For the most part, a PHEV uses the same technology that standard hybrid electric vehicles use, with a few exceptions. The battery pack on a PHEV is larger, and the hybrid system has been modified to accept a charge from household current. The hybrid drive train contains one or more electric motors, an internal combustion engine and a large battery bank. Electronic controls in the vehicle control the rate of battery charging and discharging, and also control the operation of the internal combustion engine.

A few manufacturers have introduced – or plan to introduce – diesel electric hybrid vehicles, mostly for the European markets. A diesel engine is more efficient, and offers better overall fuel economy than an internal combustion engine does, but diesel fuel can be significantly more expensive and does not "burn clean." In the past several years, significant improvements to the diesel engine have reduced the particulate emissions of vehicles that use the technology. "Clean" diesel options are becoming more common and are being adapted for use with hybrid electric vehicles. Currently, there are no plug-in diesel-electric hybrids in production.

Statistically, there are an insignificant number of plug-in hybrid electric vehicles in operation today. Most PHEVs in service today are custom modifications of standard hybrid vehicles. Conversion kits for certain vehicles have been created, and kits can range in cost from a few thousand dollars to about $10,000 for the most common conversions.

A large part of the conversion expense is related to the battery needs of a PHEV. Currently, most PHEVs use nickel-metal hydride battery packs. Toyota, which plans to bring a mass produced Prius PHEV to market in the 2010 model year, will initially use a nickel-metal hydride battery pack, but has designed the vehicle with conversion to a lithium-ion battery source at some point in the future. Toyota estimates that the all-electric range of the Prius PHEV will be less than 10 miles.

Chevrolet will bring the Volt to market in late 2010, and plans to use a lithium-ion battery pack with the vehicle. Chevrolet has said that the all-electric range of the Volt will be in the neighborhood of 40 miles. To accomplish this, the Volt uses a 600-V battery pack, which is about twice the size of the most robust conventional hybrid battery pack.

A PHEV never requires household current to charge. If the driver doesn't plug in a PHEV, the car will operate in its HEV mode at all times, relying on the internal combustion engine to supply power to its generator. In contrast, electric cars do require an external charging source for their batteries. Periodically, these vehicles must be charged to remain operational.

Unfortunately for consumers, EV manufacturers have not settled on connector standards. Also unsettled is the issue of current. Some vehicles charge on 220V, while other charge on 110V. Electric vehicles typically come with a number of adapters to enable the use of public charging stations. When an EV charges at home, an EV or PHEV may increase the daily household electrical consumption by 25% or more.

One of the major advantages of a PHEV is its exceptionally low fuel consumption. Over the course of a year, a PHEV may consume as little as one-seventh the amount of gasoline that a conventional vehicle does. For most drivers, the all-electric range of a fully charged PHEV will enable them to complete their daily commute without using any gasoline at all.

What are the major disadvantages of a PHEV? First, the cost of a PHEV is likely to be higher than that of a regular hybrid electric vehicle. Most of the cost differential can be attributed to the increased battery needs of the car. The increased battery requirements also mean increased cost when the battery pack requires replacement. Currently, manufacturers warranty their HEV battery packs for about 8-10 years. Insufficient data exist to know how long mass produced HEV and PHEV battery packs will last, but most hybrid vehicles have not experienced significant battery problems during what would be considered the normal life expectancy of the vehicle.

Industrialized nations have a well-established network of refineries, pipelines, storage facilities, transportation operations and retail sales outlets for gasoline. There is no such supporting infrastructure for PHEVs. Over time, if PHEVs are widely accepted by consumers, municipalities and private companies may invest in the construction of a charging infrastructure for PHEVs. Without a standardized charging system in place, the primary benefits of PHEVs will be limited to short-distance travel.

A third disadvantage of the PHEV is that the impact on the nation's electrical infrastructure is not yet clear. If PHEVs are widely accepted by consumers, the increased load on the electrical grids could be significant. Meeting the new demand for electricity could require the construction of new power plants, many of which would be coal-fired. Electricity produced by coal-fired power plants will merely shift the carbon emissions from the tailpipe to the smokestack, and will not produce significant reductions in greenhouse gas emissions. Achieving this goal through the use of PHEVs would also require the construction of clean power plants. These new plants would be fired by more expensive natural gas or would use nuclear power, a technology that has not yet proven its safety in the minds of the public.

CMU Says Volt Won't Be A Consumer Hit

Despite GM's protestations about the desirability of the car's 40-mile all-electric range, the cost to manufacture and replace the Li-ion battery pack will doom the car's commercial success, and relegate it to a collector curiosity. According to the report, smaller cars with smaller battery packs will provide better consumer value than the Volt will. Hybrids with an all-electric range of ten miles or less or improvements to current hybrid design will more likely provide the consumer with the right mix of fuel efficiency, acquisition and operational costs, and charging times.

Jeremy Michalek wrote a professor of engineering at CMU the study, which will be published in a future issue of Energy Policy. The research team constructed computer models of PHEVs that account for the impact of various battery sizes on fuel economy, greenhouse gas emissions and charging cycles.

The study found that for moderate travel, which the group defined as those trips between 20 and 100 miles, PHEVs produced fewer greenhouse gas emissions, but fell short on cost-effectiveness. The models indicated that hybrid electric vehicles were more cost efficient with the study's controls. PHEVs became more attractive from a cost perspective only when the price of fuel was high, the price of batteries was low, the cost of electricity generation was reduced or other costs, like carbon taxes, were added to the model.

Carbon taxes are not currently applied as such, however the automakers do face fines if the combined average fuel economy of their fleet does not meet federal standards. Regulations do not govern the tailpipe emissions of any model in particular, so models with lower fuel efficiency and higher carbon emissions can be offset by sales of higher fuel economy models from the same manufacturer.

Recently, several states won the right to regulate tailpipe emissions, a reversal of a long-standing policy that preserved federal control of vehicle emissions. The change in policy means that states can enact tougher emissions standards than those imposed by the federal government. Even with increased restrictions on emissions, and changes to other study variables, the author concludes that the most effective PHEVs will be small urban vehicles whose drivers have access to regular charging facilities.

Source: Carnegie Mellon University PDF link

Photo Credit: MR38

NTEA Show Features Hybrid Work Trucks

In addition to providing fuel economy on the road, the hybrid system can also power booms, aerial buckets and tools for up to 90 minutes without needing power from the engine. The system significantly reduces carbon emissions and noise associated with the trucks. Navistar is sponsoring the City of Chicago's bid for the 2016 Summer Olympics.

Kraft Foods also announced that it had taken delivery of an International DuraStar Refrigerated Hybrid delivery truck this week. The truck is the first of its kind, and Kraft will use it to deliver frozen foods to retail outlets. According to Mike Cole, Kraft's North American Director of Transportation, the truck is part of the company's efforts to reduce carbon emissions and fuel consumption. The new vehicle is expected to produce a fuel savings of as much as 30 percent over a conventionally powered delivery truck.

Honda has also added a Class 8 hybrid delivery vehicle to its fleet. The truck, which is built for Honda by Peterbilt, will be used to deliver parts to dealerships in Tennessee and Georgia. The company will evaluate the truck's performance in comparison to a conventional vehicle that drives the same routes. The test period for the truck is expected to last about a year.

The truck features a parallel hybrid system developed by Eaton Corp. The hybrid system powers the truck's climate control systems and electrical accessories, and incorporates stop-start technology to provide electrical power when the vehicle is idling.

Photo Credit: Image Courtesy of Navistar

FEV Opens Hybrid, EV Development Center

The HEVDC will facilitate the development of hybrid power trains and related technologies by providing accurate testing facilities. The facility will initially test hybrid power trains and transmissions, electric motors, and charging stations for EVs and PHEVs. The HEVDC's charging station is the first in Michigan and will also be used for testing and validation purposes.

The HEVDC features multiple battery emulation systems and a chassis dynamometer to facilitate testing while minimizing downtime. The setup also permits full testing of all hybrid system components at once. The HEVDC can test powertrains of any size and the battery emulators can provide as much as 900V on demand, about three times that required of today's HEVs.

The testing center will help automotive manufacturers test hybrid powertrain designs, as well as integration of those designs into pre-production and production vehicles.

FEV says that it expects to add personnel to meet the demand for the testing center. FEV provides gasoline, diesel and electric powertrain engineering, design and testing services for a variety of commercial automotive applications.

Photo Credit: FEV

PSA Peugeot Citroën Will Make Mini Cars

Daimler plans to produce an all-electric version of the SmartForTwo and Volkswagen will produce the Audi Up!, an all-electric mini car with a top speed of about 80 miles per hour and a range of about 60 miles. Renault has a small electric vehicle in development for sale in 2011. Toyota has also announced the development of a short-range all-electric vehicle for the 2012 model year.

The development of small electric vehicles is in response to both perceived consumer demand and the technological realities of current battery capabilities. EV batteries perform better in smaller vehicles. It's not surprising that most of the smaller EVs are initially destined for the European market, where consumers are more likely to make short trips and less likely to want larger vehicles. The companies have not yet indicated whether any of these vehicles will be available for sale to the North American market.

Small EVs or city cars may have a passenger capacity of only two or three adults, but are likely to be less expensive than gas-electric or diesel-electric hybrids. Whether electric cars will be cleaner than hybrids remains to be seen, since power-plant emissions must be taken into consideration when determining the carbon footprint of a PHEV. However, all-electric vehicles that have a gasoline generator on board used only for battery recharging will produce lower carbon emissions than gas-electric hybrids.

Photo Credit: Mitsubishi Motor Sales Of America

Toyota Puts Hybrid Development Into High Gear

Most electrical power plants in the United States are fired by coal, natural gas or petroleum, all of which release carbon dioxide into the air. Coal, the most common power plant fuel, releases the most CO2 into the atmosphere as it is burned to make electricity. Natural gas, less commonly used in power plants, is cleaner by a scant 50 percent.

In a head-to-head comparison, an all-electric vehicle such as a Tesla Roadster that charges off of house current might actually be responsible for more CO2 emissions than a Prius or Insight would when the emissions from a coal-fired power plant are taken into consideration. Hybrid cars also emit less CO2 than most highly efficient gasoline-only vehicles and those powered by diesel or "clean diesel" engines.

So do EVs and PHEVs make sense? If you're switching to one from a larger, older or less efficient vehicle, a PHEV or EV can indeed reduce your carbon footprint. The story raises an issue, however, that has been discussed before. The overall impact of large-scale migration to PHEVs, EVs and HEVs won't reduce carbon emissions significantly unless the fossil-fueled power plants are modernized at the same time. Conversion of the plants to natural gas can reduce carbon emission, but the cost of a natural gas-fired plant will substantially increase consumer cost and will reduce the rate at which consumers convert to vehicles with electric drive trains.

One potential alternative is a hydrogen-powered vehicle. BMW has tested its hydrogen FCV at Argonne National Laboratories, and those tests show that the vehicle actually emits air that is slightly cleaner than the air it takes in. Unfortunately, the vehicle won't be mass-produced anytime in the near future because the supporting infrastructure is not yet available.

The moral of the story? If you're buying an alternative-fuel vehicle for environmental reasons, make sure that you're really helping Mother Nature, and not just shifting the problem to someone else's exhaust pipe.

Source: International Business Times

Photo: Courtesy of Toyota

Aptera Close To Starting Production On EV

The Aptera 2e is a three-wheeled creature that seats just two passengers, and according to the company, will get more than 100 mpg and the company says the hybrid version, the Aptera 2h - available sometime in 2010 - will average more than 300 mpg. The company, whose assembly plant is in Vista, CA, will start cranking out vehicles with a very distinct profile in the fourth quarter of 2009. The vehicles will range in price from $25,000 to $40,000.

The company says that it has taken reservations for more than 4,000 vehicles to date and expects the Aptera to appeal mostly to tech-savvy men who are looking for a second or third vehicle. Initially, the company expects to produce about 10,000 vehicles per year and has plans to step up production to 100,000 units in the next two years.

Aptera is being fronted by Idealab, Esenjay Petroleum and Google.org, but its three-wheel design excludes it from eligibility for interest loans from the federal government for fuel-efficient cars. No matter, the company says; it has plenty of cash to fulfill its Q4 production. Aptera is still taking reservations for vehicles. To reserve an Aptera, visit the company Web site. You'll need to put down a $500 refundable deposit and be prepared to wait.

Now for the bad news: you can't buy an Aptera 2e unless you live in California. The company is working to get sales restrictions in other states lifted but has no timetable for expanded sales.

Photo Credit: Photo Courtesy of Aptera

Following that, the industry says, companies should turn to development of biofuels, and EV development should wait until those options have been completely explored. Based on the overall bottom-line of a conventional vehicle, the industry executives say that consumers will get a better deal by buying cars that are more efficient and cleaner-burning than they will by switching to an electric vehicle.

This debate makes Texas a state divided. On one hand, Texas is home to many local oil producers that would clearly suffer if oil consumption decreased. On the other hand, it also wants to be at the forefront of the alternative energy movement. Last week, Texas governor Rick Perry said that he would support a state tax credit of $5,000 for buyers of plug-in electric vehicles in certain Texas cities that have run afoul of the EPA's air quality regulations. Those tax credits could combine with federal tax credits on PHEVs that would slice another $7,500 off of the price tag.

The big concern in Texas (and other states) is that a large-scale switch to PHEVs would substantially increase the demand for electricity from the grid. Most electrical power plants are coal-fired, which means that gains made at the tailpipe in terms of emissions are offset by the added emissions from coal-fired electricity plants. Analysis shows that in this scenario, the CO2 reductions would be modest at best.

Texas also has a fledgling wind-power industry, but has no practical transmission system to take the converted power to the grid. Perry's plan would put the state's dollars into building a transmission system that could allow the state to make effective use of alternative energy generation, and potentially extend the emissions gains made by PHEVs.

In the short term, multiple alternative energy sources should be developed and considered. Competitive technologies often produce the best possible outcomes because they spur the development of newer, cleaner and more efficient methods of achieving the same end. The bottom-line cost of a new technology is only an immediate or intermediate concern. Once a technology is deemed reliable, and can be mass-produced or supported in sufficient quantity to meet demand, the issue of increased costs may drop out altogether.