Introduction to electric cars

The recent introduction of mass-market electric cars has generated waves in the industry. As strange it may seem, there have been many early introductions of electric cars to the public over the past 100-150 years. Obviously none of these have caught on well enough to see mass adoption but research into these early cars and electrical technology have given us a few significant advancements. These include the rechargeable battery which is one of the most essential ingredients to the mass adoption of the EV (electric vehicle). The original implementation of the rechargeable battery has been improved upon dramatically but the basic concept and necessity remains.


The latest iteration of the electric car is thoroughly modern and has benefited from years of improvements in technology of the traditional gasoline car. Technologies developed for the gas car including in-car electronics, GPS navigation, the various creature comforts that are already in place have all been implemented in their electric counterparts, as is progress in general development of semi-autonomous to full autonomous driving cars. Advancements in all these technologies have helped make the electrics compelling as an end product and should be one of the factors help scale up demand going forward. 

We've seen some compelling and practical examples of EVs in the market that are in most respects equal or better than their gas counterparts. The rechargeable lithium-ion battery is the predominant battery technology used in the pure electric vehicle. The cost of these Li-Ion packs (given in $/kWh) have steadily dropped over the past few years and should continue on this trajectory to making them more affordable. Data shows that prices of Li-Ion batteries in $/kWh have fallen around 75% since 2010. Battery cost is the main reason that EVs are more expensive that internal combustion engine cars today.


There is research ongoing to increase energy density of Li-Ion battery packs to accomplish the end result of lowering overall weight. The energy density of Li-Ion is improving at the rate of 5% - 6% every year. Ideally, one ultimately hopes for the highest economies of scale and commoditization of these battery packs similar to what has happened with most other technological innovations. The one example that is most glaring in renewables is the solar panel whose prices have plummeted over the past few years. Research into alternative battery technologies that will hit the key metrics ultimately to help mass adoption is also underway.

So what is an electric vehicle or EV?

An EV is a mode of transport that runs on electricity from a rechargeable battery bank. Typically this battery bank supplies electric power to an electric motor that converts electrical energy to mechanical energy (rotation of the wheels) similar to how a kitchen blender converts electricity from a wall socket to turning motion of the blades. In the figure shown below, the battery is powering a motor through a controller to enable forward motion. EV batteries are rated in Kilowatt hours (kWh).


                                                                      Figure 1: Schematic of an EV


I have heard that term. What is a Kilowatt hour?

The kilowatt hour is a unit of energy. One kilowatt is 1000 watts. It is the power that is consumed (or that can be generated) over a period of time, typically measured over a period of one hour. A simple example to understand this would be a microwave oven rated at a constant load of 1000 Watts (1 kW) running for an hour would consume 1000 Watt hours (or 1 kWh) of energy.

I have seen something like a 60kWh or 80kWh rating for an EV. What does it mean?

It is the energy capacity of the battery. Weight of the payload and all else being equal, a higher energy capacity number gives you more range. The larger the value the more time it needs to charge completely from a fully depleted state.

What is MPGe on an EV's window sticker?

The acronym stands for 'Miles Per Gallon equivalent'. It is a U.S EPA (Environmental Protection Agency) measure based on a formula which has determined that one gallon of gasoline has energy content equivalent to 33.7 kWh of electricity. The MPGe number is calculated based on a specific mix of city and highway driving.

What is range and range anxiety?

The range is the number of miles that the car can travel on a full charge. It typically takes a few hours depending on the energy capacity of the battery to charge the battery completely. Range anxiety is the worry that you will run out of charge and be stranded on the road with no charging stations available when you need it.

How can I overcome range anxiety?

By making sure your battery is completely 'topped up' before your journey. Typically a full battery should have adequate range for the average commute, for multiple days. If you are taking a trip, it will help to plan and map out where along your route there may be public charging stations for you to stop and plug in to recharge your vehicle.

Okay, more importantly, how much will it cost me to charge my electric car at home?

It depends on how much your electric utility charges you for electricity in your home and the size of your battery. On the average, U.S consumers pay around $0.12 per kWh. Several electric utilities offer time-of-use rates that are lower during off-peak hours of the day, typically late night to early in the morning. Click on a car in the charging calculator page to find out how much it will cost you to charge a particular car model in your zip code, not including incentives or lower rates offered by your utility --but before that let's complete this section. On that page you can also read if there are special discounts or incentives for buying or charging your EV, in your local area or state or ones offered by your utility.

I have no clue when they say Plug-in hybrid, Regular hybrid or a Pure electric car. Tell me the differences.

Okay, let's hit the road and learn more. View the slide show below.

basic EV schematic

Internal Combustion Engine (ICE) vehicle

ICE vehicles comprise the vast majority of the world's vehicles. They superseded early electric and steam vehicles to become the predominant technology to power personal transport. Pollution caused by vehicle smoke wasn't an issue at the time of their introduction and the liquid fuel could easily be stored in tanks at dispensing stations anywhere. The advantage that lies in the high calorie per volume (or energy content) in fossil fuels is one of the barriers to mass adoption of other vehicle technologies.

How they are powered

These are conventional vehicles that burn a liquid fuel (gasoline/diesel) for propulsion

Example models

Honda Accord

BMW 328d

Ford F150

Fuel consumption rating

Fuel consumption depends on the size of engine, application and performance characteristics. Typically a larger vehicle with a large engine or one built for higher power, torque and performance will consume more fuel.

Overall rating: Fair