Hybrid, schmybrid Friday April 25, 2008, 4 comments

Among all the things I am getting tired of hearing from the mainstream media (war, famine, oil prices, recessions, subprime lending mess, American primaries, terrorism, China-Tibet tensions, Olympic protests, cancer, plastics, genetically modified foods, blah blah blah blah blah…) I think that the hybrid thing is really starting to get to me.

Treehugger is falling all over itself mourning Volkswagen’s decision to not bring the hybrid Golf concept car to market. For myself, I can’t help but cheer.

We all know the difference between a hybrid vehicle and a normal one, right? A normal vehicle has an internal combustion engine that outputs power through a spinning shaft to a series of gears that eventually turn the wheels of the vehicle to move it.

A hybrid vehicle has an internal combustion engine that outputs power through a spinning shaft, through a series of gears to an electric generator. The electrical output of this generator charges a bank of nickel-metal hydride (NiMH) batteries. These batteries, in turn, feed electric motors that turn the wheels of the vehicle to move it. To me this seems much more complex than the normal car, and more complexity means more expense.

Hybrid vehicles have the option of operating for some time from the energy stored in the batteries, but until so-called “plug-in” hybrids come to market, this is irrelevant because the power to charge those batteries must come from the internal combustion engine. The difference between a hybrid vehicle and a normal one is therefore one of power transmission from the internal combustion engine to the wheels.

The power transmission system of a hybrid vehicle may be slightly more efficient than that of a normal vehicle, but if it exists, it is a marginal difference. Hybrid vehicles are marking up high efficiency rates because they are powered by small internal combustion engines. The combined mileage (highway and city) of a 2009 VW Jetta TDI (2.0L 4-cylinder diesel engine) is approximately 50mpg, while the Toyota Prius (1.5L f-cylinder gasoline engine), poster child of the hybrid revolution, achieves 46mpg.

You read that right, a standard diesel engine in a bigger car achieves 10% better fuel efficiency than a hybrid. But environmentalism isn’t just about fuel efficiency, regardless of what the mainstream media is telling people. The total environmental impact of a vehicle, from cradle to grave, must be considered.

When that Jetta is finally retired, it will be melted down for scrap, and the metal from that transmission will be recycled (or downcycled, possibly) into new products using processes we already have in place. What happens to the Prius and the batteries in it? And that’s assuming those batteries last the life of the car. Plug-in hybrids might change this equation a bit, but that plug-in energy still needs to be generated somehow (coal seems a likely source, at least for the United States), and those batteries still need to be recycled safely.

As I’ve written before, the Prius is less energy efficient than a Hummer over its entire lifespan. Now take fuel economy into consideration, and compare that Prius to a diesel VW Jetta, or the new TSI engines that VW is working on. Non-hybrid cars that get better mileage than hybrids, at less cradle-to-grave cost to the environment, with far less complexity.

Seems like a better idea to me.


Comments

Mike Friday April 25, 2008


I’m afraid you’ve gotten a few things wrong in your ideas about hybrid cars, as well as a few things right.

Of course, I’m going to focus in on the misinformation you have here, but just to let you know, I thought this was well written and (although mistaken) an interesting read.

First, you don’t seem to fully understand how hybrid cars work. If we focus in on just the Prius, a full hybrid (because you did), the electric motor and the gas motor alternate between powering the car. The electric motor powers the vehicle at low speeds or when stopped, while the gas engine kicks in at higher speeds.

The gas engine can recharge the battery pack, but that’s the least efficient way of doing it. It does happen when the battery pack gets low or when the car is traveling at higher speeds, but the best way is to recharge the battery through regenerative braking. Not only does it save wear and tear on the brakes, but it also recaptures some of the energy you used to accelerate the car in the first place.

Also, the gas engine, when it is not recharging the battery, will shut down when the vehicle is stopped. This eliminates the wasted gas from idling.

The Prius does have a smaller, more efficient engine. But to compare it against the diesel engine is misleading, since a diesel engine is more efficient than a gas engine.

Unfortunately, the diesel engine has a few issues that are hard to overcome in the US. First, the cost of the diesel engine is more expensive than the gas engine. Second, despite being more efficient, diesel costs more in the states, somewhat pushing back on the savings you would like to see when you fuel up.

Then there’s the emissions/ smell/ reputation problem.

Still, many would call for a diesel hybrid as an even more efficient choice. Too bad that means you need to add together the extra cost of a diesel engine, plus the extra cost of the electric motor.

Also, please do not use the Hummer vs Prius argument. It’s been dismissed as an embarrassing study by a Marketing company. Look it up on Slate before you try to use it again.

One last point, batteries always need to be recycled. Whether you talk about the smaller ones you find in all cars or the battery packs you see in hybrids. Most of all cars built today get recycled. I don’t see how that’s relevant.

Hybrid cars do have their issues, but you haven’t raised them here.

sarah Friday April 25, 2008


I’m not sure I catch your drift on why it is unfair to compare the hybrid to a diesel. The point is to identify the most fuel efficient and environmentally friendly car on the road, and so anything goes. The hybrid is less efficient and economic than a diesel jetta even when you take into account the higher cost of diesel fuel. Despite such benefits as the engine shutting down, it still uses more fuel.

You are right about the reputation problem though, and this whole issue is all about that. Reputation over objective facts.

Mike Friday April 25, 2008


I’m sorry, I didn’t mean to imply it was unfair to make the comparison, I just meant it was misleading to imply hybrids aren’t efficient because the diesel engine is.

Adrian Saturday April 26, 2008


“I’m afraid you’ve gotten a few things wrong in your ideas about hybrid cars, as well as a few things right.”

“Of course, I’m going to focus in on the misinformation you have here, but just to let you know, I thought this was well written and (although mistaken) an interesting read.”

Hello Mike, and welcome to the site. I appreciate the kind words about the writing, and I am always happy to be corrected when I am wrong. That said, I will respond to your points individually.

“First, you don’t seem to fully understand how hybrid cars work. If we focus in on just the Prius, a full hybrid (because you did), the electric motor and the gas motor alternate between powering the car. The electric motor powers the vehicle at low speeds or when stopped, while the gas engine kicks in at higher speeds.”

“The gas engine can recharge the battery pack, but that’s the least efficient way of doing it. It does happen when the battery pack gets low or when the car is traveling at higher speeds, but the best way is to recharge the battery through regenerative braking. Not only does it save wear and tear on the brakes, but it also recaptures some of the energy you used to accelerate the car in the first place.”

An admitted oversight. I implied that hybrid cars operate in a similar way to diesel-electric train engines. Nonetheless, while the method discussed was incorrect, the fact remains that ALL the locomotive energy comes from the gasoline engine. This will remain true until the plug-in hybrids come to market. But as I said, even then, there are environmental and technological concerns. The North American power grid can barely handle summertime demand as it is. What is going to happen when people have their cars plugged into that grid as well as their air conditioners? All that aside, the fundamental difference between a hybrid and a normal car is one of power transmission between the engine and the wheels, not one of power generation.

“Also, the gas engine, when it is not recharging the battery, will shut down when the vehicle is stopped. This eliminates the wasted gas from idling.”

I completely agree, regenerative braking and auto-off at idle make the vehicle even more efficient! By recapturing potential kinetic energy at the wheel and converting it back into electricity that is stored in the hybrid’s power transmission (batteries) instead of converting it to heat as a normal car does, the hybrid should be even more fuel efficient. And yet, with all this, VW still manages to make diesel vehicles that achieve 10% better fuel economy. A normal car cannot make use of regenerative braking, but auto-off at idle could be incorporated, further increasing the diesel’s efficiency.

“The Prius does have a smaller, more efficient engine. But to compare it against the diesel engine is misleading, since a diesel engine is more efficient than a gas engine.”

The point I was trying to make is that hybrids are not the more environmentally intelligent choice. While hybrids are more efficient than normal gasoline powered cars, they are also much more complex systems, with complex environmental and economical end-of-life requirements. VW decided that the hybrid system was too complex to be practical in the marketplace, and has come up with alternatives that achieve equal or superior fuel efficiency. Even more, they’ve managed this at initial purchase prices that are comparable to existing vehicles – both hybrid and normal.

“Unfortunately, the diesel engine has a few issues that are hard to overcome in the US. First, the cost of the diesel engine is more expensive than the gas engine. Second, despite being more efficient, diesel costs more in the states, somewhat pushing back on the savings you would like to see when you fuel up.”

Diesel engines are more expensive than normal gasoline engines, but this increase in cost is comparable to the premium one pays to own a hybrid. In terms of a hybrid-diesel comparison, its a wash.

It is my contention that diesel is more expensive the world over. As diesel engines achieve approximately 35% greater efficiency than a normal gasoline engine, diesel remains economically superior to gasoline as long as diesel is less than 35% more expensive than gasoline.

“Then there’s the emissions/ smell/ reputation problem.”

New VW diesels meet and exceed the most stringent emissions requirements in North America and Europe. The smell/reputation problem is more serious, but it has been overcome in Europe, and VW still manages to sell large number of TDI Jettas in North America. It would be a matter of education, but nonetheless a difficult hurdle to overcome. VW is addressing this hurdle by introducing highly efficient smaller engines like the 1.4TSI, which achieves comparable mileage to the 1.9 TDI without the societal resistance of the diesel engine.

“Still, many would call for a diesel hybrid as an even more efficient choice. Too bad that means you need to add together the extra cost of a diesel engine, plus the extra cost of the electric motor.”

And this is why VW will not bring the diesel hybrid golf to market – no matter how loud the crying from Treehugger.

“Also, please do not use the Hummer vs Prius argument. It’s been dismissed as an embarrassing study by a Marketing company. Look it up on Slate before you try to use it again.”

I looked up and read the Slate response to the hybrid/hummer issue . It is an interesting read, and does somewhat soften my opinions on hybrids, but not enough to change my mind. While the article does dismiss large parts of this study, it does gloss over some relevant facts. And while the original report was poorly written, it nonetheless did raise factors that hybrid enthusiasts deflect or ignore completely. So I am perhaps prepared to accept that hybrids are more environmentally friendly than Hummers. I’m not sure how impressed I am by this.

At this time there exists no cost- or environmentally-effective way to recycle the batteries in a hybrid. I have read that Toyota has started a recycling program, and I consider this a very positive step in the right direction, but the fact remains that the cost – but economical and environmental – of recycling the power transmission system of a hybrid is far higher than the cost of recycling the power transmission system of a normal car.

The article also mentions that opponents of hybrids often ‘unfairly’ amortize the costs of building such a recycling infrastructure over the comparatively short production run of hybrids. This is a legitimate environmental and economic cost associated with hybrids, and dismissing this cost is disingenuous at best.

“One last point, batteries always need to be recycled. Whether you talk about the smaller ones you find in all cars or the battery packs you see in hybrids. Most of all cars built today get recycled. I don’t see how that’s relevant.”

As stated above, the relevance is environmental. The one small battery in a normal car contains far less dangerous material to recycle at the end of the vehicle’s life. Because there is no efficient way to recycle any of these batteries, the fewer we produce and use, the better. The power transmission system of a normal car, in contrast, is readily recyclable using existing systems.

“Hybrid cars do have their issues, but you haven’t raised them here.”

I think I have raised several valid points about hybrids that have not been addressed adequately by the technology.

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