{"id":152906,"date":"2024-11-04T07:29:00","date_gmt":"2024-11-04T06:29:00","guid":{"rendered":"https:\/\/renewable-carbon.eu\/news\/?p=152906"},"modified":"2024-10-29T13:04:50","modified_gmt":"2024-10-29T12:04:50","slug":"are-hydrogen-engines-truly-zero-emissions","status":"publish","type":"post","link":"https:\/\/renewable-carbon.eu\/news\/are-hydrogen-engines-truly-zero-emissions\/","title":{"rendered":"Are Hydrogen Engines Truly Zero Emissions?"},"content":{"rendered":"\n\n\n

Internal combustion engines (ICE) but without the emissions. The idea is certainly\u00a0appealing. Keeping the same internal combustion engines (ICE) that have powered cars,\u00a0buses, and trucks for well over a century, but eliminating the damaging and climate-affecting emissions that escape from the tailpipe. Currently, electrification is the primary\u00a0route to decarbonizing transportation, but battery electric solutions bring many challenges,\u00a0meaning adoption is likely to be a slow process – IDTechEx estimates that 11% of all car\u00a0sales in 2023 were fully electric.<\/strong>
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Could engines running on hydrogen keep the best of both worlds, familiar and mature ICE\u00a0technology with zero emissions? IDTechEx\u2019s report, \u201cHydrogen Internal Combustion\u00a0Engines 2025-2045: Applications, Technologies, Market Status and Forecasts<\/a>\u201d, explores\u00a0the emissions credentials of this potentially disruptive technology.<\/p>\n\n\n

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\"An
An overview of the chemical reactions involved in a petrol\/diesel engine, hydrogen engine,\u00a0and hydrogen fuel cell. The lack of carbon in combustion within hydrogen engines\u00a0eliminates CO2<\/sub>\u00a0emissions (apart from trace amounts from motor oil). \u00a9 IDTechEx<\/figcaption><\/figure><\/div>\n\n\n


A carbon-free fuel, so no carbon in the exhaust?<\/h3>\n\n\n\n

Combustion is a high-temperature chemical reaction between a fuel and an oxidant (in the\u00a0case of engines, this is atmospheric oxygen). In a conventional ICE fuelled by petrol or\u00a0diesel, the hydrocarbon reacts with oxygen and nitrogen in the air at high temperatures to\u00a0produce heat, water vapor, carbon dioxide, and nitrous oxides. No carbon is present in the\u00a0chemical reaction when switching to a pure hydrogen fuel; therefore, no CO2<\/sub>\u00a0is formed\u00a0and emitted into the atmosphere. There is a slight caveat to this zero CO2<\/sub>\u00a0however.\u00a0IDTechEx research indicates that a small amount of motor oil will be burned in an ICE.\u00a0Motor oil is essential to lubricate the intricate moving parts and prevent damage from\u00a0metal-metal contact. Most engines will burn a small amount of oil due to leakages or\u00a0blowback in the system, and as all motor oils currently in use are hydrocarbon-based, this\u00a0does lead to a small amount of CO2<\/sub>\u00a0being produced. However, when compared to the\u00a0amount of CO2<\/sub>\u00a0emitted by a conventional ICE, the amount is negligible. IDTechEx\u00a0estimates that less than 1kg of CO2<\/sub>\u00a0would be produced per 1,000 miles from burning\u00a0motor oil in an H2<\/sub>ICE vehicle, compared with 272kg in a conventional ICE. Thus, an\u00a0H2<\/sub>ICE would have around 99.7% less CO2<\/sub>\u00a0emissions than a conventional ICE.<\/p>\n\n\n

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IDTechEx research outlines the key engine parameters and the impacts these have\u00a0downstream on thermal NOx formation. NOx is a key pollutant of concern regarding\u00a0H2ICE, and tailpipe emissions must be kept as low as possible for H2ICE to offer credible\u00a0emissions reductions. \u00a9 IDTechEx<\/figcaption><\/figure><\/div>\n\n\n



Nitrous oxides pose the greatest challenge<\/h3>\n\n\n\n

While there is no carbon in the fuel, the combustion of hydrogen causes very high\u00a0temperatures in the combustion chamber, and this does lead to nitrous oxide formation.\u00a0Nitrous oxides (NOx<\/sub>) have been recognized as greenhouse gases (GHGs) and harmful to\u00a0air quality for decades. Increasingly strict regulations on the permissible tailpipe emissions\u00a0of NOx<\/sub> have been implemented globally as the harms of NOx<\/sub> have become more\u00a0apparent. For H2<\/sub>ICE to have credible emissions reductions, it must also show that it can\u00a0reduce NOx<\/sub> emissions substantially. The formation of thermal NOx<\/sub> (NOx<\/sub> formed in high-temperature combustions) is a highly complex interplay of factors and engine parameters.

IDTechEx breaks down each of these factors in turn within the report, examining the latest\u00a0academic research and industry trends such as:<\/p>\n\n\n\n