Mass spectrometry (MS) has become an indispensable tool for the detailed chemical analysis of materials used in energy production, spanning both traditional fossil fuels and modern renewable alternatives. This review explores advanced ionization sources and ultrahigh-resolution MS technologies in analyzing energy materials such as petroleum, biomass, biofuels, and bio-oil. Highlighted ionization techniques include electrospray ionization, atmospheric pressure chemical ionization, atmospheric pressure photoionization, laser desorption/ionization, and matrix-assisted laser desorption/ionization, all crucial for qualitative and quantitative assessments, as well as ultrahigh-resolution Fourier transform ion cyclotron resonance and Orbitrap mass analyzers. This review underscores the remarkable compositional detail achievable with state-of-the-art MS systems, providing molecular-level insights vital for advancing energy sectors. Introducing the concept of harvesting MS, we illustrate how these techniques can overcome challenges and optimize energy operations. Through case studies, this article highlights how these insights enhance energy production efficiency and sustainability, paving the way for future innovations.