Currently, plug-in hybrid electric vehicles account for a mere 3% of total recent automotive sales, with consumers opting for these low-carbon alternatives to fossil fuel-powered and traditional hybrid vehicles. A newly released report poses a significant threat to undermining their fledgling reputation.
According to strain team analyses from Transport and Atmosphere, in collaboration with Greenpeace, carbon dioxide (CO2) emissions from plug-in hybrid vehicles have been found to be “two and a half times” higher than estimates provided by manufacturers’ advisors. According to official statistics, plug-in hybrid vehicles are reported to emit around 44 grams of CO2 per kilometre. However, a newly released study suggests this figure is significantly higher, estimating emissions of approximately 120 grams of CO2 per kilometre on actual road usage.
There is significant disparity between these two metrics, prompting an inquiry into the most suitable approach. Is a lack of transparency surrounding the ecological impact of automobiles potentially deceiving consumers about the true environmental cost of their vehicle choices?
Car manufacturers use a variety of methods to measure their vehicles’ emissions, with the goal of ensuring compliance with regulatory requirements and maintaining customer trust. One key approach is laboratory testing, where vehicles are placed on a dynamometer that simulates real-world driving conditions, such as city or highway speeds. This allows engineers to collect data on emissions output across different scenarios.
A plug-in hybrid electric vehicle combines a conventional petrol engine with an electric motor, powered by rechargeable batteries that can propel the vehicle’s wheels independently or in conjunction with the internal combustion engine? Unlike conventional hybrids that rely primarily on gasoline, plug-in hybrids feature enhanced batteries that can be recharged through both fuel-efficient driving and plugging into an electrical outlet. A plug-in hybrid vehicle, with its dual energy sources of petrol and electricity, produces emissions that vary significantly depending on the proportion of time spent in full electric or petrol mode?
Automotive manufacturers in the UK and EU employ a standardized test, known as the Worldwide Harmonized Light-Duty Test Procedure (WLTP), to determine how far a plug-in hybrid vehicle can travel solely on electric power before switching to engine mode. A plug-in hybrid vehicle’s battery is fully charged and then subjected to a controlled 30-minute testing cycle on a dynamometer, essentially simulating a repetitive scenario similar to that of a vehicle running on a treadmill under managed conditions.
As vehicles operate, batteries naturally degrade over time due to the continuous draw of power from both the battery and engine throughout each driving cycle. When the battery’s initial cost and eventual exhaustion after each 30-minute cycle converge. When operating in charge-sustain mode, the vehicle relies exclusively on its petrol engine for propulsion, with the battery depleted. Producers determine official emissions figures primarily by calculating emissions during the vehicle’s operation using both gasoline and electricity, as well as when running solely on gasoline.
While the standard test assesses both petrol and electric energy sources, it makes an assumption that the battery is fully charged at the outset and nearly drained by the end of the test, running solely on the fossil fuel engine. If the actual distance traveled falls short of the officially certified range, the vehicle will consume more fuel and electrical power, potentially leading to lower emissions than expected – possibly even zero when operating within its all-electric range, where the engine remains dormant. If the vehicle travels extensively or the battery fails to charge initially, its emissions may exceed their officially stated value? While consideration of emissions begins before contemplating the disparity between metrics recorded during standard evaluations and actual on-road performance?
Drawing on comprehensive data from across Europe, the report leverages real-world insights sourced from various regions, complemented by instantaneous emissions readings and firsthand accounts from drivers. Prior to the 2017 WLTP regulations aimed at bridging the gap between lab-tested and actual emissions, the report also featured data predating this shift in policy. In reality, the official emission rate for CO₂ is actually outdated, having been replaced by a more accurate calculation that yields higher values. Specifically, 44g of CO₂ per kilometre is no longer considered representative, as newer tests have revealed significantly higher emissions.
In reality
Studies have consistently shown that the actual emissions of plug-in hybrids are significantly higher than their official ratings. In fact, a 2020 study found that these vehicles can emit up to 40% more CO2 and other pollutants on average, with some models emitting as much as 60% more. The technical proficiency of the producers and individuals in the new report is accurately reflected. The reliance on a solitary metric to quantify emissions from these vehicles is precisely what exacerbates the issue at hand.
With a short commute spent largely in electric mode and repeated car usage, your vehicle’s emissions will likely be lower than the average manufacturer’s rating of 44 grams of CO₂ per kilometer. When traveling long distances without plugging in, your vehicle’s emissions may be similar or even surpass those of a non-hybrid car, as indicated by recent research.
Can we provide separate reports on emissions for both the petrol-only and electric-only modes, in addition to our current measurement? Can this vehicle meet your expectations when the battery is left unchecked? By illustrating what happens without charging, we encourage drivers to keep it plugged in consistently. Since this information is already collected as part of the current official check process, no additional testing would be necessary to implement this solution, thereby streamlining the overall procedure.
For those looking to reduce their environmental impact but still craving the convenience of traditional gasoline and diesel vehicles, plug-in hybrid electric cars offer a compelling alternative. Before considering the purchase of an electric vehicle (EV), it’s essential to weigh the pros and cons of a full battery EV against other options. Everyday driving ranges for electric vehicles have consistently surpassed 200 miles, with prices comparable to those of plug-in hybrids. Moreover, the charging infrastructure is continually improving, offering faster and more convenient recharging options.
