scope for these technologies to play an important role in the production of high value chemicals

The final group of technologies is known as solar to fuels. This technology harnesses sunlight to split water into hydrogen and oxygen and has been referred to as ‘artificial photosynthesis’. Solar to fuels is an active area of scientific innovation, with potential to lead to a disruptive future process; however it is currently a subject of basic research with elements undergoing technological development. There are no current estimates for potential output and questions over ultimate cost and efficiency.

This briefing challenges the established view that steam methane reforming is the only solution to producing hydrogen at scale for the next 30 years. The science presented here, tells a different story. Electrolysis has the potential to be deployed to produce low-carbon hydrogen in the near to mid-term alongside steam methane reforming, provided the challenges above are met.

EDF plans vast hydrogen production at UK nuclear plants' by Andrew Lee in Recharge on 26 Feb 2020 [article]

EDF is looking at plans for massive production of hydrogen to be powered by its fleet of UK nuclear plants, including the giant Hinkley Point C project, Recharge has learned.

A consortium led by the French energy group believes linking electrolysers to nuclear-generated electricity “would produce enough hydrogen to meet a significant portion of the forecasted demand in the UK”, while combining the reliable, baseload output of nuclear with the low-carbon credentials of ‘green hydrogen’ production powered by variable renewables such as offshore wind.

The EDF-led Hydrogen to Heysham (H2H) consortium recently wrapped up a study that concluded the nuclear-powered hydrogen was feasible on technical and safety grounds, with the potential to be scaled-up from a planned demonstrator project at its Heysham 2 nuclear power station in northwest England.

The study said: “EDF Energy’s nuclear new-build project, Sizewell C, which is currently in development, could support the modular installation of large-scale electrolysers. Hinkley Point C, which is already in construction, also presents the same opportunity.”

The 3.2GW Hinkley Point C, being built amid considerable controversy in southwest England, will be the UK’s first new nuclear plant for 20 years when it enters service, currently scheduled for 2025 or later.

The H2H consortium — which includes EDF’s newly-formed Hynamics unit dedicated to commercialising hydrogen technologies — cites a range of advantages for nuclear-powered hydrogen production via electrolysis (the process of splitting water molecules into hydrogen and oxygen using an electric current). They include the stable output of nuclear generation that the researchers reckon will ensure 93% utilisation of the electrolyser and the ability to re-use the other by-product of the process — oxygen — in the nuclear cycle, further adding to its economic case.

The more hours per day that an electrolyser is used, the lower the levelised cost of the hydrogen produced, which makes nuclear-powered hydrogen a potentially cheaper option than green H2 produced from more intermittent wind or solar.

The researchers are planning an initial 2MW system, comprising a 1MW alkaline and 1MW proton exchange membrane (PEM) electrolyser, capable of producing up to 800kg of hydrogen per day and testing the performance of the two main electrolyser technologies.

The report estimated a future electrolyser capacity of about 550MW across its fleet could produce about 220,000kg of hydrogen per day by 2035, with a levelised cost of hydrogen as low as £1.89/kg ($2.44/kg) depending on power price and falling technology costs over a 20-year project cycle.

Recharge reported in January how a new study by the Hydrogen Council and consultant McKinsey reckoned renewable hydrogen’s price will fall to about $1-1.50/kg in optimal locations, and roughly $2-3/kg under average conditions, over the next five to 10 years. The International Energy Agency puts the current price of grey H2 produced from unabated fossil fuels at $1-1.80/kg.

R&D

The US ARPA-e is funding projects to improve electrolyzers for generating hydrogen[1][2]

Uses

Heating

Heating systems: it’s time to talk about hydrogen Molly Lempriere; Power-Technology.com; 2 Aug 2017

Heating and cooling of buildings and in industrial activities account for almost half of all energy demand in the EU, and yet the decarbonisation of the heating system has seen little progress. This is finally changing as cleaner heating continues to be discussed and researched. One popular suggested solution is switching the heating network from natural gas to hydrogen. This was the key topic of conversation at a recent event run by DNV GL. The seminar, entitled ‘Developing and Operating a Safe Hydrogen Network’, brought together around 100 professionals from gas distribution networks and other interested parties to discuss hydrogen’s potential.

BEIS pipes £25m into hydrogen demo for heating Tom Grimwood; Utility Week; 25 Apr 2017

The Department for Business, Energy and Industrial Strategy (BEIS) has revealed plans to pipe £25 million into a new research programme exploring the use of hydrogen for heating. The aims of the demonstration project include defining a hydrogen quality standard and developing and trialling hydrogen fuelled appliances for homes and businesses. The department has launched a £5 million tender to find a contractor to manage the programme, which will run from 2017 to 2020. The tender notice states that the programme will “serve to support and inform future policy appraisal in government and to inform the development of policies and measures to meet UK carbon budgets.”

UK

The H21 North of England (formerly Leeds City Gate) project is "a detailed engineering solution for converting 3.7 million UK homes and businesses from natural gas to hydrogen, in order to reduce carbon emissions". Hydrogen will be generated from natural gas coming ashore from North Sea gas fields, with CO2 being sequestered in underground reservoirs.

Climate change hope for hydrogen fuel Roger Harrabin; BBC; 2 Jan 2020

The natural gas supply at Keele University is being blended with 20% hydrogen in a trial that's of national significance.

Adding the hydrogen will reduce the amount of CO2 that’s being produced through heating and cooking.

As a fuel, hydrogen functions in much the same way as natural gas. So staff in the university canteen say cooking on the 20% hydrogen blend has made no difference to their cooking regime.

The project – known as HyDeploy - is the UK’s first live trial of hydrogen in a modern gas network. Keele was chosen because it has a private gas system.

Its hydrogen is produced in an electrolyser - a device that splits water (H2O) into its constituents: hydrogen and oxygen. The machine is located in a glossy green shipping container in the corner of the university’s sports field.

The gas distribution firm Cadent, which is leading the project, says that if a 20% blend were to be rolled out across Britain, it would reduce emissions of CO2 by six million tonnes - equivalent to taking 2.5 million cars off the road.

The hydrogen could be generated pollution-free by using surplus wind power at night to split water molecules using electrolysis.

Transport

The Hebrides electricity to hydrogen project uses Hydrogen to fuel Postal delivery vehicles.

The HY4 is a four-seater aeroplane powered by electricity generated from Hydrogen in fuel cells. It first flew at Stuttgart airport in Germany in 2016.