Agricultural energy analysis and better energy use efficiency will contribute to sustainable development, adaptation to climate change and ensure maintainable production. A case study from Hau Giang province agriculture energy was conducted to compare the cultivation of paddy rice (PR) and upland crops, including corn, mungbean (MB), and black sesame (BS). The life cycle assessment methodology was used to estimate energy consumption and biomass energy production. Based on input-output energy inventoried results, the energy use efficiency, energy productivity, specific energy, and net energy were analyzed. Selected crops require 39,501–59,638 MJ ha^–1 crop^–1 that was higher than energy providing for PR. Crop cultivation required a large amount of energy from fossil fuels and electricity (12,946–34,375 MJ ha^–1 crop^–1). Biomass production achieved 779,670 MJ ha^–1 crop^–1 through corn cultivation, follow by rice farming (198,723 MJ ha^–1 crop^–1), BS and BS production (103,292 and 63,012 MJ ha^–1 crop^–1, respectively). Corn and PR reached the best energy analysis index because of their high biomass production. This study’s results underlined the benefit of net energy from agricultural systems case study in Hau Giang province (19,380–720,032 MJ ha^–1 crop^–1).