Are Electric Cars More Fuel Efficient Than Gas Cars?

Electric cars are widely believed to be more energy efficient than gas-powered cars, but determining the truth is complicated. While electric cars convert more of their stored energy into motion, gas cars can tap into a more concentrated fuel source. Carefully comparing efficiency requires looking at miles (or kilometers) traveled per unit of energy consumed. This analysis examines efficiency through fuel economy ratings, ownership costs, environmental impact, and future prospects to determine if electric cars are definitively more efficient.

How Fuel Efficiency is Measured

Fuel efficiency for gasoline cars is measured in miles per gallon (MPG). This metric represents how many miles a car can travel on one gallon of gasoline. The EPA has standards for city and highway MPG ratings based on controlled tests. City driving tends to result in lower MPG since stop-and-go conditions require more acceleration. Highway driving typically yields higher MPG ratings.

Electric cars do not use gallons of gasoline, so their efficiency is measured differently. The key metric is miles per kilowatt hour (miles/kWh). This represents how many miles the electric car can drive on one kilowatt hour of electricity from the battery pack. The EPA uses controlled tests to determine mile/kWh ratings for city and highway driving, similar to MPG tests for gas cars.

Understanding these metrics allows drivers to accurately compare the fuel efficiency of gas and electric vehicles. Gas mileage tells you how far you can drive per gallon of gas, while mile/kWh rates reveal how far you can go per unit of electricity. We’ll examine the differences in these ratings in more detail throughout this article.

MPG Ranges for Gas Cars

Gas cars vary in the fuel economy they achieve due to differences in size, weight, engine type, and other factors. According to the United States Department of Energy, the average new gasoline passenger vehicle achieves around 25 miles per gallon (mpg) in typical real-world driving conditions.

Pure gas-powered compact cars typically get 25-35 mpg, midsize cars achieve 20-30 mpg, while full-size sedans and SUVs average closer to 15-25 mpg. The most fuel efficient non-hybrid gas models on the market today can reach 40+ mpg on the highway. This includes smaller, lightweight vehicles utilizing the latest efficiency-boosting technologies like turbocharging, direct injection, and advanced transmissions.

Several factors influence the average mpg a gas car will achieve like driving style and behavior, vehicle maintenance, terrain, weather, and road conditions. More city driving versus highway driving will also negatively impact mpg due to lower speeds and more stops and starts. And driving with heavy loads like cargo, passengers and towing can reduce MPG as well.

Mile/kWh Ranges for Electric Cars

Electric cars are powered by large lithium-ion battery packs that are rated in kilowatt-hours (kWh), similar to how gas tanks are rated by gallons. The energy efficiency of electric cars is measured by miles per kWh (mi/kWh). The typical range for electric cars is 3-4 miles per kWh. For example, a Tesla Model 3 with a 75 kWh battery pack can achieve between 240-315 miles on a full charge. Other popular electric models have similar efficiency:

• Nissan Leaf: 112 mi from a 40 kWh battery (2.8 mi/kWh)
• Chevy Bolt: 238 mi from a 60 kWh battery (3.97 mi/kWh)
• Tesla Model S: 370 mi from a 100 kWh battery (3.7 mi/kWh)

Several factors impact the real-world energy efficiency and range of electric cars:

• Battery size – More kWh capacity means more range.
• Driving style – Aggressive acceleration and high speeds reduce efficiency.
• Climate control use – Heating, AC, defrost decrease range.
• Terrain and elevation – Hills and mountains increase energy use.
• Cargo/passenger weight – More weight means more energy needed.

Understanding the mile/kWh rating can help predict how far an EV can drive under different conditions. Overall, electric cars achieve very high fuel efficiency compared to gas vehicles.

Direct Comparison of Efficiency

Several studies have directly compared the fuel efficiency of electric and gas vehicles under real-world driving conditions. These studies attempt to convert MPG and mile/kWh figures into a common measurement to allow an apples-to-apples comparison.

In general, these studies have found that electric vehicles are more efficient than gas vehicles in terms of miles driven per unit of energy consumed. For example, a 2019 AAA study tested a variety of 2019 model year vehicles on city, highway, and combined driving cycles. They found electric vehicles achieved energy efficiency ranging from 2.7-3.4 miles per kWh, compared to gas vehicles that achieved 17-29 miles per gallon.

When converting these figures to a common MPGe measurement, electric vehicles achieved 59-120 MPGe across different models, while gas vehicles ranged from 23-44 MPG. This indicates EVs can go around 2-3 times farther than gas vehicles on an equivalent amount of energy.

However, there are caveats around driving style, climate, battery capacity and other factors that can impact these efficiency comparisons. Overall though, studies have consistently shown a sizeable efficiency advantage for electric vehicles over gas.

Impact of Driving Conditions

The fuel efficiency of both electric and gas cars can vary significantly depending on driving conditions. Factors like speed, terrain, weather conditions, and usage patterns can all affect the real-world fuel efficiency.

At highway speeds, gas cars tend to be less efficient than in city driving because the engine has to work harder to overcome wind resistance. Electric cars, on the other hand, are generally more efficient at highway speeds because their electric motors have full torque available at any speed.

Hilly or mountainous terrain will lower fuel efficiency for both types of cars, but especially for gas cars which have to work harder to climb hills. Regenerative braking in electric cars can offset some of that energy loss when descending hills.

Cold weather and use of heaters can reduce efficiency more in electric cars, as batteries discharge faster and heating draws significant power. Gas cars are impacted less by cold weather in terms of range.

Fuel efficiency also depends greatly on individual driving habits. Aggressive acceleration and braking will reduce efficiency more so in electric cars. Hyper-miling techniques like smooth acceleration and minimizing braking can dramatically improve efficiency in both types of vehicles.

Long-Term Ownership Costs

When considering the total cost of ownership over the lifetime of a vehicle, both fuel and maintenance costs play a significant role. For electric vehicles, the cost of electricity to charge is less than the cost of gasoline to fuel a comparable gas-powered car. Estimates indicate the fuel cost for an electric vehicle is around 1/3 to 1/2 the cost of a gas vehicle, assuming average electricity and gas prices.

However, the maintenance costs can differ quite a bit between electric and gas vehicles. Electric cars have fewer moving parts and little to no routine maintenance required on the engine or transmission. The brakes also tend to last longer on electric cars due to regenerative braking. Estimates suggest the maintenance costs for an electric car can be half as much compared to a gas car over the lifetime of the vehicle.

When accounting for both lower fuel costs and reduced maintenance, electric cars are estimated to have substantially lower lifetime ownership costs, potentially saving thousands of dollars over the typical lifespan of a vehicle. However, the upfront purchase price of electric cars is still higher. But as battery costs continue to fall, the total savings of electric cars over the life of the vehicle is expected to become more substantial.

Environmental Impact

When it comes to emissions, electric cars have a clear advantage over gas-powered cars. Gas cars emit greenhouse gases like carbon dioxide from the tailpipe, contributing to climate change. Electric cars have no tailpipe emissions. However, the electricity used to charge the batteries has to be generated somewhere. If coal power is used, indirect emissions are still produced. But electric cars allow for the flexibility to charge using renewable energy from solar and wind. Choosing a green electricity supplier can minimize the environmental impact of charging.

Numerous studies have found that even when charged from the regular electrical grid, electric cars generate far fewer lifetime emissions than gas cars. One study by the Union of Concerned Scientists found that the average EV in the US produces global warming emissions equal to a hypothetical gasoline vehicle with a fuel economy rating of 88 MPG. So while gas cars emit pollution directly from the tailpipe, electric cars shift those emissions to the power plant. But rapid growth in renewables is helping decarbonize the electrical grid over time.

Future Outlook

The future looks bright for electric vehicles. Governments around the world are implementing regulations to phase out gasoline and diesel vehicles in favor of zero-emission electric vehicles. Countries like the UK, France, Norway, and others have announced bans on new gas and diesel car sales over the next 10-15 years. These regulations will accelerate the transition to electric vehicles.

In addition, battery technology continues to improve, allowing electric vehicles to travel farther on a single charge. Lithium-ion batteries have nearly doubled in energy density over the past decade. New battery chemistries like solid-state batteries promise even greater improvements in range and charging speed. As batteries get cheaper and more efficient, electric cars will become more affordable and practical for everyday use.

With supportive policies and ongoing innovation in EV technology, electric cars are poised to dominate the automotive market in the coming decades. Their superior efficiency and sustainability will make them the vehicles of the future.

Conclusion

In summary, while electric cars generally offer superior fuel efficiency compared to gas cars, the efficiency can vary greatly depending on factors like vehicle size, battery capacity, and driving conditions. Pure electric cars convert about 59-62% of electrical energy into power at the wheels, whereas gas-powered cars only convert about 17–21% of the energy stored in gasoline. This gives electric cars an inherent efficiency advantage. However, electric car range estimates are based on mileage per kWh which varies between 3-6 miles per kWh for most models. In comparison, gas car MPG ranges between 25-50 mpg in real world driving. This makes the efficiency comparison more complex. Overall electric cars come out ahead efficiency wise, but a larger battery capacity is needed to match the range of gas cars. When it comes to environmental impact and long term ownership costs, electric cars also have advantages over gas. As electric vehicle technology continues to advance, the efficiency and practicality gap between electric and gasoline cars will likely further improve.