There is on average about 9.8 kilowatt-hours (kWh) of energy in a liter of diesel. This is a rough estimate because the exact energy content of diesel can vary depending on various factors, such as the quality of the diesel and environmental conditions. It is important to note that the energy content of diesel can be converted into kilowatts (kW) or kilowatt-hours (kWh) to measure the power output or energy consumption of a specific device or vehicle.