How Much Energy is Lost in an Electric Car

The inefficiency of converting energy into motion in vehicles is a crucial consideration for both owners and environmental enthusiasts. This article delves into the specific losses involved in electric cars (EVs) and how they compare to traditional internal combustion engine (ICE) vehicles.

Energy Losses in Vehicles: A Comprehensive View

When examining vehicles, it's useful to consider the energy losses that occur during operation. These costs do not directly contribute to advancing your journey. In the case of an electric car, the energy and heat put into the vehicle ultimately result in motion. This concept can be quantified using measures like mpgE (megajoules per kilometer for electricity).

The Energy Equation: A Numerical Breakdown

The energy contained in one gallon of gasoline is roughly equivalent to 33.7 kWh (kilowatt hours) of electricity. While these numbers might be abstract, for a more relatable comparison, consider the cost. A gallon of gasoline typically costs around $3.00, while electricity from photovoltaic (PV) solar power is about $1.00 at the wholesale generation cost. This means that, energy-wise, buying a gallon of gasoline is approximately three times more expensive than its equivalent in electricity.

Converting this energy into money, the energy loss in a vehicle is significant. When the energy we lose is not captured from the sun, it becomes an exponential increase in waste and chaos in the atmosphere and heat. According to US data, cars and light trucks currently achieve an mpgE of 25.7. In contrast, a first-generation EV today contributes to 150 mpgE, while future models powered by solar PV could achieve 297 mpgE at 180 mph. Clearly, as technology advances, the energy losses are significantly reduced in more efficient vehicle designs.

Design Elements and Their Impact

The efficiency of a vehicle is greatly influenced by its design. For example, a typical sedan has a drag coefficient (Cd) of 0.34, whereas reducing this to a more efficient coefficient of 0.07 can dramatically decrease energy losses. Electric vehicles, in particular, have fewer mechanical components, thus leading to higher efficiency.

No transmission is needed in an electric car, whereas ICE vehicles require complex transmissions. No friction from inflated rubber wheels is present in electric cars, while ICE vehicles have corresponding rolling resistance. No rear end differential with spider gears wasting energy in an electric car, as opposed to the thick grease used in ICE rear ends. Smaller frontal area in electric cars results in reduced aerodynamic drag. No energy is wasted on motor oil pumps lubricating hard metal parts that are not present in electric vehicles.

Efficiency of Electric Motors

Electric motors are significantly more efficient compared to internal combustion engines. For an electric vehicle, energy is lost due to friction, air resistance, and rolling resistance, just like any other vehicle. However, the losses in an electric motor are typically less than those in a conventional engine due to fewer moving parts and higher operational efficiency.

The entire energy input to a car, whether it's from gasoline or electricity, is ultimately converted into motion, with some portion inevitably lost to inefficiencies. This loss is more pronounced in ICE vehicles but can be greatly minimized in electric vehicles.

Conclusion

Understanding the energy losses in electric cars is not only important for efficiency and cost but also for environmental impact. By designing more efficient vehicles, moving towards renewable energy sources, and optimizing the use of electricity, we can significantly reduce the energy waste associated with transportation. The future looks promising for electric vehicles, with continuous advancements in technology leading to greater efficiency and reduced energy losses.