Research of Electric Car Batteries Satisfaction Rate

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The 21st Century Electric Car By Martin Eberhard and Marc Tarpenning Tesla Motors The electric car, once the “zero-emissions” darling of environmentalists, is sometimes maligned as an “emissions-elsewhere” vehicle, since the electricity to charge its batteries must be generated in electrical generation plants that produce emissions. This is a reasonable point, but we must then ask how much pollution an electric car produces per mile – accounting for all emissions, starting from the gas or oil well where the source fuel is extracted, all the way to the final consumption of electricity by the car’s motor. When we work through the numbers, we find that the electric car is significantly more efficient and pollutes less than all…show more content…
The famous Toyota Prius is EPA-rated to get 55 mpg in combined city-highway driving, for an energy efficiency of 0.56 km/MJ.7 Electric Cars Even with tires and gearing optimized for performance (rather that absolute efficiency), the Tesla Roadster only consumes about 110 watt-hours (0.40 mega-joules) of electricity from the battery to drive a kilometer, or 2.53 km/MJ. 8 The energy cycle (charging and then discharging) of the lithium-ion batteries in the Tesla Roadster is about 86% efficient. This means that for every 100 mega-joules of electricity used to charge such a battery, only 86 mega-joules of electricity are available from the battery to power the car’s motor. Thus, the “electrical-outlet-to-wheel” energy efficiency of the Tesla Roadster is 2.53 km/MJ x 86% = 2.18 km/MJ. The most efficient way to produce electricity is with a “combined cycle” natural gas-fired electric generator. (A combined cycle generator combusts the gas in a high-efficiency gas turbine, and uses the waste heat of this turbine to make steam, which turns a second turbine – both turbines turning electric generators.) The best of these generators today is the General Electric “H-System” generator, which is 60% efficient,9 which means that 40% of the energy content of the natural gas is wasted in

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