NON PLUG-IN HYBRIDS ARE LIKE RRSPs
Lessons learned from behind wheel of 2020 Escape, writes David Booth.
Economists have long told us that registered retirement savings plans are not a free lunch. You get a tax credit when you put the money into your RRSP, but you have to pay taxes when you make a withdrawal. As Financial Post editors point out, RRSPs are about tax deferral, not tax avoidance.
The idea is that you contribute when you’re making lots of money (i.e. paying lots of taxes) and withdraw your loot later, when you’re making less. As long as you’re paying less tax when you’re withdrawing than when you contributed, RRSPs are a net benefit.
That’s essentially how (non plug-in) hybrids work. Unlike a plug-in hybrid electric vehicle, which gets energy from an outside source (the 110/220-volt charger wired into your home network), a typical hybrid is a closed-loop energy system. Whatever juice its small electric battery sends to the wheels must be recouped from those very same wheels.
Hybrids typically have less powerful — and hopefully more frugal — gas engines, and their electric motors are a supplement to the engine. The very best allow some modest electric-only operation, but with their typically small batteries — the Escape’s is just 1.1 kWh — electric range is minimal. Non plug-in hybrids are a zerosum game: whatever energy is transferred from the battery must be recovered from the car.
That’s why hybrids are like RRSPs. You pull energy from the battery when the gas engine is at its least efficient, and then return it when the engine is at it most efficient.
That’s why all the benefit of a hybrid is in urban driving. Internal combustion engines are at their most miserly at constant speeds. Conversely, they are least efficient in stop-and-go traffic. That’s why hybridization posts its biggest gains in city driving — with the engine operating so inefficiently and plenty of opportunity to recharge the battery through regenerative braking, there’s plenty of benefit to supplementary electrification.
The reason this came up while driving the new Escape is that Ford provides a handy readout illuminating the benefits of hybridization. Besides the standard fuel-economy readout (the Escape averaged about 7.5 L/100 km in our test, regardless of whether it was driving in the city or on the highway) and trip meter, the Escape’s also delineated how many “electric” kilometres the little Ford had squeezed out.
Pointing to how efficient hybrids have become, the Escape regularly claimed that more than a third — say 85 or 90 km out of a 240-km day — were “electric” while stop-and-go driving in dense Toronto traffic. A little rudimentary math reveals that virtually all of the Hybrid’s fuel economy improvement in town is due to electrification. Unfortunately, the same doesn’t apply on the highway.
Indeed, on one long, flat portion of Ontario’s Highway
401, the Escape recorded barely two “electric” kilometres out of every hundred. With speed seldom deviating from a steady 120 km/h, the Escape’s electric motors were seldom engaged. A little simple math reveals that the paltry two per cent of the time the hybrid system is engaged can’t account for the difference between the Hybrid and base-model fuel-economy ratings of 37 mpg versus 33. Ford’s decision to equip the Hybrid with an Atkinson-cycle internal combustion engine — and its delayed intake valve closing — accounts for at least some of the increased fuel economy on the highway.
Typical EV efficiency sees every kWh of lithium-ion worth about five kilometres of electric-only range. After that, for there to be any more emissions-reducing electrification, the battery must be recharged, and since the current Escape Hybrid has no provision for plugging in, the energy to recharge must come from the car itself. To think otherwise is to believe we have invented the perpetual motion machine, and — sorry, Musk fans — even Lord Elon has yet to find a way to repeal the laws of physics.
The argument remains that, just like RRSPs, hybridization works by reducing costs when you are making too much and paying them when you can better afford to. And, just like saving for your golden years, it’s a good idea.