WHAT PERCENTAGE

[[email protected]]

What percentage of the Earths surface (excluding oceans) would need
to be covered with PVs to supply all of today's power needs assuming
10 % efficiency of the PV panels ?

 

[Henry]

What percentage of the Earths surface (excluding oceans) would need
to be covered with PVs to supply all of today's power needs assuming
10 % efficiency of the PV panels ?

Assuming 6E6 people.
Assuming energy consumption of 11.5 kW (USA1999).
Assuming 1 kW per square metre insolation.
Assuming 10% efficiency panels.

6E6 * 11.5 kW = 69E6 kW required to sustain population

=> 69E6 square metres at 100% efficiency
=> 690E6 square metres at 10% efficiency

690E6 square metres = 690 square kilometres
....a circular array less than 27 km in radius.
....a negligible percentage of the Earth's surface.

Henry.

 

[Simon]

Assuming 6E6 people.

6 million? A large city has more than that. 6E9 is more like it.

Assuming energy consumption of 11.5 kW (USA1999).

Americans consume about 2-3 times the amount of some developed countries,
and many Africans would barely compare. Also 11.5kW is a measure of power,
not energy consumption, although 11.5kW run 24/7 sounds right (for the USA).

Assuming 1 kW per square metre insolation.

Only if normal to the sun, without cloud cover.

Assuming 10% efficiency panels.

6E6 * 11.5 kW = 69E6 kW required to sustain population

Americans in the future will be forced to use less power so that rate will
have to be less for them. It is also too naive to use one value for all. I
don't suppose someone in the tropics will have my heating bill for example.
Oh and the population is continuing its relentless increase...

=> 69E6 square metres at 100% efficiency
=> 690E6 square metres at 10% efficiency

690E6 square metres = 690 square kilometres
...a circular array less than 27 km in radius.
...a negligible percentage of the Earth's surface.

Henry.

The values you calculated is the area that is normal to the sun without
being blocked, for an incorrect population.

Of course this area needs to be adapted because the world rotates, so panels
will have a variation in the power produced during any given day, and extra
need to be used to allow for overcast days. Also the location of the panels
is significant. The Sahara is a higher energy density area for sunlight than
here in blighty. Oh and don't forget the seasonal variation, and the daily
peaks in demand.

A prediction from a slightly out of date text book puts energy consumption
at 6E20J per annum (including losses, ie it's a measure of oils' calorific
value and not the energy extracted). Assuming we get 1/4 out the demand
becomes 1.5E20Jpa.

As Joe says, much of the demand is for space heating which is much more
efficient than 10%.

This equates to 4.76E12 Watts. Since much is used for heating divide by
perhaps 2, so 2.38E12 is needed as photovoltaics. Thats...
2.38E10 metres squared,
or a square with sides of around 155km, but again, that's the unshaded
normalized value. You'll need far more to generate that energy and cover for
peak demands.

Really there is no single answer to the question, only approximations with
guess work.

<little rant>
Energy demands really have to fall in the future, and they will. Air travel
will die. The days of 5.0L 2 tonne SUV's are numbered. Commuting will become
more expensive, so people will less able/less willing to commute stupid
distances on a daily basis, electrical appliances will become more efficient
and homes will be better insulated. Much can be done with regulation, but
the real changes will be due to consumer awareness and those prohibitive
energy costs. Products will also become more expensive again, so the waste
of the throw away age will dissappear, which will also reduce our energy
consumption. That's assuming global warming doesn't cause thermal runaway
first. God help us!
</little rant>

Simon.

 

[Simon]

Chances are that solar PV or nuclear will be needed
within a hundred years or so, maybe sooner if the Arabian
producers decide to limit oil production to make it last longer,
simply because a lot of auto use will have to switch to electric.

100 years is very optimistic with the current level of population. If the
Arabian producers limited production that would be a good thing. Imagine
running the wells dry and oil production stopped suddenly. Who would be
prepared? Who could cope with such a sudden loss in energy. It's a recipe
for disaster.

People seem to want to find new ways of generating more power to feed their
current excessive demand. It's actually much better to use the energy more
wisely.

Even 3 or 4 square meters of panels on top of an electric
vehicle would be very useful, and would work well with hybrid
systems, which the auto industry is dragging their feet on.

Useful but the economics don't make any sense yet. Far better to have
smaller lighter and more aerodynamic cars.

Government regulations won't help though,
good design will make the difference.

The real kick will be costs. If Americans had our fuel bills, their cars
would look a lot different. ~78 pence per litre. ($1.20?)

A hybrid will get 2 to 4 times the mileage as present
cars. Solar thermal must accompany PV to achieve the
reduction in fossil fuels.

Agreed. Along with wind, biomass, geothermal, and lower populations. If only
the pope would re-think his attitude to birth control It's not just
energy we're consuming, its the whole earth.

There just isn't enough fuel to sustain the world
as it is now, unless everybody moves to the tropics.

Which are rapidly disappearing :-(

Simon.
PS I'm not as miserable as I may sound

 

[Down Under On The Bucket Farm]

Probably about 5 percent, but a the majority of "power"
is used as thermal energy, which can be more than 50 percent
efficient.
Chances are that solar PV or nuclear will be needed
within a hundred years or so, maybe sooner if the Arabian
producers decide to limit oil production to make it last longer,
simply because a lot of auto use will have to switch to electric.

Don't worry. Shrub has new, innovative, intellectual methods of
negotiation, to help persuade those stubborn "Arabian producers"
to co-operate.

 

[Henry]

What percentage of the Earths surface (excluding oceans) would need
to be covered with PVs to supply all of today's power needs assuming
10 % efficiency of the PV panels ?

Assuming 6E9 people.
Assuming energy consumption of 11.5 kW (USA1999).
Assuming 1 kW per square metre insolation.
Assuming 10% efficiency panels.

6E9 * 11.5 kW = 69E9 kW required to sustain population

=> 69E9 square metres at 100% efficiency
=> 690E9 square metres at 10% efficiency

690E9 square metres = 690,000 square kilometres
....a circular array around 265 km in radius.
....a negligible percentage of the Earth's surface.

Henry.

 

[Henry]

Assuming 6E6 people.

6 million? A large city has more than that. 6E9 is more like it.[/QUOTE]

Doh! Mea culpa.

Americans consume about 2-3 times the amount of some developed countries,
and many Africans would barely compare. Also 11.5kW is a measure of power,
not energy consumption, although 11.5kW run 24/7 sounds right (for the USA).

11.5 kW == 11,500 Joules per Second. Looks like energy consumption to
me! That figure came from the US DoE.

Only if normal to the sun, without cloud cover.

The vast majority of the panels would be located in areas which have
negligible problems with cloud cover. Since it is expected to power the
entire population of the planet, and the planet spins, such an array
would--by necessity--be distributed across various time zones.
Normality to the sun is thus not as much of an issue as one might think.

Americans in the future will be forced to use less power so that rate will
have to be less for them. It is also too naive to use one value for all. I
don't suppose someone in the tropics will have my heating bill for example.

They wouldn't need heating--they would need cooling instead. Six of
one, half-a-dozen of the other.

The values you calculated is the area that is normal to the sun without
being blocked, for an incorrect population.

The original message has been superseded with a corrected one.

As Joe says, much of the demand is for space heating which is much more
efficient than 10%.

Granted, but the OP just wanted a figure for 10% efficient PV.

This equates to 4.76E12 Watts. Since much is used for heating divide by
perhaps 2, so 2.38E12 is needed as photovoltaics. Thats...
2.38E10 metres squared,
or a square with sides of around 155km,

My population-corrected value was a circle with radius 265 km. We're in
the same ballpark.

Really there is no single answer to the question, only approximations with
guess work.

Yup, but that's all the OP wanted. He's not thinking of building one,
just wants a rough idea. Since the original post framed the question in
terms of a percentage of the Earth's surface, he--like many
people--probably (incorrectly) thought that a non-trivial percentage of
the Earth's surface would be required.

<little rant>
Energy demands really have to fall in the future, and they will. Air travel
will die.

That's a bold prediction. Why do you think that will happen?

The days of 5.0L 2 tonne SUV's are numbered.

Is the trend in the USA still upward, or is it starting to level off?

Commuting will become
more expensive, so people will less able/less willing to commute stupid
distances on a daily basis,

And communication technologies will eliminate the need for many to do so.

electrical appliances will become more efficient
and homes will be better insulated.

Well-insulated homes are vitally important. I think something like 40%
of the average (Oz) household's energy gets used in heating/cooling the
home.

Much can be done with regulation, but
the real changes will be due to consumer awareness and those prohibitive
energy costs.

Do you think spiralling energy costs will lead to consumer awareness
which will lead to an increase in demand for efficient
items/technologies, or do you predict some other scenario?

Henry.

 

[Henry]

Although your conclusion that the array represents a small proportion of
the earth's surface, your figures are considerably off.

First of all, as of this morning, the world's population is thought to be
6.37E9, or several orders of magnitude greater than your estimate.

Yep. Typo. The article has been corrected.

Also, the 1kWh/M2 insolation is per hour.

Yeah, I guess you could write it that way. It's just simpler to write 1
kW per square metre.

So for the purpose of this
exercise, I would figure that the panels would be sited where insolation is
at least 4 and possibly 6 hours per day. One would have to do a tradeoff
between generating efficiency and transmission loss problems to find the
best sites. For the sake of argument, let's use 4 hrs.

Since solar panels are now better than 10% efficiency, I would not make any
change in this factor and allow the increased efficiency to account for
transmission losses.

In any event, with those factors plugged in, I get a circular array with a
radius of about 242 km, or a square that is 266 miles per side.

I got a circle with radius of 265 km. Same ballpark.

The approximate land surface of the earth comprise 150,000,000 sq km; so
the solar panels would occupy about 0.12% of the earth's land area.

Still, a negligible percentage.

Yup. Nearly every continent has a spare desert that could be used.

Henry.

 

[James Logajan]

What percentage of the Earths surface (excluding oceans) would need
to be covered with PVs to supply all of today's power needs assuming
10 % efficiency of the PV panels ?

Assuming only ~3 full-sun-hours/day insolation and ~10% conversion (the
theoretical thermodynamic limit is ~95% conversion efficiency (though not
with PV cells)) you'd need an area of land (or sea) of ~1,000,000 km^2 (a
square of ~1,000 km * 1,000 km) to replace ALL other sources of power for
the ENTIRE world, which is estimated to be on the order of ~400 quadrillion
BTUs/year (~4*10^20 J/year):
http://energy.cr.usgs.gov/energy/stats_ctry/Stat1.html .

By comparison, the total surface area taken up by water reservoirs is
about 500,000 km^2:
http://webworld.unesco.org/water/ihp/publications/waterway/webpc/pag21.html

I don't know what the surface area of farmland is, but I'm sure if only a
small fraction of it were turned over to direct solar power production
(as opposed to the low efficiency production of food energy) it would also
suffice.

The total land surface area of the Earth is ~150,000,000 km^2 (from
http://hypertextbook.com/facts/2001/DanielChen.shtml ) so the percentage
needed is (drum roll, please...) 100*1,000,000/150,000,000 ~=

0.67%

Less than 1% of the land surface - about twice what is consumed by water
reservoirs and probably vastly less than used for farming.

(Modified from a post I made elsewhere that assumed 20% efficiency:
http://groups.google.com/[email protected] )

 

[daestrom]

Assuming 6E9 people.
Assuming energy consumption of 11.5 kW (USA1999).
Assuming 1 kW per square metre insolation.
Assuming 10% efficiency panels.

6E9 * 11.5 kW = 69E9 kW required to sustain population

=> 69E9 square metres at 100% efficiency
=> 690E9 square metres at 10% efficiency

690E9 square metres = 690,000 square kilometres
...a circular array around 265 km in radius.
...a negligible percentage of the Earth's surface.

I would disagree a bit here. If the power required is 69e9 kW, then you
must produce that continuously, 24/7. To get this, a simple way would be to
have 24 of these 690 000 square kilometre arrays spread evenly around the
globe. Of course that isn't practical, and an array would produce for more
than just one hour out of every day (on average). So if we assume each
array is capable of generating its rated power output for, oh, say 4 hours a
day on average, then you would still need at least six of these arrays
spread out around the globe.

Still a negligible percentage, but perhaps a bit more accurate to consider
this 'duty cycle'.

daestrom

 

[Simon]

6 million? A large city has more than that. 6E9 is more like it.

Doh! Mea culpa.[/QUOTE]

11.5 kW == 11,500 Joules per Second. Looks like energy consumption to
me! That figure came from the US DoE.

Looks like a rate of consumption to me, but I'm splitting hairs.

The vast majority of the panels would be located in areas which have
negligible problems with cloud cover. Since it is expected to power the
entire population of the planet, and the planet spins, such an array
would--by necessity--be distributed across various time zones.
Normality to the sun is thus not as much of an issue as one might think.

Yes but that power is only at mid-day. You did not allow for the panels to
only produce in daylight hours. Your calculations would only give a
normalized equivalent value that the real area would need to match.

example.

They wouldn't need heating--they would need cooling instead. Six of
one, half-a-dozen of the other.

Take a siesta like the spanish

Granted, but the OP just wanted a figure for 10% efficient PV.

As Joe also pointed out, much of that demand is for space heating, and solar
colectors would be better, but you are correct, that was not the question.

My population-corrected value was a circle with radius 265 km. We're in
the same ballpark.


Yup, but that's all the OP wanted. He's not thinking of building one,
just wants a rough idea.

My main point here is that 1km^2 in the Sahara is worth much more than 1km^2
in northern Europe for example. So the question of how much area needs also
to be answered with where that area is.

That's a bold prediction. Why do you think that will happen?

What will you run the jets on? It'll not die completely, and it will be for
a while yet, but how will you fuel them? Other fuels exist, but not in the
quantities needed. Air travel will become ever more expensive.

Is the trend in the USA still upward, or is it starting to level off?

Don't know, but I doubt it (I'm not American BTW).

And communication technologies will eliminate the need for many to do so.

Well-insulated homes are vitally important. I think something like 40%
of the average (Oz) household's energy gets used in heating/cooling the
home.

I'm sure much of our heating costs is due to our need for fresh air. We have
to rely on drafts or open windows. We would benefit from a heat exchanger,
but it's a rented house, so I'm not about to fit one. Perhaps I should
pester the landlord or try for a government grant?

Do you think spiralling energy costs will lead to consumer awareness
which will lead to an increase in demand for efficient
items/technologies, or do you predict some other scenario?

Most things boil down to money. Solar panels repay their 'carbon cost' in a
couple of years or so, but may take 30 years to recover their financial
cost. (Will depend on locale of course.) While this is the case, they will
not be common, (although the market is rising by 30% per annum). At 8 pence
per KWh, PV's simply make no real sense here in the UK. (1KW peak ~> 750KWh
per annum).

With regards to how I personally see the future, don't get me started, I'll
go on for hours, and it would definately be off topic, but if fuel gets
expensive we'll all be more frugal with it. Products will all become more
expensive, more expensive to make and ship. We'll also be more inclined to
look after goods and repair them when they break rather than simply throw
out and replace. Products that are more efficient will naturally be more
desireable. All of these changes in attitude will be driven by cost, and not
because society develops a conscience.

To reduce consumption now rather than later, (and soften the impact of
deminishing fossil fuels,) you need to push up the price of fuel
artificially. Nobody likes to pay more, so it would be unpopular. In the UK
fuel is one of the most expensive in Europe. We hate that. As a result our
average car size is relatively small. Gas prices in the states is very low,
and their average car size is much bigger. The US is the worst offender in
energy consumption by a mile. No surprise really. Something else that is
abundant in the states is food, and so Americans are also the fattest race
in the world, which also explains the car size. If anything is abundant you'
ll consume it without thinking. If it's scarce you'll be far more careful.

I think I'll stop there.

Simon.

PS if anyone reading is American, I'm not trolling for a flame war!

 

[Steve Spence]

I don't know why gas prices are bouncing around
so much, it was $1.39 when I bought gas 3 days ago,
and now it is $1.59 for regular unleaded.
Higher oil prices would force more alternate energy
and PV installations to happen fast.

We were paying $1.70 for reg. unleaded a week ago, now it's $1.59

I saw an ad on TV for coal produced electricity,
and I don't understand that, grid users probably have
no idea what produced their electricity.
The US has enough coal and shale oil to last
hundreds of years, all it will take to start using it
is higher oil prices.

So maybe the real question is, "At what cost
per kilowatt does PV have to reach to be competitive
with oil from coal or shale?".

I am getting impatient waiting for a hybrid car
with some PV on the top. If a motor manufacturer
is not going to produce a low cost 20 horse DC motor,
then there should be a grass roots effort to take
front wheel drive cars and put two 220 volt 20 HP
3 phase motors in the front, one to each front wheel.
I would also like to see a car like that with
a third motor driving the rear wheels.

There is not enough real estate on top of a car to make pv more than a
trickle charger.

What will 20hp do for you?

Where will you get 220volts? a 144volt pack takes a lot of real estate, and
packs a lot of weight.

I think a solid state vibrator can easily be built
to convert 220 DC to 220 AC three phase.
A sucessful car like this would go a long way
in making PV more useful in reducing oil usage.

successful would be the key phrase ....

 

[Steve Spence]

Maybe my cars are bigger than your cars. I think
I could fit at least 6 square meters of cells on each of mine.

That's only 500 watts or so. Trickle chargers.

With three 20 hp motors the average mid size car
would do pretty good, a 4 liter motor does good to produce
40 horsepower at less than 2000 RPM.

60hp is 46kw. you only have 500 watts of pv. see a problem here?

18 or 19 12 volt batteries, a hybrid doesn't need more
than a couple of minutes at full load.
It seems some of the hybrid attempts tried to use both
the electric motor and the IC engine to power the car.

these batteries weigh over 50lbs each. think again.

 

[Jeff]

That's only 500 watts or so. Trickle chargers.

Wrong. A electric car (GM's EV1 before they were destroyed) gets 120 miles
(193 km) to 16.9 kw/h (the batteries range when fitted with the original
lead acid batteries). Breaking that down gives about 87W/h per km. Assuming
the cells get 5 good hours of light a day (or a lot of moderate light), that
generates 2.5 kw/h per day, which is about 31 km's. That's some trickle
charger. Now, most electric cars may not be as efficient, but not far off
from that. I have calculated a typical high efficiency gas car to use about
150 W/h per km at the flywheel, which has many other parasitic loads such as
alternator, water pump, power steering, much more complex drive train, runs
when idle, needs to warmed up, FI and ign needs considerable energy, no
regenitive braking, poorer aerodynamics, etc so this is a very reasonable
number. Now, the biggest thing, is I don't see where 500 W of panels would
fit on a typical car unless it was a large station wagon. Panels imbedded
into the hood might posess quite a ascetics challenge, so the roof would be
the main collection area. Window tint could also be made with solar cell
technology.

BTW, a electric motor is rated different from an gasoline engine. a 20 hp
electric motor can produce 60 to 80 hp bursts of power, often much more. A
gasoline engine is rated at it's peak power. A 100 hp gasoline engine will
produce a maximum of 100 hp, and would self destruct in a short time if run
at full power continuously. GM's EV1 produced something like 140 hp or kw/h
of energy to the wheels. It was faster accelerating then most gas powered
cars (remember an electric motor is almost always in it's peak power range
and efficiency, where a gasoline almost never is), and a non governed
prototype hit 183 miles an hour.


At wide open thottle.

60hp is 46kw. you only have 500 watts of pv. see a problem here?

No, I don't. Read above. 60 Hp is not needed to maintain speed, only for
accelerating. Unless you plain on going down a highway at 200 km/h, or going
up huge hills (don't forget regenitive braking on the way down restores most
of the energy lost), 60+ hp would only be needed for a few seconds.

If the car drives 10 km, then 0.87 kw/h was consumed. Since 1 hp used for 1
h is 0.746 kw/h, and the car takes 1 hour to get there (10km/h), then only
1.16 hp is required to maintain speed. (note, assuming 100% electrical to
mechanical energy conversion - real case is usually better then 90%, and
since the 0.087 is a real number, the hp requirements would slightly
decrease). At 100 km/h, for 1 hour, 8.7kw/h would be consumed, and would
require a 11.6 hp source to maintain speed.

Note, this is neglecting the fact that air friction is a function of speed
squared, ie the faster you go, the air resistance increases at a rate of a
constant times the speed, and times the speed again. This means that the
force slowing the car down from air friction is about 100 times greater at
100 km/h, then it is at 10 km/h. GM's EV1 was likely rated at a reasonable
speed of 50 to 70 km/h. This means the above simple calculations mean that
the required hp level at 10 km/h is much lower then calculated, and higher
at fast highway speeds.


Ever stick together 10 to 20 9V alkaline batteries - that will produce
about 90 to 180 volts. Voltage is not a measure of battery size. Storage
capacity is.

these batteries weigh over 50lbs each. think again.

GM's EV1 had 16.9 kw/h of storage with the old lead acid batteries before
they switched over to NiMH, which brought the mileage up to 18- miles from
120. The lead acid battery bank weighed about 1500 lbs, if a remember
correctly. The voltage is in the order of 320 V.


Properly called an inverter. For a motor drive its called a VFD, short for
variable frequency drive. DC motors are outdated by this technology that is
more efficient, easier to control, and has nothing like commutators and
brushes to wear out. The motors are also very simple (although more complex
to understand, and the internal electronics are very complex, but easily
handled by cheap microprocessors).


Why? Separate motors do have their advantages for all when drive and
handling purposes, but for an every day generally vehicle, there is no need.
I like high performance driving, so I would prefer separate control on al
the wheels, but for the average 95% who want to get groceries and go to work
with their car, along with taking the family to uncle Bob's house don't care
for that much, especially if it adds more cost.

 

[Jeff]

See my other post on this subject! At 0.087 kw/h per km (GM's EV1), a 500W
panel would do well, if you could fit it.

 

[Jeff]

Bullshit. From http://www.gmev.com/faq/faq.htm
"Expected real-world range was 55-95 miles for the high-capacity
lead-acid EV1." That's 88-153 km.
The battery capacity was 18.7 kwh. (You can't even get the units
right)

Actually, the numbers I gave were from differnt sources, after reading many
reveiw awhile back.I "KNOW" I read on several sites that the 25 kwh NiMh
battery bank range was typically up to 180 miles. Now that i think about it
some more, the EV1 had 3 battery revisions. The original was 16.9 kwh lead
acid, then a high capcity lead acid, then the HiMh. Sorry about the units, I
had a long sleepless night and was not thinking about the units when posted,
although I did notice something did not look right.

Wrong again. Try 122 Wh/km to 212 Wh/km. Note the correct units as
well.

OK, even so if I was 40 to 243% off (that must be one big hill it was
climbing at highway speeds for that drop to 212 Wh/km efficiency. A gas car
would do just as bad), the point is still vaild, just not as much so.

<<snip>>
Why bother, your basing everything else on this crap. Care to try
again?

Sure! at the numbers you gave, the 2.5kWh/day gives between 11.8 and 20.5 km
extra range for free per day. That's not neglectable.

You did that wrong as well. See
[email protected]

That's a emal address or something.

Wrong again. You based your number on fuel used per mile, so all
parasitic loads were included.

I was tring to show how large the parasitic drains were. Sure the output
from the engine is higher, but what you actually get to use is much less.
These loads are not present on a EV. I'll do a quick calc for you: Car uses
0.1 L /km (typical good economy car 10 L per 100 km), 38,000 kj/L of
gasoline = 3,800 kj/km. Assuming 20% real efficiency (25% is not reached
often in reality for a significant amount of time in a ICE), 760 kj/km are
output from the engine. This corrisponds to 211 Wh/km. Now subtract 15 to
30A @ 13.8 V = 200 W to 400W to maintain the fuel injection and ign system
not present on a EV, another 500 to 2000 W for the water pump, another 300 W
for the power steering pump on avgerage, several times more drive train loss
(no transmission needed in a EV), lower arowdynamics due to better design
(EV's take care of his, and it could be done to ICE cars). All these
parasitics not present on a EV can easily add up to 30 to 80 wh/km, possibly
much more.

Bullshit.

OK, prove it.

For some reason I doubt most cars would last long at wide open throttle at
5,500 to 6,500 rpm, assuming they are on a safe road like a race track. I
doubt a brand new car would reach 10,000 km's before a major engine failure
like rod bearings or burnt valves would happen. Electric motors ARE rated
differntly.

140 hp or kw/h? Are you saying 1 hp=1Kwh?

No, 1hp = 746 W. I couldn't remember which the EV was rated in. It is 140
hp.

Your units don't match up,
nor do the numbers. Further, the power rating you cite was for the
motor, the power measured at the wheels is less.

This is why I used the power avalible from the flywheel, after all the
inherent ICE parasitics are removed, that's actually used to move the
gasoline car. The electric car has at least a 90% electric to mechanical
conversion efficiency, so the numbers should be simular.

0-60 mph in 9 seconds? I hardly think so.

Mid range performance. Off the get go it is kind of slow.

LOL, there was much more to that prototype than just a lack of a
governor.

Yes, it did have many mods, but the drive train was nearly identical. They
were pushing the motor to it's limits. Thermal problems were the real
limiting factor.It's real signifigance is that a EV is capable of that
speed. A much more impressive vehical is the T zero discussed in the link
below.

Jeff, do you just make this stuff up? Exactly what is the source of
your information?

Many a web site on the EV1 about 5 months ago. I still have some links
somewhere - I'll see if I an find them.

And here is a link for you to check out - A electric car will do 0 to 60 MPH
in 3.6 seconds!, gets 160 Wh/km at 60 MPH, (remember, speed carries a V^2
term!), and a range at this speed of over 300 miles. Also contains much
other good info. Those RAV4's were pigs on power!

http://www.acpropulsion.com/EAASV_101803.pdf

One other thing, batteries of today can easily be charged in 1 to 2 hours
from dead to almost full, it just requires enough energy to do it. Faster
charging migh pose some problems, like heat build up. Slower charging is a
little easier on the batteries, and most batteries charge up to about 80 %
rapidly, and the rest takes a while.

 

[K. Jones]

How do you figure that?

a 20 hp

more.

Really? Cite please.
(you do know what the "service factor" on an electric motor nameplate is,
right?)

A

OK, prove it.

Ummm, no. You made the claim, it's up to you to prove it.

For some reason I doubt most cars would last long at wide open throttle at
5,500 to 6,500 rpm, assuming they are on a safe road like a race track. I
doubt a brand new car would reach 10,000 km's before a major engine failure
like rod bearings or burnt valves would happen. Electric motors ARE rated
differntly.

Rated differently? Could you explain that better?

K. Jones

 

[Jeff]

How do you figure that?

2nd link from a google serch:

http://www.austinev.org/evalbum/motor.html

Here's a small motor:

http://www.cloudelectric.com/item.html?PRID=735634

Here's larger motors:

http://www.electroauto.com/catalog/motors.shtml

more.

There are racing EV motors that produce a much bigger peak then that
(something like a 10 or 11 times factor). They however run coolant through
them. I think some were rated over 350 HP peak, IIRC.

Really? Cite please.
(you do know what the "service factor" on an electric motor nameplate is,
right?)

Look here:

http://www.electroauto.com/catalog/motors.shtml

We're not talking cheap fractional HP commercial motors here, and even those
can produce more HP then rated for short periods of time.

Ummm, no. You made the claim, it's up to you to prove it.

See below - If you run your gasoline engine like that, expect to replace it
quite often. Even running a car at really high RPM's at light throttle will
kill a engine in short order, muchless wide open at high RPM's.

Rated differently? Could you explain that better?

When was the last time you heard of a gasoline engine rated for 200 HP
giving more then that? Most gasoline engines have a problem even making the
claimed HP. One other intereresting thing between electric and gas motors is
that the electric motor is always in it's peak power, where a gas motor is
not. This means that a smaller electric motor can do the same acceleration
as a large gas motor. See AC propulsion's T zero
http://www.acpropulsion.com/ - it has a 150 kw peak power electric motor
(~200 hp), and it woops Corvette's, Porsche's, Ferrari's, etc. It's even
faster now with Li ION batteries, and it can go 300 miles between recharges
@ 60 MPH http://www.acpropulsion.com/EAASV_101803.pdf

 

[K. Jones]

2nd link from a google serch:

http://www.austinev.org/evalbum/motor.html

This guys opinion. Not exactly a valid cite.

However,
Intermittant duty vs continious duty.
The type of duty is usually available in the motor literature.

Auto manufacturers also cite HP @ 'X' rpm, and state that it's peak HP when
so.
What is the difference?
Shaft HP is no different than shaft HP......

Here's a small motor:

http://www.cloudelectric.com/item.html?PRID=735634

Here's larger motors:

http://www.electroauto.com/catalog/motors.shtml


There are racing EV motors that produce a much bigger peak then that
(something like a 10 or 11 times factor). They however run coolant through
them. I think some were rated over 350 HP peak, IIRC.

Ohhhh, "special _racing_ motors". Hmmm, apples to apples then.
My ICE peak HP is 275.....except when I flip the switch and throw _roughly_
a 100 HP shot of NOS on it....then it's closer to 400HP.....
"in bursts". Sure isn't going to last all day running like that, neither is
a 20HP electric motor likely to last very long when stressed beyond design.
What is the difference?

Look here:

http://www.electroauto.com/catalog/motors.shtml

We're not talking cheap fractional HP commercial motors here, and even those
can produce more HP then rated for short periods of time.

Basically any "motor" can.

time

See below - If you run your gasoline engine like that, expect to replace it
quite often. Even running a car at really high RPM's at light throttle will
kill a engine in short order, muchless wide open at high RPM's.
throttle

track.

Hang on. You're talking about "special racing electric motors".
Thousands of "race ICE's" will run 5,500 to 6,400 rpm all day long.
What is the difference?

II doubt your 20HP electric motor would reach 10,000km's when run at
"60 or 80HP" before a major failure.
What is the difference?

When was the last time you heard of a gasoline engine rated for 200 HP
giving more then that?

How old are you? Lots and lots. It was routine for manufactures to, ummm,
"understate" the HP of many, many muscle cars.

Most gasoline engines have a problem even making the
claimed HP.

*SOME*, and only by cheap import manufactures. ASME is working on a
standard to eliminate this kind of "false advertising".

One other intereresting thing between electric and gas motors is
that the electric motor is always in it's peak power,

Say again? What kind of electric motor is "always in it's peak
power"...regardless of speed or load?
The cite for this should prove interesting!

where a gas motor is

not. This means that a smaller electric motor can do the same acceleration
as a large gas motor. See AC propulsion's T zero
http://www.acpropulsion.com/ - it has a 150 kw peak power electric motor
(~200 hp), and it woops Corvette's, Porsche's, Ferrari's, etc. It's even
faster now with Li ION batteries, and it can go 300 miles between recharges
@ 60 MPH http://www.acpropulsion.com/EAASV_101803.pdf

I'm not trying to "rain on your parade", or dampen your enthusiasm for EV's.
Just trying to get you to tone down your wild claims, that are "all over the
map"

K. Jones

 

[Jeff]

This guys opinion. Not exactly a valid cite.

Do a serch under google - there should be ton of refernces.

However,
Intermittant duty vs continious duty.
The type of duty is usually available in the motor literature.

Auto manufacturers also cite HP @ 'X' rpm, and state that it's peak HP when
so.

Not anymore, as you also noted. See below. big numbers help sell stuff (to
morons!), and lying about hp makes bigger numbers.

What is the difference?
Shaft HP is no different than shaft HP......

Yes, that is true, however the electric motors can be safely "overpowered"
for several minutes. That may be a better term to discribe it. Gasoline
motors produce their max hp, and that's it - you cant produce any more
without modifications. There is another thing about more efficient use of
torque, discussed below.


Did you look at that last site? It's a EV motor manufacture.

Ohhhh, "special _racing_ motors".

The others are not racing motors. That was just one extreme example dumping
in more then 10 times the continuous rating.

Hmmm, apples to apples then.
My ICE peak HP is 275.....except when I flip the switch and throw _roughly_
a 100 HP shot of NOS on it....then it's closer to 400HP.....

Fine. But normally, like when driving down a highway, it is moving your car
with 20 to 40 hp. Anything more then that is not continuous. I doubt you use
275 or more HP for more then a minute or two?

"in bursts". Sure isn't going to last all day running like that, neither is
a 20HP electric motor likely to last very long when stressed beyond design.
What is the difference?

The electric motors are designed for it. The only stress is heat build up,
unlike a ICE. Heat build up reduces the permeability of magnetic materials,
and therefore the power drops. If the heat gets too serious, the windings
can become damaged. In an 3 phase motor, the only moving part is a iron
core - hardly anything to break.

Look at this EV motor manufactures ratings. This is typical of other
electric motor manufactures, however they are usually rated in kW usually
with a max rating and a continuous rating.

http://www.electroauto.com/catalog/motors.shtml


Some EV motors, mostly the AC ones are starting to rate their motors in peak
power, and have a continuous rating. This is a smart move, since people are
accustomed to peak power ratings. www.acpropulsion.com rates their AC-150
drive at 150 kW peak (which is several minutes), and 50 kW continuous (in
one of their spec shhets or white papers).

Basically any "motor" can.

A ICE can not produce more power then it's rated for, unless mods are done
to it.

An electric motor is rated for a continuous power, and safely overload for
several minutes.


It''s just differnt ratings. It would be MUCH less confusing to use the peak
HP for each, however there are good reasons for the ratings.

track.

Hang on. You're talking about "special racing electric motors".

No, I'm not - I just referred to a special racing motor that pushed it to
the extremes. A 3 to 4 times the continuous power rating is typical.

Thousands of "race ICE's" will run 5,500 to 6,400 rpm all day long.
What is the difference?

And they get rebuilt after a few good races, depending on how well they are
built, and how hard they are stressed. Not really relivent anyway, same as
the racing motor I pointed out.

I
I doubt your 20HP electric motor would reach 10,000km's when run at
"60 or 80HP" before a major failure.
What is the difference?


How old are you? Lots and lots. It was routine for manufactures to, ummm,
"understate" the HP of many, many muscle cars.

Muscle cars, Too bad I was not around for them. They were gone for decades.
Newer cars are not rated the same. Looks like you know what I mean from what
you wrote below, however since numbers sell, all the manufactures have to
lie at least a bit - high performance cars are generally a little more
accurate (but then the Camaro's and Firebirds had a slightly lower power
rating then the Corvettes with the same engine (same heads, cam, dual cat,
everything). Go figure). High performance cars used to be underrated power
wise, along with the speedometer, to help offset insurance costs.

*SOME*, and only by cheap import manufactures. ASME is working on a
standard to eliminate this kind of "false advertising".


Say again? What kind of electric motor is "always in it's peak
power"...regardless of speed or load?
The cite for this should prove interesting!

Check out the Tzero at AC propulsion's website. It's rated for 200 HP PEAK
(67 hp continuous), woops Corvettes, Ferrari's, Porsche's, Lamborghinis, and
with the LiION battery pack, it does 0 -60 MPH in 3.6 seconds, with a 300
mile range at 60 MPH.

http://www.acpropulsion.com/EAASV_101803.pdf

The reason is the electric motor produces a high, continuous torque over
most of it's power range. A gasoline engine produces a high amount of torque
over a small RPM range, and when you switch gears it produces a fraction of
the torque to the wheels. Torque is what moves a vehicle, and is related to
F=MA, where F = force, from the tires converting the torque to force, M =
mass of the vehicle, and A = acceleration.. Solving for A = F/M, so clearly
increasing the torque will increase the force, and thus the acceleration.

http://www.acpropulsion.com/PDF files/Living with an EV.pdf - see
section 2.4, as it has a nice torque curve of a electric, vs gas. (BTW, if
the car had 200 hp of power on take off, that sloped line would continue up
to the y axis of the graph, so it's not using the full 200 hp until some
time down the road)

where a gas motor is

I'm not trying to "rain on your parade", or dampen your enthusiasm for EV's.
Just trying to get you to tone down your wild claims, that are "all over the
map"

Unfortunately, they are not wild claims - just a different industry ;-(