by yesplease » Thu 12 Oct 2006, 04:56:20
$this->bbcode_second_pass_quote('The_Toecutter', 'I') say let it stand on its own merits. It doesn't need tax credits so much as it needs someone to actually start producing these vehicles in large quantities(without mass production, price will be high).
Actually, from the DIY/limited use standpoint, I disagree. An add-on plug-in EV sytem, with a small pack, say enough for 30 miles at 30mph, and a small motor/controller designed for low speed/city use is definitely competative compared to the equivalent cost of gasoline over the same number of city miles, which is dictated by the number of cycles to 80% DoD the pack can stand.
For instance a Vette, which gets ~20mpg city, can have a 6 battery t-105 pack that takes it roughly 30m@30mph (150ah assumed), or 30m@20mph with stops/accelerations. For the first 15k miles, the money spent on the system will probably be what's saved in gas. But after the cost of the controller/motor/wheel/mounting (say ~$1k) is absorbed, the pack would save the driver ~$1k per 15k miles city. As the car gets smaller and it's city mpg increases, this advantage decreases, but is still present for almost all cars.
The flipside being that at highway speeds, it's not terribly cost effective. But, if the driver has a significant chunk of their commute spent in traffic, especially stop and go traffic on the highway, the pack could save quite a bit of cash, w/o the need for mass-prouction. This is reflected on the other end of the spectrum, with the Tesla Roadster trumping other high end ICE powered vehicles that don't have the advantages of mass production in terms of performance, and overall cost.
$this->bbcode_second_pass_quote('Doly', 'W')here do you get these figures from? My understanding was that to turn all vehicles into electric we would need to roughly double electricity production.
That's a huge simplifcation that comes from comparing the amount of electricity in a gallon of gas and the number of gallons we use directly to EVs. The problem is gasoline cars tend to be ~15% efficient, while EVs tend to be ~70% efficient at using the energy stored on the vehicle.
For a decent estimate, we can look at this
Chevy S-10 conversion, and
past data on the number of vehicle miles traveled to get an idea about how much electricity we'd need. According to the eia page, we traveled ~1.5 trillion miles in 1988, and ~1.7 trillion miles in 1996. We'll guestimate that right now we average ~2 trillion miles per year.
According to the NREL, a vehicle that gets ~25mpg EPA combined, needs ~10kwh to travel 45miles at 45mph, or, taking into account a significant percentage of city driving, something like 10kwh to go 35miles at 35mph, about the average speed and distance of the average driver. And since this vehicle is slightly more efficient than the EPA average, we'll drop that to 30 miles at 35mph for the average vehicle (something like 21mpg combined). So, we know that we have a rate of 10kwh/30miles, or 1kwh/3miles.
In terms of electricity, we'll need roughly (1kwh/3miles)(2trillion miles). Or about ~.7 trillion kwh per year. According to the CIA factbook, we consumed ~3.66 trillion kwh in 2003. So we would need ~20% of what we produce per year. The thing is, on average the grid is only at ~50-60% capacity, roughly 75% during the day and 25% at night. So when people drive home and plug their cars in, they could be set on timers so the increase in consumption happens when consumption is at it's lowest point.
The overestimate comes from assuming every car gets ~10mpg, and since there are 33.6kwh per gallon, and we drive ~2 trillion miles per year, we'd need 3.36kwh/mile, so (3.369kwh/mile)(2 trillion miles) is roughly 7 trillion kwh per year, or double current electricity production. The difference comes from the estimates for vehicle efficiency, half what the average new vehicle gets, and the difference in EV efficiency compared to ICE efficiency.
Another factor influencing EV efficiency is the limited capacity of battery packs. To have range similar to ICE powered vehicles, the EVs need to be better at rolling, and moving through the air. A side effect is they are also more efficient, which reduces the amount of electricity needed by a significant amount.
$this->bbcode_second_pass_quote('Doly', 'I') see two problems with that. One, that coal is polluting and a carbon dioxide source, leading to climate change. Two, that we have had plenty of time to develop sustainable technology in the last two centuries, and we haven't exactly done it, have we?
The counterpoint would be that we haven't developed sustainable technology because it's not profitable for big business to do so. Compare a 5kw solar system and EV that may cost $40k initially, but can allow the consumer to not pay any electricity or gasoline bills, and reduce the cost of repairs for the next 30-50 years depending on the longevity of the system/EV.
Over those thirty years, the consumer will not pay something that's significantly more than the initial $40k investment. In fact, they may realize that by having a small/aerodynamic EV, and switching to appliances that consume less electricity, they can opt for a smaller solar system, and save even more money. The most profitable business' are based off of services, not products that require replacement infrequently. Cars, and the fuel that powers them, are more profitable if they are inefficient and unreliable.