Sunday, December 24, 2006

Electric Vehicles Aren't What You Think

Tesla RoadsterDo you think electric cars are all slow-moving, small and golf-car-like? Well you're wrong in at least 1 instance.

The Tesla Roadster - a $100,000 sports car - does 0 to 60 in 4 seconds, goes 135mph and has a range about 250 miles. While it still takes about 3.5 hours to deliver a full charge, this is better than other vehicles.

And Tesla does have plans for more conventional cars in the future, but their idea is to convince you that your prejudices against these things are unfounded.

People have strange ideas about renewable technology. Solar energy - photovoltaics - cost about $30 per watt in the 70s during the oil embargo. Today, that same watt of electricity is less than $3, but people cling to the idea that solar is too expensive. (With oil at $60 per barrel and going up, and the cost of solar going down, are you sure that solar is "too expensive?")

And "too expensive" compared to what? Is a Lincoln Navigator too expensive? Is a Corvette too expensive? You can find cheaper alternatives, why aren't you making these purchase decisions on strictly economic terms? Is the Tesla too expensive? Compared to what?

Batteries continue to be a problem. They are much better than they were, but cost is still high for the lithium-ion and similar batteries.

So some industries have done without the batteries and gone to diesel-electric drive. (The railroads did this for economy in the 1940s and 50s or earlier.)

The Fast Electric Yacht System provides performance and installation costs similar to diesel engines, and yet deliver much better fuel economy.

Item Factory Diesel Factory Gas FEYS
Engine / Motors 420 HP Diesel (2) 410 HP MPI Gas (2) 133 HP Motors (4)
Fuel Capacity 300 300 150
Genset 9 kw Onan (Diesel) 10 kw Onan (Diesel) 400 kw (Diesel)
Total Vessel Weight 20,400 lbs. 20,000 lbs. 19,900 lbs.
Cruising Speed 22 kts 21 kts 25 kts
Top Speed 30 kts 28
28 kts
Range 215 miles 187 miles 212 miles
Noise (at helm, cruise) 92 DB 92 DB 78 DB
Fuel Burn at Cruise with Genset 36 GPH 42 GPH 24 GPH
Estimated Cost of Propulsion System $76,100 $36,100 $73,425

If you are wondering why electric motors can deliver this performance while the system is only rated at 133 HP (266 HP per drive shaft) instead of in the range of the internal combustion engines, it has to do with the way engines are rated. Internal combustion engines are rated at the maximum horse power that can be generated for 15 minutes without overheating. (This means at 16 minutes the alarm is going off.) Electric motors are rated at continuous horse power.

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