Dwindling oil supplies in the face of growing demand have accelerated interest in developing biomass-based systems for the production of bioenergy, biofuels and bioproducts. The current global focus on sustainable development and the goal to transition from a fossil fuel-based to a renewable-based economy brings with it the challenge of assessing the sustainability of the wide array of different potential systems. Not only are we asked to assess the sustainability of existing systems, we must also assess the sustainability of proposals for individual bioenergy plants through entire systems that encompass production of biomass though its conversion to energy and product delivery to consumers. Current concerns about the impact of growing biomass for energy on food security in the poorest regions of the world intensifies the need for reliable, manageable, comprehensive approaches to assessing the sustainability of biomass systems at all scales (UN-Energy 2007).