As a generalization, it's safe to say that there are few things in this world more odious to an environmentalist than the mining of metals and minerals, except if those activities are conducted in an obscure, faraway place, and if the fruits of those activities bear the cool, sleek moniker of "clean."

There's a modern-day "Heart of Darkness" being perpetrated in the Democratic Republic of Congo, where tens of thousands of children as young as four are forced to haul rocks to the surface from mines dug by hand as part of a cobalt-mining operation, under conditions that would make Upton Sinclair, or, for that matter, Joseph Conrad, blush.  Last August, the Daily Mail printed an article describing these conditions, where they also reported that each electric car requires an average 15 kg (33 lbs) of cobalt in its batteries.

To give credit where due, according to Benchmark Minerals, Panasonic has enabled Tesla to reduce its cobalt consumption by 60% over the last six years by utilizing nickel-cobalt-aluminum (NCA) technology versus nickel-cobalt-manganese (NCM), which remains the standard for the electric vehicle (E.V.) industry.  Nevertheless, replacement technology for cobalt is still at least ten years out, and the projected "EV surge is far more significant than the reduction of cobalt intensity which is close to its limit[.] ... [M]ore cobalt will be needed and the reliance on Democratic Republic of Congo as the primary supplier [60% of worldwide production] will increase."

On May 17, 2018, the Wall Street Journal reported that "[p]rices of lithium and cobalt more than doubled from 2016 through last year, but the rally has cooled off recently amid worries about oversupply."  The market responded in typical fashion by ramping up worldwide production (i.e., mining) of lithium and, to a lesser extent, cobalt.  Consumption levels of nickel, manganese, and aluminum are no doubt on the rise as well.

E.V.s and plug-in hybrids are eligible for federal tax credits up to $7,500, depending upon the battery capacity, and most E.V.s are eligible for the maximum amount.  Some states offer additional subsidies.  Colorado is the most generous.  This from The Complete Colorado:

Currently those with EV or AFV [Alternative Fuel] vehicles receive up to $20,000 in Colorado income tax credits over and above the $7,500 the federal government already grants.  The credit is based on size and weight of vehicle.  Light passenger vehicles get $5,000, which, unlike most states and the federal credit, can be used as a rebate, and trucks get $7,000-$20,000.

As of 4/18/2018, a bill to repeal this electric vehicle subsidy (S.B. 18-047) was postponed indefinitely by the Colorado House Committee on Transportation and Energy.

All such subsidies should be eliminated.  If we stopped subsidizing electric trucks and buses, for example, we would likely see more conversions of truck and bus fleets to compressed natural gas (CNG), which is cheaper; more efficient; and, I argue, more environmentally desirable than the electric alternative.

All is imperfect, but the market is not the insidious spawn of Darth Vader.  We're better off if complex, dynamic solutions have to prove their worth by competing on many levels in the real world, as opposed to a having a few masterminds (at the prodding, or shall we say incentivizing, of parties with vested interests) distort the field with edicts from above.