Difference between revisions of "Green Hydrogen"
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It is very clean-burning and when combined with oxygen in a fuel cell, hydrogen produces heat and electricity with only water vapor as a by-product.<ref>https://www.nrel.gov/research/eds-hydrogen.html </ref> | It is very clean-burning and when combined with oxygen in a fuel cell, hydrogen produces heat and electricity with only water vapor as a by-product.<ref>https://www.nrel.gov/research/eds-hydrogen.html </ref> | ||
=== Production of Hydrogen === | === Production of Hydrogen === | ||
| − | There are different methods of hydrogen production, which determines how climate-friendly the hydrogen is. There is a color scheme used to distinct these different production methods:<ref>https://www.weforum.org/agenda/2021/12/what-is-green-hydrogen-expert-explains-benefits/</ref><ref>https://www.eia.gov/energyexplained/hydrogen/production-of-hydrogen.php</ref><ref>[https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2020/Nov/IRENA_Green_hydrogen_policy_2020.pdf IRENA (2020), Green Hydrogen: A guide to policy making]</ref><ref><nowiki>https://cleantechnica.com/2021/10/14/hydrogen-heating-cooking-would-cost-homeowners-100000-extra-over-15-years/</nowiki> </ref> | + | There are different methods of hydrogen production, which determines how climate-friendly the hydrogen is. There is a color scheme used to distinct these different production methods:<ref>https://www.weforum.org/agenda/2021/12/what-is-green-hydrogen-expert-explains-benefits/</ref><ref>https://www.eia.gov/energyexplained/hydrogen/production-of-hydrogen.php</ref><ref name=":1">[https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2020/Nov/IRENA_Green_hydrogen_policy_2020.pdf IRENA (2020), Green Hydrogen: A guide to policy making]</ref><ref><nowiki>https://cleantechnica.com/2021/10/14/hydrogen-heating-cooking-would-cost-homeowners-100000-extra-over-15-years/</nowiki> </ref> |
* '''Grey hydrogen is''' produced by splitting fossil fuels like methane (CH<sub>4</sub>) (sourced from natural gas) or coal with steam into H<sub>2</sub> and CO<sub>2</sub>. '''Every ton of hydrogen produced from natural gas also produces 8–10 tons of CO<sub>2</sub>'''. Since hydrogen produced from coal produces significantly higher CO<sub>2</sub> emissions (20-35x), it is sometimes also called brown or black hydrogen instead of grey. | * '''Grey hydrogen is''' produced by splitting fossil fuels like methane (CH<sub>4</sub>) (sourced from natural gas) or coal with steam into H<sub>2</sub> and CO<sub>2</sub>. '''Every ton of hydrogen produced from natural gas also produces 8–10 tons of CO<sub>2</sub>'''. Since hydrogen produced from coal produces significantly higher CO<sub>2</sub> emissions (20-35x), it is sometimes also called brown or black hydrogen instead of grey. | ||
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| + | '''Global production numbers''' | ||
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| + | According to IRENA, each year 120 million tons of hydrogen are produced globally, mostly based on natural gas and coal (95% of production)<ref name=":1" />. 5% of the global hydrogen production is produced by electrolysis but not with renewable energy sources. Only 0.02% of today’s pure hydrogen production is coming from renewable sources.<ref>IRENA (2020): [https://irena.org/-/media/Files/IRENA/Agency/Publication/2020/Dec/IRENA_Green_hydrogen_cost_2020.pdf Green Hydrogen Cost Reduction: Scaling up Electrolysers to Meet the 1.5⁰C Climate Goal]</ref> | ||
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| + | '''Production of Green Hydrogen''' | ||
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| + | The production of green hydrogen not only needs renewable electricity but requires fresh water. To produce one ton of hydrogen, 9,000 liters of water must be consumed.<ref name=":2">https://www.rechargenews.com/energy-transition/vast-majority-of-green-hydrogen-projects-may-require-water-desalination-potentially-driving-up-costs/2-1-1070183</ref> | ||
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| + | Since the optimal production sites for green hydrogen are often located in water-scarce areas, ensuring environmentally sustainable water extraction and consumption practices is essential to scale up and maintain global production capacity.<ref>https://www.powerfuels.org/news/veranstaltungen/2021/water-consumption-for-the-production-of-green-hydrogen/</ref> In areas with access to sea water, one solution could be to desalinate water which, however, would need an additional 1kWh of electricity per m<sup>3</sup> of purified water.<ref name=":2" /> | ||
| + | |||
| + | Overview on Hydrogen production and energy generated: | ||
| + | {| class="wikitable" | ||
| + | | rowspan="3" |One ton of hydrogen needs | ||
| + | |9000 l of water for electrolysis | ||
| + | |- | ||
| + | |50 MWh for PEM and Alkaline electrolysis<ref name=":3">https://www.carboncommentary.com/blog/2021/6/11/some-rules-of-thumb-of-the-hydrogen-economy</ref> | ||
| + | |- | ||
| + | |(9 MWh additional need in case of water needs to be desalinated, resulting total energy demand of 59 MWh) | ||
| + | |- | ||
| + | |One ton of hydrogen generates | ||
| + | |33.3 MWh of electricity<ref name=":3" /> | ||
| + | |} | ||
Revision as of 10:03, 3 November 2022
work in progress
Overview
Falling costs for hydrogen produced with renewable energy, combined with the urgency of cutting greenhouse-gas emissions, has given clean hydrogen unprecedented political and business momentum. Its potential role for the energy transition and the road to net zero has raised high expectations over the last years and months.
This article sheds light on (green) hydrogen, its use, market and costs, as well as its advantages and disadvantages.
What is Hydrogen?
Hydrogen (H2) is the simplest and lightest element as well as the most abundant element in the universe. Each atom of hydrogen has only one proton and one electron. Hydrogen occurs naturally on earth only in compound form with other elements in liquids, gases, or solids. Hydrogen combined with carbon (hydrocarbons) exists in petroleum, natural gas, and coal. Hydrogen combined with oxygen is water (H2O).[1][2]
As a secondary source of energy, hydrogen carries energy produced from other resources like fossil fuels, water, or biomass. To produce hydrogen by separating it from other elements (electrolysis), it needs more energy than hydrogen provides when converted to useful energy. Hydrogen has the highest energy content of any common fuel by weight (about three times more than gasoline), but it has the lowest energy content by volume (about four times less than gasoline). [1]
It is very clean-burning and when combined with oxygen in a fuel cell, hydrogen produces heat and electricity with only water vapor as a by-product.[3]
Production of Hydrogen
There are different methods of hydrogen production, which determines how climate-friendly the hydrogen is. There is a color scheme used to distinct these different production methods:[4][5][6][7]
- Grey hydrogen is produced by splitting fossil fuels like methane (CH4) (sourced from natural gas) or coal with steam into H2 and CO2. Every ton of hydrogen produced from natural gas also produces 8–10 tons of CO2. Since hydrogen produced from coal produces significantly higher CO2 emissions (20-35x), it is sometimes also called brown or black hydrogen instead of grey.
- Blue hydrogen is produced as well by splitting methane or coal with steam, but unlike grey hydrogen, most (not all) CO2 emissions are captured and stored for reducing its climate impact.
- Turquoise hydrogen: using processes such as pyrolysis, the methane is split into H2 and solid carbon black which can be more easily stored. At the moment, turquoise hydrogen is still at the pilot stage.
- Green hydrogen is produced by splitting water into hydrogen and oxygen using renewable electricity. No emissions occur.
Besides this color scheme, sometimes the wording “low-carbon hydrogen” is used. This refers to both green hydrogen and blue hydrogen, see IEA (2022): Africa Energy Outlook.
Global production numbers
According to IRENA, each year 120 million tons of hydrogen are produced globally, mostly based on natural gas and coal (95% of production)[6]. 5% of the global hydrogen production is produced by electrolysis but not with renewable energy sources. Only 0.02% of today’s pure hydrogen production is coming from renewable sources.[8]
Production of Green Hydrogen
The production of green hydrogen not only needs renewable electricity but requires fresh water. To produce one ton of hydrogen, 9,000 liters of water must be consumed.[9]
Since the optimal production sites for green hydrogen are often located in water-scarce areas, ensuring environmentally sustainable water extraction and consumption practices is essential to scale up and maintain global production capacity.[10] In areas with access to sea water, one solution could be to desalinate water which, however, would need an additional 1kWh of electricity per m3 of purified water.[9]
Overview on Hydrogen production and energy generated:
| One ton of hydrogen needs | 9000 l of water for electrolysis |
| 50 MWh for PEM and Alkaline electrolysis[11] | |
| (9 MWh additional need in case of water needs to be desalinated, resulting total energy demand of 59 MWh) | |
| One ton of hydrogen generates | 33.3 MWh of electricity[11] |
References
- ↑ 1.0 1.1 https://www.eia.gov/energyexplained/hydrogen/
- ↑ https://www.britannica.com/science/hydrogen
- ↑ https://www.nrel.gov/research/eds-hydrogen.html
- ↑ https://www.weforum.org/agenda/2021/12/what-is-green-hydrogen-expert-explains-benefits/
- ↑ https://www.eia.gov/energyexplained/hydrogen/production-of-hydrogen.php
- ↑ 6.0 6.1 IRENA (2020), Green Hydrogen: A guide to policy making
- ↑ https://cleantechnica.com/2021/10/14/hydrogen-heating-cooking-would-cost-homeowners-100000-extra-over-15-years/
- ↑ IRENA (2020): Green Hydrogen Cost Reduction: Scaling up Electrolysers to Meet the 1.5⁰C Climate Goal
- ↑ 9.0 9.1 https://www.rechargenews.com/energy-transition/vast-majority-of-green-hydrogen-projects-may-require-water-desalination-potentially-driving-up-costs/2-1-1070183
- ↑ https://www.powerfuels.org/news/veranstaltungen/2021/water-consumption-for-the-production-of-green-hydrogen/
- ↑ 11.0 11.1 https://www.carboncommentary.com/blog/2021/6/11/some-rules-of-thumb-of-the-hydrogen-economy
