Dissertation Defense Notice - D. Kamath

Mon, December 14, 2020 2:00 PM - Mon, December 14, 2020 4:00 PM at Virtual

Dipti KamathMs. Dipti Kamath will defend her dissertation on December 14, 2020, at 2:00 PM.

Department: Civil & Environmental Engineering and Environmental Science & Policy Program

Title: Prospective Life-Cycle Assessment of Second-Life Electric Vehicle Batteries and Uranium Extraction in the Us

Advisor: Dr. Annick Anctil

Webinar Information: 

Passcode: dkdfns


Large-scale integration of renewable energy in the electricity grid creates issues such as intermittency and lack of load and peak matching. Battery storage and nuclear energy are both low-carbon options that can supplement variable electricity generation and will be necessary for large-scale renewables deployment. However, with changes in resources and technology, it is important to anticipate future issues that might arise with these energy options to ensure the low cost and carbon footprint of electricity. In this dissertation, the main aim is to conduct a prospective life-cycle assessment (LCA) of second-life electric vehicle batteries (SLBs) as energy storage and uranium extraction for nuclear energy in the US.

Current battery technologies, in particular lithium-ion batteries, are expensive and can increase the carbon footprint of the grid, due to charge-discharge losses. A possible cheaper and greener alternative for energy storage is to use remanufactured SLBs from electric vehicles (EVs) that have reached end-of-life (EOL). With the increase in EV sales, a large number of batteries are expected to reach EOL in the near future. Although SLBs can have 70 to 80% of remaining capacity, it is unknown whether they will perform at par with new batteries in various applications. It is also unknown whether SLBs provide cost and carbon emission reduction compared to new batteries, nor is there any information on SLB demand.

Accelerated life testing was conducted on EOL EV battery cells to assess their performance in residential energy storage, commercial fast-charging, and utility-level peak shaving applications. A LCA and an economic evaluation were conducted to calculate the life-cycle carbon footprint and levelized cost of electricity of using SLBs and new batteries in the three applications mentioned above. A system dynamics model was developed to compare the economic and carbon benefits of EV battery recycling and remanufacturing in the US from 2017 to 2050.

Residential energy storage performed the best during the accelerated life testing of battery cells. Using SLBs instead of new batteries can reduce the levelized costs and carbon footprint for all three applications. Remanufacturing reduced the life-cycle carbon footprint of batteries by 2 to 16% compared to recycling only. The economic value of remanufacturing is expected to decrease over time with the decreasing price of new batteries, necessitating policies that can incentivize SLB uptake, given that the SLB market is still emerging.

In contrast, nuclear energy is a mature technology in use since the 1950s. Over time, uranium ore grades have decreased globally, and open-pit and underground mining methods are being replaced by in-situ leaching (ISL)—alkaline and acidic. Alkaline ISL is the most prominent uranium extraction method in the US and is promising for many recently discovered uranium deposits. As future mines are expected to use alkaline ISL for uranium extraction in the world, assessing the environmental impacts of alkaline ISL is necessary to assess those of future nuclear power plants in the US and elsewhere. Currently, there is no environmental LCA for alkaline ISL. We performed the first LCA of alkaline in-situ leaching for extracting US-based uranium ores of grade 0.036-0.4% U3O8. The carbon footprint of alkaline ISL was found to be almost twice the reported values of acidic ISL, but considerably lower than open-pit and underground mining methods.

The results thus obtained by combining the effect of changes in ore grades and technology can be included in the nuclear fuel cycle modeling, to better estimate the environmental impacts of future nuclear energy generation. Similarly, the results for SLB-based applications show lower cost and carbon emissions compared to new batteries. It is, therefore, important to identify anticipated future changes in resources or technology and include them in the present-day sustainability analysis of electricity generation. Prospective life-cycle assessment, as shown in this dissertation, is a key analysis tool to analyze various low-carbon energy options to ensure the low cost and environmental impacts of electricity generation today and in the future.