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Discussion in 'Technical' started by CitroenSM, Sep 23, 2010.
What money? You have no sense
I really hope you are right about everything. If they are the best in the next 20 years then I will be happy to drive one around.
I think I will always miss the sound of a big V8, but if they become as efficient as you say then Im all for it. I guess we will just have to wait and see.
Electric cars are going to take over commuter cars, not fun cars. Dont worry
Jay Leno said the same exact thing.
You drive the electric car to work, etc.
Then on the weekend, you have fun in the gas guzzler!
Like usual people fail to realise the reality when they talk about electric cars.
For starters two thirds of the worlds electricity production is by fossil fuels so in terms of CO2 emissions an electric car isn't better than a fuel efficient conventional car.
Electric cars isn't a new technology, they have been around about as long as the combustion engined car. The reason they haven't been used is because they haven't been competitive.
Battery technology have not improved that significantly. A typical lead acid battery will offer an energy density of about 30 Wh/kg, a NiMH battery about 80 Wh/kg and a lithium ion iron phosphate battery about 130 Wh/kg. There are lithium ion cobalt oxide batteries that can offer energy densities of about 200-250 Wh/kg, but these have several drawbacks such as high cost that makes them unsuitable for mass production cars. Still there is certainly no 20 fold increase in energy density compared to regular lead acid batteries. Even the best, most expensive batteries can't reach a ten fold increase. With production type batteries, the increase is closer to 4 than 20, that's for sure.
If we take a modern 130 Wh/kg cell this is also calculated on the cell alone, when the full capacity is used. The usuable capacity for a built pack is much lower. Chevrolet Volts battery pack does for instance offer about 62 Wh/kg of usuable capacity. In other words, Volts 170 kg battery pack can store as much energy as a little less than one kg of gasoline. Since each kWh of battery capacity cost 500 euros or so, the battery is also a very expensive component.
Interresting isn't what I would call it.
For a 24h Le Mans race we talk about roughly 30 pitstops each for about 90 litres of fuel. The total fuel consumption during a race is thus around 2700 litres or 2.2 tons. One kg of diesel contain about 12 kWh, so essentially one car uses about 26.4 MWh during a race. Let's say that an electric car would need 1/3 of this energy, that is still 8.8 MWh. Assuming we were using high energy density batteries offering about 200 Wh/kg we would need 44 tons of batteries for the race. Assuming 30 stops each battery pack would have a weight of 1.5 tons. This is of course totally unrealistic.
I dont understand why everyone thinks im saying electric cars are better than conventional cars right now. Theyre not. Im talking in 20 years.
the newest lithium nanowire batteries have clocked in at nearly 700 wh/kg (cell only). Are they near production ready? No. Again, not talking about today. Talking about 20 years from now.
The % of energy produced by non-fossil fuels is on the upswing for a significant portion of the developed world, and even at 65%, its still a significant benefit.
That doesnt factor in many of the potential ancillary benefits of going to a different layout, like the large possible weight reductions due to many of the packaging benefits.
I'm not saying that an electric powered race car could do it today or in 5 years time. In 20-25 years down the road I can see batteries being a lot more powerful, durable, lighter, and reliable enough to be used in a race application. Electric race cars will be on the grid in the future. Someone will go for it, wheather it be Audi, Ferrari, or GM.
In Sweden there are discussions and even some plans to put electric wires overhead on highways so long long-range and high weight vehicles (trucks, etc) could run their motors and charge their batteries.
We had a team, and the car is still around (but not the batteries and chargers).
It would be awesome if highways had a recharge lane for electric vehicle that you pull into and are changed for the time you are in that lane.
You can lay them out in 1 mile sections every so often and have an rfid tolling entrance.
"For starters two thirds of the worlds electricity production is by fossil fuels so in terms of CO2 emissions an electric car isn't better than a fuel efficient conventional car."
This is entirely untrue. Like Phano has already mentioned, making electricity in HUGE scale is way more efficient than powering a single car, no matter how efficient it is.
Combined cycle fossil fuel plants are now reaching 60% efficiency [most still probably make 50-55% to be truthful]
Gasoline cars are still down in the 20% range. Diesels can reach as much as 40% but only in specific situations. These are all figures measured at optimal steady speed conditions. Electric motors on the other hand convert nearly 100% of stored power into kinetic energy regardless of rpm. Not to mention that under braking, that energy will be converted back into stored energy unlike fossil fueled propelled vehicles that lose all that energy every time you stop [discounting hybrids of course]
In practice, only about 15% or even less of your fuel will have gone to actually moving you, the rest lost in heat. Electric cars, even when drawing all their power from fossil fuels, will have used about 55%
gas cars are in the ~30% efficiency ranges, to be fair.
electric motors do have some inefficient ranges as well, and there are transmission (ie from powerstation) and charging losses to factor in.
Still big upsides for electric cars though.
just turn all the highways into giant slot-car tracks
dont need to steer, have points (like trains) that your car automatically switches to turn off, and have some anti collision shit set up.
i should patent that shit
I know, the whole concept is waste of money.
Today, in five years or twenty the situation will be the same. Gasoline or a similar chemical fuel simply have a much higher energy density than batteries, there are theoretical limits what you can do with batteries. Batteries also don't improve that fast, only about 8-10% year.
Lifecycle studies have concluded that an electric car is about equal to a fuel efficient diesel car when it comes to lifetime emissions of CO2.
Then you're making a common mistake by comparing the efficiency of the latest natural gas fired combined cycle powerplants, and then assume this is a good representation how efficient power plants are today. That is not the case. Even today the most efficient coal power plant only have an efficiency of about 47%, but many have efficienies in the 30%-range. Such a plant can emit more than 1 kg CO2 per kWh produced. There are also not insignificant losses in the grid, in developed countries with good grid we're talking about 8% in losses, but with poor grids these losses can be up to 30%. The electrical car itself - from the plug to the wheels - is also only about 60% efficient (the electric motor itself about 90%, but that is only part of the story). So for an electric car running on electricity from one of those 60% efficient combined cycle plants the total efficiency is just above 30%, with an inefficient coal fired power plant you're down at about 15%.
A gasoline engine is today about 35% efficient at its peak, a diesel about 42%. Today, the engines spend most of their time in loadpoints where the average efficiency is much lower but the average efficiency is rapidly increasing due to various technologies. Compared to electric cars these technologies are much more cost effective. Rengerative braking is also not exclusive to electric cars, or even electric hybrids.
And I think youre still negating the fact that were talking in the future. Nobody is saying theyre better, or more cost effective, or anything at this point in time, only that were moving in the direction where widespread adoption is becoming realistic, and the upside is much higher than with gas vehicles for many applications.
Youre also not including the large benefits that can come with other savings, such as the weight reduction possibilities or electric cars, which results dont manifest in powertrain efficiencies, but do help in total energy usage.
coal power plants. laff.
If humans are logical everything will be nuclear.
IMO...no I don't want everything to be Nuclear powered, with what happened in #$%#shima I,(Japan), March 11, 2011. Do to 9.0 magnitude Tōhoku earthquake and tsunami and Chernobyl (Ukrainian USSR, now Ukraine), on April 26, 1986. Do to these incidences I'm saying, "oh f**k no!!".
Information and dates, came from wikipedia.com.
2 stroke used to be the cutting edge design. It was legislation of pollutants that killed it.
Two stroke will save the IC engine.
Electric cars are if something heavier than regular cars due to the heavy battery.
Chernobyl, which was a very serious nuclear accident is not expected to cause more than around 4000 additional deaths (actual deaths that are known to be caused by Chernobyl are still at less than 100). With #$%#shima it is unlikely that any increase in radiation related deaths will ever be detected.
At the same time, the American Lung Association state that coal power kills 13,000 people every year in the USA alone. That's like three Chernobyls a year. Yet it is nuclear power that scares people.
In the US, about 40,000 people die every year due to car accidents, ten times more people than due to Chernobyl. Does that mean we should stop driving?
Not to mention the Banqiao dam disaster that ended up killing about 200,000 people. Clearly hydroelectricity is some really dangerous stuff, a ban anyone?
Not to mention the release of toxic heavy metals, GHG, SO2, NOx and radiation due to wind power and photovoltaics...