HEVs, PHEVS, and EVs at a glance

The past couple of years I notice a sudden leap of hybrid vehicles on the road, especially in California. Prius, the bullet looking, mid-size hatchback four-door passenger cars was introduced to the United States in 2000. Just in 2011 alone, 172,000 Prius are sold in the country. It’s not a surprise to see a Prius every couple blocks you travelled. As electric vehicles enter the mainstream marketplace and quickly caught our attention, consider the types of fuel-efficient autos that are out there and see which one fits you the best before joining the why-not-get-a-hybrid bandwagon. This blog post attempts to give readers the basic of EVs.

There are currently three types of electric-drive vehicles,

  1. Hybrid electric vehicles (HEVs
  2. Plug-in hybrid electric vehicles (PHEVs)
  3. All electric vehicles (EVs)

Hybrid electric vehicles
The Prius that you normally see on the road belongs to this category. These vehicles are already quite well established in the mainstream marketplace.
These vehicles are powered by an internal combustion engine just like any other conventional vehicles, and an electric motor that uses energy stored in batteries. The electric power provide extra power and miles therefore allow for a smaller engine. Results are better fuel economy without diminishing performance. Some HEVs achieve fuel economy of 40 to 50 mpg. They don’t require a plug to charge the battery. Charging rely on regenerative braking and the internal combustion engine. The idea is that the vehicle capture the energy lost during braking by using the electric motor as a generator and storing the captured energy in the battery.

Plug-in hybrid electric vehicles
PHEVs, like a hybrid, are powered by conventional fuels and electricity energy stored in batteries. Yet, it uses electricity from the grid to charge the battery. PHEVS have a larger battery pack (hence costs more) than HEVs, making it possible to drive using only electric power. Chevy Volt, for example, can deliver 35 miles on a single charge, and up to 50 miles depending on drivers’ behavior. It is possible for households to survive on a PHEV’s “all-electric range” and many household in fact do just that.

All electric vehicles
EVs run only on electrical power. Batteries are charged by plugging the vehicle into an electric power source. The EPA considers EVs to be zero-emission vehicles because they require to combustion and therefore produce no emission. Electricity production, however, contribute to air pollution.

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Charging time often comes as the priority concern for many potential buyers of PHEVS and EVs. Charging these vehicles requires plugging them into charging equipment/infrastructures called electric vehicle supply equipment (EVSE). Charging times can vary from 30 minutes to as much as 20 hours, depends on how depleted the battery is, the battery size, capacity, and the type of battery and EVSE. Currently there are three EVSE options. Level 1 EVSE does not require the installation of a charging station. A connector will connect the vehicle’s battery and a standard 120 V outlet. Level 1 charging can take 4-20 hours to reach a full charge. Level 2 EVSE offers charging through a 208 V or 240 V outlet (adding about 25 miles of range per hour of charging time) and requires installation of home charging or use of public charging equipment. This is the most common installation at home because it can easily charge a typical EV battery overnight. Level 3 charging (also known as Direct-Current) offers the fastest charging rate available because it operates at higher voltage and current than Level 2 charging. This equipment is not yet widely available. According to the Electric Power Research Institute, establishment of public charging stations at shopping centers, parking lots, hotels, government offices etc. are expected to take place in 2-5 years across most states to help facilitate the penetration of electric vehicles and address consumers’ “range anxiety”. Hydro-Quebec, a utility company at Canada is working on an charging system that can fully recharge a typical EV in about 5 minutes.

As battery technology continues to develop and mature, and innovative material design for autos (ultra-light vehicles made of carbon composite materials require smaller engine and batter capacity equivalent) begins to take place, costs of electric vehicles would come down drastically and consumers’ concern over range and battery cost would go down. Electric vehicles would become such a competitive option to consumers, even without any federal incentives.