Regional temperature differences significantly affect the emissions of Plug-in Hybrid Electric Vehicles (PHEVs) and Hybrid Electric Vehicles (HEVs) primarily due to impacts on battery efficiency, electric driving range, and use of auxiliary systems like cabin heating.
Effects of Temperature on PHEVs and HEVs Emissions
- Reduced Battery Efficiency and Electric Range in Cold Climates
At low ambient temperatures (e.g., around −7 °C), PHEVs exhibit reduced battery efficiency and shorter pure electric driving range. This leads to increased operation of the internal combustion engine (ICE), which produces higher tailpipe emissions. Studies show that overall CO2 emissions for PHEVs were about 30% higher at −7 °C compared to 23 °C due to these factors. The reduced electric operation time means more reliance on gasoline engine combustion, thus increasing emissions. - Increased Energy Demand for Cabin Heating
Cold temperatures increase the demand for cabin heating, which draws additional energy from the battery in PHEVs and HEVs or requires more fuel combustion in HEVs. In PHEVs, this additional energy demand leads to faster battery depletion, reducing electric-only driving and increasing fuel use emissions. For instance, CO2 emissions from PHEVs increased by up to 72% when tested at −7 °C with heating on versus warmer conditions. - Regional Grid Emissions Influence in PHEVs
The overall greenhouse gas emissions from PHEVs also depend on the carbon intensity of the regional electricity grid used to charge the vehicles. For example, PHEVs charged in regions with high GHG intensity grids (like the Upper Midwest U.S.) produce more emissions compared to those in regions with cleaner grids (like the Pacific Coast). Moreover, temperature-induced inefficiencies in battery performance cause up to a 15% increase in annual energy consumption in colder or hotter regions, further affecting emissions. - Impacts on HEVs
Although HEVs do not rely on plug-in electric batteries as much as PHEVs, low temperatures still reduce the efficiency of their batteries and increase engine warm-up times. This results in more fuel consumption and tailpipe emissions in cold climates. The effect is less pronounced than in PHEVs but still contributes to increased emissions in colder regions.
Summary
| Factor | Effect of Cold Temperature on PHEVs and HEVs |
|---|---|
| Battery efficiency | Decreases, reducing electric range and increasing reliance on ICE |
| Cabin heating demand | Increases energy consumption, leading to higher CO2 emissions |
| Electric-only operation time | Shortens, causing higher emissions from fuel combustion |
| Regional grid emission factor | Higher grid carbon intensity in colder regions increases overall PHEV emissions |
| Overall emission increase | PHEV CO2 emissions can increase 30-72% at low temps; effects on HEVs are also negative |
Thus, regional temperature differences cause higher emissions for PHEVs and HEVs in cold climates primarily by reducing electric driving efficiency and increasing fuel combustion, while regional electricity grid emissions further modulate the total emissions from PHEVs.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-do-regional-temperature-differences-affect-the-emissions-of-phevs-and-hevs/
