[amsat-bb] Re: Solar Power (I was wrong)
Interesting topic. Here in the desert, Las Vegas, NV, I've seen a few homes with solar panels on their roofs. Not a lot but a few here and there. Actually, I see more with roof heating systems for the pools than anything else. However, I'm sure there are more out there than I'm seeing. In any case, a topic has risen about generating and selling power back to the utility company.taxes. Some states are now implementing taxes on residential owners who generate and "sell back" their power to the utility company. Pennsylvania happens to be one of them. I believe the standing is if you sell back over 50,000 watts of power you will incur additional taxes, adding to your state personal income tax. Apparantly, after 50,000 watts your considered a "generating" or "generator" entity and are subject to tax. Lets say you were able to generate and sell back 100,000 watts to the utility company. The first 50,000 watts would be "free". From then on out, it's taxed. Not sure what rate they are or would be applying but lets say 15 cents per KW. At 50,000 watts that would be $7.50. Doesn't sound like much, then again 15 cents per KW is probably nowhere near what they really want. I believe you will see this happen more often as states look for additional revenue. 73, Jeff WB3JFS - Original Message - From: "Robert Bruninga" To: Sent: Thursday, October 01, 2009 5:37 PM Subject: [amsat-bb] Solar Power (I was wrong) > 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...@amsat.org. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite pro
[amsat-bb] Re: Solar Power (I was wrong)
I've recently looked into PV home installations in California. Unfortunately, here at least, the power company is only required to pay you the WHOLESALE cost of electricity. This amounts to 3 to 4 cents per kw-hr. Hence, most folks size their PV system to exactly meet their needs. I have three friends who have had systems running for 3 years. You get credits from the power company for the power you generated during the year. Then they even up at the end of the year. If you made more electricity than you used, you lose it. If you made less, then you owe them the difference. Since they have sized the systems correctly, they owe very little money. One of my friends installed a water spray system to cool the panels since they lose efficiency fast as the temperature goes up. Also, it doesn't take much dust or bird poop to cut the efficiency. So if you install a system, be prepared to get on the roof every month or so to clean the panels. Regards, Pete WA6WOA --- On Thu, 10/1/09, Jeff Yanko wrote: From: Jeff Yanko Subject: [amsat-bb] Re: Solar Power (I was wrong) To: bruni...@usna.edu, amsat-bb@amsat.org Date: Thursday, October 1, 2009, 6:04 PM Interesting topic. Here in the desert, Las Vegas, NV, I've seen a few homes with solar panels on their roofs. Not a lot but a few here and there. Actually, I see more with roof heating systems for the pools than anything else. However, I'm sure there are more out there than I'm seeing. In any case, a topic has risen about generating and selling power back to the utility company.taxes. Some states are now implementing taxes on residential owners who generate and "sell back" their power to the utility company. Pennsylvania happens to be one of them. I believe the standing is if you sell back over 50,000 watts of power you will incur additional taxes, adding to your state personal income tax. Apparantly, after 50,000 watts your considered a "generating" or "generator" entity and are subject to tax. Lets say you were able to generate and sell back 100,000 watts to the utility company. The first 50,000 watts would be "free". From then on out, it's taxed. Not sure what rate they are or would be applying but lets say 15 cents per KW. At 50,000 watts that would be $7.50. Doesn't sound like much, then again 15 cents per KW is probably nowhere near what they really want. I believe you will see this happen more often as states look for additional revenue. 73, Jeff WB3JFS - Original Message - From: "Robert Bruninga" To: Sent: Thursday, October 01, 2009 5:37 PM Subject: [amsat-bb] Solar Power (I was wrong) > 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 ga
[amsat-bb] Re: Solar Power (I was wrong)
Bob, I *never* consider your posts as "Off Topic"! As others have replied, it varies greatly state-by-state. I have a very good friend who installed a grid-tie system at his house. He was $30,000 out-of-pocket, and got some fraction of that back in tax credits. Where he lives in California (Orange County), the utility DOES NOT buy power back from him; he only reduces his bill, a significant amount in summer, and less in the winter. IIRC, he told me his lowest power bill was a few dollars, and his highest was $45~$50. His bill *was* running $200 and higher before he bought his system. Jim KQ6EA --- On Thu, 10/1/09, Robert Bruninga wrote: > From: Robert Bruninga > Subject: [amsat-bb] Solar Power (I was wrong) > To: amsat-bb@amsat.org > Date: Thursday, October 1, 2009, 5:37 PM > 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...@amsat.org. > 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 > ___ Sent via amsat...@amsat.org. 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
[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? 73, Jeff WB3JFS - Original Message - From: Pete Rowe To: bruni...@usna.edu ; amsat-bb@amsat.org ; Jeff Yanko Sent: Thursday, October 01, 2009 6:46 PM Subject: Re: [amsat-bb] Re: Solar Power (I was wrong) I've recently looked into PV home installations in California. Unfortunately, here at least, the power company is only required to pay you the WHOLESALE cost of electricity. This amounts to 3 to 4 cents per kw-hr. Hence, most folks size their PV system to exactly meet their needs. I have three friends who have had systems running for 3 years. You get credits from the power company for the power you generated during the year. Then they even up at the end of the year. If you made more electricity than you used, you lose it. If you made less, then you owe them the difference. Since they have sized the systems correctly, they owe very little money. One of my friends installed a water spray system to cool the panels since they lose efficiency fast as the temperature goes up. Also, it doesn't take much dust or bird poop to cut the efficiency. So if you install a system, be prepared to get on the roof every month or so to clean the panels. Regards, Pete WA6WOA --- On Thu, 10/1/09, Jeff Yanko wrote: From: Jeff Yanko Subject: [amsat-bb] Re: Solar Power (I was wrong) To: bruni...@usna.edu, amsat-bb@amsat.org Date: Thursday, October 1, 2009, 6:04 PM Interesting topic. Here in the desert, Las Vegas, NV, I've seen a few homes with solar panels on their roofs. Not a lot but a few here and there. Actually, I see more with roof heating systems for the pools than anything else. However, I'm sure there are more out there than I'm seeing. In any case, a topic has risen about generating and selling power back to the utility company.taxes. Some states are now implementing taxes on residential owners who generate and "sell back" their power to the utility company. Pennsylvania happens to be one of them. I believe the standing is if you sell back over 50,000 watts of power you will incur additional taxes, adding to your state personal income tax. Apparantly, after 50,000 watts your considered a "generating" or "generator" entity and are subject to tax. Lets say you were able to generate and sell back 100,000 watts to the utility company. The first 50,000 watts would be "free". From then on out, it's taxed. Not sure what rate they are or would be applying but lets say 15 cents per KW. At 50,000 watts that would be $7.50. Doesn't sound like much, then again 15 cents per KW is probably nowhere near what they really want. I believe you will see this happen more often as states look for additional revenue. 73, Jeff WB3JFS - Original Message - From: "Robert Bruninga" To: Sent: Thursday, October 01, 2009 5:37 PM Subject: [amsat-bb] Solar Power (I was wrong) > 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 ke
[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}
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.
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?)
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
> Date: Thu, 1 Oct 2009 18:46:28 -0700
> From: ptr...@yahoo.com
> To: bruni...@usna.edu; amsat-bb@amsat.org; wb3...@cox.net
> Subject: [amsat-bb] Re: Solar Power (I was wrong)
>
>
> One of my friends installed a water spray system to cool the panels since
> they lose efficiency fast as the temperature goes up. Also, it doesn't
> take much dust or bird poop to cut the efficiency. So if you install a
> system, be prepared to get on the roof every month or so to clean the
> panels.
>
>
>
> Regards,
>
> Pete
>
> WA6WOA
>
_
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___
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[amsat-bb] Re: Solar Power (I was wrong)
My simple math says it'll take almost 16 years to be reimbursed on a $30k system. Initial outlay: $30,000 US tax credit: 5% (I guessed, I have no idea so this number could be high or low) US reimbursement: $1500 (this is not real money, but a reduction in taxable income) Total: $28,500 (realizing you *still* paid $30k out-of-pocket and only saw a $1500 savings in taxable income) Savings per year: $1800 (someone posted earlier that their friend realized a savings of ~$150 / month) $30k / 1.8k = 15.83 years One of the points of the post, I think, was to make ourselves less dependent on foreign oil, not, necessarily a savings in utility costs for the household. The other point was to build and experiment. So, if you want to build it and try it out, do so. Personally, I do not think PV cells are that efficient. To get the 12VDC I need to power my remote, low-powered SCADA repeaters, I have to install PV cells that generate about 19 - 20 VDC and run them through charge controllers. I've just lost more than 30% in generated electricity to heat. I suppose I could investigate and have the company purchase more efficient PV cells, but I've been told numerous times, "That's not your job." Now, if someone could tell me how to do it more efficiently, I'm all ears. 73, Joel, W4JBB Jeff Yanko wrote: > 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? > > > 73, > > Jeff WB3JFS > - Original Message - > From: Pete Rowe > To: bruni...@usna.edu ; amsat-bb@amsat.org ; Jeff Yanko > Sent: Thursday, October 01, 2009 6:46 PM > Subject: Re: [amsat-bb] Re: Solar Power (I was wrong) > > > I've recently looked into PV home installations in California. > Unfortunately, here at least, the power company is only required to pay you > the WHOLESALE cost of electricity. This amounts to 3 to 4 cents per kw-hr. > Hence, most folks size their PV system to exactly meet their needs. I have > three friends who have had systems running for 3 years. You get credits from > the power company for the power you generated during the year. Then they even > up at the end of the year. If you made more electricity than you used, you > lose it. If you made less, then you owe them the difference. Since they have > sized the systems correctly, they owe very little money. > One of my friends installed a water spray system to cool the panels > since they lose efficiency fast as the temperature goes up. Also, it doesn't > take much dust or bird poop to cut the efficiency. So if you install a > system, be prepared to get on the roof every month or so to clean the panels. > > Regards, > Pete > WA6WOA > > --- On Thu, 10/1/09, Jeff Yanko wrote: > > > From: Jeff Yanko > Subject: [amsat-bb] Re: Solar Power (I was wrong) > To: bruni...@usna.edu, amsat-bb@amsat.org > Date: Thursday, October 1, 2009, 6:04 PM > > > Interesting topic. Here in the desert, Las Vegas, NV, I've seen a > few homes > with solar panels on their roofs. Not a lot but a few here and > there. > Actually, I see more with roof heating systems for the pools than > anything > else. However, I'm sure there are more out there than I'm seeing. > In any > case, a topic has risen about generating and selling power back to > the > utility company.taxes. Some states are now implementing taxes > on > residential owners who generate and "sell back" their power to the > utility > company. Pennsylvania happens to be one of them. I believe the > standing is > if you sell back over 50,000 watts of power you will incur > additional taxes, > adding to your state personal income tax. Apparantly, after 50,000 > watts > your considered a "generating" or "generator" entity and are > subject to tax. > Lets say you were able to generate and sell back 100,000 watts to > the > utility company. The first 50,000 watts would be "free". From > then on out, > it's taxed. Not sure what ra
[amsat-bb] Re: Solar Power (I was wrong)
> 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
[amsat-bb] Re: Solar Power (I was wrong)
Hi Greg and all,
> -Original Message-
> From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
> Behalf Of Greg D.
> Sent: vrijdag 2 oktober 2009 6:13
> To: ptr...@yahoo.com; bruni...@usna.edu; amsat-bb@amsat.org;
> wb3...@cox.net
> 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
___
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[amsat-bb] Re: Solar Power (I was wrong)
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-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On > Behalf Of Jeff Yanko > Sent: vrijdag 2 oktober 2009 4:49 > To: Pete Rowe; bruni...@usna.edu; amsat-bb@amsat.org > 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? ___ Sent via amsat...@amsat.org. 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
[amsat-bb] Re: Solar Power (I was wrong)
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...@amsat.org. 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-
[amsat-bb] Re: Solar Power (I was wrong)
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 ___ Sent via amsat...@amsat.org. 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
[amsat-bb] Re: Solar Power (I was wrong)
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 " 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
[amsat-bb] Re: Solar Power (I was wrong)
> ... 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...@amsat.org. 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
[amsat-bb] Re: Solar Power (I was wrong)
I think you are also forgot the price of a Building permit - in this county 1-2K Doc - Original Message - From: "Robert Bruninga" To: "'Greg D.'" ; ; ; Sent: Friday, October 02, 2009 11:27 AM Subject: [amsat-bb] Re: Solar Power (I was wrong) > ... 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...@amsat.org. 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 ___ Sent via amsat...@amsat.org. 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
[amsat-bb] Re: Solar Power (I was wrong)
In a message dated 02/10/2009 18:41:31 GMT Standard Time, bruni...@usna.edu writes: 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!. Sorry Bob, But a few percent is certainly not correct for the installation I'm responsible for. I have a set of panels pointing at the horizon at my local school and they are about 40% down at midday. The efficiency is directly related to the amount of sun falling on the panelwell some relationship to the tan of the angle in radiansor whatever it was I calculated and then measured. Actually the angle to the sun is critical for max efficiency. (Obviously missed completely by the %7'!** who approved this installation.) _http://www.sunnyportal.com/Templates/PublicPageOverview.aspx?plant=7350f0ac -1a01-4248-89cc-90607f32caaf&splang=en-GB_ (http://www.sunnyportal.com/Templates/PublicPageOverview.aspx?plant=7350f0ac-1a01-4248-89cc-90607f32caaf&spla ng=en-GB) If you want to check out the efficiency of an installation near you, just have a quick search of the "publicly available plants" at _www.sunnyportal.com_ (http://www.sunnyportal.com) David G0MRF ___ Sent via amsat...@amsat.org. 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
[amsat-bb] Re: Solar Power (I was wrong)
Hi Bob, While I'm at my summer place in the Upper Peninsula of Michigan (EN56), I run my satellite station purely by solar power. It is not by any means a high tech setup, but it works for me. I bought my 15watt solar panel from a RV (recreational vehicle) center, and charge up two 26 amp hour gel cell batteries. I also use one of those " $10 Dayton specials" power units with a 17ah battery and 400 watt inverter. This runs the laptop and rotator. But not for long. I think I've got less than $250 into the whole system. This is not by any means the most effective or efficient system to have, but it is portable and works for Field Day. So if I make contact with you from EN56, it's done from solar power. 73 de Doug KA8QCU - Original Message - From: "Robert Bruninga" To: "'Greg D.'" ; ; ; Sent: Friday, October 02, 2009 14:27 Subject: [amsat-bb] Re: Solar Power (I was wrong) > > ... 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...@amsat.org. 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 ___ Sent via amsat...@amsat.org. 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
