All-Electric Cars

June 9th, 2009 by Potato

Tim from Canadian Dream made a minor mistake last week in his thoughts on electric cars. “Where are you getting the power to fuel the cars? …Depending on…”

Ah, “Depending on”. I love those words, they open up so many possibilities for playing with numbers and outlining scenarios. They can make life so interesting.

Really the only factor Tim discusses is where the power comes from: coal is dirtier than other sources like hydroelectric or natural gas, so, he concludes, maybe you shouldn’t get an electric car if you live somewhere where there’s a lot of coal generation. After all, electric cars aren’t completely clean, they get their juice from the grid. The thing is, that’s one of the few variables that isn’t a factor in making the decision to go to an electric car — several studies I’ve seen have said that electric cars are so much more efficient that they always beat out regular gas cars, even if 100% of the power comes from coal [though other studies, such as the german WWF one, indicate that for real-world power mixes electric cars beat out gassers, but may narrowly emit more CO2 on 100% coal — but that’s with a highly optimistic 6.6 L/100 km fuel consumption assumed for the gas car; they figure an electric car on coal would produce 200 g of CO2/km, and a gas car only 160 g/km — but for the US, the average is 210-250 g/km, and probably higher for real-world driving]. With the really efficient hybrids it becomes more of a toss-up, but still not something you need to worry about with all the other factors to consider.

Why is that? Well, first off thousands of tiny internal combustion engines on the road is a fairly inefficient way to move people around: in the best case, a conventional car is only about 25% efficient (at most). That is, only about 25% of the energy in the gasoline gets translated into actually moving the car (and none of it when you’re idling/creeping in construction season). Hybrids do better (especially those with atkinson-cycle engines), topping 30%, to as much as 37% efficiency (and perhaps touching 40% for the 2010 Prius). Now, here’s where my numbers differ from Tim’s: I’ve heard that properly run coal power plants can top 50% thermal efficiency, whereas Tim says in the comments it’s 30-40% — if that’s the case then a hybrid can beat out an all-electric in cases with high levels of coal use.

Now of course, even if the thermal efficiency is higher, you have to consider that coal has more carbon emissions per unit of energy than oil does — but then, even Alberta isn’t a 100% coal-fired province (though it is up around 75%).

Plus there are other pollutants to consider beyond just carbon dioxide: just like having a tiny engine is inefficient, having a tiny exhaust scrubber is also inefficient, so you can generally get fewer bad things out of a centrally-managed power plant than a distribution of cars (pollutants like nitric oxide, carbon monoxide, etc). You also shift those pollutants from sidewalk level in the downtown core to a distant location where the power plant is — good for the people living in the cities, even if it’s a wash to the atmosphere. Coal may have more sulphur and mercury though. By charging off-peak, the extra demand can actually help improve the power grid by smoothing out the demand (and with a smart grid, electric cars could give back power when needed).

Now that’s sort of the worst-case scenario for electrics, and even there they might lose out to hybrids on some counts, but at worst it’s a wash with a gasser. But most provinces do have cleaner energy mixes than that in real life (and Albertans aren’t reading this anyway) — this a no-brainer factor.

So what are the other “depending on” factors?

Cost: hey, batteries are expensive, and at this point electric cars are limited-production items, so the up-front cost is often steep. Since electricity is cheaper than gas, joule-for-joule, in every locale I know of (or at least, mile-for-mile), you can do a lifecycle analysis and may find that in the long-term an electric will be a wash or even cheaper, but the upfront cost is a hill to overcome, especially if you need to install 220V service or a special charger in your garage. That analysis gets worse if you move a lot.

Access to charging: It might be nice to charge at work or the mall, but probably isn’t strictly necessary. However, if you live in an apartment building (or even a house with street parking rather than a driveway/garage), odds are an electric car won’t work for you just because you don’t have good access to charging.

Going Off-Grid: No one I know has their own oil refinery in their backyard (Reggie would, but it’s against the condo bylaws), but if you want to be self-sufficient (for instance, to get away from the coal use in your local grid), you can install your own solar panels or wind generator or other renewable energy source and charge your car at home.

Range: Electric cars will have a limited range, and until fast charging stations or battery swaps become common-place, that’s probably going to make range the #1 “depending on” issue for people considering an electric car. They won’t work for everyone, but the fact is most people do most of their driving in a very limited area: to work, to the mall, to the curling club, home again. For something like 95% of trips people make, the range on an electric will suffice. Many households also have more than one car, so an electric commuter and a larger, gas (or hybrid)-powered “cottage van” would probably work.

Practicality: Batteries have much lower energy density than gasoline, so they take up a fair bit of space. This makes the equivalent electric car slightly less practical than a gasoline one. Plus, electric cars tend to be tweaked for efficiency (small, often 2-seater commuter vehicles). This is not a requirement of electric cars — there’s nothing really stopping one from making an electric Cadillac Escalade, it’s just that the batteries and motors to make that behemoth move (esp. with any kind of decent acceleration) would be prohibitively expensive. Although it would greatly improve the handling and roll-over characteristics since you tend to put the batteries in the floor.

Maintenance: Even though it only takes seconds, some people just don’t like the idea of having to plug in every night. On the flip side, electric cars have much fewer maintenance requirements: no oil changes, no exhaust testing, no belts to replace, no spark timing to fiddle with, no air intake filter. You’ll still have to remember to do your cabin air filter and top up the washer fluid periodically, and eventually the friction brakes will need servicing, but they’ll likely last 4 or 5 times longer thanks to the reduced wear with regenerative braking.

Canadian Winters: I wish I could say for sure that batteries have no problem with Canadian winters, but unfortunately, your range will be cut down if only from the energy needed to run a heater (not a problem gas cars typically have since 75+% of their energy is lost to heat anyway). High-voltage batteries do look to perform better than the lead-acid starter battery in your car, and the car will run, but more real-world testing is still going to be needed. But other than that it doesn’t look like there will be any major problems.

Battery Chemistry: Nickel-metal batteries are a time-tested technology that have been working great in automotive applications, from the EV-1 and Rav4 EVs to the variety of hybrids on the road today such as the Prius, Insight, Civic, Escape, etc. They last essentially the life of the car with very few failures. However, due to some bad politicking, they are patent-protected by a company that seems to have little interest in selling batteries affordably, or possibly at all. So pretty much all electric cars are going with either older lead-acid batteries or new lithium-ion batteries. While lithium ion batteries are lighter and can put out more power, they don’t have the track record yet to say for sure that the heat issues have been solved or that they can last for a long time (they may have a time decay/aging as well as decaying with use/mileage).

Existence: For now, there really aren’t many choices for electrics. Most of the new ones (like the Zap and the Zenn) are “glorified golfcarts” or neighbourhood electric vehicles — low-speed cars that are not capable or safety-rated for highway speeds. That adds extra limitations, making it harder to settle for one — and of course, they’re only legal in two provinces. There are some Rav4EVs from the late 90’s CARB zero emission experiment rolling around, and from the sounds of things they seem to be in great shape still… but very few of them are offered for sale (hey, their owners were the fanatics who got an electric car in the 90’s!). The Volt, though a PHEV, is a powerpoint dream that’s perpetually just a year away… and that doesn’t look any rosier with GM in bankruptcy. Which pretty much leaves the Tesla. Their roadster has the usual limitations of a two-seater sports car, including a hefty price tag. They’ve unveiled their model S, a luxury sedan to come soon (and I desperately want to see how they wedged those kiddie seats in there to make it a 5+2 seater, ’cause I just don’t believe it from the exterior shots). A variety of others are in the works, such as a mystery car from Nissan (and I for one fully expect the Honda Clarity to surprise! come out as an EV in a few years, since it’s basically an EV now with a fuel cell where the battery should be… the hydrogen fuel cell test car is a clever smoke screen for the competition). There are a few do-it-yourself kits — I’ve seen a 1980’s-vintage Civic at Sunnybrook that was converted to electric, with the trunk and backseat replaced with an array of lead-acid batteries — as well as garages that will rip the gas engine out of a car for you and do a full conversion (a PriusChat member recently gave his Porsche that treatment).

PHEV: Plug-in hybrids, through conversions and maybe soon OEMs (Volt??) will let you have your cake and eat it too: you can have a reduced all-electric range (and reduced all-electric speed in the case of the Prius conversions), perhaps just enough for your daily commute, letting you run cleanly (and cheaply?) off the grid for most of your driving, while having the security blanket of a gas engine that gives you the essentially unlimited range our current cars and gas station infrastructure provide.

They’re not going to work for everybody, but if they work for even 50% of the 66% of families with more than one car then we’d off to a flying start.

Hmm, I don’t know how I have a whole post on EVs and didn’t manage to link to Darell’s EVnut page. There you go.


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