This study investigated the energy characteristics of a 100 hp-class agricultural tractor under representative agricultural operations using field-measured workload data and a scenario-based energy analysis framework. Six representative operations, including moldboard plowing, subsoiling, rotary tillage, baler operation, transport operation, and loader operation, were analyzed to evaluate operation-level energy characteristics under realistic agricultural conditions. The results showed that tractor energy demand varied substantially depending on the workload characteristics of each task. Traction-intensive operations exhibited sustained high-power demand, whereas rotary tillage showed the highest specific energy consumption (SEC) because of continuous power take-off (PTO)-driven operation. Utility-oriented operations generally exhibited lower SEC values than traction- and PTO-intensive operations. Scenario-based analysis further demonstrated that workload composition strongly influenced annual energy use (AEU). The traction-intensive scenario exhibited the highest AEU, whereas the utility-oriented scenario showed the lowest cumulative annual energy demand. Sensitivity analysis revealed that annual operating hours had an approximately proportional influence on AEU across all scenarios. The proposed framework provides a practical basis for evaluating workload-dependent tractor energy characteristics and offers useful insights for future agricultural tractor electrification strategies.