{"id":41359,"date":"2024-10-27T16:35:33","date_gmt":"2024-10-27T12:35:33","guid":{"rendered":"https:\/\/autoscommunity.com\/?p=41359"},"modified":"2024-10-27T16:37:40","modified_gmt":"2024-10-27T12:37:40","slug":"are-hydrogen-engines-truly-zero-emissions","status":"publish","type":"post","link":"https:\/\/autoscommunity.com\/2024\/10\/27\/are-hydrogen-engines-truly-zero-emissions\/","title":{"rendered":"Are Hydrogen Engines Truly Zero Emissions?"},"content":{"rendered":"

Internal combustion engines (ICE) but without the emissions. The idea is certainly appealing. Keep the same internal combustion engines (ICE) that have powered cars, buses, and trucks for over a century, but eliminate the damaging and climate-affecting emissions that escape from the tailpipe.<\/strong><\/p>\n

Electrification is currently the primary route to decarbonizing transportation. Still, battery-electric solutions present many challenges, meaning adoption is likely to be slow. IDTechEx<\/a> estimates that 11% of all car sales in 2023 were fully electric.<\/p>\n

Could engines run on hydrogen offer the best of both worlds: familiar and mature ICE technology with zero emissions? IDTechEx\u2019s report, \u201cHydrogen Internal Combustion Engines 2025-2045: Applications, Technologies, Market Status and Forecasts<\/a>,\u201d<\/span>\u00a0explores the emissions credentials of this potentially disruptive technology.<\/p>\n

No Carbon in the Exhaust?<\/h5>\n

Combustion is a high-temperature chemical reaction between a fuel and an oxidant (in the case of engines, this is atmospheric oxygen). In a conventional ICE fuelled by petrol or diesel, the hydrocarbon reacts with oxygen and nitrogen in the air at high temperatures to produce heat, water vapour, carbon dioxide, and nitrous oxides.<\/p>\n

No carbon is present in the chemical reaction when switching to a pure hydrogen fuel, so no CO2<\/sub><\/a> is formed and emitted into the atmosphere. However, there is a slight caveat to this zero CO2 level. IDTechEx research indicates that a small amount of motor oil will be burned in an ICE.<\/p>\n

Motor oil is essential to lubricate the intricate moving parts and prevent damage from metal-metal contact. Most engines will burn a small amount of oil due to leakages or blowback in the system, and as all motor oils currently in use are hydrocarbon-based, this does lead to a small amount of CO2<\/sub>\u00a0being produced.<\/p>\n

However, the amount of CO2 emitted by a conventional ICE\u00a0is negligible. IDTechEx<\/a> estimates less than 1kg of CO2<\/sub> would be produced per 1,000 miles from burning motor oil in an H2ICE vehicle, compared with 272 kilograms in a conventional ICE. Thus, an H2ICE would have around 99.7% less CO2<\/sub> emissions than a traditional ICE.<\/p>\n

\"IDTechEx
IDTechEx research outlines the key engine parameters and the impacts these have downstream on thermal NOx formation. NOx is a key pollutant of concern regarding H2ICE, and tailpipe emissions must be kept as low as possible for H2ICE to offer credible emissions reductions. Source: IDTechEx<\/figcaption><\/figure>\n
Nitrous Oxides Pose the Greatest Challenge<\/h5>\n

While the fuel contains no carbon, hydrogen combustion causes high temperatures in the combustion chamber, forming nitrous oxide. Nitrous oxides (NOx) have been recognized as greenhouse gases (GHGs) and harmful to air quality for decades.<\/p>\n

As the harms of NOx have become more apparent, increasingly strict regulations on the permissible tailpipe emissions of NOx have been implemented globally. For H2ICE to have credible emissions reductions, it must also show that it can reduce NOx emissions substantially. The formation of thermal NOx (NOx formed in high-temperature combustions) is a highly complex interplay of factors and engine parameters.<\/p>\n

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