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Comment Re:Credentials? WTF (Score 1) 301

According to the American Petroleum Institute, the heating value, or energy stored in a gallon of gasoline, is approximately 131,760,000 Joules. Therefore, a 20 gallon tank in a typical passenger car holds around 2.64 billion Joules of energy. Given the well-known “tank to wheel” inefficiency of vehicles powered by IC engines and if one (unrealistically) assumes that the “battery to wheel” efficiency of a future battery powered EV is 100% and the total vehicle weight is unchanged, then the EV would need to store somewhere on the order of 1/4th of this energy, or 659 megajoules, to have comparable driving range. Even if advances in battery or capacitor technology make this possible at reasonable cost and with more or less the same overall volume and weight, the issue of “refueling” or recharging the system is governed by simple physics that cannot be avoided. For example, to deliver 659 megajoules of electricity to a vehicle in 10 minutes requires a power of 1.1 megawatts. At a standard household maximum voltage of 220V, the current required is just under 5000 amps, much higher than the electrical current typically found in even very large-scale industrial equipment. Modern homes typically have electrical service rated at around 250 amps at 220 volts, and therefore if 100% of the electrical power available in the typical US home was directed toward the vehicle, recharging with the energy equivalent of a 20 gallon tank of gasoline would take about 3.3 hours. If the vehicle charger was designed to deliver a somewhat more realistic 50 amps of current at 220V (thus making it easily the most powerful electrical device in the typical home) the charging time would be more than 16 hours. Current could be lowered and charging times reduced somewhat by using higher voltages. However, the prospect of changing the basic electrical supply infrastructure to millions of homes in the US to enable vehicle charging is unrealistic, at best. Thus, given physical limitations on charging, there simply is no possible way that purely electrically powered vehicles can ever achieve a range of more than a few hundred miles per day unless some system for rapid swapping of battery packs is devised. However, given the current and projected future cost of batteries, a scenario whereby at least two separate battery systems are required for each vehicle is even more unrealistic. Although electrically powered vehicles may occupy a significant niche in the future US vehicle market, the fundamental physics of recharging will restrict them to relatively short-range and local usage only, regardless of future advances in battery technology. Therefore, most individuals who own a single car will not choose an EV because it eliminates the option of longer trips. In the most optimistic scenario, the EV will very likely always be the “second” car a family owns.

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