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Monday, March 5, 2012

Electric dreams

Two days after each other, two different cities, the same thing - promo for electric cars. It happens all around the world. But I don't understand, why is someone putting such an effort and funds into promoting this in a time where the battery technology isn't there and the the electric car is still not a 100% viable replacement for fossil fuel driven vehicles.

Left : Prague (CZ), right : Bratislava (SK)

Firstly there is the driving range. There are not too many comparison articles on the web. A nice overview gives this one. It comes out, that more or less current electro cars have driving range on batteries is between 65 and 150 kilometres (40 - 100 miles) under ideal conditions.When the ideal conditions are not there, the range goes down. Actually there are many factors causing the ideal conditions occure very rare. Heating in cold weather, air condition in hot weather, hills in the city, faster driving on highways around cities etc.

Saab with it's ePower technology counts to the most advanced. It claims 200 km (124 miles) in a 9-3 SportCombi. This is one of the best results. The leader in this category is Tesla Roadster showing 400 km (245 miles).

Saab ePower dashboard

This basically says, electro cars are usable in city traffic. When it comes to a business trip to another city or driving to a vacation, there comes a problem. It also means that at least now, if someone wants such an electro techno dream, he has to have another conventional (or hybrid) car.

Charge time is another thing. The least time 6 hours, while 10+ hours counts as normal. In the european cities the majority of the drivers doesn't has a garage with electricity. I've seen some experimental "docking stations" in the grachts of Amsterdam with included credit card reader as well as some charging stations on highways in Europe, but it is still a rare thing these days.

A great competition to the Tesla Roadsters 245 km is a vehicle called Detroit Electric declaring 320 km (200 miles). This car was invented in 1907. Yes, you read it correctly, more than 100 years ago. A natural question comes : how far the development of the batteries advanced from that time ?

According to a study Automobiles on Steroids: Product Attribute Trade-Offs and Technological Progress in the Automobile Sector by Christopher R. Knittel is saying, that todays batteries are 4 - 10 times more powerful in comparison to the beginning of 20th century. So why there is a small progress in increasing the driving range ?

Firstly the cars became heavier, mostly due to many safety and other mechanisms. I couldn't find the Detroit Electric wight, but the most known Ford Model T from the same time weighted around 540 kg. The cars of today are rarely around one ton, often 1.2- 1.5 tons.

Secondly the speed has increased significantly. The mentioned retro cars were driving around 20 kmh (12 mph), while todays car are driving much faster. It is not only about the weight but also aerodynamic characteristics of the car. These were improved but still with increasing speed, the aerodynamic resistance increases at a high rate.

And thirdly the element between the driving wheel and the seat. People (incl. me) love to drive faster, than they need to. Todays car is giving this possibility and drivers are using it. That costs energy.

Detroit Electric charging. Photo : Cress-Dale Photo Co., Seattle.

Next thing is price. These car expensive initially. Look here for an overview. It would be fine, if the lower costs of operating would compensate the price difference. Do they ? The Belfer Center for Science and International Affairs of Harvard University did a sophisticated study to answer this question.The answer is no. You can read the summary as well as the whole study [pdf].

The last thing is environment. Yes, it's fine, that the electric baby doesn't has CO2 emissions. But the conventional power stations have and, at least in Europe, the nuclear power station are in many countries shut down. So to get the increased demand of electricity, there will be demand on the power stations. And on the price as well.

So why everybody is so pushing on the electric cars ? It also affects Saab, because some of the companies, which would like to buy the bankrupted Saab want to build electric vehicles in Trollhattan. Fine, but who will buy them ?

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