Understanding PHEV Fuel Economy
Plug-in hybrid electric vehicles combine a battery-powered electric motor with a conventional gasoline engine. The key advantage is that short daily trips can be completed entirely on electric power, while the gas engine provides range for longer journeys. Your actual fuel economy depends heavily on your driving patterns and how often you charge.
If your daily commute is shorter than the EV range, you may rarely use gasoline at all. The EPA rates PHEVs using MPGe (miles per gallon equivalent), where 33.7 kWh of electricity equals the energy in one gallon of gasoline. This calculator gives you a personalized estimate based on your actual driving habits.
How PHEV Economy Is Calculated
PHEV vs Gas vs BEV Comparison
| Vehicle Type | Annual Fuel Cost* | CO2/year (tonnes) | Range Anxiety |
|---|---|---|---|
| Gas Car (30 MPG) | $1,703 | 4.6 | None |
| PHEV (30mi EV range) | $850-1,200 | 2.0-3.5 | None |
| BEV (Full Electric) | $550-700 | 1.0-2.0 | Moderate |
*Based on 12,000 miles/year, $3.50/gal gas, $0.13/kWh electricity
Frequently Asked Questions
How important is charging frequency for PHEV economy?
Charging frequency is the single most important factor in PHEV fuel economy. A PHEV that is charged daily and driven within its electric range can achieve over 100 MPGe. The same vehicle that is never charged operates as a conventional hybrid, typically achieving 35-45 MPG. Charging at work as well as at home effectively doubles your electric range.
What is MPGe and how is it calculated?
MPGe (miles per gallon equivalent) is a metric developed by the EPA to compare the energy efficiency of electric and gas vehicles. One gallon of gasoline contains approximately 33.7 kWh of energy, so MPGe measures how many miles a vehicle can travel on 33.7 kWh of electricity. A vehicle achieving 100 MPGe travels 100 miles on the energy equivalent of one gallon of gas.
Are PHEVs better for the environment than regular hybrids?
Yes, when charged regularly. PHEVs produce significantly less CO2 when operating on electricity, especially if the electricity comes from renewable sources. However, an uncharged PHEV may actually be less efficient than a regular hybrid due to the extra weight of the larger battery pack.