What is EV and Why is it Important?

Written by Jarrod Rhodes | 08 August 2010

An electric vehicle (EV), also referred to as an electric drive vehicle, is a vehicle which uses one or more electric motors for propulsion. Depending on the type of vehicle, motion may be provided by wheels or propellers driven by rotary motors, or in the case of tracked vehicles, by linear motors. Electric vehicles can include electric cars, electric trains, electric lorries, electric airplanes, electric boats, electric motorcycles and scooters, and electric spacecraft. Nowadays, there is an electric vehicle boom.

Electric vehicles first came into existence in the mid-19th century, when electricity was among the preferred methods for automobile propulsion, providing a level of comfort and ease of operation that could not be achieved by the gasoline cars of the time. At one time the internal combustion engine (ICE) had completely replaced the electric drive as a propulsion method for automobiles, but electric power has remained commonplace in other vehicle types, such as trains and smaller vehicles of all types.

Electric vehicles are different from fossil fuel-powered vehicles in that they can receive their power from a wide range of sources, including fossil fuels, nuclear power, and renewable sources such as tidal power, solar power, and wind power or any combination of those. However it is generated, this energy is then transmitted to the vehicle through use of overhead lines, wireless energy transfer such as inductive charging, or a direct connection through an electrical cable. The electricity may then be stored onboard the vehicle using a battery, flywheel, supercapacitor, or fuel cell. Vehicles making use of engines working on the principle of combustion can usually only derive their energy from a single or a few sources, usually non-renewable fossil fuels. A key advantage of electric or hybrid electric vehicles is their ability to recover braking energy as electricity to be restored to the on-board battery (regenerative braking) or sent back to the grid (V2G). At the beginning of the 21st century, increased concern over the environmental impact of the petroleum-based transportation infrastructure, along with the spectre of peak oil, led to renewed interest in an electric transportation infrastructure. As such, vehicles which can potentially be powered by renewable energy sources, such as hybrid electric vehicles, plug-in hybrids and battery electric vehicles, are becoming more popular.

Advantages to Electric Vehicles

Mechanical

Electric motors are mechanically very simple.

Electric motors often achieve 90% energy conversion efficiency^[25] over the full range of speeds and power output and can be precisely controlled. They can also be combined with regenerative braking systems that have the ability to convert movement energy back into stored electricity. This can be used to reduce the wear on brake systems (and consequent brake pad dust) and reduce the total energy requirement of a trip. Regenerative braking is especially effective for start-and-stop city use.

They can be finely controlled and provide high torque from rest, unlike internal combustion engines, and do not need multiple gears to match power curves. This removes the need for gearboxes and torque converters.

Electric vehicles provide quiet and smooth operation and consequently have less noise and vibration than internal combustion engines. While this is a desirable attribute, it has also evoked concern that the absence of the usual sounds of an approaching vehicle poses a danger to blind, elderly and very young pedestrians. To mitigate this situation, automakers and individual companies are developing systems that produce warning noises or distinctive sounds when electric vehicles are moving slowly, up to a speed when normal motion and rotation (road, suspension, electric motor, etc.) noises become audible.

Environmental

Electric vehicles release almost no air pollutants at the place where they are operated. In addition, it is generally easier to build pollution control systems into centralised power stations than retrofit enormous numbers of cars.

Another advantage is that electric vehicles typically have less noise pollution than an internal combustion engine vehicle, whether it is at rest or in motion. Electric vehicles emit no tailpipe CO2 or pollutants such as NOx, NMHC, CO and PM at the point of use.

Energy resilience

Electricity is a form of energy that remains within the continent where it was produced and can be multi-sourced. As a result it gives the greatest degree of energy resilience.

Energy efficiency

Electric vehicle 'tank-to-wheels' efficiency is about a factor of 3 higher than internal combustion engine vehicles.

Cost of recharge

The GM Volt will cost "less than purchasing a cup of your favorite coffee" to recharge. The Volt should cost less than 2 cents per mile to drive on electricity, compared with 12 cents a mile on gasoline at a price of $3.60 a gallon. This means a trip from Los Angeles to New York would cost $56 on electricity, and $336 with gasoline. This would be the equivalent to paying 60 cents a gallon of gas.

Stabilization of the grid

There is potential to allow battery powered electric vehicles to enhance the electric grid response by feeding electricity into the grid during peak air conditioning times (mid-afternoon) while allowing sufficient charge for expected evening use as determined by the vehicle's predicted use profile.

Furthermore, our current electricity infrastructure may need to cope with increasing shares of variable-output power sources such as windmills and PV solar panels. This variability could be addressed by adjusting the speed at which EV batteries are charged, or possibly even discharged.

Some concepts see battery exchanges and battery charging stations, much like gas/petrol stations today. Clearly these will require enormous storage and charging potentials, which could be manipulated to vary the rate of charging, and to output power during shortage periods, much as diesel generators are used for short periods to stabilize some national Grids.

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