Here’s a little thought experiment. I’m going to be using the second generation Toyota Prius Prime as a proxy for PHEVs in terms of performance.
The Toyota Prius Prime has a battery capacity of 8.8 kWh. Its electric range is at 40 km (25 mi).
The USA has 111 million registered passenger cars in 2017. If this entire fleet were to be converted to PHEVs, this would put a total of roughly 980 GWh of batteries on wheels. Keep in mind that this calculation excludes buses and cargo trucks. If these batteries need to be replaced every 10 years, the USA would need to manufacture 98 GWh per year. Once completed, the Tesla Gigafactory is set to give an annual battery production of 150 GWh/y, though it is currently running at a production capacity of roughly 20 GWh/y.
In 2011, passenger cars traveled a total of 2.2 trillion km while 127 million registered passenger cars were recorded that same year. This puts the distance traveled per car per day at 48 km (30 mi). Interestingly, the Prius Prime is shown to have an all-electric range of 40 km (25 mi). It has been reported that the Prius Prime’s fuel economy measures at 2.9 L/100 km for commutes up to that 48 km distance. That would be equivalent to 67.2 million m³ of gasoline consumed or 423 million barrels of gasoline based on the 2.3 trillion miles traveled in 2016. Gasoline consumption in that same year for transportation was roughly 3,410 million barrels — almost almost an order of magnitude higher.
While PHEVs might not wean cars completely off of gasoline, it does have potential to cut very deeply into gasoline demand while we wait for batteries and other technologies to scale up production capacity to sufficiently high levels. What’s more, if the demand for motor fuel does contract by nearly an order of magnitude, this enable the possibility of biofuels making up a greater share of transportation fuels.
What are your thoughts?
EDIT: Removed mentions of the word “vehicle” and replaced them with “passenger cars” to avoid confusion. Also added a source for the 2016 motor gasoline consumption in the USA.