Posted by Ahem A Rivet's Shot on June 2, 2010, 4:45 pm
On Wed, 02 Jun 2010 17:01:29 +0100
> The PV array link you pointed at is the cheapest I have seen on offer -
> has anyone here obtained one? Or are they vapourware?
The string ribbon process mentioned appears to belong to Evergreen
Solar, it looks to be a very clever process for producing silicon PV cells.
--
Steve O'Hara-Smith | Directable Mirror Arrays
C:>WIN | A better way to focus the sun
The computer obeys and wins. | licences available see
You lose and Bill collects. | http://www.sohara.org/
Posted by wmbjkREMOVE on June 2, 2010, 11:20 pm
On Wed, 02 Jun 2010 17:01:29 +0100, Martin Brown
>On 02/06/2010 16:35, wmbjkREMOVE@citlink.net wrote:
>> On Wed, 2 Jun 2010 09:38:28 +0100, Ahem A Rivet's Shot
>>
>>> On Tue, 01 Jun 2010 17:18:57 -0700
>>> wmbjkREMOVE@citlink.net wrote:
>>>
>>>> On Tue, 1 Jun 2010 23:56:08 +0000 (UTC), don@manx.misty.com (Don
>>>> Klipstein) wrote:
>>>>
>>>>
>>>>> Compare that to the 1 KW
>>>>> per square meter that I have some impression that solar cell arrays are
>>>>> rated at...
>>>>
>>>> Where'd you get that impression? Here's a typical module.
>>>
>>> Probably from reading the specs and knowing about the typical
>>> efficiency of PV cells. The output rating of PV cells is usually quoted
>>> under "full sun" conditions of around 1000 W per sq. metre.
>>>
>>>> http://sunelec.com/index.php?main_page=product_info&cPath=5&products_id7 .
>>>> ~135W per sq. meter.
>>>
>>> That's the electrical output of that panel,
>>
>> No kidding?
>>
>>> which given the normal
>>> efficiency of panels like that (10-15%) means an insolation of around 1000 W
>>> per sq. meter. Actually the specs for that panel claim 13.1% efficiency so
>>> slightly over 1000 W per sq. metre is required to achieve that output.
>>>
>>>>> That sounds to me like 34-47 dollars per watt in Philadelphia, if the
>>>>> panels are laid horizontally.
>>>>
>>>> GIGO
>>>
>>> Not so - those were pretty accurate calculations.
>>
>> If Klipstein mounts one of the modules I referenced above in full sun
>> in Philly on a cool day and measures the output, he'll conclude that
>> it costs out at ~$ per Watt, not the $0-$0 he managed to arrive at.
>That is their price per peak output per watt installed and seems
>unusually low.
I picked a module that I know several of my neighbors have purchased.
Occasionally the same site I mentioned has modules for even less.
The downward trend for PV is likely to continue, same as the upward
trend for grid energy. Which makes long-term estimates silly if they
don't include some allowances.
>$/W is still about the going rate
A better argument is that PV generally requires other hardware that
increases the basic cost.
> and some are closer to
>$/W where you paying a premium for higher efficiency.
Some might be selling for $00 per W. If you were buying, which would
you seek out? Here's the thing - the people who are buying find the
low prices, and the people who seek to discourage others from buying
find higher prices.
>But unless you can arrange continuous sunlight the average output over
>the year allowing for clouds and including diffuse light is something
>like 1/8 to 1/10 of peak installed capacity. So his $0-40/W delivered
>for use is basically in the right ballpark in the long term.
Nonsense. I've lived off-grid for ~15 years. My costs for the solar
portion (including batteries, inverters, trackers, etc, but not
counting sweat equity), were ~ $3 per watt. PV was ~$ back then.
Inverters were similar to current prices, but batteries were less.
>Operating at peak efficiency with a clear sky and normal incidence
>sunlight then the array can achieve peak performance, but the rest of
>the time it does not by a long way. And obviously at night it is idle.
Again, no kidding?
>> motor, but>20% plus overall. PV economics aren't great, especially if
>> one is willing to ignore the unbilled-cost of grid energy and the
>> unsustainability of the billed cost. So those who seek to be negative
>> about the economics really don't need to exaggerate.
>I think you just have to be clear about what measure you are using.
Sure. Most people use Wh and specify location, application, and
everything that's required to make it all work. Dollar per W is a
strange measure.
>The PV array link you pointed at is the cheapest I have seen on offer -
>has anyone here obtained one? Or are they vapourware?
Yes, several posters here (AEH), including me, have used that outfit,
and many have purchased at ~$ per watt. Choices at the low end of the
price scale are sometimes limited though. A friend had to pay a little
over $ a few months ago to get modules with a voltage that fit his
application. And some of the best deals are on stuff that isn't UL
rated, which can be an issue.
Wayne
Posted by krw@att.bizzzzzzzzzzzz on June 3, 2010, 1:11 am
On Wed, 02 Jun 2010 16:20:37 -0700, wmbjkREMOVE@citlink.net wrote:
>On Wed, 02 Jun 2010 17:01:29 +0100, Martin Brown
>>On 02/06/2010 16:35, wmbjkREMOVE@citlink.net wrote:
>>> On Wed, 2 Jun 2010 09:38:28 +0100, Ahem A Rivet's Shot
>>>
>>>> On Tue, 01 Jun 2010 17:18:57 -0700
>>>> wmbjkREMOVE@citlink.net wrote:
>>>>
>>>>> On Tue, 1 Jun 2010 23:56:08 +0000 (UTC), don@manx.misty.com (Don
>>>>> Klipstein) wrote:
>>>>>
>>>>>
>>>>>> Compare that to the 1 KW
>>>>>> per square meter that I have some impression that solar cell arrays are
>>>>>> rated at...
>>>>>
>>>>> Where'd you get that impression? Here's a typical module.
>>>>
>>>> Probably from reading the specs and knowing about the typical
>>>> efficiency of PV cells. The output rating of PV cells is usually quoted
>>>> under "full sun" conditions of around 1000 W per sq. metre.
>>>>
>>>>>
http://sunelec.com/index.php?main_page=product_info&cPath=5&products_id7 .
>>>>> ~135W per sq. meter.
>>>>
>>>> That's the electrical output of that panel,
>>>
>>> No kidding?
>>>
>>>> which given the normal
>>>> efficiency of panels like that (10-15%) means an insolation of around 1000 W
>>>> per sq. meter. Actually the specs for that panel claim 13.1% efficiency so
>>>> slightly over 1000 W per sq. metre is required to achieve that output.
>>>>
>>>>>> That sounds to me like 34-47 dollars per watt in Philadelphia, if the
>>>>>> panels are laid horizontally.
>>>>>
>>>>> GIGO
>>>>
>>>> Not so - those were pretty accurate calculations.
>>>
>>> If Klipstein mounts one of the modules I referenced above in full sun
>>> in Philly on a cool day and measures the output, he'll conclude that
>>> it costs out at ~$ per Watt, not the $0-$0 he managed to arrive at.
>>
>>That is their price per peak output per watt installed and seems
>>unusually low.
>I picked a module that I know several of my neighbors have purchased.
>Occasionally the same site I mentioned has modules for even less.
>The downward trend for PV is likely to continue, same as the upward
>trend for grid energy. Which makes long-term estimates silly if they
>don't include some allowances.
Smart money (government need not apply) waits on the sidelines to see where
the crossing is, if any.
>>$/W is still about the going rate
>A better argument is that PV generally requires other hardware that
>increases the basic cost.
>> and some are closer to
>>$/W where you paying a premium for higher efficiency.
>Some might be selling for $00 per W. If you were buying, which would
>you seek out? Here's the thing - the people who are buying find the
>low prices, and the people who seek to discourage others from buying
>find higher prices.
>>But unless you can arrange continuous sunlight the average output over
>>the year allowing for clouds and including diffuse light is something
>>like 1/8 to 1/10 of peak installed capacity. So his $0-40/W delivered
>>for use is basically in the right ballpark in the long term.
>Nonsense. I've lived off-grid for ~15 years. My costs for the solar
>portion (including batteries, inverters, trackers, etc, but not
>counting sweat equity), were ~ $3 per watt. PV was ~$ back then.
>Inverters were similar to current prices, but batteries were less.
>
>>Operating at peak efficiency with a clear sky and normal incidence
>>sunlight then the array can achieve peak performance, but the rest of
>>the time it does not by a long way. And obviously at night it is idle.
>Again, no kidding?
>>> motor, but>20% plus overall. PV economics aren't great, especially if
>>> one is willing to ignore the unbilled-cost of grid energy and the
>>> unsustainability of the billed cost. So those who seek to be negative
>>> about the economics really don't need to exaggerate.
>>
>>I think you just have to be clear about what measure you are using.
>Sure. Most people use Wh and specify location, application, and
>everything that's required to make it all work. Dollar per W is a
>strange measure.
>>The PV array link you pointed at is the cheapest I have seen on offer -
>>has anyone here obtained one? Or are they vapourware?
>Yes, several posters here (AEH), including me, have used that outfit,
>and many have purchased at ~$ per watt. Choices at the low end of the
>price scale are sometimes limited though. A friend had to pay a little
>over $ a few months ago to get modules with a voltage that fit his
>application. And some of the best deals are on stuff that isn't UL
>rated, which can be an issue.
>Wayne
Posted by Paul Keinanen on June 2, 2010, 8:11 pm
On Wed, 02 Jun 2010 08:35:00 -0700, wmbjkREMOVE@citlink.net wrote:
>If Klipstein mounts one of the modules I referenced above in full sun
>in Philly on a cool day and measures the output, he'll conclude that
>it costs out at ~$ per Watt, not the $0-$0 he managed to arrive at.
Unfortunately the Earth does not constantly turn the same face against
the sun.
In places close to th equator with only rare clouds (such as Sahara)
with dual axis tracker, in principle the nominal power would be
avaible 50 % of the time, thus the average cost would be $/W.
However, the air mass losses close to the horizon will limit the full
power time to 8-10 hours a day, thus at least $/W in ideal cases.
For fixed installations in ideal cases 1/4 of the peak power would be
available on average (hence $/W) .
For higher latitudes, the winter atmospheric losses will reduce the
available power significantly, even with ideal orientation.
In many places, there are those pesky things called clouds ....
This will further reduce the annual energy output and hence increase
the cost/W.
>To avoid starting with worst case PV costs he could google "best price
>PV". And he could skip even more GIGO by using HOMER or some such.
>http://homerenergy.com/ Which would prevent erroneous assumptions such
>as his 5% of production for tracking.
While 5 % may be a lot, but on the other hand, can you buy a system
with a solar panel mounted on a dual tracker capable of surviving
snow/ice/sand storm/hurricanes for $/W (peak) ?
Posted by Sylvia Else on June 5, 2010, 2:18 am
On 2/06/2010 9:56 AM, Don Klipstein wrote:
>>
>>> vaughn wrote:
>>>>
>>>>>
>>>>> I don't believe in these alleged economies of scale. Solar panels
>>>>> already represent a large industry. The economies of scale, such as
>>>>> they are, have already been obtained.
>>>>
>>>> Not so, especially not so at the consumer level. At the consumer
>>>> level PV panels remain a nitch product, so lack of retail competition
>>>> and huge shipping costs because of a lack of any local distribution
>>>> channel presents significant barriers.
>>>>
>>>> Vaughn
>>>
>>> Harbor Freight sells several panels& systems. They do mail order
>>> and have a lot of retail stores in the US.
>>>
>>> <http://www.harborfreight.com/catalogsearch/result/index/?category=&q=s
>>> olar&limit2>
>>
>> OUCH! the larger panels there are 6-8 dollars a watt
> http://en.wikipedia.org/wiki/File:Insolation.png :
> It appears to me that Philadelphia gets year-round-average insolation
> of 175 watts, at least 170 per square meter. Compare that to the 1 KW
> per square meter that I have some impression that solar cell arrays are
> rated at...
> That sounds to me like 34-47 dollars per watt in Philadelphia, if the
> panels are laid horizontally.
You're forcing a comparison of apples and oranges if you use that approach.
Figures for output are peak numbers, but anyone running the financials
knows that you have then to apply data relating to insolation, which are
location dependent.
The figure of $/peak watt is much more useful in practice.
Sylvia.
> has anyone here obtained one? Or are they vapourware?