2.4.4. Environmental Costs and Residual Values

Environmental costs are estimated in step P, and these include carbon dioxide emissions (CO2e) [51] as well as estimates of nitrogen oxides (NOx)/non-methane organic gases (NMOG), carbon monoxide (CO), and particulate matter (PM). Formaldehyde (HCHO) is a constant, based on Tier 3 standards of the Environmental Protection Agency (EPA) [52]. BEV cars are non-emissive (although there is carbon emission in the production phase). Other vehicles are assigned emission standards based on estimates from [53]. Table 3 illustrates the estimates by vehicle type.


**Table 3.** Simulation emissions estimates by selected vehicle type.

\* imputed as mean of ICEV and PHEV.

In step Q, the simulation evaluates whether the vehicles have reached their usable lifespan. If not, steps K through P are repeated until that lifespan has been reached. Then, in step R, residual value for the selected vehicles is estimated based on Moody's Analytics *Electric Vehicle Residual Value Outlook* [54]. Gasoline cars retained on average 45% of their value over 4 years. Electric vehicles retained barely more than 25% of their value after adjustment for tax credits [54]. The geometric residual rate per year for gasoline and non-gasoline cars is then 82%, and 71%, respectively. In other words, 0.824 = 0.45 and 0.714 = 0.25. These geometric values are applied to the user-selected life span (not to exceed 10 years). PHEVs are estimated to be 0.75 (closer to BEV), while non-plug-in hybrids are estimated at 0.78 (closer to gasoline vehicles).

Finally, landfill lithium ion battery (LIB) waste is estimated in step S [55,56]. The concern for LIB waste is that; (1) it is highly toxic to humans, (2) it requires cobalt, which is often extracted irresponsibly with child labor, and (3) it may be recycled [55]. Waste in pounds is estimated by a uniform distribution between 100 and 544 pounds, the minimum and maximum specified in Figure 1 of [56].
