The Focus on Plug-in Electric Vehicles Over Range Extended Hybrids: Understanding the Efficiency Trade-offs
Why is there so much emphasis on plug-in electric vehicles (PHEVs) compared to range extended hybrids that can also charge via a plug? This question delves into the efficiency trade-offs and practicalities of these two vehicle types. In this article, we explore why PHEVs are currently more favored, and the reasons for the growing focus on them from both consumer and industry perspectives.
Consumer Perspective: The Need for Practicality
Many consumers, especially in urban areas, find themselves driving short distances on a daily basis. For them, owning a second car or a vehicle with extended driving range is often unnecessary. Many trips cover 95% or less of the total distance they travel in a day. By carting around a petrol motor and maintaining it when not in use, the added complexity and increased costs often outweigh the benefits. Therefore, the emphasis on vehicles like PHEVs, which can operate in electric mode for shorter trips, is more appealing.
Technological and Efficiency Differences
The key difference between plug-in hybrid electric vehicles (PHEVs) and range extended hybrids lies in their power train configurations and efficiency. Series hybrids like the Chevrolet Volt or BMW i3 with REx range extenders are known for their poor mileage compared to parallel or power-split hybrids like the Toyota Prius or Hyundai Ioniq Hybrid. In series hybrids, the internal combustion engine (ICE) is primarily used to generate electricity, which then drives the vehicle. Each stage in this process introduces losses, leading to overall inefficiency.
Parallel hybrids and power-split hybrids, such as the Toyota Prius and Hyundai Ioniq Hybrid, use the ICE more efficiently since it is directly connected to the transmission. When driving in electric mode, these vehicles can reduce the use of the ICE, thus operating more efficiently.
Current and Future Trends in Vehicle Technology
I personally believe that plug-in hybrids are a temporary phenomenon for typical passenger vehicles. The complexity of carrying two modes of propulsion and managing two types of fuel is less desirable than a vehicle that operates smoothly with just one. Supporting and building out infrastructure for multiple fuel types, gas and electric, is also a significant challenge.
The solutions to these challenges are beginning to emerge. As battery technology improves and costs decrease, electric vehicles (EVs) are rapidly becoming more practical. Tesla has brought us most of the way there, and now the Chevy Bolt and Nissan Leaf are getting closer to providing a good balance of affordability and range. In a few decades, it is expected that the majority of passenger vehicles sold in the US will be all-electric.
Conclusion
While range extended hybrids may have a place in certain applications and scenarios, the focus on plug-in electric vehicles has grown due to their efficiency, practicality, and evolving technology. As the infrastructure and battery technology continue to advance, it is likely that the future of personal transportation will be dominated by electric vehicles, making the current focus on PHEVs a natural and necessary step towards this more sustainable and efficient automotive landscape.