Maybe it's time to move it down here. Or maybe it's done. Anyway. Electric vehicles (EVs) have their plusses and minuses -- like everything else. Here's a short, and by no means complete, list from my point of view, mostly obvious but maybe a few less so.
Plusses:
Higher efficiency measured from the vehicle energy input point. This is due to the relatively high efficiency of Li storage batteries, switching power electronics and electric motors. Regeneration during braking helps further. Pure EVs with large batteries are better able to take advantage of regen. Essentially zero consumption when stopped.
Excellent driving experience. No reciprocating parts makes for low vibration and noise, especially when stopped or at low speeds. Instantaneous power control (both positive and negative) allows for a high level of driving precision and smoothness. Fast acceleration occurs without drama or excessive wear (except for tires) or even much extra energy consumption. The increase from rapid starts is mostly due to the longer time spent in cruise with the resulting higher aerodynamic loss.
No warm-up required and cold shutdowns do not cause damage. Great for those of us who need to reposition vehicles now and then or make short trips.
No reduction in performance with altitude.
Lower direct operating cost in the current market. (My daily driver costs ~ $.04 / mi for electricity -- about the same per-mile cost as tires).
Lower maintenance and the potential for lower lifetime cost as batteries become cheaper. We're just about there for high-utilization operators whose mission profile fits.
Home or shop/depot charging eliminates trips to the gas station. Charging time is essentially zero for intermittently utilized vehicles that sit by a charger when not in use.
Easy and efficient integration into an electric energy-infrastructure. More below.
Minuses:
Range comes at a high cost in purchase-price and weight.
Charging is slow, which is an issue for cross county travel or other high utilization. Mitigated to some extent with larger batteries and high-power chargers. (A larger battery can absorb charge more rapidly adding more miles per minute of charge.) With current batteries the last 20% of charge is much slower so a driving schedule that allows charging to 80% saves a lot of time. Current EVs can charge from 20% to 80% in roughly 30 minutes given a powerful enough charger. Advances in this area are likely.
Many apartment dwellers, and others without private, electrified parking, must rely on inconvenient (and often expensive) public chargers.
Low ambient temperature reduces battery capacity and winter driving consumes more emery reducing range. Partially mitigated by thermal management of the battery, such as charging up to the moment of departure to warm the battery.
Extended high power operation, such as racing on a track, can exceed the battery's thermal limit. This has been mitigated in race-oriented cars through thermal management.
High weight that does not go down as fuel is burned. This compromises handling while being partially mitigated by placing the battery down low. Not too much of a concern outside of serious motorsports though there are knock-on effects such as tire and road wear.
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Toward an Electric Energy Infrastructure
As we face an ever more diverse range of energy sources (some of which may not yet have been discovered or developed) we need an infrastructure that can efficiently combine and distribute their energy. Electricity has some advantages:
It is highly fungible. Thanks to power electronics, it is easy and relatively cheap to convert any format (Voltage, frequency, phase) into another. Varying sources such as solar and wind are easy to accommodate.
Electrical machines usually achieve 80% - 90% efficiency at converting in and out of mechanical energy. This is better than combustion engines or current schemes for electrolyzing water into Hydrogen.
Electricity is relatively cheap and safe to transport (PG&E's current problems not withstanding
). DC transmission lines are efficient for long distances where their lower loss offsets rectifier/inverter losses.
So far there is no intercontinental transmission of electric power, but it is not out of the question. This could be quite useful for large-scale leveling of intermittent sources, such as solar.
The elephant-in-the-room minus is storage, both for utility scale load-leveling, which is especially important for intermittent sources, and for vehicles, including air vehicles, that can't be on a cord. Rail transport and the like (hyperloop) distinctly do not belong to this class. Our great hope, for now, is battery technology, which is advancing nicely. Clearly, wider use of batteries will require extracting raw materials and efficient reuse of those materials is required for this to be at all sustainable. This is where I believe we should be directing our efforts.
I've been an EV queen for quite a while. The stable consists of a 2000 Easy Go golf car (to be converted to Li when the current Pb-acids go TU), a 2015 Tesla S 85 D (6 years and going strong), and a 2020 Sur Ron Light Bee electric dirt bike (2 kWh of pure fun).
--Frank
