The size of the battery in plug-in hybrid electric vehicles (PHEVs) significantly influences their emissions profile in several ways:
- Battery production emissions: Larger batteries require more raw materials and energy to manufacture, leading to higher embedded emissions. A midsized PHEV typically has a battery about one-sixth the size of a full battery electric vehicle (BEV), resulting in roughly one-sixth the emissions from battery production compared to BEVs.
- Electric driving range and fuel use: Larger batteries allow PHEVs to drive more miles purely on electricity before switching to the internal combustion engine (ICE). This reduces tailpipe emissions during electric operation but increases reliance on electricity consumption, shifting emissions to the power generation side depending on the grid mix. Conversely, smaller batteries mean more frequent use of the ICE, thus higher tailpipe emissions compared to larger battery PHEVs.
- Lifecycle greenhouse gas (GHG) emissions: PHEVs with smaller batteries tend to have lower overall lifecycle emissions compared to BEVs because they use fewer critical minerals and have lower manufacturing emissions. Despite using some gasoline, PHEVs achieve significant lifetime emission reductions—about 46% on average in the US—by combining electric driving with efficient hybrid operation.
- Grid dependency and regional emissions: The environmental benefits of larger batteries and greater electric range depend heavily on the cleanliness of the electricity grid. If the grid relies on fossil fuels like coal, the emissions benefits of electric driving diminish, sometimes causing PHEVs to have comparable or slightly higher well-to-wheel emissions than conventional vehicles when running on grid electricity alone.
In summary, larger batteries in PHEVs increase production emissions but enable greater electric-only driving, reducing tailpipe emissions. Smaller batteries lower manufacturing emissions and reduce dependence on critical minerals but result in more ICE use. The optimal battery size balances these factors and is influenced by the electricity generation mix and driving patterns—PHEVs with moderate battery sizes generally show better overall emissions performance than full BEVs across many real-world scenarios.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-does-the-size-of-the-battery-influence-the-emissions-of-phevs/
