Plug-in hybrids use far more gasoline in the real world than regulatory agencies account for, according to a new analysis of data by the International Council on Clean Transportation, the research group that broke the Volkswagen dieselgate scandal.
The ICCT analyzed data both from Fuelly, an app which helps drivers track their fuel efficiency, and from the California Bureau of Automotive Repair (BAR). It then compared this data to regulatory agency estimates and found that PHEVs are not driving on electric power nearly as often as the EPA had assumed they are.
This could have significant implications for the way plug-in hybrid cars are regulated since they seem to produce more emissions and use more gasoline in practice than previously thought.
The data showed that PHEVs spend 26-56% less time in all-electric drive mode (this is called the “utility factor”), and therefore consume 42-67% more fuel than EPA labeling suggests.
Further, the unbiased data from BAR looked worse than the self-reporting data from Fuelly:
Researchers think this is because self-reported MPG data will skew towards drivers who pay more attention to efficiency, and thus are more likely to drive in a more efficient manner and remember to plug in their cars. But the data from BAR doesn’t include this bias, so in reality, PHEV shortcomings probably skew on the high end of these percentage estimates.
The ICCT had even more drastic results in an earlier study in Europe. In that study, fuel usage and emissions for PHEVs were 3-5 times higher than WLTP estimates suggested. Part of this was due to company cars where a company would pay for fuel, but not electricity, and thus were never plugged in, but were purchased by the company in order to get PHEV incentives. But even for non-company cars, the disparity between WLTP and real-world estimates was even larger than in the US.
Research lead Aaron Isenstadt showed us a table of the best- and worst-performing PHEV models, and pointed out that, as expected, “range-extended” models (like the i3 and Volt) which focus on using the engine as a backup generator for an ample battery tended to have higher electric usage. Whereas PHEVs with vestigial batteries like the original Plug-in Prius, or where the target customer was less environmentally-minded like the Range Rover and Panamera, were barely ever plugged in.
BestEDS
BAR data (MY19+, automatic collection)
Electric drive share
Fuelly data (MY11+, user-reported)
Electric drive share
1st
2019 Chevrolet Volt
0.623
2014 BMW i3 REX
0.900
2nd
2019 Volvo S60 AWD
0.548
2016 BMW I3 REX
0.875
3rd
2022 BMW 530e Sedan
0.499
2017 BMW i3 REX
0.864
4th
2021 BMW 330e xDrive
0.486
2015 BMW I3 REX
0.824
5th
2019 Volvo XC60 AWD
0.442
2016 Cadillac ELR
0.807
WorstEDS
BAR data (MY19+, automatic collection)
Electric drive share
Fuelly data (MY11+, user-reported)
Electric drive share
5th
2020 BMW 530E
0.116
2014 Porsche Panamera S E-Hybrid
0.115
4th
2022 Volvo XC90 T8 AWD Recharge
0.080
2013 Toyota Prius Plug-in Hybrid
0.113
3rd
2020 Land Rover Range Rover PHEV
0.062
2014 Toyota Prius Plug-in Hybrid
0.082
2nd
2022 Hyundai Tucson Plug-in Hybrid
0.054
2014 Honda Accord Plug-in Hybrid
0.045
1st
2022 Kia Niro Plug-in Hybrid
0.051
***
0.000
*** 5 models showed higher overall fuel consumption than their label CS fuel consumption, resulting in presumed/default 0% EDS
Isenstadt said that the only model he would consider a high-achiever is the BMW i3 REX. Other models fell far short of expected EPA numbers. The EPA generally expects PHEVs to use electric drive 80% of the time or more (though this scales up and down based on battery size), and only the i3 crossed the EPA’s bar.
The i3 was notable for its large (~100 mile) battery and small, optional engine (with a corresponding very small gas tank). This resulted in it being treated more like an electric car with occasional gas capability, as opposed to many of today’s PHEVs which operate in blended mode.
We also spoke with Stephanie Searle, the study’s project manager, about the results. She wanted to highlight just how large the disparity was between regulatory and real-world numbers – not just a few percent, but more than 50%.
Searle noted that the BAR numbers were the first time ICCT had used unbiased, non-self-reported numbers in its analysis, and the fact that they were worse than the self-reported numbers means that the problem is perhaps worse than previous research indicates. She considers the BAR numbers to be more robust, but also noted that even the self-reported numbers from Fuelly, where you would expect efficiency-conscious drivers to live, showed a massive disparity.
Policy recommendations
The ICCT hopes that its research will influence policy around PHEVs by providing regulators with more data about the actual carbon reductions (or relative lack thereof) achieve by PHEV deployment.
The ICCT issued five specific recommendations to the EPA:
Adjust the regulatory utility factor downwards for PHEVs to reflect current real- world performance.
Require in-use data reporting for specific PHEV models to receive a higher utility factor reflective of said in-use data
Adopt minimum electric driving range requirements, similar to California’s range requirements for zero-emission vehicle crediting in its Advanced Clean Cars II regulation
Adopt maximum engine power-to-weight limits
Establish a higher utility factor corresponding to the purchase of PHEV by drivers with demonstrated home chargers or manufacturer assistance with charging access
It also recommended that manufacturers could incentivize regular charging by assisting with home charger installation and by actively reporting cost of driving to users, and that tax administrators could incentivize PHEV purchases by restricting tax credits to PHEV models which display high utility factors. The US government recently expanded EV tax credits in the Inflation Reduction Act, allowing even small-battery (>7kWh) PHEVs access to the full $7,500 credit, a contrast to ICCT’s recommendations.
Will EPA follow California?
Further, the EPA is currently considering new emissions rules for 2027 and later model year vehicles. It’s expected to announce them this coming spring.
Searle hoped that these coming rules would be heavily influenced by California’s recent “Advanced Clean Cars II” standard. When that standard was unveiled, we at Electrek said it could be better, but part of California’s reason for making easier rules was because it wanted to set a standard that could be applied to other states in the country where EV sales aren’t as high as in CA.
The new California rules ban the sale of new gas cars after 2035, but allow up to 20% of new vehicles to be PHEVs. These PHEVs do need to meet minimum range requirements, in the hopes that cars with larger batteries will be more likely to be plugged in.
These findings show that even those California rules might overestimate the emissions reductions from PHEVs, and more consideration should be put into how to maximize the percentage of time people spend on electric drive, rather than using gasoline.
Do PHEVs matter?
All that said, this grousing over PHEVs may not matter much in the long run. ICCT says production costs are dropping faster for BEVs than PHEVs, which means all this may be a moot point in the future. Since PHEVs are basically two cars in one, falling battery prices may make BEVs an even clearer better choice for both buyers and manufacturers. PHEVs are currently rather popular in Europe, with similar market share as BEVs (partially due to the company car effect mentioned above), but have lagged far behind BEVs in the US, and it doesn’t look like they’re going to catch up.
But as long as we are in the current battery-constrained production scenario we are in, the ICCT’s new data will help regulators understand the relative carbon reduction potential of PHEVs as compared to BEVs, and that the benefit of PHEVs may be smaller than previously expected.
FTC: We use income earning auto affiliate links.More.
An Islamic Revolutionary Guard Corps speed boat sailing along the Persian Gulf during the IRGC marine parade to commemorate Persian Gulf National Day, near the Bushehr nuclear power plant in the seaport city of Bushehr, in the south of Iran, on April 29, 2024.
Nurphoto | Nurphoto | Getty Images
The number of vessels navigating the critically important Strait of Hormuz appears to be declining, according to the world’s largest shipping association, amid deepening fears of a widening conflict in the Middle East.
Jakob Larsen, head of security at Bimco, which represents global shipowners, said all shipowners were closely monitoring developments in the region and some have already paused transits in the Strait of Hormuz due to the deterioration of the security situation.
His comments come shortly after the U.S. on Saturday attacked three major Iranian nuclear enrichment facilities, a massive escalation in its involvement with Israel’s effort to cripple Tehran’s nuclear program.
Iran has condemned the attack, saying it reserves all options to defend its sovereignty and people.
“Before the US attack, the impact on shipping patterns was limited,” Bimco’s Larsen said.
“Now, after the US attack, we have indications that the number of ships passing is reducing. If we begin to see Iranian attacks on shipping, it will most likely further reduce the number of ships transiting through the [Strait of Hormuz],” he added.
The Strait of Hormuz, which connects the Persian Gulf to the Arabian Sea, is recognized as one of the world’s most important oil chokepoints.
In 2024 and the first quarter of 2025, for instance, flows through the narrow waterway made up roughly 20% of global oil and petroleum product consumption, according to the U.S. Energy Information Administration. Around 20% of global liquified natural gas (LNG) also transited through the Strait of Hormuz last year, primarily from Qatar.
The inability of oil to traverse through the waterway, even temporarily, can ratchet up global energy prices, raise shipping costs and create significant supply delays.
Yet, in the aftermath of the U.S. attacks on key nuclear sites, Iran’s parliament reportedly approved the closure of the waterway, risking alienating its neighbors and trade partners.
Standby mode
Andy Critchlow, EMEA head of news at S&P Global Commodity Insights, said some anecdotal evidence suggested a slowdown in shipping navigation through the Strait of Hormuz following the U.S. strikes on Fordo, Natanz and Isfahan.
“The pace at which tankers are entering the Strait of Hormuz has definitely slowed. We have indications from shippers that they are putting tankers and vessels on standby, so they are waiting for an opportune moment to enter the Strait,” Critchlow told CNBC’s “Europe Early Edition” on Monday.
“At the same time, there have been reports that suppliers of LNG, for example, in the Gulf have told lifters of LNG to wait before entering, so [as] not to loiter in the Gulf, keep vessels out of that region,” he added.
Japan’s Nippon Yusen, one of the world’s largest ship operators, recently introduced a standby to enter the Strait of Hormuz to limit the length of its stay in the Persian Gulf, according to S&P Global Commodity Insights, citing a company spokesperson.
Nippon Yusen’s policy, which comes as part of a precautionary measure following the escalation of Isreal-Iran tensions since June 13, means ships are asked to pause for a day or a couple of days when there is flexibility in the shipping schedule, S&P Global Commodity Insights reported on Monday.
The company has not implemented a navigation halt in the Strait of Hormuz, however.
Japan’s Mitsui O.S.K Lines also instructed vessels to limit time spent in the Gulf following U.S. strikes on Iranian nuclear facilities, Reuters reported Monday, citing a company spokesperson.
Spokespeople at Nippon Yusen and Mitsui OSK Lines were not immediately available to comment when contacted by CNBC.
Satellite image of the Strait of Hormuz, a strategic maritime choke point with Iran situated at the top with Qeshm Island and the United Arab Emirates to the South. Imaged 24 May 2017.
Gallo Images | Getty Images
German container shipping firm Hapag-Lloyd said it is continuing to sail through the Strait of Hormuz.
“However, the situation is unpredictable and could change within a matter of hours. In this case, our emergency and response plans, which we maintain as part of our crisis management system, come into effect,” a Hapag-Lloyd spokesperson said.
Insurance costs to spike
Peter Sand, chief analyst at pricing platform Xeneta, said container shipping activity in the Persian Gulf and upper Indian Ocean appears to be continuing as expected for now.
“All companies access the risk individually – but the current situation requires them all to do so several times a day. Staying in close dialogue with national intelligence agencies and their own captains onboard the ships,” Sand told CNBC by email.
Insurance costs, meanwhile, have “probably” been hiked again, Sand said, noting Iran’s parliament reportedly approved the closure of the Strait of Hormuz.
Any final decision to close the waterway rests with the country’s national security council, and its possibility has raised the specter of higher energy prices and aggravated geopolitical tensions, with Washington calling upon Beijing to prevent the strait’s closure.
Reporters photograph an operational timeline of a strike on Iran at the Pentagon on June 22, 2025, in Arlington, Virginia, U.S.
Andrew Harnik | Getty Images News | Getty Images
The United States conducted airstrikes on three of Iran’s nuclear sites on Saturday, entering Israel’s war against Tehran. The timing was unexpected. On Thursday, U.S. President Donald Trump said he was still considering U.S. involvement and would arrive at a decision “within the next two weeks.”
Financial and political analysts had largely taken that phrase as code word for inaction.
“There is also skepticism that the ‘two-week’ timetable is a too familiar saying used by the President to delay making any major decision,” wrote Jay Woods, chief global strategist at Freedom Capital Markets.
Indeed, Trump has commonly neglected to follow up after giving a “two week” timeframe on major actions, according to NBC News.
And who can forget the TACO trade? It’s an acronym that stands for “Trump Always Chickens Out” — which describes a pattern of the U.S. president threatening heavy tariffs, weighing down markets, but pausing or reducing their severity later on, helping stocks to rebound.
“Trump has to bury the TACO before the TACO buries him … he’s been forced to stand down on many occasion, and that has cost him a lot of credibility,” said David WOO, CEO of David Woo Unbound.
And so Trump followed up on his threat, and ahead of the proposed two-week timeline.
“There will be either peace, or there will be tragedy for Iran far greater than we have witnessed over the last eight days,” Trump said on Saturday evening.
But given Trump’s criticism of U.S. getting involved in wars under other presidents, does America bombing Iran add to his credibility, or erode it further?
Oil prices pare gains U.S. crude oil were up 1.1% to $74.65 per barrel, while global benchmark Brent climbed 1.12% to $77.88 per barrel early afternoon Singapore time. The commodity pared gains from earlier in the day, when prices jumped more than 2% in oil’s first trading session after Saturday’s events. That said, multiple analysts raised the prospect of oil hitting $100 per barrel, especially if exports through the Strait of Hormuz are affected.
[PRO] Eyes on inflation reading Where markets go this week will depend on whether the conflict in the Middle East escalates after the U.S.’ involvement. Investors should also keep an eye on economic data. May’s personal consumption expenditures price index, the Federal Reserve’s preferred gauge of inflation, comes out Friday, and will tell if tariffs are starting to heat up inflation.
And finally…
A trader on the floor of the New York Stock Exchange during the first session of the new year on January 2, 2025, in New York City, U.S.
The U.S. joining the war between Israel and Iran might seem like a geopolitical flash point that would send markets tumbling.
Instead, investors are largely shrugging off the escalation, with many strategists believing the conflict to be contained — and even bullish for some risk assets.
“The markets view the attack on Iran as a relief with the nuclear threat now gone for the region,” said Dan Ives, managing director at Wedbush, adding that he sees minimal risks of the Iran-Israel conflict spreading to the rest of the region and consequently more “isolated.”
Furthermore, rhetoric around the idea of shutting down the Hormuz waterway has been recurring from Iran, but it has never been acted upon, with experts highlighting that it is improbable.
A trader on the floor of the New York Stock Exchange during the first session of the new year on January 2, 2025, in New York City, U.S.
Timothy A. Clary | Afp | Getty Images
The U.S. joining the war between Israel and Iran might seem like a geopolitical flashpoint that would send markets tumbling. Instead, investors are largely shrugging off the escalation, with many strategists believing the conflict to be contained — and even bullish for some risk assets.
As of 1 p.m. Singapore time, the MSCI World index, which tracks over a thousand large and mid-cap companies from 23 developed markets, declined only 0.12%. Safe havens are also trading mixed, with the Japanese yen weakening 0.64% against the dollar, while spot gold prices slipped 0.23% to $3,360 per ounce. The dollar index, which measures the U.S. dollar against a basket of currencies, rose 0.35%.
“The markets view the attack on Iran as a relief with the nuclear threat now gone for the region,” said Dan Ives, managing director at Wedbush, adding that he sees minimal risks of the Iran-Israel conflict spreading to the rest of the region and consequently more “isolated.”
While the gravity of the latest developments should not be dismissed, they are not seen as a systemic risk to global markets, other industry experts echoed.
On Saturday, U.S. President Donald Trump said that the United States had attacked Iranian nuclear sites. Traders are now keeping a close eye on any potential countermeasures from Iran following the U.S. strikes on its nuclear facilities.
Iran’s potential closure of the Strait
Iran’s foreign minister warned that his country reserved “all options” to defend its sovereignty. According to Iranian state media, the country’s parliament has also approved closing the Strait of Hormuz, a pivotal waterway for global oil trade, with about 20 million barrels of oil and oil products traversing through it each day.
“It all depends on how Iran responds,” said Peter Boockvar, chief investment officer at Bleakley Financial Group. “If they accept the end of their military nuclear desires… then this could be the end of the conflict and markets will be fine,” he told CNBC. Boockvar is not of the view that Iran will carry out the disruption of global oil supplies.
The worst-case scenario for markets would occur if Iran were to close the Strait, which is unlikely, said Marko Papic, chief strategist at GeoMacro Strategy.
“If they do, oil prices go north of $100, fear and panic take over, stocks go down ~10% minimum, and investors rush to safe havens,” he said.
However, markets are subdued now given the “limited tools” that Tehran has at its disposal to retaliate, Papic added.
The idea of shutting down the Hormuz waterway has been a recurring rhetoric from Iran, but it has never been acted upon, with experts highlighting that it is improbable.
In 2018, Iran warned it could block the Strait of Hormuz after the U.S. pulled out of the nuclear deal and reinstated sanctions. Similar threats were made earlier in 2011 and 2012, when senior Iranian officials — including then-Vice President Mohammad-Reza Rahimi — said the waterway could be closed if Western nations imposed more sanctions on Iran’s oil exports due to its nuclear activities.
“Tehran understands that, if they were to close the Strait, the retaliation from the U.S. would be swift, punitive, and brutal,” Papic added.
In a similar vein, Yardeni Research founder Ed Yardeni said the latest events have not shaken his conviction in the U.S. bull market.
“Geopolitically, we think that Trump has just reestablished America’s military deterrence capabilities, thus increasing the credibility of his ‘peace through strength’ mantra,” he said, adding that he is targeting 6,500 for the S&P 500 by the end of 2025.
While predicting geopolitical developments in the Middle East is a “treacherous exercise,” Yardeni believes that the region is in for a “radical transformation” now that Iranian nuclear facilities have been destroyed.