<p>For off-road vehicles and machines that are often operated under extreme conditions, a&#xa0;mandatory reduction in greenhouse gas emissions is foreseeable in the medium term in addition to the legal requirements for pollutant emissions. To evaluate an effective reduction, both the operation, which must take place without the use of fossil fuels, and the entire life cycle must be considered. In order to achieve these goals, various concepts for the use of renewable fuels and electrical energy exist and are presented in the article. In particular, the direct use of green hydrogen in fuel cells or combustion engines offers great opportunities as they can operate not only CO₂-free, but with extremely low or zero emissions. However, there are still some challenges to overcome in terms of storage, infrastructure, robustness and costs. Some examples such as electric heavy-duty vehicles, fuel cell vehicles, and hybrid solutions with combustion engines, which are both operational and in use as demonstrators, will be presented. It can also be shown that the decisive prerequisite for a&#xa0;real CO₂ reduction is the use of renewable energy and only secondarily the energy converter.</p><p>The choice of the most effective and best-suited propulsion concept depends on the application, framework conditions and infrastructure. An open cross-technology approach is necessary to find the best solutions for use under extreme conditions.</p>