Plug-in hybrid

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A plug-in hybrid electric vehicle (PHEV) is a type of

As of December 2019[update], the global stock of PHEVs totalled 2.4 million units, representing one-third of the stock of

A plug-in hybrid's all-electric range is designated by PHEV-[miles] or PHEV[kilometers]km in which the number represents the distance the vehicle can travel on battery power alone. For example, a PHEV-20 can travel 32 km (20 miles) without using its combustion engine, so it may also be designated as a PHEV32km.[9]

For these cars to be battery operated, they go through charging processes that use different currents. These currents are known as Alternating Current (AC) used for on board chargers and Direct Current (DC) used for external charging.^[10]

Other popular terms sometimes used for plug-in hybrids are "grid-connected hybrids", "Gas-Optional Hybrid Electric Vehicle" (GO-HEV) or simply "gas-optional hybrids".

Invention and early interest

The

The July 1969 issue of Popular Science featured an article on the General Motors XP-883 plug-in hybrid. The concept commuter vehicle housed six 12-volt lead–acid batteries in the trunk area and a transverse-mounted DC electric motor turning a front-wheel drive. The car could be plugged into a standard North American 120 volt AC outlet for recharging.^[22]

Revival of interest

In 2003,

With the availability of hybrid vehicles and the rising gas prices in the United States starting around 2002, interest in plug-in hybrids increased.[25] Some plug-in hybrids were conversions of existing hybrids; for example, the 2004 CalCars conversion of a Prius to add lead acid batteries and a range of up to 15 km (9 mi) using only electric power.^[26]

In 2006, both Toyota and General Motors announced plans for plug-in hybrids.^[27][28] GM's Saturn Vue project was cancelled, but the Toyota plug-in was certified for road use in Japan in 2007.^[29]

In 2007, Quantum Technologies and

In 2007, Chinese car manufacturer BYD Auto, owned by China's largest mobile phone battery maker, announced it would be introducing a production PHEV-60 sedan in China in the second half of 2008. BYD exhibited it in January 2008 at the North American International Auto Show in Detroit. Based on BYD's midsize F6 sedan, it uses lithium iron phosphate (LiFeP0₄)-based batteries instead of lithium-ion, and can be recharged to 70% of capacity in 10 minutes.^[33]

In 2007 Ford delivered the first

On January 14, 2008, Toyota announced they would start sales of lithium-ion battery PHEVs by 2010,[38]^[39] but later in the year Toyota indicated they would be offered to commercial fleets in 2009.^[40]

On March 27, the

Launched in China in December 2008, the BYD F3DM became the world's first mass-produced plug-in hybrid automobile.^[50]

The BYD Qin, released in China in December 2013, replaced the F3DM.^[51]

On December 15, 2008, BYD Auto began selling its

Deliveries to retail customers of the limited edition

Sales of the Porsche 918 Spyder began in Europe in May 2014.

The BMW i8 was released in Europe in June 2014.

In February 2016, BMW announced the introduction of the "iPerformance" model designation, which will be given to all BMW plug-in hybrid vehicles from July 2016. The aim is to provide a visible indicator of the transfer of technology from

In December 2017, Honda began retail deliveries of the Honda Clarity Plug-In Hybrid in the United States and Canada, with an EPA rated electric-only range of 76 km (47 miles).^[104]

In 2013, Volkswagen started production on the Volkswagen XL1, a two-person limited production diesel-powered plug-in hybrid vehicle designed to be able to travel 100 km/L (280 mpg_‑imp; 235 mpg_‑US) on diesel, while still being both roadworthy and practical. The model is built with a 800 cc (49 cu in) TDI twin-cylinder, common-rail 35 kW (47 hp) turbo-diesel and a 20 kW (27 hp) electric motor. The model is unique in that it is one of the only mass produced plug-in diesel hybrid vehicles and one of the only mass produced diesel hybrid vehicles in general.^{[105][106][107]}

Technology

Powertrains

PHEVs are based on the same three basic powertrain architectures of conventional hybrids; a series hybrid is propelled by electric motors only, a parallel hybrid is propelled both by its internal combustion engine and by electric motors operating concurrently, and a series-parallel hybrid operates in either mode. While a plain hybrid vehicle charges its

The battery charger can be on-board or external to the vehicle. The process for an on-board charger is best explained as AC power being converted into DC power, resulting in the battery being charged.[10] On-board chargers are limited in capacity by their weight and size, and by the limited capacity of general-purpose AC outlets. Dedicated off-board chargers can be as large and powerful as the user can afford, but require returning to the charger; high-speed chargers may be shared by multiple vehicles.

Using the electric motor's inverter allows the motor windings to act as the transformer coils, and the existing high-power inverter as the AC-to-DC charger. As these components are already required on the car, and are designed to handle any practical power capability, they can be used to create a very powerful form of on-board charger with no significant additional weight or size. AC Propulsion uses this charging method, referred to as "reductive charging".^[110]

Modes of operation

A plug-in hybrid operates in

Charge-depleting mode allows a fully charged PHEV to operate exclusively (or depending on the vehicle, almost exclusively, except during hard acceleration) on electric power until its battery state of charge is depleted to a predetermined level, at which time the vehicle's internal combustion engine or fuel cell will be engaged. This period is the vehicle's all-electric range. This is the only mode that a battery electric vehicle can operate in, hence their limited range.^[112]

Mixed mode describes a trip using a combination of multiple modes. For example, a car may begin a trip in low speed charge-depleting mode, then enter onto a freeway and operate in blended mode. The driver might exit the freeway and drive without the internal combustion engine until all-electric range is exhausted. The vehicle can revert to a charge sustaining-mode until the final destination is reached. This contrasts with a charge-depleting trip which would be driven within the limits of a PHEV's all-electric range.

Most PHEV's also have two additional charge sustaining modes:

Battery Hold; the electric motor is locked out and the vehicle operates exclusively on combustion power, so that whatever charge is left in the battery remains for when mixed mode or full electric operation are re-engaged, whilst regenerative braking will still be available to boost the battery charge. On some PHEVs, vehicle services which use the traction battery (such as heating and air conditioning) are placed in a low power consumption mode to further conserve the remaining battery charge. The lock-out of the electric motor is automatically overridden (charge permitting) should full acceleration be required.

Self Charge; the electric motor's armature is engaged to the transmission, but is connected to the battery so that it runs as a generator and therefore recharges the battery whilst the car is in motion, although this comes at the expense of higher fuel consumption, as the combustion engine has to both power the vehicle itself and charge the battery. This is useful for 'charging on the move' when there are limited places to plug the vehicle in.

Electric power storage

The optimum battery size varies depending on whether the aim is to reduce fuel consumption, running costs, or emissions, but a 2009 study^[113] concluded that "The best choice of PHEV battery capacity depends critically on the distance that the vehicle will be driven between charges. Our results suggest that for urban driving conditions and frequent charges every 10 miles or less, a low-capacity PHEV sized with an AER (all-electric range) of about 7 miles would be a robust choice for minimizing gasoline consumption, cost, and greenhouse gas emissions. For less frequent charging, every 20–100 miles, PHEVs release fewer GHGs, but HEVs are more cost effective."

PHEVs typically require deeper

The cathodes of some early 2007 lithium-ion batteries are made from lithium-cobalt metal oxide. This material is expensive, and cells made with it can release oxygen if overcharged. If the cobalt is replaced with iron phosphates, the cells will not burn or release oxygen under any charge. At early 2007 gasoline and electricity prices, the break-even point is reached after six to ten years of operation. The payback period may be longer for plug-in hybrids, because of their larger, more expensive batteries.^[118]

Nickel–metal hydride and lithium-ion batteries can be recycled; Toyota, for example, has a recycling program in place under which dealers are paid a US$200 credit for each battery returned.^[119] However, plug-in hybrids typically use larger battery packs than comparable conventional hybrids, and thus require more resources. Pacific Gas and Electric Company (PG&E) has suggested that utilities could purchase used batteries for backup and load leveling purposes. They state that while these used batteries may be no longer usable in vehicles, their residual capacity still has significant value.^[120] More recently, General Motors (GM) has said it has been "approached by utilities interested in using recycled Volt batteries as a power storage system, a secondary market that could bring down the cost of the Volt and other plug-in vehicles for consumers".^[121]

There are several companies that are converting fossil fuel non-hybrid vehicles to plug-in hybrids:^[125][126]

Many early plug-in hybrid electric vehicle conversions have been based on the Toyota Prius.^[128] Some of the systems have involved replacement of the vehicle's original NiMH battery pack and its electronic control unit. Others add an additional battery back onto the original battery pack.^[129]

Target market

In recent years, demand for all- electric vehicles, especially in the United States market, has been driven by government incentives through subsidies, lobbyists, and taxes.

Plug-in hybrids provide the extended range and potential for refueling of conventional hybrids while enabling drivers to use battery electric power for at least a significant part of their typical daily driving. The average trip to or from work in the United States in 2009 was 11.8 miles (19.0 km),^[133] while the average distance commuted to work in England and Wales in 2011 was slightly lower at 9.3 miles (15 km).^[134] Since building a PHEV with a longer all-electric range adds weight and cost, and reduces cargo and/or passenger space, there is not a specific all-electric range that is optimal. The accompanying graph shows the observed all-electric range, in miles, for four popular U.S. market plug-in hybrids, as tested by Popular Mechanics magazine.^[135]

A key design parameter of the Chevrolet Volt was a target of 40 miles (64 km) for the all-electric range, selected to keep the battery size small and lower costs, and mainly because research showed that 78% of daily commuters in the U.S. travel 40 mi (64 km) or less. This target range would allow most travel to be accomplished electrically driven and the assumption was made that charging will take place at home overnight. This requirement translated using a lithium-ion battery pack with an energy storage capacity of 16 kWh considering that the battery would be used until the state of charge (SOC) of the battery reached 30%.^[136][137]

In October 2014 General Motors reported, based on data collected through its

Plug-in hybrids have the potential to be even more efficient than conventional hybrids because a more limited use of the PHEV's internal combustion engine may allow the engine to be used at closer to its maximum efficiency. While a Toyota Prius is likely to convert fuel to motive energy on average at about 30% efficiency (well below the engine's 38% peak efficiency), the engine of a PHEV-70 would be likely to operate far more often near its peak efficiency because the batteries can serve the modest power needs at times when the combustion engine would be forced to run well below its peak efficiency.^[112] The actual efficiency achieved depends on losses from electricity generation, inversion, battery charging/discharging, the motor controller and motor itself, the way a vehicle is used (its duty cycle), and the opportunities to recharge by connecting to the electrical grid.

Each

In real world testing using normal drivers, some Prius PHEV conversions may not achieve much better fuel economy than HEVs. For example, a plug-in Prius fleet, each with a 30 miles (48 km) all-electric range, averaged only 51 mpg_‑US (4.6 L/100 km; 61 mpg_‑imp) in a 17,000-mile (27,000 km) test in Seattle,[150] and similar results with the same kind of conversion battery models at Google's RechargeIT initiative. Moreover, the additional battery pack costs US$10,000–US$11,000.^[151][152]

Operating costs

A study published in 2014 by researchers from Lamar University, Iowa State University and Oak Ridge National Laboratory compared the operating costs of PHEVs of various electric ranges (10, 20, 30, and 40 miles) with conventional gasoline vehicles and non-plugin hybrid-electric vehicles (HEVs) for different payback periods, considering different charging infrastructure deployment levels and gasoline prices. The study concluded that:^[153]

• PHEVs save around 60% or 40% in energy costs, compared with conventional gasoline vehicles and HEVs, respectively. However, for drivers with significant daily vehicle miles traveled (DVMT), hybrid vehicles may be even a better choice than plug-in hybrids with a range of 40 mi (64 km), particularly when there is a lack of public charging infrastructure.
• The incremental battery cost of large-battery plug-in hybrids is difficult to justify based on the incremental savings of PHEVs' operating costs unless a subsidy is offered for large-battery PHEVs.
• When the price of gasoline increases from US$4 per gallon to US$5 per gallon, the number of drivers who benefit from a larger battery increases significantly. If the gas price is US$3, a plug-in hybrid with a range of 10 mi (16 km) is the least costly option even if the battery cost is $200/kWh.
• Although
  Level-2 chargers
  .

Cost of batteries

Disadvantages of PHEVs include the additional cost, weight and size of a larger

According to the 2010 NRC study, although a mile driven on electricity is cheaper than one driven on gasoline, lifetime fuel savings are not enough to offset plug-ins' high upfront costs, and it will take decades before the break-even point is achieved.[156] Furthermore, hundreds of billions of dollars in government subsidies and incentives are likely to be required to achieve rapid plug-in market penetration in the U.S.^[155][156]

A 2013 study by the

A study published in 2011 by the Belfer Center, Harvard University, found that the gasoline costs savings of PHEVs over the vehicles' lifetimes do not offset their higher purchase prices. This finding was estimated comparing their lifetime net present value at 2010 purchase and operating costs for the U.S. market, and assuming no government subidies.^[159][160] According to the study estimates, a PHEV-40 is US$5,377 more expensive than a conventional internal combustion engine, while a battery electric vehicle (BEV) is US$4,819 more expensive. The study also examined how this balance will change over the next 10 to 20 years, assuming that battery costs will decrease while gasoline prices increase. Under the future scenarios considered, the study found that BEVs will be significantly less expensive than conventional cars (US$1,155 to US$7,181 cheaper), while PHEVs, will be more expensive than BEVs in almost all comparison scenarios, and only less expensive than conventional cars in a scenario with very low battery costs and high gasoline prices. BEVs are simpler to build and do not use liquid fuel, while PHEVs have more complicated powertrains and still have gasoline-powered engines.^[159]

Emissions shifted to electric plants

Increased

According to a 2009 study by The National Academy of Science, "Electric vehicles and grid-dependent (plug-in) hybrid vehicles showed somewhat higher nonclimate damages than many other technologies."[164] Efficiency of plug-in hybrids is also impacted by the overall efficiency of electric power transmission. Transmission and distribution losses in the USA were estimated at 7.2% in 1995^[165] and 6.5% in 2007.^[166] By life cycle analysis of air pollution emissions, natural gas vehicles are currently the lowest emitter^{[citation needed]}.

Tiered rate structure for electric bills

The additional electrical consumption to recharge the plug-in vehicles could push many households in areas that do not have off-peak tariffs into the higher priced tier and negate financial benefits.^[167] Customers under such tariffs could see significant savings by being careful about when the vehicle was charged, for example, by using a timer to restrict charging to off-peak hours. Thus, an accurate comparison of the benefit requires each household to evaluate its current electrical usage tier and tariffs weighed against the cost of gasoline and the actual observed operational cost of electric mode vehicle operation.

Greenhouse gas emissions

The effect of PHEVs on greenhouse emissions is complex. Plug-in hybrid vehicles operating on

The Argonne study found that PHEVs offered reductions in petroleum energy use as compared with regular hybrid electric vehicles. More petroleum energy savings and also more GHG emissions reductions were realized as the all-electric range increased, except when electricity used to recharge was dominated by coal or oil-fired power generation. As expected, electricity from renewable sources realized the largest reductions in petroleum energy use and GHG emissions for all PHEVs as the all-electric range increased. The study also concluded that plug-in vehicles that employ biomass-based fuels (biomass-E85 and -hydrogen) may not realize GHG emissions benefits over regular hybrids if power generation is dominated by fossil sources.[170]

Oak Ridge

A 2008 study by researchers at Oak Ridge National Laboratory analyzed oil use and greenhouse gas (GHG) emissions of plug-in hybrids relative to hybrid electric vehicles under several scenarios for years 2020 and 2030.^[173] The study considered the mix of power sources for 13 U.S. regions that would be used during recharging of vehicles, generally a combination of coal, natural gas and nuclear energy, and to a lesser extent renewable energy.^[173][174] A 2010 study conducted at Argonne National Laboratory reached similar findings, concluding that PHEVs will reduce oil consumption but could produce very different greenhouse gas emissions for each region depending on the energy mix used to generate the electricity to recharge the plug-in hybrids.^[175][176]

Environmental Protection Agency

This section needs to be updated. Please help update this article to reflect recent events or newly available information. (December 2023)

In October 2014, the

In addition, the EPA accounted for the upstream CO₂ emissions associated with the production and distribution of electricity required to charge the PHEVs. Since electricity production in the United States varies significantly from region to region, the EPA considered three scenarios/ranges with the low end of the range corresponding to the California powerplant emissions factor, the middle of the range represented by the national average powerplant emissions factor, and the upper end of the range corresponding to the powerplant emissions factor for the Rockies. The EPA estimates that the electricity GHG emission factors for various regions of the country vary from 346 g CO₂/kW-hr in California to 986 g CO₂/kW-hr in the Rockies, with a national average of 648 g CO₂/kW-hr.[177] The following table shows the tailpipe emissions and the combined tailpipe and upstream emissions for each of the 10 MY 2014 PHEVs available in the U.S. market.

National Bureau of Economic Research

Most emission analysis use average emissions rates across regions instead of marginal generation at different times of the day. The former approach does not take into account the generation mix within interconnected electricity markets and shifting load profiles throughout the day.

Production and sales

This section needs to be updated. Please help update this article to reflect recent events or newly available information. (December 2023)

Production models

Since 2008, plug-in hybrids have been commercially available from both specialty manufacturers and from mainstream producers of internal combustion engine vehicles. The

Global sales of plug-in hybrids grew from over 300 units in 2010 to almost 9,000 in 2011, jumped to over 60,000 in 2012, and reached almost 222,000 in 2015.[86] As of December 2015^[update], the United States was the world's largest plug-in hybrid car market with a stock of 193,770 units.^[86] About 279,000 light-duty plug-in hybrids were sold in 2016,^[185] raising the global stock to almost 800,000 highway legal plug-in hybrid electric cars at the end of 2016.^[186][187] A total of 398,210 plug-in hybrid cars were sold in 2017, with China as the top selling country with 111,000 units, and the global stock of plug-in hybrids passed the one million unit milestone by the end of 2017.^[183]

Global sales of plug-in electric vehicles have been shifting for several years towards fully electric battery cars. The global ratio between all-electrics (BEVs) and plug-in hybrids (PHEVs) went from 56:44 in 2012, to 60:40 in 2015, to 66:34 in 2017, and rose to 69:31 in 2018.^[184][188]

By country

The Netherlands, Sweden, the UK, and the United States have the largest shares of plug-in hybrid sales as percentage of total plug-in electric passenger vehicle sales. The Netherlands has the world's largest share of plug-in hybrids among its plug-in electric passenger car stock, with 86,162 plug-in hybrids registered at the end of October 2016, out of 99,945 plug-in electric cars and vans, representing 86.2% of the country's stock of light-duty plug-in electric vehicles.^[190]

Sweden ranks next with 16,978 plug-in hybrid cars sold between 2011 and August 2016, representing 71.7% of total plug-in electric passenger car sales registrations.^{[191][192][193][194][195]} Plug-in hybrid registrations in the UK between up to August 2016 totaled 45,130 units representing 61.6% of total plug-in car registrations since 2011.^[196] In the United States, plug-in hybrids represent 47.2% of the 506,450 plug-in electric cars sold between 2008 and August 2016.^[197]

In November 2013 the Netherlands became the first country where a plug-in hybrid topped the monthly ranking of new car sales. During November sales were led by the

The following table presents the top ranking countries according to its plug-in hybrid segment market share of total new car sales in 2013:

Top 10 countries by plug-in hybrid market share of new car sales in 2013[203]
Ranking	Country	PHEV market share(1) (%)	Ranking	Country	PHEV market share(1) (%)
1	Netherlands	4.72%	6	Iceland	0.25%
2	Sweden	0.41%	7	Finland	0.13%
3	Japan	0.40%	8	United Kingdom	0.05%
4	Norway	0.34%	9	France	0.05%
5	United States	0.31%	10	Switzerland	0.05%
Note: (1) Market share of highway-capable plug-in hybrids as percentage of total new car sales in the country in 2013.

By model

According to

The following table presents plug-in hybrid models with cumulative global sales of around or more than 100,000 units since the introduction of the first modern production plug-in hybrid car, the BYD F3DM, in 2008 up until December 2020:

Government support and public deployment

Subsidies and economic incentives

Several countries have established

The American Recovery and Reinvestment Act of 2009^[231] modifies the tax credits, including a new one for plug-in electric drive conversion kits and for 2 or 3 wheel vehicles.^[232] The ultimate total included in the Act that is going to PHEVs is over $6 billion.^[233]

In March 2009, as part of the American Recovery and Reinvestment Act, the

• US Department of Energy announced it would dole out $30 million in funding to three companies over three years to further the development of plug-in hybrids^[235]
• USDOE announced the selection of Navistar Corporation for a cost-shared award of up to $10 million to develop, test, and deploy plug-in hybrid electric (PHEV) school buses.^[236]
• DOE and Sweden have a MOU to advance market integration of plug-in hybrid vehicles^[237]
• PHEV Research Center
• Plug-in hybrids in California
  ).
• Washington state PHEV Pilot Project^[240]
• Texas Governor Rick Perry's proposal for a state $5,000 tax credit for PHEVs in "non-attainment" communities
• Seattle, that includes City's public fleet converted vehicles, the Port of Seattle, King County and the Puget Sound Clean Air Agency^[241]

European Union

Organizations that support plug-in hybrids include the World Wide Fund for Nature,^[243] National Wildlife Federation,^[244] and CalCars.^[245]

Other supportive organizations are

FPL and Duke Energy has said that by 2020 all new purchases of fleet vehicles will be plug-in hybrid or all-electric.[248]

See also

References

Further reading

• American Council for an Energy-Efficient Economy, Plug-in Electric Vehicles: Challenges and Opportunities, June 2013
• Argonne National Laboratory, Cradle-to-Grave Lifecycle Analysis of U.S. Light-Duty Vehicle-Fuel Pathways: A Greenhouse Gas Emissions and Economic Assessment of Current (2015) and Future (2025–2030) Technologies Archived 2020-08-12 at the Wayback Machine (includes estimated cost of avoided GHG emissions from BEVs and PHEVs), June 2016.
• Boschert, Sherry (2007). Plug-in Hybrids: The Cars that will Recharge America (1st ed.). New Society Publishers.
  OCLC 74524214
  .
• International Council on Clean Transportation, Driving Electrification – A Global Comparison of Fiscal Incentive Policy for Electric Vehicles, May 2014
• International Energy Agency (IEA) and Electric Vehicles Initiative (April 2013), Global EV Outlook 2013 – Understanding the Electric Vehicle Landscape to 2020
• International Energy Agency (IEA) – IA-HEV (May 2013), Hybrid and Electric Vehicles – The Electric Drive Gains Traction Archived 2021-02-26 at the Wayback Machine
• Lee, Henry, and Grant Lovellette (2011).Will Electric Cars Transform the U.S. Vehicle Market? Belfer Center, Harvard University
• Nevres, Cefo (2009). Two Cents per Mile: Will President Obama Make it Happen With the Stroke of a Pen?. Nevlin.
  OCLC 463395305
  .
• Sandalow, David B., ed. (2009). Plug-In Electric Vehicles: What Role for Washington? (1st. ed.). The Brookings Institution.
  OCLC 895434772
  .
• Michalek, Jeremy (February 2015). "CMU team finds regional temperature differences have significant impact on EV efficiency, range and emissions". Green Car Congress.
• Romm, Joseph J. and Fox-Penne, Peter. (2007). Plugging into the Grid: How Plug-In Hybrid-Electric Vehicles Can Help Break America's Oil Addiction and Slow Global Warming. Progressive Policy Institute
  .
• U.S. Environmental Protection Agency, Application of Life-Cycle Assessment to Nanoscale Technology: Lithium-ion Batteries for Electric Vehicles
  , April 2013.
• US Office of Energy Efficiency and Renewable Energy
  • Plug-In Hybrid Electric Vehicle Value Proposition Study Final Report, July 2010.
  • Plug-in Hybrid Electric Vehicles.
  • Alternative Fuels and Advanced Vehicles Data Center (AFDC), including list of books and publications.
• US National Highway Traffic Safety Administration
  • Interim Guidance Electric and Hybrid Electric Vehicles Equipped with High Voltage Batteries – Vehicle Owner/General Public Archived 2013-12-09 at the Wayback Machine
  • Interim Guidance Electric and Hybrid Electric Vehicles Equipped with High Voltage Batteries – Law Enforcement/Emergency Medical Services/Fire Department Archived 2013-12-09 at the Wayback Machine

External links

Wikimedia Commons has media related to Plug-in electric hybrid-powered vehicles.

Wikiquote has quotations related to Plug-in hybrid.

• Plug In America – Non-profit advocacy group.
• eGallon Calculator: Compare the costs of driving with electricity.
  U.S. Department of Energy
  .