THE TRANSITION TO RENEWABLE ENERGY: IMPLICATIONS FOR THE ENERGY-WATER NEXUS

The transition from fossil fuels to renewable (solar, wind, hydropower) energy sources will reduce the world’s carbon footprint but also bring about major changes in the water footprint associated with power generation. The water footprint of energy production is not restricted to the direct water withdrawal and consumption through the life cycle of energy production (e.g., mining/hydraulic fracturing, processing, cooling thermoelectric plants), but also includes water quality degradation. Due to the high levels of contaminants, the release of even small volume of the wastewater from fossil fuels (e.g., oil produced water, shale flowback water, coal ash effluents) through spills, leaks, or inadequate management to the environment severely affects the water quality of the receiving water and thus induces a large impaired-water intensity, which commonly is not evaluated in the energy-water nexus paradigm. Water quality degradation associated with decades of fossil fuels utilization has generated large losses of clean water volumes beyond the direct water use. Likewise, mining, processing, and recycling of critical raw materials needed from renewable energy will introduce new frontiers for the energy-water nexus. On one hand, the water footprint of renewable energy sources is typically much lower than that of fossil fuels, and therefore, electricity generated from solar and wind utilizes much lower water volumes. For example, installation of rooftop photovoltaic (PV) solar in the U.S. can significantly reduce the water footprint of the electricity sector in the U.S. On the other hand, water use for mining of critical raw materials such as lithium, particularly in arid regions like the Lithium Triangle in South America and Western U.S., induces new risks that can exacerbate the local water stress. In addition, contaminants in liquid and solid wastes generated from lithium mining and processing pose additional risks to the quality of nearby water resources. This presentation highlights current research of water resources associated with the legacy of a hard rock lithium mine in North Carolina and wastewater from the lithium mining and lithium-carbonate processing in the Salar de Uyuni in Bolivia that aims to characterize and delineate the potential contaminants from lithium extraction.