Plug-In Hybrid Electric Cars: Benefits and Conversions

Would you like a car that gets 100 miles per gallon? A plug-in hybrid electric vehicle does just that.

prius plugin

The Toyota Prius plug-in hybrid is scheduled to be released in 2012.


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The following is an excerpt from Build Your Own Plug-In Hybrid Electric Vehicle  by Seth Leitman. (McGraw-Hill, 2009). Written by clean energy guru and electric vehicle expert Leitman, this hands-on guide gives you the latest technical information and easy-to-follow instructions for building a plug-in hybrid electric vehicle (PHEV). This excerpt is from Chapter 1, “Why Plug-In Hybrid Electric Cars Can Happen Now,” and Chapter 2, “PHEVs Save the Environment and Energy.”

What is a plug-in hybrid electric vehicle? Why should I take a hybrid electric car and convert it to a plug-in hybrid?

The best way I can put it is to say that a plug-in hybrid is cleaner and more energy-efficient than a hybrid electric car. A plug-in hybrid can be a gas car with electric batteries that have a range of 20, 30, 40, 50, 60 or 70 miles, or it can be a hybrid electric car that has a purely zero-emission vehicle (ZEV) range of 20, 30, 40, 50, 60 or 70 miles.

Why Should You Convert Your Car to a Plug-In Hybrid Electric Vehicle?

If you use your car for commuting to work or driving around town, a plug-in hybrid acts as an electric car all the time you are driving. How important is that? Well, let’s put it this way: I am an electric vehicle purist at heart, and to transform the automobile market, we need more electric and fewer gasoline-powered cars.

You should convert your car simply because a plug-in hybrid electric car is one of the cleanest, most efficient, and most cost-effective forms of transportation around — and it is really fun to drive.

Plug-in hybrid electric vehicles (PHEVs) combine the benefits of pure electric vehicles and those of hybrid electric vehicles. Like pure electric vehicles, they plug in to the electric grid and can be powered by the stored electricity alone. Like hybrid electric vehicles, they have engines that enable them to have a greater driving range and that can recharge the battery.

The cost of the electricity needed to power plug-in hybrids for all-electric operation has been estimated at less than one-quarter of the cost of gasoline. Compared with conventional vehicles, PHEVs can reduce air pollution, dependence on petroleum, and the greenhouse gas emissions that contribute to global warming. Plug-in hybrids use no fossil fuel during their all-electric range if their batteries are charged from nuclear and renewable energy sources. Other benefits include improved national energy security, fewer fill-ups at the filling station, the convenience of recharging at home, opportunities to provide emergency backup power to the home, and vehicle-to-grid applications.

I remember when I worked for the State of New York at the New York Power Authority and my boss at the time, Bart Chezar, retired. Before leaving, he told me that the next step toward full electric vehicles would be the plug-in hybrid and that I should never lose sight of that. I never did, and that is the message of this book.

But wait, there’s more:

  • If your driving is mostly local, you’ll almost never need to gas up.
  • Lifetime service costs are lower for a vehicle that is mainly electric.
  • A PHEV can provide power to an entire home in the event of an outage; a fleet of PHEVs could power critical systems during emergencies.

Reduce Our Reliance on Oil and Clean the Environment at the Same Time!

July 2007 EPRI-NRDC Definitive Study: PHEVs Will Reduce Emissions If Broadly Adopted

In July 2007, the Electric Power Research Institute (EPRI) and the National Resources Defense Council (NRDC) did one report that included multiple studies on plug-in hybrids. The report stated that scientists have confirmed that, unlike gasoline cars, plug-ins will get cleaner as they get older — because our power grid is getting cleaner.

For people who are looking for the most effective way to end our addiction to oil, PHEVs make sense because carmakers can build them now, with today’s technology and using today’s infrastructure. The study showed that with the increase in the number of PHEVs on the road and the evolving characteristics of the power grid (in terms of capacity and carbon intensity), PHEVs will vastly reduce greenhouse gases over the next 40 years. The second study showed that increased PHEV use will reduce greenhouse gases over the next 20 years; even if, in the worst-case scenario, we still use lots of coal, nationwide air quality in terms of other emissions will also improve.

Three more points: Both reports match up well with previous studies. They reinforce the Pacific National Lab’s January 2007 findings that we won’t have to build new power plants for cars that charge at night. And we’re gratified that General Motors recognizes this study as validation of its decision to evolve toward the electrification of transportation.

California Air Resource Board/ZEV States Report 

California, New York, Massachusetts and some other states have had zero-emission-vehicle programs since the early 1990s, because battery electric vehicles in those states, taking into account power plants, are far cleaner than gasoline cars in reducing urban air pollution and smog. The issue keeps being raised, although studies are conclusive.

The “well-to-wheel” emissions of electric cars are lower than those from gasoline internal combustion vehicles. A California Air Resources Board (CARB) study showed that battery electric vehicles emit at least 67 percent less greenhouse gases than gasoline cars — even more assuming the power is generated with renewable energy sources. A PHEV with only a 20-mile all-electric range emits 62 percent less.

U.S. Department of Energy Argonne National Lab

Two government studies have found that PHEVs would result in large reductions even on the national grid (which is 50 percent coal). The GREET 1.6 emission models done in 2001 by the DOE’s Argonne National Lab estimates that hybrids reduce greenhouse gases by 22 percent and plug-in hybrids by 36 percent. An Argonne researcher reached consensus with researchers from other national labs, universities, the Air Resources Board, automakers, utilities and Arthur D. Little to estimate in July 2002 that PHEVs using nighttime power reduce greenhouse gases by 46 to 61 percent.

PHEVs Are Cheaper to Run and Maintain

A 2006 research estimate in California found that the operating costs of plug-ins charged at night were equivalent to 75 cents per U.S. gallon (3.8 L) of gasoline.

The EPRI-NRDC report further concluded that the cost of electricity for a Prius PHEV would be about $0.03 per mile ($0.019 per kilometer), based on 0.26 kWh/mi (129 mpg) and a cost of electricity of 10 cents per kilowatt hour.

During 2008, many government and industry researchers have been focusing on determining what range for all-electric operation is economically optimum for the design.

20 to 25 Cents per Gallon?!

Using the average U.S. electricity rate of 9 cents per kilowatt-hour (kWh), 30 miles of electric driving will cost 81 cents. If we optimistically assume that the average fuel economy in the United States is 25 miles per gallon, at $3 a gasoline, this equates to 75 cents a gallon for the equivalent electricity. Compared with a regular hybrid’s real-world 45 miles per gallon, it’s effectively $1.20 a gallon.

PHEVs are meant to be plugged in at night. In many areas of the country, overnight power is available at a lower cost. As PHEVs start to enter the marketplace, we’ll see increasing support from electric utilities; they’ll offer reduced nighttime rates to provide incentives for off-peak charging. In some areas where wind and hydropower are wasted at night, the rate can be as low as 2 to 3 cents per kWh. That’s 20 to 25 cents a gallon.

Purchase Costs

Calcars and others are charging $15,000 for a conversion. However, a conversion by building your own will cost much less and will increase the payback.

People routinely pay more for such options as sunroofs, automatic transmissions, V8 engines and leather seats. These are “features” — and no one asks about the payback. A J.D. Power survey shows that buyers will pay more for cars with the “environmental feature.” How much more? The high demand for the Honda Civic Hybrid tells us that it’s at least $3,000.

The Bottom Line

A 2003 EPRI battery study shows that mass-produced PHEVs have already reached life-cycle cost parity with gas-powered vehicles — using gas prices from three years ago!

This means that the more maintenance-free electrical systems of PHEVs offset the initial higher cost of batteries.


The costs and benefits of cars extend far beyond an individual driver to society as a whole. But when people talk about payback, they refer only to the net dollars to the driver. Because this question never comes up when people pay a premium for features like leather seats, we point out that millions of people want the “environmental feature” (see J.D. Power and Associates’ 2004 report). Car and Driver’s Patrick Bedard writes amusingly but tellingly about this issue.

Despite this, a 2003 EPRI study — assuming only $2 a gallon gas, zero buying incentives, and a PHEV premium of $3,000 to $5,000 more than standard hybrids —shows that the total lifetime cost of ownership for a PHEV will be lower than that for any other vehicle type — so the payback will be there.

Safety First

On another safety issue, while electric vehicles do not emit noise pollution, there has been concern about hybrid vehicles being unsafe for visually impaired pedestrians because the vehicles’ engines don’t make noise.

The Baltimore-based National Federation of the Blind presented written testimony to the U.S. Congress asking that a minimum sound standard for hybrids be included in the emissions regulations. The president of the group, Marc Maurer, stated that he’s not interested in returning to gas-guzzling vehicles; the group just wants fuel-efficient hybrids to have some type of warning noise. “I don’t want to pick that way of going, but I don’t want to get run over by a quiet car, either,” Maurer said.

Manufacturers are aware of the problem but have made no pledges yet. Toyota is studying the issue internally, said Bill Kwong, a spokesman for Toyota Motor Sales USA.

“One of the many benefits of the Prius, besides excellent fuel economy and low emissions, is quiet performance. Not only does it not pollute the air, it doesn’t create noise pollution,” Kwong said. “We are studying the issue and trying to find that delicate balance.”

The Association of International Auto Manufacturers Inc., a trade group, is also studying the problem, along with a committee established by the Society of Automotive Engineers. The groups are considering “the possibility of setting a minimum noise level standard for hybrid vehicles,” said Mike Camissa, the safety director for the manufacturers’ association.

You Can Do It!

What is happening with plug-in hybrid electric vehicles is merely the beginning. As battery technology improves, PHEVs will get faster, have a longer range, and be even more efficient. All the available technology has just about been squeezed out of internal combustion engine vehicles, and they are going to be even more environmentally squeezed in the future. This will hit each buyer right in the pocketbook — incremental gains will not come inexpensively. Internal combustion engines are nearly at the end of their technological lifetime.

Electric vehicles have also been around for more than 100 years, so making a hybrid car and PHEV will greatly improve their range and performance. When you do it yourself, any choice you wish to make for more speed, acceleration or range is readily accommodated. Just do it.

To learn much more about plug-in hybrid conversions, read Build Your Own Plug-In Hybrid Electric Vehicle, and visit the California Cars Initiative.

Electric Utilities Love PHEVs

Even the most wildly optimistic projections for electric vehicles show only a few million PHEVs in use by early in the 21st century. At somewhere around that level, EVs will begin making a dent in the strategic oil, greenhouse gas and air quality problems. But until you have 10 to 20 million or more electric vehicles, you’re not going to require additional electric generating capacity. This is because of the magic of load leveling. Load leveling means that if PHEVs are used during the day and recharged at night, they perform a great service for their local electric utility.

How electricity is generated varies widely from one geographic region to another, and even from city to city in a U.S. region. In 1991, the net fuel mix used by electric utilities was 54.87 percent coal, 21.73 percent nuclear fission, 9.75 percent hydroelectric, 9.36 percent natural gas, 3.93 percent oil and 0.35 percent geothermal and other. Those electric utility plants that produce electricity at the lowest cost (i.e., those fueled by coal and hydro) are used to supply base-load demands, while peak demands are met by less economical generation facilities (i.e., gas and oil).

When owners recharge their PHEVs in the evening hours (valley periods), they receive the benefit of an off-peak (typically lower) electric rate. Because recharging PHEVs raises the valleys and brings up its base-load demand, the electric utility is able to utilize its existing plant capacity more efficiently. This is a tremendous near-term economic benefit to our electric utilities because it represents a new market for electricity sales with no additional associated capital asset expense.

Reprinted with permission from Build Your Own Plug-In Hybrid Electric Vehicle , published by McGraw-Hill, 2009.