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PHEVs Can Achieve Similar Emissions Reductions As Full EVs, Depending

I am one of those nerdy types that keeps track of lots of things in spreadsheets. I track per mile fuel costs for my electric and plug-in hybrid vehicles. I also track how much electricity I am using at home versus on the road/away from home. I’m a little extra, I admit. But I wonder, how close are my EV and PHEV in terms of their overall lifecycle emissions?


Since I lack the equipment to measure how much my Tesla Model 3 EV and Kia Sorento Plug-in Hybrid (PHEV) emit via their fueling and driving, I have to rely on published studies and my own measurements of fuel consumption for my vehicles (be that electricity or gasoline). The majority of the electricity I consume comes from renewable sources (I live and do a majority of my driving in Washington State and I also have solar panels on my roof), so I tend to have some of the best case scenarios when it comes to the carbon “costs” of my electricity used as fuel as well as the actual monetary costs of that fuel. I also have only used about 65 gallons of gasoline over the last 6,000 miles I’ve covered in my PHEV, so I might be described as a model PHEV driver since I am able to cover most of the miles I drive on battery. This is important to point out because of course, not everyone drives the same PHEV that I do, not all PHEVs have the same capabilities, nor does everyone drive as efficiently as I tend to. Some may actually be more efficient! For reference, my own records indicate that I currently average 3.33 miles per kWh and 36.41 MPG while driving on gas in my Sorento PHEV and I average 4.16 miles per kWh in my Tesla Model 3.

ICCT graph comparing ICE, PHEV and EV lifecycle emissions

According to The International Council on Clean Transportation and a study done on EVs versus PHEVs versus traditional gas and diesel powered vehicles, EVs were capable of 57 - 66% lower emissions compared to gas and diesel cars and PHEVs were capable of 10 - 45% lower emissions. I’ll call out that this study was done in Germany which has a very significant amount of renewable generating capacity (42.1% of consumption in 2019), and only a small number of different EV and PHEV SUVs and crossovers. Washington State by comparison generates 75% of its power from renewable resources according to the U.S. EIA with the vast majority of that coming from hydroelectric sources. Thus, with significantly “cleaner” electricity, and different vehicle sizes and efficiencies, my actual life cycle emissions would be different of course. But as best as I can estimate from the examples used in the study, my Model 3 would have a little better (i.e. lower) lifetime emissions figure than the Hyundai Kona EV and my Sorento PHEV would be close to (but perhaps a little higher/worse than) the Kia Niro PHEV. For the sake of argument let’s say for my Model 3 this comes out to a value around 68% lower lifetime carbon emissions (compared to an equivalent gas powered vehicle) and to about 43% lower lifetime carbon emissions for my Sorento PHEV. If you also consider that my Sorento is several hundred pounds heavier than the Model 3, and less aerodynamically efficient due its size, shape and ground clearance, the 25% difference makes sense. If I compared the Sorento to a larger EV like the Model X, that difference would likely shrink to about 10 - 15%. That is what I am getting at in my title. More or less equivalently sized/classed PHEVs and EVs, depending on how they are driven, and assuming enough battery capacity to complete most driving on electricity and very good efficiency when running on gasoline, can achieve similar lifecycle emissions reductions (within 10 - 15% of each other).

I realize this wasn’t particularly precise, and there are lots of factors that could skew the scenarios for drivers of other plug-in vehicles, with different driving styles in different parts of the world. As they say, your mileage may vary. Please leave any questions or comments below.

Images courtesy of Justin Hart and The International Council on Clean Transportation.

Justin Hart has owned and driven electric vehicles for over 14 years, including a first generation Nissan LEAF, second generation Chevy Volt, Tesla Model 3, an electric bicycle and most recently a Kia Sorento PHEV. He is also an avid SUP rider, poet, photographer and wine lover. He enjoys taking long EV and PHEV road trips to beautiful and serene places with the people he loves. Follow Justin on Twitter for daily KIA EV news coverage.


geemy (not verified)    November 25, 2022 - 9:30AM

if you consider the amount of emissions reductions per kWh of battery, hybrids and phevs save definitely WAY MORE than EVs especially long range ones with big batteries, and especially considering most countries still generate a lot of emissions to produce electricity. it would be way more efficient to convert all gas cars to hybrid first, then all hybrids to phevs, then eventually all phevs to be once electricity has transitioned to renewables.