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the electric car

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NutmegCT

NutmegCT

Great Pumpkin
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On a relatively "everything else is equal" basis (distance, speed, vehicle weight, etc.), if a car is only powered by a motor running off rechargable batteries (instead of a gasoline engine), can I figure the amount of electricity needed to charge the batteries for a given distance "used up" by using "power" equivalents?

In other words, if I assume 115,000 BTU in 1 gallon gasoline:

1 kWh = 3,333 BTU, cost = $0.20 (here in Connecticut)
1 gallon gasoline = 115,000 BTU, cost = $4.00 (here in Connecticut)
115,000 BTU gasoline / 3,333 BTU elec = 35 kWh = 1 gal gasoline

Therefore:
35 kWh x $.20 = $7.00 ($7 of elec has the same energy as $4 of gas)

If my car uses one $4 gallon of gasoline to go X distance, then to go the same distance on electricity would take $7? And thus to recharge the battery for that same distance "discharge" would be $7?

give or take? :crazy:

If I'm anywhere in the ballpark, seems that - all other car and driving variables being equal - it'll still be quite a while 'til the fully electric ("plug-in") car becomes preferable to a gasoline car for the individual driver.

Unless the driver has a very low expense for electricity. Edit: and I don't imagine electricity is going to get cheaper in the near future.

T.
 
Well maybe, but gas engines are quite inefficient. At best, only about 25% of the energy contained in the gas is converted from thermal energy into mechanical energy.

Of course there are inefficiencies with electric also, starting with the rechargeable batteries which only return about 80% of what you put in.

However you also ignored the fact that in most locations, you can get a special watt meter which reduces the cost for non-peak hours which is when you are likely to charge the car.

As for overall efficiency,having some electric cars charging up at night would increase to overall efficiency of the electrical system. At night the system is really quite underloaded. It is easy enough to stop gas turbines or diesel generators, but large coal powered plants don't shut down overnight, and they are significantly less efficient when underloaded. So, charging some electric vehicles would have the effect of increasing to overall efficiency.
 
Tom, you did not include any consideration for the energy efficiency of the electric motor compared to the gasoline engine. The gasoline engine wastes much energy in heat and the inefficiency of motion and friction within the engine.

I did not post fast enough - probably due to internal inefficiency. :yesnod:
 
Thermal loss, Tom :wink:
 
AHA!

So if I do some efficiency factor fudging ...

Gasoline engine 30% efficient; electric motor 80% efficient

The calculation becomes:

35 kWh / .8 eff = 43.75 kwh
1 gal gas / .3 eff = 3.33 gal

35 kwh * $.20 = $7.00 (electricity cost) (cheaper for most of the rest of the USA)
3.33 * $4.00 = $13.32 (gasoline cost)

Thus electric car is half the cost to run (and recharge) as gasoline car ... all other things being equal.

If I'm anywhere close this time around, I've done a 180 in my thinking. Well, strip my gears and call me shiftless!

T.
 
In April of this year, US drivers drove 245.9 billion miles(2,950.8 billion miles per year). If we replaced all gasoline and diesel cars and light trucks (245 million) with electric cars, and assume you drive 12000 miles a year, and your car gets 200 miles on a charge and you only charge when needed. That means you charge your car 60 times a year or every 6 days. So every day 40,833,333 cars will need recharging.

Given this demand for power is new how many 2 gigawatt power stations would we need to charge them?

Please do not ask me to do the computations. I am only good at asking questions.
 
TR6oldtimer said:
In April of this year, US drivers drove 245.9 billion miles(2,950.8 billion miles per year). If we replaced all gasoline and diesel cars and light trucks (245 million) with electric cars, and assume you drive 12000 miles a year, and your car gets 200 miles on a charge and you only charge when needed. That means you charge your car 60 times a year or every 6 days. So every day 40,833,333 cars will need recharging.

Given this demand for power is new how many 2 gigawatt power stations would we need to charge them?

Please do not ask me to do the computations. I am only good at asking questions.
Click to expand...

<span style="font-style: italic"><span style="font-weight: bold">Probably none! In fact, some of the less efficient power plants could be retired. why? the energy consummed to drill, pump, refine, and distribute petroleum based fuels would almost disappear and this demand would be replaced by that required to charge automotive batteries. </span></span>
 
another fillip to the mix - most of the cars would be recharged at night, when there's much less demand (now) for electricity.

Generating stations that now exist have been designed for meeting "peak" demand; when that demand isn't there, most of the stations stay online, despite there not being a need for all that peak power. You don't easily shut down a coal-burning (or nuclear?) generating station just for the overnight hours.

T.
 
THe nice thing about electric cars (and I do not believe EVs can save the world) is that they use NO fuel when stopped at a red light, and electric at slow speeds....

Which in city driving must be figured in your "miles per gallon"
or maybe we need "energy per hour"

Ohhhh Prius has another "chip" set-up for Europe which keeps it on electric till a higher MPH

If it costs $5 a day to recharge your EV , you can bet people will do it when they get to work (wrong time of day ! )

and using Solar panels at home will not charge your EV at night (duhh)


So it really is a problem of where you get "Free" green energy to run all the plug in EVs that everyone wants....

Beaulieu

waiting for 5 pound car batteries to replace the 20 pound ones.....
 
Base line power needs for the most part are provided by the large steam driven nuclear, gas, and coal plants. For efficiencies, the power companies like to run these things at steady state. Smaller plants, often called peaker plants are used to pick up the demand over base line. These plants are usually gas turbine and to some extent hydro-electric. Other then hydro-electric, operation of peak load generators is more expensive.

In 2006, the US generated 4,064,702,000 megawattshours or an average 11,136,170 megawattshours daily from all sources. Peak power operations on average represent about 25% of all power generated in a day (I assumed 12 hours), so baseline power generation is 8,352,127 megawattshours and peak is 2,784,042.

If your electric car could go 200 miles in four hours on a full charge(assuming the equivilent of 25 mile per gallon of gas), it would have used 175 kilowatts of electricity (43.75 kwh*4). Changing from kilowatt-hours to megawatt-hours we have .175 megawatt-hours consumed.

Using my number of 40,833,333 cars charging every night, you would need 7,145,833 megawatt-hours of additional power capacity (.175*40,833,333). Even running the peak power generation plants all night would still leave a deficit of 4,361,791 megawatt-hours.

So how many 2 gigawatt power plants would be needed? Let's assume it takes 12 hours to charge the batteries, and for ease of computation, the batteries charge at an even rate, then the excess hourly demand for these 12 hours would be 363,483 megawatts(4,361,791/12) or 363.4 gigawatts of new power generation. We would need 182 new 2 gigawatt power plants just to charge all our electric cars over night.

I have to admit, that I do not hold these calculations to be reality I can prove because of the assumptions made, but even if I missed the mark by 50% we will need more electrical power, not to mention a significant up grading of electric transmission lines.

Fortunately moving to 100% electric cars and light trucks will not happen over night, but unless we are prepared to increase our electrical production as more electric cars are put on the market, there will be another crisis.

It was a kind of fun exercise.
 
NutmegCT said:
another fillip to the mix - most of the cars would be recharged at night, when there's much less demand (now) for electricity.

Generating stations that now exist have been designed for meeting "peak" demand; when that demand isn't there, most of the stations stay online, despite there not being a need for all that peak power. You don't easily shut down a coal-burning (or nuclear?) generating station just for the overnight hours.

T.
Click to expand...

Tom: The "base loaded" fossil generating plants can not easily be modified for cycling operation, that is on-off, on-off. The components are not designed for the thermal extremes. No doubt the future will be in distributed generation. We will have many smaller efficient generating sources closer to the load. BTW, all those millions of electric cars plugged into their charging stations each night represent a significant reserve capacity. With proper design consideration, and during a crisis, they could provide power to the grid. Such schemes are currently under consideration.
 
beaulieu said:
and using Solar panels at home will not charge your EV at night (duhh)
Click to expand...

however, you could collect free solar during daylight hours and store the energy in a stationary battery bank in your home - then transfer the energy to your car at night. Solar panels will be incorporated into the car itself, and this is planned for the Prius in a couple of years.
 
TR6oldtimer said:
So how many 2 gigawatt power plants would be needed? Let's assume it takes 12 hours to charge the batteries, and for ease of computation, the batteries charge at an even rate, then the excess hourly demand for these 12 hours would be 363,483 megawatts(4,361,791/12) or 363.4 gigawatts of new power generation. We would need 182 new 2 gigawatt power plants just to charge all our electric cars over night.
Click to expand...

<span style="font-size: 11pt">Ray: See my post above. As we move away from a petroleum based economy our need for the tremendous load represented by that industry will diminish. The electrical energy required to refine a gallon of gasoline will be replaced by that required to charge electric vehicle batteries. So, although some older "base loaded" fossil stations will be retired, you wont see another large (> 300mw) power plant in the near future. Distributed Generation is the wave of the future, with many smaller generating plants, including fossil, hydo, solar, wind, etc, sited closer to their load centers.</span>
 
angelfj said:
Ray: See my post above. As we move away from a petroleum based economy our need for the tremendous load represented by that industry will diminish. The electrical energy required to refine a gallon of gasoline will be replaced by that required to charge electric vehicle batteries. So, although some older "base loaded" fossil stations will be retired, you wont see another large (> 300mw) power plant in the near future. Distributed Generation is the wave of the future, with many smaller generating plants, including fossil, hydo, solar, wind, etc, sited closer to their load centers.[/size]
Click to expand...

The purpose of looking at what would be needed to make all cars and light trucks electric was to take what appears to be a good solution to oil to the limit. What would work well for one or a few, does not work well for all. There are consequences and they need consideration before a benevolent government mandates it.

Back to your point.
In my scenario, the amount of electrical power needed to charge the cars over night creates a new peak 12 hour power demand nearly equal the the 24 hour baseload. So while there would be a reduction in demand by a decrease in the power used to produce fossil fuels, it would not be enough, or even noticeable, to offset the new demand.

So where can we get what is needed?

Hydro-electric plants are no longer an option in this country due to environmental concerns and the fact few satisfactory locations exist.

Geo-thermal has potential, but is limited to a few good locations.

Solar and wind can supplement our needs, but cannot replace baseload because they are not a stable source of power (the sun goes down, the wind doesn't blow or blows to strong).

Here in Santa Cruz County a community of 340,000 with no industrial base, we use about 2 gigawatt hours of electricity a day. Computations were made on what would be needed to make the county 100% solar. Surprisingly it would only take one square mile of land for the solar arrays. The model included producing enough electricity during the day to offset what was needed at night. While this model made some feel good that the amount of energy the county used was all from solar, the county still had to rely on fossil or nuclear for power at night or when the solar output was reduced due to weather.

Anyway, whether we build 182 2 gigawatt plants, or 1,213 300 megawatt plants, we will need more power plants in the future.

Today it is very difficult to build coal plants, and nearly impossible to build nuclear plants, solar and wind will not be enough.

In the near future the angst we are experiencing over high gas prices will be nothing compared to when (as California has experienced) we routinely start living with brown outs or rolling black outs. This will come unless we as a nation address our electrical needs now, with the technologies we have now, while at the same time adding alternative power sources to supplement traditional producers.
 
Ray: I understand your point. I believe the key to all of this is planning. It better not be a governmental body! Remember Katrina? There are many expert organizations that can get involved with industrial and electric utilities, including for example, IEEE, EPRI and the Edison Electric Intitute. I've been an IEEE mamber for many years and believe me there is no lack of knowledge regarding a phased transition plan for future electrical needs. This has been under study for decades. For a number of reasons, I believe the transition to electric vehicles for most consumers will be gradual.
 
One of the things that I've always been concerned about with electric cars and hybrids is what will be done with the batteries when they're spent? Seems to me that there's a lot of nasty things in batteries that, in all likelihood, will end up in landfills. I've had the same concern with the long-life fluorescent lightbulbs designed for home use. They contain mercury, and though there are state programs and some private programs to recycle, I often wonder if people really do it. Just a thought that goes along with some of these great technologies -- what to do on the back end.
 
VW had some electric VW buses in the 80s , one is in their museum in Wolfsburg,
a bank of batteries were the back floor, they could be forklifted out and replaced,
the battery bank could be rebuilt , the top taken off to get to the lead which would be remelted ,

It was a good idea for the time , but we still have heavy lead acod batteries to drag around...

Beaulieu
 
www.teslamotors.com/ is using lithium computer batteries


lightweight but expensive , and no idea if you can recycle them....
 
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