电动汽车的缺点

Task 1：

Disadvantages of electric vehicles

Overall average efficiency from US power plants (33% efficient) to point of use (transmission loss 9.5%), (US DOE figures) is 29.87% . Accepting 90% efficiency for the electric vehicle gives us a figure of only 26.88% overall efficiency. That is lower than internal combustion lined vehicles (Petrol/Gasoline 30% efficient, Diesel engines 45% efficient - Volvo figures).Diesel engines can also easily run on renewable fuels, bio diesel, vegetable oil fuel (preferably from waste sources), with no loss of efficiency. Using grid electricity entirely negates the efficiency advantages of electric vehicles.

This comparison isn't entirely fair, though, since it compares tank-to-flywheel efficiency of gasoline and diesel powered engines to the well-to-wheel efficiency of electric motors. It also fails to recognize that the practical efficiency of the internal combustion engine is significantly lower in actual use, because of transmission and idling losses.

To achieve a sound conclusion, one would also have to take into account the refining and delivery losses of gasoline and diesel, and the energy efficiency of bio fuel production. (Output fuel energy divided by the sum of the invested energy and energy in the biomass). The equivalent for fossil electricity production would also need to be considered (mining and transportation of coal to the power station for example, or the Co2 produced building renewable electricity generation).

电动汽车的缺点

美国发电厂（有效率33%）到使用点（输电损失9.5％）的总平均效率为29.87％（美国能源部数字）。90％的电动车辆接受效率却给我们一个只有总效率为26.88％的数字，这个数据低于内燃机车（汽油/汽油30％效率，柴油发动机效率45％ - 沃尔沃数字）。柴油发动机还可以轻松地运行可再生燃料，生物柴油，植物油燃料（最好来自废物源），没有效率损失，使用电网电力完全否定了电动汽车的效率优势。

然而，这种比较并不完全公平，因为将汽油和柴油发动机的油箱与飞轮的效率与电动机的轮毂效率进行比较。它也未能认识到，由于传动和空转损失，内燃机的实际效率在实际使用中显着降低。

为了得出一个合理的结论，还必须考虑汽油和柴油的精炼和输送损失以及生物燃料生产的能量效率。（输出燃料能量除以投入的能量和生物质中的能量的总和）。类似的化石电力生产也需要考虑（例如，煤炭开采和运输到发电站，或者二氧化碳生产的建筑可再生能源发电）。