The objective of this research is to assess the sustainability of various renewable energy technologies, ranging from small solar panels to utility-scale wind farms. While potential environmental impacts associated with these technologies are broad, the focus here is greenhouse gas (GHG) emissions and freshwater withdrawal. GHG impacts are global in nature; however, for freshwater consumption the environmental carrying capacity is spatially dependent varying widely by location. In this study, eco-efficiency is measured by use of the Sustainability Target Method (STM) to relate economic value to environmental impact and determine an absolute measure for sustainability. The research presented here provides a generic methodology for determining freshwater carrying capacity with an application to New Jersey. Dynamic system simulation is used as a complement to the lifecycle assessment methodology to create a robust technique for analyzing sustainability and eco-efficiency at the system and process level, focusing on energy use and GHG, as well as water consumption.