IRENA's World Energy Transitions Outlook presents a comprehensive and cost-effective pathway to limit global average surface temperature rise to 1.5°C above pre-industrial levels by 2050. To achieve this, it is necessary to decarbonise all sectors of the economy by around mid-century. However, there are currently sectors that are hard to decarbonise - namely heavy-duty trucks, shipping, aviation, iron and steel, and chemicals and petrochemicals. These sectors alone represent a quar