You only need about 35 hp to keep a 4000lb car cruising at 70 mph. The idea? Run the powertrain totally on battery, then toss in a 50 or 70 hp engine just to charge it up.<p>It's flipping the hybrid script: instead of using electric for low demand and gas for more juice, it's electric for the main power and gas just for the battery.<p>This puts the heavy lifting on the 90% efficient powertrain and eases up on the super inefficient 25% one.<p>Toyota should've been all over this back in 2015.