To determine the energy output of a diesel generator, you can use the following formula:
```
Energy Output (kWh) = Power Output (kW) x Operating Time (hours)
```
For example, if you have a 10 kW diesel generator that you operate for 8 hours, the energy output would be:
```
Energy Output = 10 kW x 8 hours = 80 kWh
```
This means that the generator produced 80 kilowatt-hours of energy during that 8-hour period.
It's important to note that the actual energy output of a diesel generator can be affected by several factors, including the load it is powering, the efficiency of the generator, and the fuel consumption rate.