| |
CX2SA > SATDIG 02.10.09 21:07l 817 Lines 30949 Bytes #999 (0) @ WW
BID : AMSATBB4511
Read: GUEST
Subj: AMSAT-BB-digest V4 511
Path: IZ3LSV<IK2XDE<DB0RES<ON0AR<HS1LMV<CX2SA
Sent: 091002/1904Z @:CX2SA.LAV.URY.SA #:6726 [Minas] FBB7.00e $:AMSATBB4511
From: CX2SA@CX2SA.LAV.URY.SA
To : SATDIG@WW
Today's Topics:
1. Symposium weather (Alan P. Biddle)
2. Re: Solar Power (I was wrong) (Bob Bruninga )
3. Re: Solar Power (I was wrong) (Marc Vermeersch)
4. Out of the Office (Martha)
5. Re: Solar Power (I was wrong) (Marc Vermeersch)
6. Re: College Satellite nights, Thursday night (Rodney Waln)
7. Re: Solar Power (I was wrong) (Edward Cole)
8. Re: Solar Power (I was wrong) (Mike and Paula Herr)
9. Re: Solar Power (I was wrong) (k0vty@xxxx.xxxx
10. Re: Solar Power (I was wrong) (Robert Bruninga)
----------------------------------------------------------------------
Message: 1
Date: Fri, 2 Oct 2009 07:21:58 -0500
From: "Alan P. Biddle" <APBIDDLE@xxxxxx.xxx>
Subject: [amsat-bb] Symposium weather
To: "AMSAT-BB" <amsat-bb@xxxxx.xxx>
Message-ID: <C6D7583334BF445A9DFBF1AC2B676279@xxxxxx>
Content-Type: text/plain; charset="iso-8859-1"
Morning,
For those who will be attending the Symposium, the forecast looks like a
good stretch of Fall weather. Crisp, mostly clear, but the possibility of a
few showers.
Wed Oct 7
H 74?
L 56?
Thu Oct 8
H 67?
L 49?
Fri Oct 9
H 66?
L 48?
Sat Oct 10
H 65?
L 52?
Sun Oct 11
H 66?
L 50?
Alan
WA4SCA
------------------------------
Message: 2
Date: Fri, 2 Oct 2009 09:03:18 -0400 (EDT)
From: "Bob Bruninga " <bruninga@xxxx.xxx>
Subject: [amsat-bb] Re: Solar Power (I was wrong)
To: "Amsat Reflector" <amsat-bb@xxxxx.xxx>
Message-ID: <20091002090318.ABT30813@xxxxx.xxxx.xxx>
Content-Type: text/plain; charset=us-ascii
> My simple math says it'll take almost
> 16 years to be reimbursed on a $30k system.
Its more like 5.5 years.. I'll show you my numbers for Maryland:
> Initial outlay: $30,000
> US tax credit: 5%
No, Federal Credit is 30%
> US reimbursement: $1500 (this is not
> real money, but a reduction in taxable income)
at 30% it is $9,000 and it is a *credit*, not a deduction, so that is cash
in your pocket off the tax you pay.
Then most states, give either similar Tax *credits* or grants, in my state
it would be about $4,000 check, payable to me when installation is complete.
Then the county makes up the difference to 50% of the cost of the system.
> Total: $28,500
No, here, my net outlay is reduced to 50% or only $15,000.
> Savings per year in electricity: $1800
That, plus Solar Energy Renewable credits paid to you by the power company
or brokers at about $250 per KW capacity for a 4 Kw system = $1000 per year.
They buy this credit from you so that they dont have to build solar
systems. By paying you this credit, they get to subtract the capacity from
the amount they are required to build by the year 2020? or whatever. So add
the two and you get a payback of $2800/year.
> $30k / 1.8k = 15.83 years
* My numbers show $15k / 2.8 = 5.3 years (even less if electric rates go up)
> One of the points of the post, I think,
> was to make ourselves less dependent on
> foreign oil..
> Personally, I do not think PV cells are
> that efficient. To get the 12VDC I need
> to power my remote... repeaters, I...
> lose more than 30% in generated heat.
Yes! That was my mistake too. Energy Storage in batteries is very
inefficient. About 30% or more losses. But GRID-TIE systems are 95%
efficient PLUS you are selling the power to the grid at PEAK rates in the
middle of the day, and buying it back at discout rates at night. Net effect
is not a loss, but a GAIN. Of course, this does not help at a repeater, but
do not carryover these losses to a Grid Tie system where it does not apply...
> they only last so long.
> Twenty years, tops maybe?
> Do they really pay for themselves?
You bet for sure! Compare that to a $30,000 car, which is junk in 10 years
and you have nothing. The solar system cost $30,000 (actually $15K) and you
MAKE $15k in the first 5 years, and for the next 15, you make $45,000, and
then your array has decayed to maybe only 80% of its original life... but it
is still MAKING money at then CURRENT rates...
The 20 and 30 year life does not mean they die, it is just that their power
has dropped by XX%... Im guessing that the threshold is 80%?
> in California. .. the power company is
> only required to pay you the WHOLESALE
> cost of electricity. This amounts to 3
> to 4 cents per kw-hr.
Ah, but if you pay 15 cents per KWH during the day to run your home, and you
have enough solar to balance that, then the payback to you is still 15 cents
per KwH. Its only the excess you generate that pays you the low rates.
The key word is "net metering". In other states with net-metering, they
have to give you the full 15 cents credit for the excess power you generate.
But in most all cases, you cannot beuild up credits beyond a year cycle.
> ... bird poop to cut the efficiency.
> be prepared to get on the roof every
> month or so to clean the panels.
AMEN. PV cells are in series. One big splat that covers one CELL, reduces
the power of the ENTIRE PANEL. A single Flag Pole shadow across a roof, can
reduce the power of the entire roof array tremendously...
>> if you sell back over 50,000 watts
>> of power you will incur additional taxes,
>> ... you are considered a "generator"
I assume that is NET. To build up that much excess capacity would require
an array on my house covering 3 times the roof area I have available. And
it would make no sense to build an array that big, since you aleady know
that you get paid peanuts for excess net power (wholesale).
>> Lets say you were able to generate
>> and sell back 100,000 watts to the
>> utility company.
Yes, that is my annual consumption. But my array will be sized so that I
generate 100,000 in that same year. SO the NET "sell back" is ZERO. And I
got all my electricity for FREE that year. You are right, that if I make my
array TWICE as big as I need, and spent about $100,000 for it, that then, I
would generate twice the electricity I need, and would not get paid but
probably HALF the rate for it PLUS the taxes you mentino. Oh, and that
array would coer 8,000 square feet almost an Acre... So I would not worry
about a homeower making the mistake of building too big a system...
>>> > 1) Solar panels (PV) are 1% of what they cost in 1970
>>> 2) PV dropped 40% this year due to 2007 Energy Boom and 2009 economic bust
>>> 4) $5,000 to $20,000 tax and cash back incentives for YOU
>>> 5) Grid-tie systems operate at 95% efficiency compared to 70% of battery
systems
>>> 6) Local electric rates DOUBLED in the last 2 years
>>> 7) Laws require utilities to pay you the same peak rates they charge you.
>>> 8) Solar Energy credits can gain an additional $275 per 1Kw system per
year
>>> 9) Payback is at least 10% per year or better
>>> 10) The same money in the bank gets 1% interest
------------------------------
Message: 3
Date: Fri, 2 Oct 2009 17:08:56 +0200
From: "Marc Vermeersch" <amvm@xxxxxx.xx>
Subject: [amsat-bb] Re: Solar Power (I was wrong)
To: "'Greg D.'" <ko6th_greg@xxxxxxx.xxx>, <amsat-bb@xxxxx.xxx>
Message-ID: <001901ca4372$43670c40$ca3524c0$@xx>
Content-Type: text/plain; charset="us-ascii"
Hi Greg and all,
> -----Original Message-----
> From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
> Behalf Of Greg D.
> Sent: vrijdag 2 oktober 2009 6:13
> To: ptrowe@xxxxx.xxxx bruninga@xxxx.xxxx amsat-bb@xxxxx.xxxx
> wb3jfs@xxx.xxx
> Subject: [amsat-bb] Re: Solar Power (I was wrong)
>
>
>
>
>
>
>
> I've always wondered why the solar panel makers don't put water tubing
> on the back side of the panels. Boost the efficiency, and get hot
> water for the house or pool at the same time. Seems like a no-brainer.
> {shrug}
I guess this is too complex for the additional gain in efficiency? According
to the documentation, a raise in temperature of 25K decreases the efficiency
by about 8-10% for the Suntech panels I have installed. Being 50degrees
North, temperature is rarely a problem for me anyway. :-)
>
> Unfortunately for me, I have large trees shading the house (big enough
> that I'm hoping I'm coming out ahead with lower air conditioning
> bills), and a roof angle exposure that is not solar-friendly even if
> they weren't there. So I was thinking, if I had space for just a few
> panels, perhaps I could go low-tech with a system built from a scrap
> UPS. After all, I've got an APRS station - PC, TNC, radio, and
> internet connection - using power constantly, and I often find
> perfectly good UPSs being tossed out (i.e. free) because the battery is
> shot and not worth replacing.
>
> Put the solar cells in place of the UPS' battery, and modify the power
> failure detect circuitry to work backwards - give preference to the
> battery/solar side, only switching to the line side if there is
> insufficient "battery" power. This will give me free 120 vac whenever
> the sun shines. At night, it would power-fail back over to the line,
> and only then would the power company's meter start to spin. I'd
> probably put a regular UPS down stream from the hacked-up one, in case
> the failover/back from line to solar wasn't real clean.
That is almost exactly what a grid-connected system does.
In addition it also synchronizes (voltage and frequency) with the grid AND
it doesn't disconnect from the grid. This allows for sharing the load
between the panels and the grid. And for having the meter spin backwards
when it puts your "overproduction" in the grid.
The more clever systems also search the MPP (Maximum Power Point) of the
panels and optimize production of AC Power that way. If you run disconnected
from the grid you will only produce what you use, overcapacity is wasted.
> The biggest problem I see is that most of the solar panels available
> these days are in the 50-60 volt range, which means that you'd need to
> do a conversion down to battery voltage first. (Maybe put two panels
> in series and run them into a regular 12v DC power supply?)
A step down switching regulator can easily handle that at >95% efficiency.
For instance the MAX5035 can handle voltages up to 75V.
> Now, I just need to find a source of free-to-cheap solar panels. I
> almost bought a set at a local Ham swap ($10 ea) that had cracked
> surface glass but were otherwise functional, but I didn't think they'd
> survive the trip home in my car (no place big enough to lay them flat).
> (I'd need to weatherproof them too....)
>
> Anyway, just a thought...
>
> Greg KO6TH
>
BR,
--
/\/\arc
------------------------------
Message: 4
Date: Fri, 2 Oct 2009 11:19:05 -0400
From: Martha <martha@xxxxx.xxx>
Subject: [amsat-bb] Out of the Office
To: AMSAT BB <amsat-bb@xxxxx.xxx>, Board of Directors <bod@xxxxx.xxx>,
officers@xxxxx.xxx
Message-ID:
<956751cf0910020819q3eb20e44s80d4515aa38b7504@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
I will be out of the AMSAT office from Wednesday, October 7th - October
12th. Hope to see many of you at the AMSAT Space Symposium and Annual
Meeting next week.
--
73- Martha
------------------------------
Message: 5
Date: Fri, 2 Oct 2009 17:18:42 +0200
From: "Marc Vermeersch" <amvm@xxxxxx.xx>
Subject: [amsat-bb] Re: Solar Power (I was wrong)
To: "'Jeff Yanko'" <wb3jfs@xxx.xxx>, <amsat-bb@xxxxx.xxx>
Message-ID: <001a01ca4373$a053b1a0$e0fb14e0$@xx>
Content-Type: text/plain; charset="us-ascii"
Hi Jeff and all,
I got 25 years warranty on the panels, meaning that after 25years at least
80% of the power output will remain.
The weak point in the installation is the converter which has an life
expectancy of 8-10 years. It is also cheap in the overall picture. Less than
5% of the cost of the total installation: 1200euros for a 5KW peak
converter.
BR,
--
/\/\arc
> -----Original Message-----
> From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
> Behalf Of Jeff Yanko
> Sent: vrijdag 2 oktober 2009 4:49
> To: Pete Rowe; bruninga@xxxx.xxxx amsat-bb@xxxxx.xxx
> Subject: [amsat-bb] Re: Solar Power (I was wrong)
>
> Hi Pete,
>
> FB on friends and their systems. What will happen is since each state
> has its own PUC, Public Utility Commission, and laws there will be 50
> different ways of handling how to reimburse, tax or otherwise garnish
> money from this process.
>
> I've also been wondering. Since a basic grid-tie system can cost from
> $15,000 to $25,000, they only last so long. Twenty years, tops maybe?
> Do they really pay for themselves, even wth tax credits, when you have
> to replace them in say twenty years?
------------------------------
Message: 6
Date: Fri, 2 Oct 2009 09:04:56 -0700 (PDT)
From: Rodney Waln <kc0zhf@xxxxx.xxx>
Subject: [amsat-bb] Re: College Satellite nights, Thursday night
To: amsat-bb@xxxxx.xxx
Message-ID: <522423.72594.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
hi, i would like to thank those that made it possable,
i got on mid pass AO-51 QRP (0005z) and there were 2 college stations that i
worked
Kansas (K0KU), Stanford (W6YX), thank you for being on,
Rodney
kc0zhf
------------------------------
Message: 7
Date: Fri, 02 Oct 2009 08:05:58 -0800
From: Edward Cole <kl7uw@xxxxxxxxx.xxx>
Subject: [amsat-bb] Re: Solar Power (I was wrong)
To: bruninga@xxxx.xxxx <amsat-bb@xxxxx.xxx>
Message-ID: <200910021606.n92G68WI087572@xxxx.xxxxxxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 04:37 PM 10/1/2009, Robert Bruninga wrote:
>Since Satellite design is heavy into Solar power, and I talk
>about that a lot, you may have heard me compare my Solar car to
>Solar panels on the roof of your house as not economical, I WAS
>WRONG. I was overlooking many recent changes in the
>environment:
>
>1) Solar panels (PV) are 1% of what they cost in 1970
>2) PV dropped 40% this year due to 2007 Energy Boom and 2009
>economic bust
>4) $5,000 to $20,000 tax and cash back incentives for YOU
>5) Grid-tie systems operate at 95% efficiency compared to 70% of
>battery systems
>6) Local electric rates DOUBLED in the last 2 years
>7) Laws require utilities to pay you the same peak rates they
>charge you.
>8) Solar Energy credits can gain an additional $275 per 1Kw
>system per year
>9) Payback is at least 10% per year or better
>10) The same money in the bank gets 1% interest
>
>So I was wrong in not keeping current with all the changing
>environment, and now I am full speed to get my system approved
>and built and correct any miss-guidance I may have helped
>propagate.
>
>Sorry. I am claiming this particular email is on-topic because
>of public statements to the contrary I have made at satellite
>forums. But this hot topic should probably spin off elsewhere.
>We need a HAM Solar Power group somewhere...?
>
>Summary: Do NOT make the mistake (as most of us do) of thinking
>in terms of stand-alone Battery back-up solar power systems .
>They cost more and you don't need it in most places where you
>have access to the grid. They cost $5 to $10,000 more, are only
>70% efficient (compared to 95% for grid-tie) and are a never
>ending maintenance headache. Instead, most any enterprising ham
>should be able to provide his own backup power using a cheap 1
>kW inverter for about $150 from any auto store or radio shack
>running off his car's 12V system for any power outages.
>
>That, a few deep cycle batteries, (and using CFL lightbulbs in
>your house) will give you enough emergency power to operate your
>full Ham station, all the lights in the house you want plus your
>refrigerator for as long as you can buy gas. But the other
>99.99% of the time, sell your solar power to the power company
>(at peak rates during the day) and buy it back cheap at night
>(you win and you don't even have to worrry about batteries)...
>
>And even if your grid-tie solar array produces nothing (in the
>way of AC power) when the grid goes out, you still have many
>Killowatts of DC power on your roof, that you can surely find
>lots of things to do with until the grid comes back. For
>example, have the electrician wire a 250 volt string of the 200
>Watt solar panels in the array to a DPDT switch so they can be
>disconnected from the Grid Tie system and the 250 VDC can be
>available to you. THen you can plug in as many modern DC/DC
>pwer supplies into that 250 VDC to give you LOTS of amps at 12
>volts, or ... almost any modern gizmo has a universal power
>supply input that will run on anything from 110V to 330V DC as
>is.
>
>Anyway, for similar hints www.aprs.org/FD-Prius-Power.html
>
>Sorry for the off-topic. But I was wrong. PV works! (even in
>Maryland). If you live in the SW, you are lucky, and it works
>TWICE as much or at HALF the price!
>
>A Born-again Home PV junkie
>Bob, WB4APR
>
>
>_______________________________________________
>Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
>Not an AMSAT-NA member? Join now to support the amateur satellite program!
>Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Couple comments:
A 12-vdc battery back-up for your stations requires no conversion to
AC, since most ham gear runs on 12v. A PV to battery system will
keep one going when "the lights go out"! may not happen much down
there in "civilization" but here in Alaska, several outages a year
happen, some go for days. We have a 2500w standby gen that outputs
240vac to feed the main ckt breaker (with mains isolated). We have
to load shed some areas of the house in that scenario. The same ckt
can be connected to my shack to feed a small breaker box that
supplies 240vc to the HV Power Supplies. (obviously we do not run
the big amps when the power is out).
I have installed many PV panels in remote sites over the years. They
are much more efficient these days. It gets more challenging to
depend on solar year-round since winter sunlight is only 5.5
hours/day. At my company's sites we opted to use supplemental solar
during the warmer months when there is long sunlight and have an auto
switch that detects low voltage to switch to the primary
oxygen-activated alkaline battery plant (15vdc @ 10,800 AH). The
primary batteries have a life of 3-years+ so we schedule their
replacement (involves helicopter delivery= $2500) on the third year
($5500). Cheaper power exists but due to extreme weather on the
mountain (-30F and >200mph winds), it is not feasible to visit the
mountain 8-months/year!
If one is still planning to utilize a stand-alone PV electric system,
then they should look at the sine-wave inverters that are very
efficient (some at 98%). They do cost more!
Side Note: one of Alaska's utilities is installing 27 wind generators
to supply the grid (on an island 8-miles from Anchorage). These are
the 300-foot prop "babies"! I'm sure that this implies megawatts.
73, Ed - KL7UW, WD2XSH/45
======================================
BP40IQ 500 KHz - 10-GHz www.kl7uw.com
500-KHz/CW, 144-MHz EME, 1296-MHz EME
DUBUS Magazine USA Rep dubususa@xxxxxxx.xxx
======================================
------------------------------
Message: 8
Date: Fri, 02 Oct 2009 09:56:39 -0700
From: Mike and Paula Herr <herr@xxxxxxxx.xxx>
Subject: [amsat-bb] Re: Solar Power (I was wrong)
To: amsat-bb@xxxxx.xxx
Message-ID: <4AC630C7.6050402@xxxxxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I've had a solar grid inter tie set up here in California for a number
of years, so I have had a tad bit of experience. The cost can be
somewhat deceptive. I have heard prices of $20,000 to $30,000 banded
around. At installation there is a healthy rebate from the California
Public Utility commission, many other states have similar set ups. Then
there are tax credits for Federal. California recently dropped their
state credits. Plus, usually even a small installation, while not
bringing you down to zero cost electrically, does bring your peak into
the lower tiers of cost.
Out of pocket mine cost me about $6,000. And it is working great. No, I
do not have to clean them off every month. My monthly electrical bill is
about $25. I am now in the process of adding a wind turbine to the mix.
So look at the entire mix, ie cost, rebates and credits, and effects on
the bill.
Just my 2 cents
73
Mike WA6ARA
>
> Since Satellite design is heavy into Solar power, and I talk
> about that a lot, you may have heard me compare my Solar car to
> Solar panels on the roof of your house as not economical, I WAS
> WRONG. I was overlooking many recent changes in the
> environment:
>
> 1) Solar panels (PV) are 1% of what they cost in 1970
> 2) PV dropped 40% this year due to 2007 Energy Boom and 2009
> economic bust
> 4) $5,000 to $20,000 tax and cash back incentives for YOU
> 5) Grid-tie systems operate at 95% efficiency compared to 70% of
------------------------------
Message: 9
Date: Fri, 2 Oct 2009 12:50:07 CDT
From: k0vty@xxxx.xxx
Subject: [amsat-bb] Re: Solar Power (I was wrong)
To: bruninga@xxxx.xxxx amsat-bb@xxxxx.xxx
Cc: amsat-bb@xxxxx.xxx
Message-ID: <20091002.125008.3424.9.k0vty@xxxx.xxx>
Content-Type: text/plain; charset=us-ascii
Afternoon Sir:
I have enjoyed your postings on the BB.
However this time I have to ask a question of you.
The term Grid-Tie for the purpose of Solar efficiencies has me stumped
If you would be so kind I would like an explination.
As the old saying goes , "when one in the class does not understand, bet
on 5 more in the same conditon"
Additionally if there is data on where such a system is currently
available, that might help.
Best Regards
Joseph Murray ( K0VTY)
Amsat # 860
Amsat Coordinator NE.
=========================
On Fri, 2 Oct 2009 09:03:18 -0400 (EDT) "Bob Bruninga "
<bruninga@xxxx.xxx> writes:
> > My simple math says it'll take almost
> > 16 years to be reimbursed on a $30k system.
>
> Its more like 5.5 years.. I'll show you my numbers for Maryland:
>
> > Initial outlay: $30,000
> > US tax credit: 5%
>
> No, Federal Credit is 30%
>
> > US reimbursement: $1500 (this is not
> > real money, but a reduction in taxable income)
>
> at 30% it is $9,000 and it is a *credit*, not a deduction, so that
> is cash in your pocket off the tax you pay.
>
> Then most states, give either similar Tax *credits* or grants, in my
> state it would be about $4,000 check, payable to me when
> installation is complete. Then the county makes up the difference
> to 50% of the cost of the system.
>
> > Total: $28,500
>
> No, here, my net outlay is reduced to 50% or only $15,000.
>
> > Savings per year in electricity: $1800
>
> That, plus Solar Energy Renewable credits paid to you by the power
> company or brokers at about $250 per KW capacity for a 4 Kw system =
> $1000 per year. They buy this credit from you so that they dont
> have to build solar systems. By paying you this credit, they get to
> subtract the capacity from the amount they are required to build by
> the year 2020? or whatever. So add the two and you get a payback of
> $2800/year.
>
> > $30k / 1.8k = 15.83 years
>
> * My numbers show $15k / 2.8 = 5.3 years (even less if electric
> rates go up)
>
> > One of the points of the post, I think,
> > was to make ourselves less dependent on
> > foreign oil..
>
> > Personally, I do not think PV cells are
> > that efficient. To get the 12VDC I need
> > to power my remote... repeaters, I...
> > lose more than 30% in generated heat.
>
> Yes! That was my mistake too. Energy Storage in batteries is very
> inefficient. About 30% or more losses. But GRID-TIE systems are
> 95% efficient PLUS you are selling the power to the grid at PEAK
> rates in the middle of the day, and buying it back at discout rates
> at night. Net effect is not a loss, but a GAIN. Of course, this
> does not help at a repeater, but do not carryover these losses to a
> Grid Tie system where it does not apply...
>
> > they only last so long.
> > Twenty years, tops maybe?
> > Do they really pay for themselves?
>
> You bet for sure! Compare that to a $30,000 car, which is junk in
> 10 years and you have nothing. The solar system cost $30,000
> (actually $15K) and you MAKE $15k in the first 5 years, and for the
> next 15, you make $45,000, and then your array has decayed to maybe
> only 80% of its original life... but it is still MAKING money at
> then CURRENT rates...
>
> The 20 and 30 year life does not mean they die, it is just that
> their power has dropped by XX%... Im guessing that the threshold is
> 80%?
>
>
>
> > in California. .. the power company is
> > only required to pay you the WHOLESALE
> > cost of electricity. This amounts to 3
> > to 4 cents per kw-hr.
>
> Ah, but if you pay 15 cents per KWH during the day to run your home,
> and you have enough solar to balance that, then the payback to you
> is still 15 cents per KwH. Its only the excess you generate that
> pays you the low rates.
>
> The key word is "net metering". In other states with net-metering,
> they have to give you the full 15 cents credit for the excess power
> you generate. But in most all cases, you cannot beuild up credits
> beyond a year cycle.
>
> > ... bird poop to cut the efficiency.
> > be prepared to get on the roof every
> > month or so to clean the panels.
>
> AMEN. PV cells are in series. One big splat that covers one CELL,
> reduces the power of the ENTIRE PANEL. A single Flag Pole shadow
> across a roof, can reduce the power of the entire roof array
> tremendously...
>
> >> if you sell back over 50,000 watts
> >> of power you will incur additional taxes,
> >> ... you are considered a "generator"
>
> I assume that is NET. To build up that much excess capacity would
> require an array on my house covering 3 times the roof area I have
> available. And it would make no sense to build an array that big,
> since you aleady know that you get paid peanuts for excess net power
> (wholesale).
>
> >> Lets say you were able to generate
> >> and sell back 100,000 watts to the
> >> utility company.
>
> Yes, that is my annual consumption. But my array will be sized so
> that I generate 100,000 in that same year. SO the NET "sell back"
> is ZERO. And I got all my electricity for FREE that year. You are
> right, that if I make my array TWICE as big as I need, and spent
> about $100,000 for it, that then, I would generate twice the
> electricity I need, and would not get paid but probably HALF the
> rate for it PLUS the taxes you mentino. Oh, and that array would
> coer 8,000 square feet almost an Acre... So I would not worry about
> a homeower making the mistake of building too big a system...
>
> >>> > 1) Solar panels (PV) are 1% of what they cost in 1970
> >>> 2) PV dropped 40% this year due to 2007 Energy Boom and 2009
> economic bust
> >>> 4) $5,000 to $20,000 tax and cash back incentives for YOU
> >>> 5) Grid-tie systems operate at 95% efficiency compared to 70% of
> battery systems
> >>> 6) Local electric rates DOUBLED in the last 2 years
> >>> 7) Laws require utilities to pay you the same peak rates they
> charge you.
> >>> 8) Solar Energy credits can gain an additional $275 per 1Kw
> system per year
> >>> 9) Payback is at least 10% per year or better
> >>> 10) The same money in the bank gets 1% interest
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the
> author.
> Not an AMSAT-NA member? Join now to support the amateur satellite
> program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
>
>
____________________________________________________________
$5,000 a Week For Life
Publishers Clearing House winner annouced on NBC. Enter now.
http://thirdpartyoffers.juno.com/TGL2141/c?cp=ivXBCqEdejvr9UOvcHT2YAAAJ1CmZcBa
4CCYwgQDaZ1FJwo1AAQAAAAFAAAAAArXIzwAAAMlAAAAAAAAAAAAAAAAAAkBmQAAAAA=
------------------------------
Message: 10
Date: Fri, 2 Oct 2009 14:27:09 -0400
From: "Robert Bruninga" <bruninga@xxxx.xxx>
Subject: [amsat-bb] Re: Solar Power (I was wrong)
To: "'Greg D.'" <ko6th_greg@xxxxxxx.xxx>, <ptrowe@xxxxx.xxx>,
<amsat-bb@xxxxx.xxx>, <wb3jfs@xxx.xxx>
Message-ID: <8FE137DF1E0A45DF8A03FA305117ECD9@xxxxx.xxxx.xxx>
Content-Type: text/plain; charset="us-ascii"
> ... I have... a roof angle exposure that is
> not solar-friendly...
That was another error I had made in my situation.
Again, there is a BIG difference between solar design for
stand-alone battery systems (must point south, optimum angle,
etc) and grid-tie systems that can be anything from SE to SW and
even FLAT and still be only a few percent off peak!.
The economics are entirely different.
The remote/battery system, MUST provide a minimum power on the
worst winter days and weather of the year. It MUST be optimized
for winter.
On the other hand, the grid tie system only has to have a good
AVERAGE power averaged over a year. And you can make more money
in a month of summer sun making money at HIGH payback rates than
you can get all winter (3 months).
Even a FLAT array makes more power in the 3 summer months than
the optimum tilt angle array does.
And lastly, anything pointed SE to S to SW is about the same for
a grid-tie system. You lose at most about 5% SE or SW compared
to South. Again, the reason is not obvious. But any tilted
array is only going to see the sun for 180 degrees of path
across the sky. Even the ideal South facing tilted array does
not see the morning sun nor the evening sun in the summer when
you are getting your most payback.. It only sees the midle 6
hours. Since the sun is up much longer than that most seasons,
then getting those 6 hours averaged before noon (SE) or getting
them in the afternoonn (SW) makes little difference for a
grid-tie array, though, I'd favor SW, since peak electric rates
apply longer in the afternoon than in the morning. So you want
to maximize your power when electricity rates are highest.
Again, I am sharing this off topic with everyone, because I too
learned that my thinking was all wrong based on my previous
experiences with stand-alone power systems and that a
grid-tie-system has completely diffeerent economics to my normal
thinking...
You can play with all the angles and directions for grid-tie
systems on-line with the solar energy calculator here:
Yes, SOUTH with a latitude tilt is best... But based on annual
AVERAGEs:
Southeast only lost 5%
Southwest only lost 5%
Droping the tilt to the angle of my roof 25 deg only lost 1%!
Droping the tilt to FLAT on the ground only lost 14%
(but if I tilt them up to 45deg Sept to April) I GAIN 20%! And
that is a +5% over optimum south.
http://www.nrel.gov/rredc/pvwatts/version1.html
On the other hand, ANY shade will significantlly cut into your
power budget.
Bob, Wb4APR
------------------------------
_______________________________________________
Sent via amsat-bb@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
http://amsat.org/mailman/listinfo/amsat-bb
End of AMSAT-BB Digest, Vol 4, Issue 511
****************************************
Read previous mail | Read next mail
| |
