here<\/a>.\u00a0But if you first want to learn more about why there are so many colours of hydrogen, keep on reading.<\/p>\nThe hydrogen colour spectrum<\/h2>\n
Hydrogen is a colourless gas. It\u2019s the most abundant element in the Universe, but it rarely occurs naturally as a gas on Earth. Instead, it combines with many elements to form molecules that are important for life, like water.<\/p>\n
All the hydrogen used by the energy industry is always produced in some way. The energy industry uses different colours to describe what source of energy has been used in the hydrogen production.<\/p>\n
\u201cYou need a primary source of energy to produce hydrogen \u2013 for example solar, wind or nuclear power. Some forms of hydrogen production create CO\u2082 as a by-product, and it makes a world of difference what is done with the CO\u2082,\u201d Rintam\u00e4ki explains.<\/p>\n
Green hydrogen\u00a0is the cleanest option. It is produced from water via electrolysis with renewable electricity, without any CO\u2082 as a by-product.\u00a0Blue hydrogen\u00a0is produced by splitting fossil natural gas into hydrogen and CO\u2082 and then capturing and storing the CO\u2082.\u00a0Grey hydrogen\u00a0is created the same way as blue hydrogen, however the carbon dioxide is not captured but released into the atmosphere.\u00a0Pink hydrogen\u00a0is made via electrolysis using nuclear power.<\/p>\n
What about brown, black, white and yellow hydrogen?<\/h2>\n
\u201cTransforming coal into gas is the oldest way of producing hydrogen. The end product is called either brown or black hydrogen. It\u2019s a highly polluting process that releases CO\u2082 in the atmosphere \u2013 and thus not described in our dictionary of future fuels,\u201d Rintam\u00e4ki says.<\/p>\n
\u201cWhite hydrogen refers to the naturally occurring hydrogen on Earth, while yellow hydrogen is simply one type of green hydrogen. It is called yellow because it is created solely with solar power. At W\u00e4rtsil\u00e4 Energy, we try to keep things simple, and just speak about the four main types of hydrogen: green, blue, grey and pink,\u201d he concludes.<\/p>\n
Terminology<\/h2>\nGreen hydrogen<\/h3>\n
Green hydrogen is produced by splitting water via electrolysis, which produces only hydrogen and oxygen. However, the electrolysis process requires electricity. For hydrogen to be labelled green, the electricity used in production must come from renewable energy sources, like solar, wind or hydropower. Green hydrogen is sometimes also called\u00a0renewable hydrogen.<\/p>\n
Blue hydrogen<\/h3>\n
Blue hydrogen is produced by splitting fossil natural gas into hydrogen and CO\u2082 \u2013 and then capturing, storing, or reusing the CO\u2082 to mitigate environmental impacts. Blue hydrogen is sometimes also called\u00a0low carbon hydrogen.<\/p>\n
Grey hydrogen<\/h3>\n
Most hydrogen nowadays comes from fossil natural gas. Grey hydrogen is produced the same way as blue hydrogen: by splitting natural gas into hydrogen and CO\u2082. Hydrogen is called\u00a0grey\u00a0whenever the excess CO\u2082 is not captured. Grey hydrogen is sometimes also called\u00a0fossil hydrogen.<\/p>\n
Pink hydrogen<\/h3>\n
Pink hydrogen is made from water via electrolysis just like green hydrogen but using nuclear energy as its source of power. Nuclear-produced pink hydrogen is sometimes also called\u00a0purple hydrogen\u00a0or\u00a0red hydrogen.<\/p>\n
Power-to-X technology<\/h3>\n
\u2018Power-to-X\u2019 is used as an umbrella term for various emerging technology solutions for electricity conversion, energy storage, and energy reconversion, all of which use renewable electricity to produce for example synthetic fuels.<\/p>\n
Power-to-X technology essentially means turning energy into something else. For instance, renewable electricity can be turned into synthetic natural gas by combining CO\u2082 captured from the air and hydrogen.<\/p>\n
Direct air capture<\/h3>\n
Direct air capture (DAC) is a process that extracts CO\u2082 directly from the air. The captured CO\u2082 can then be converted to many products that normally originate from fossil materials.<\/p>\n
Currently, frontrunner DAC technology can be used for example in an office building\u2019s ventilation to reduce CO\u2082 levels inside the building. In the future, DAC may be used on an industrial scale to filter excess carbon dioxide out of the air.<\/p>\n
Methanisation<\/h3>\n
Methanisation is a process that uses renewable electricity to combine hydrogen and CO\u2082, turning it into methane. Currently most of the methane used for heating, transport and power generation is fossil. Methanisation \u2013 also called Power-to-Gas \u2013 provides a carbon neutral alternative.<\/p>\n
Synthetic fuels (eFuels)<\/h3>\n
Synthetic fuels are not the same thing as fossil fuels, which are a finite resource. Synthetic fuels, or eFuels, are created by generating fuel from CO\u2082. In synthetic fuel production, CO\u2082 is used as a raw material for creating for example gasoline, diesel, and substitute natural gas, together with electricity from renewable sources and hydrogen.<\/p>\n
Carbon neutral vs carbon negative<\/h3>\n
Energy is carbon neutral if the amount of CO\u2082 emissions released into the atmosphere during energy production is the same as the amount of CO\u2082 emissions removed from the atmosphere during the process. If the amount of CO\u2082 emissions removed during energy production is greater than the emissions released, energy is labelled carbon negative.<\/p>\n
Net zero<\/h3>\n
Energy is net zero, if the\u00a0CO\u2082\u00a0emissions generated during energy production are offset by the same amount of\u00a0CO\u2082 elsewhere, for example through reforestation schemes, making the \u201cnet total\u201d of emissions zero.\u00a0Net zero carbon emissions are considered a synonym for carbon neutrality.<\/p>\n
Carbon free<\/h3>\n
When energy sources are labelled carbon free, the energy is produced by a resource that generates no carbon emissions.\u00a0Examples include\u00a0solar and wind energy \u2013 or when speaking about fuels, hydrogen and ammonia.<\/p>\n
Hydrogen blends<\/h3>\n
Hydrogen blending refers to blending natural gas with hydrogen. The blend can then be used by the conventional end-users of natural gas to generate power and heat, as long as the technology itself allows it. Using hydrogen blends may require some adjustments to the technology \u2013 especially when talking about higher shares of hydrogen. At present, hydrogen blending is at a fairly early stage of development, but it is a promising option for expanding the use of hydrogen to reduce the environmental impact of natural gas.<\/p>\n
Decarbonisation<\/h3>\n
Decarbonisation refers to reducing or removing CO\u2082 emissions for example through reducing or stopping the use of fossil fuels, switching to cleaner fuels, and using electric vehicles in transportation.<\/p>\n
In the energy industry, decarbonisation means reducing \u2018carbon intensity\u2019 i.e., cutting or eliminating the emissions per unit of electricity generated (grams of carbon dioxide per kilowatt-hour).<\/p>\n
Decarbonisation is needed to mitigate or reverse climate change and lowering the CO\u2082 levels in the atmosphere.<\/p>\n
Hydrogen economy<\/h3>\n
The hydrogen economy is an envisioned future, in which hydrogen delivers a substantial fraction of a nation\u2019s energy. In a hydrogen economy, hydrogen would be used both as a fuel and an energy carrier to help offset fluctuations in solar and wind power production and consumption.<\/p>\n
Future fuels<\/h3>\n
Future fuels refer to a wide range of promising, carbon-neutral fuels, which can be used to advance decarbonisation. Future fuels include, for example, green hydrogen and hydrogen-based fuels such as synthetic methane, ammonia, and methanol, as well as bio and synthetic liquefied natural gas (LNG).<\/p>\n<\/div>\n<\/div>\n<\/div>\n
Text: Joanna Sinclair<\/strong><\/div>\nPhoto:\u00a0 W\u00e4rtsil\u00e4<\/strong><\/div>\n<\/div>\n<\/div>\n<\/section>\n<\/div>\n\n
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