Hi:  I believe these figures for conversion efficiency are out of date
and much too low.  First Solar CdTe now achieves 10.6% and SunPower
polysilicon now achieves 17%%.  You can check the company websites to
confirm.
http://www.firstsolar.com/ 
http://www.sunpowercorp.com/Products-and-Services/Residential-Solar-Pane
ls.aspx 


Dr. Stephen R. Humphrey, Director of Academic Programs, 
School of Natural Resources and Environment, 
Box 116455, 103 Black Hall, University of Florida 
Gainesville, FL  32611-6455  USA 
Tel. 352-392-9230, Fax 352-392-9748 
http://snre.ufl.edu 


-----Original Message-----
From: Bioenergy and Sustainable Technology Society
[mailto:[log in to unmask]] On Behalf Of Nathan Mitten
Sent: Wednesday, March 12, 2008 3:32 PM
To: [log in to unmask]
Subject: Re: Help! I Have Solar Power Questions

Here are some approximate answers to her questions.  Any of the details
could be investigated further to get exact answers but this would take
more time.  Hopefully this helps....

1. Standard Dimensions for Solar Panels (according to watts).

A ROUGH guide to solar land area needs:
-1000 Watts/m2 of incident solar radiation
-Assuming a 10% panel efficiency gives 100 Watts/m2 (most panels are 1-
2m2)
-This gives a power of 404.6 kW/acre or 1000 kW/hectare -This gives an
energy production of 2023 kWh per day per acre
	Or 5000 kWh per day per hectare

Note:
	Poly and mono silicone (current common technology): 10%-13%
efficiency
	Amorphous silicone: 5%-6%
	CIGS (Shell): 8%-9%
	CdTe (First Solar): 7%
	1 acre = 4046 m2
	Assume a 20% capacity factor (this would be about 5 sun hours
per day which is a good yearly average for Northern FL)



2. Standard height required for solar panels when mounted.
	As far as I know there is not a standard height for ground
mounted systems.  Most rack mount or pole mount systems would be on the
order of
10-15 feet.  Many systems have a larger number of shorter rows and would
therefore be less than this.


3. Does landscape buffering (trees, shrubs) disrupt solar power
generation?
	Only if they directly shade the panels, or have debris that
falls on them that cannot be cleaned on a regular basis.  Anything to
the north side is not a problem as the solar is always south or in mid
summer, more or less directly overhead.  Shade to the east and west is
only a problem in the morning and evening.  Most importantly is the
shading to the south.  A rule of thumb could be that however tall the
tree or shrub is to the south, it should be at least double or even
triple that distance away from the array.
This minimum distance should be investigated further if it is to be
implemented as a code.


4. How far must buffering be from panels to maintain generation?

	I'm not sure if I understand this question.


5. Must panels be distanced a certain length from each other?

	If they are non-tracking (most are) they can be right next to
each other in the longitudinal direction and most mounting systems will
be.  In the latitudinal direction, they can shade each other when the
sun is lower in the sky (winter) and therefore must be separated.  The
exact distance for a particular latitude requires some more advanced
calculation similar to the southern shading in question 3.


6. Is there a minimum lot area for solar power plants?
	There is no minimal lot area if it meets the other requirements
for shading.  A substation will be needed for the inverters and circuit
breakers (as close to the array as possible) but this will be
insignificant compared to the array land area.  Cost reduction do to
scaling should be considered for any large scale plant.  $10/watt or
$10,000/kW is a rule of thumb for residual before rebates and credits
but for larger scale systems and with prices dropping this cost should
be lower.  Also, the mounting system framing for ground mounting (as
opposed to roof mounting) will add to cost so this needs to be factored
in.


Nate Mitten
PhD Program
University of Florida, Mechanical and Aerospace Engineering Chair, ASES
Clean Energy and Water Division
Phone: (717) 303-9424
Email: [log in to unmask]


-----Original Message-----
From: Bioenergy and Sustainable Technology Society
[mailto:[log in to unmask]] On Behalf Of Heck,Patrick T
Sent: Tuesday, March 11, 2008 11:55 AM
To: [log in to unmask]
Subject: Help! I Have Solar Power Questions

Hello BESTers,

I was contacted about solar power today and was hoping someone on the
list might be able to answer a few questions, as I'm definitely not the
right person to ask.  These questions comes from a staffer in the
local/regional planning council who is updating land regulations but
before she can do it needs some information, which can't seem to be
located anywhere!

She noted that, in order for a solar power plant to be erected within an
area zoned agriculture-1 or agriculture-2 certain land development
regulations must be met.  In order to inform what land regulations are
appropriate for solar power plants the following information is
required:


1.       Standard Dimensions for Solar Panels (according to watts).


2.       Standard height required for solar panels when mounted.


3.       Does landscape buffering (trees, shrubs) disrupt solar power
generation?


4.       How far must buffering be from panels to maintain generation?


5.       Must panels be distanced a certain length from each other?


6.       Is there a minimum lot area for solar power plants?


In advance, thanks to all those who can help!

BEST,
Patrick





Patrick T. Heck
Communications Specialist
SNRE, Research and Outreach/Extension Office
1053 McCarty Hall D
Phone (352) 392-7622
Fax (352) 846-2856
[log in to unmask]<mailto:[log in to unmask]>