New user

getravi · July 2014

Hi all. I am a new user and wanted to present my hybrid system I put together a year and a half ago that runs my 2000 sq ft home 12 hours a day 100% off grid. It uses 10KW PV panels, 6KW pure sine wave inverter, 16 EXIDE group 31 lead acid 12 volt deep cycle batteries, 4 morningstar MPPT 60 charge controllers and one 50 amp automatic transfer switch to switch back to grid power.

My city does not allow grid tie systems and so I needed to stay completely off grid and this was the solution I came up with. My daily summer production averages 43Kwh as designed. I have my charge controllers configured to email me a reminder to fill the batteries every 60 days. My daily consumption is a constant 4000 watts. In all, I use everything I produce!

My need for going solar was to offset my electric bill during the day which accounts for the need to be off grid 50% of the time. To minimize the costs, I built all the equipment equipment myself including: battery bank monitors, battery voltage monitors, breaker monitors, circuit breaker monitors, combiner boxes etc.

I am hoping someone can look over my design and make some comments. To help others in this endeaver, I have saved documents regarding all calculations, gauging, code etc. and why I chose my design as I did.

I have been running my system successfully for the last year and half with no problems, staying off grid 12 hours a day. The system was designed to keep me running on solar power and sending excess to the batteries for charging and acting as a buffer.

I am having difficulty attaching my drawing to this post, so if someone can help me out, I would appreciate it.

Cariboocoot · July 2014

Re: New user

Welcome to the forum.

The first question any of us would have is: Why go off-grid to save on your electric bill? You do realize you're substituting power that costs cents per kW hour with power that costs dollars, don't you? Almost never is off-grid cheaper than the available utility. Just how expensive are your electric rates?

You say your usage is 43 kW hours. Per day? That's a fairly substantial amount of power and would indicate that further conservation methods might be in order. 4kW average continuous indicates some pretty big power demands. Much depends on where you are and how many people are in the household of course. Especially children who have never heard of the word 'OFF'.

10 kW of PV would produce around 20 kW hours AC for most battery systems, so at least half of your power is coming from solar. That same amount of panel on a grid-tie system would produce all of it. Hurrah for the inefficiencies of battery-based systems!

You don't say what your system Voltage is but I would hope it is 48. I don't know the Amp hour capacity of those batteries either, so it's hard to say how well they fit in. Sixteen 12 Volt batteries on a 48 Volt system would be four parallel strings, and that can have problems even at the high Voltage. The panels could support around 1600 Amp hours @ 48 Volts which is quite large: 19 kW hours DC @ 25% DOD. If I were to build a battery bank of that capacity I would not be piling up small 12 Volt units to do so.

On the whole I think I would have spent the whole budget on conservation rather than build an off-grid system where grid is available.

I know; I'm a bad guy with all negative comments. Possibly because I spend so much time fixing systems gone wrong. And some of those have been designed by 'professionals'.

getravi · July 2014

Re: New user

I very much appreciate your input. I live near St.Louis Missouri where the summer time temperature aerages 100+ degrees, hence our Air condition is pretty much on all the most of the time. The air conditioner itself uses about 3000W. In the winter, we use space heaters in addition to our gas furnace to lower the gas bill. Now to that, add things like, washing machine, computer server, tv, microwaves, fans etc. and you see why I average about 4000 watts continuous and hence, about 40KWh at the end of 12 hours. This also happens to be what I also produce by my PV array. The battery bank (48 volt system 420Ah) provides enough amperage for when ever things like the microwave, or inductive loads like furnace motor or air conditioner or sumb pump kick in. The battery bank also provide me the power early and late in the day when the sun begins to go down.

As far as being on the grid, that is not an option around here. So, I have no other alternative but this unless you can think of something else. I have calculated my return on investment to be less than 10 years. My brother inlaw's medical practice uses 3 times the amount of power as me and wants to do the same thing as me. He too has the same problem and must stay completely off grid. I wish i could use a grid tie inverter and not feed the power back to the grid and avoid batteries for him. His needs are for day time only. I dont see any other options do you?

Cariboocoot · July 2014

Re: New user

getravi wrote: »

I very much appreciate your input. I live near St.Louis Missouri where the summer time temperature aerages 100+ degrees, hence our Air condition is pretty much on all the most of the time. The air conditioner itself uses about 3000W. In the winter, we use space heaters in addition to our gas furnace to lower the gas bill. Now to that, add things like, washing machine, computer server, tv, microwaves, fans etc. and you see why I average about 4000 watts continuous and hence, about 40KWh at the end of 12 hours. This also happens to be what I also produce by my PV array.

I see room for conservation there. A/C is how old and what SEER rating? How's the household insulation? Windows? If you are having to supplement a gas furnace with electric space heaters than odds are the place is losing therms in both directions. You really should look into an energy audit; it can only save you money.

The battery bank (48 volt system 420Ah) provides enough amperage for when ever things like the microwave, or inductive loads like furnace motor or air conditioner or sumb pump kick in. The battery bank also provide me the power early and late in the day when the sun begins to go down.

Only 420 Amp hours? Are you sure? That 6kW inverter should have a minimum 600 Amp hours on it and the array could push more current than that battery bank could stand. I think maybe you mean the batteries are 420 Amp hours (although that is doubtful for a 12 Volt battery) and the whole bank is then 4 * 420 or 1680 Amp hours. If not and you are relying on loads to suck up the surplus current then you are running the risk of frying that battery bank.

As far as being on the grid, that is not an option around here. So, I have no other alternative but this unless you can think of something else. I have calculated my return on investment to be less than 10 years. My brother inlaw's medical practice uses 3 times the amount of power as me and wants to do the same thing as me. He too has the same problem and must stay completely off grid. I wish i could use a grid tie inverter and not feed the power back to the grid and avoid batteries for him. His needs are for day time only. I dont see any other options do you?

You are confusing on grid with grid-tie. Grid-tie is when your solar can sell surplus power back to the grid. On grid is when you don't use solar for power. As I said I doubt your electric rates are so high that the off-grid power production is saving you anything. Off-grid power comes at a cost in the $1 per kW hour and up range; you must amortize the capital expenditure over the expected equipment lifespan and divide by the kW hours production expected. It comes out a poor value every time.

It is in fact possible to use hybrid grid-tie inverters with 'SELL' turned off so that they never send power to the grid, only pull from it when needed. If your B-I-L's practice is suffering from high utility bills he needs to do an energy audit first. No one ever loses out by reducing electric use whether that power comes from grid, solar grid-tie, or off-grid sources.

There is also grid interactive using off-grid inverter-charger which has a built-in transfer switch. With a little adapting the automatic generator start function can be used to connect the grid to the AC IN whenever batteries get below a certain Voltage point, making the inverter think it's got generator power. Then the grid takes over the loads and recharges the batteries through the inverter. There are lots of these installations, usually in areas where the grid is unreliable and they need the UPS ability to keep things running.

getravi · July 2014

Re: New user

Sorry, I meant 460Ah in Batteries. I have 4 parallel strings of 48 volt batteries . Each string is made of four 12 volt batteries (Exide group 31 lead acid deep cycle batteries) wired in series. Each battery has 115Ah capacity. Four parallel strings would mean 115*4=460Ah Total.

Yes, I agree, I have do do an energy audit and add insulation to this old house.
Yes, I am relying on loads to suck up all the surplus current since I use all I produce, hence such a small battery bank.

You mentioned there are grid tie inverters that can have "SELL" turned off, thus not needing batteries. That is what I wanted to begin with since my city and my brother inlaws city do not allow us to send power back to the grid. They city told us that we must stay off the grid. Upon talking to everyone around, I was told, I need to be off-grid and came up with the design I currently have.

What inverters have the ability to turn off "SELL" feature.

How can I submit a JPG of my system to this forum. The system keeps rejecting it.

solar_dave · July 2014

Re: New user

You might need to resize the JPG to comply with the board size limit.

Cariboocoot · July 2014

Re: New user

getravi wrote: »

Sorry, I meant 460Ah in Batteries. I have 4 parallel strings of 48 volt batteries . Each string is made of four 12 volt batteries (Exide group 31 lead acid deep cycle batteries) wired in series. Each battery has 115Ah capacity. Four parallel strings would mean 115*4=460Ah Total.

Yes, I agree, I have do do an energy audit and add insulation to this old house.
Yes, I am relying on loads to suck up all the surplus current since I use all I produce, hence such a small battery bank.

You mentioned there are grid tie inverters that can have "SELL" turned off, thus not needing batteries. That is what I wanted to begin with since my city and my brother inlaws city do not allow us to send power back to the grid. They city told us that we must stay off the grid. Upon talking to everyone around, I was told, I need to be off-grid and came up with the design I currently have.

What inverters have the ability to turn off "SELL" feature.

How can I submit a JPG of my system to this forum. The system keeps rejecting it.

Hybrid inverters still need batteries.
The idea of using standard grid-tie inverters to offset only household loads is not an easy thing to accomplish. The problem being the GTI doesn't 'know' the difference between power going to the house and the power going back to the grid. There are a few threads on the forum discussing ways of managing this, but there are no simple solutions to it.

There is also the SMA system using the battery-based Sunny Island as the 'main' inverter and then AC coupling their Sunny Boy GTI's to it to provide the extra power when the sun shines. Since these are designed to work together they work very well to achieve the goal of small battery supplemented by AC only as-needed. Once again the grid can be called on when the solar can not manage all the demand by means of a transfer switch.

To improve your existing system the best thing you could do is redesign the battery bank so that it is larger capacity and fewer batteries in parallel. At minimum you should use sixteen L16 size of 320 or more (up to 430) Amp hours as two parallel strings of eight in series (they are 6 Volt). That would give you 640 or more Amp hours. As I said before you have the capacity to support 1600 Amp hours. You could be using (expensive) 2 Volt cells (500 to 1600 Amp hours each) to make it all one string. You could also use forklift batteries (if physically possible - they are monolithic monsters) which may be more readily available in your area.

Why do this? Three reasons: 1). reduce the ripple current on the inverter caused by the 10kW of PV pulsing at full Voltage; 2). reduce risk of high current cooking the batteries; 3). increase the amount of stored power that can be used later which otherwise may go unrealized if there doesn't happen to be demand for it at the time of production.

getravi · July 2014

Re: New user

I did consider these battery options initially. However, the cost of these batteries were so high compared to what I spent. I spent a total of $1800 including 0 AWG wires for connection for the 16 batteries. The same Ah in Trojan, Concorde, Surrette, Rolls etc were coming out more than 4 times more for the same capacity. This is why I went this route. I kept all my wires exactly the same length in order to keep the wire resistances equal and I have monitored the current flow accross each battery string every few months for the last year and a half. They all draw nearly equally.

I just submitted a drawing of my hybrid system that should help shed further light on what I am doing to the forum moderator. Hopefully he can post it for all to see. In this system, I have an automatic transfer switch that alows me to switch back to grid in case my battery bank is depleted. It is also used in the evening for the remaining 12 hours of the day when I turn off the inverter and automatically return to the grid. Normally, the PV sytem provides all the power to the entire house and any excess power goes to charge the batteries.

This way, I conform to my city's requirement of not feeding power back onto their grid, yet still use their power seemlessly as needed.

You will also notice in my drawing that the main panel is pretty much empty! The whole house runs on its own subpanel at the bottom of the drawing. The power to the subpanel automatically comes either from the PV side or the grid side via the automatic transfer switch.

Cariboocoot · July 2014

Re: New user

I just think you are up against the standard off-grid problem: the panels can produce power that you don't get to use because you can't store it all for when it is needed.

Consider this: your average power demand is 4kW, but your array is 10kW (capable of probably 7-8kW). So if the load demand is 3kW less than production capacity you lose that power.

In theory I can produce well over 4kW hours per day here. The most that has run up on the meter has been 3.5 kW hours because I can't store it all (no battery system can) and must rely on load management to maximize production (as all battery systems must). This is why a battery-based system typically has an end-to-end efficiency of 52%, brought up by the amount of power used during the day that would otherwise go unrealized due to the batteries being full.

In your case even increasing to the 600 Amp hour minimum for a 6kW 48 Volt inverter would be a plus.

BTW, what brand/model is your inverter?

Cariboocoot · July 2014

Re: New user

Bill;

I can't make out a single detail of either of those images. Could be the comp here or my eyes - neither of which are as good as they ought to be.

BB. · July 2014

Re: New user

Try again, as uploaded image with larger forum defaults:

-Bill

Attachment not found.

This one looks much better for me...

getravi · July 2014

Re: New user

It is an AIMS pure sine wave industrial grade 6000 watt 120Volt with surge to 18000 (for 20 seconds continuous) with MPPT controller built in (pre-production model) MPPT function not being used yet.

I was thinking of ordering another 16 batteries but wanted to ask you guys if you thought it was too late since my existing bank is already 1.5 years old. I personally don't think so since I have maintained them very well. Adding another 16 batteries would get me to a total of 920Ah.

Regarding my 4KW constant usage and 10KW PV array; the reason I sized it that way to begin with is that (1) 4KW is constant for 12 hours a day, but 10KW production via PV is not constant for 12 hours.

4KW * 12 hours = 48KWh consumptioni
10KW * 5 hrs average sunlight *.77 panel efficiency = expected 38.5 Khw production

I typically use 43KWh and produce 43Kwh. When I did my battery sizing calculations, I noted that it would take about 3 hours to charge the 16 batteries (which is what it does take) while I continue to use remaining power from the PV to the the rest of the house.

Each morning, I start my batteries at about 51volts and end at about 51 volts.

BB. · July 2014

Re: New user

Ravi,

Don't spend any more money just yet... Personally, I would highly suggest you reseach other battery configurations (such as 6/4/2 volt batteries with very large AH ratings)... This will allow you to use even just a single string of large 2 volt cells. This reduces both the number of cells to service and the "issues" that can occur with lots of parallel battery strings (poor current sharing, a single open cell can take out a string without you noticing, or a single shorted cell can over charge the rest of the string and discharge the whole bank over time, etc.).

You also need to look at what your battery bank is doing during the day... How high of charging voltage are you reaching (around 58-59 volts usually) and how long it is held (around 2-6 hours recommended, longer time for deeper cycling).

And, you should get a good hydrometer (assuming flooded cell batteries) and measure/log the temperature compensated specific gravity for each cell.

-Bill

waynefromnscanada · July 2014

Re: New user

getravi wrote: »

I have calculated my return on investment to be less than 10 years. I dont see any other options do you?

Would be very interesting to see how you came up with the less than 10 years return on investment. Especially as all things considered, including battery replacement in probably under 5 years in your case, your off grid power will end up costing you possibly 10 times as much per Kwh as utility grid power. Where are the savings, where is the return on investment? If this system was a hobby you enjoyed having, including monitoring the SG and watering 96 battery cells, that's one thing, but if it's purpose was to save money - - that's a whole different story.
As to other options? Three things instantly come to mind.
1) Conserve, conserve, conserve.
2) Replace all your appliances, TVs, computers and AC with new Energy Star high efficiency units, and TURN THEM OFF when not actually using / needing them.
3) Insulate your home!
These are just for starters.
And adding another 16 batteries? No Go! You already have 4 parallel strings which is one more than the max suggested and workable 3 parallel strings. Not to mention bring the total # of cells needing water and SG monitoring to 192 !!!

Cariboocoot · July 2014

Re: New user

Oh no: an AIMS inverter. Start saving now for its replacement.

Nor should you buy more batteries; you should buy different ones. Greater capacity from fewer units is the goal.

Regarding my 4KW constant usage and 10KW PV array; the reason I sized it that way to begin with is that (1) 4KW is constant for 12 hours a day, but 10KW production via PV is not constant for 12 hours.

Something of a flaw in that logic. You are exactly right that the 10kW production is not constant. So you oversize the array to provide 4kW when solar production is less than optimum. But then when it is optimum you have a large surplus capacity which is not realized because there is no place for it to go; lack of storage. That's PV dollars wasted.

Vic · July 2014

Re: New user

Hi getravi,

It is good that you seem fairly happy with your off-grid system.

All of the major points have been covered.

AIMS inverters have a poor reputation. As Cariboocoot Marc mentioned, it would be a good idea to quickly build a surplus of funds (perhaps from the "ROI") to replace the AIMS inverter. If you search this Forum for " aims " , you will find a number of references. Most are not positive about the quality, functionality or reliability of AMIS inverters. Certainly would not refer to them as "Industrial grade". Here is one Thread:

http://forum.solar-electric.com/showthread.php?23434-New-solar-setup-and-AIMS-inverters&highlight=aims

When you are ready to replace the AIMS, please consider Outback Power, Magnum, and perhaps Schneider Electric. These companies make very solid, reliable and honestly-rated inverters, which, generally have built-in battery chargers.

I have no axe to grind in this, Good Luck! Vic

getravi · July 2014

Re: New user

Yes, it is a hobby and it is also an investment into the future to help shed some of the utility bills and leave behind a green home for the kids.
Here in southern Illinois (close to St.Lous, Missouri) my summer electric bill is usually about $300/month from about April-September and about $200/month in the winter. With my solar installation, I was able to drop that in half.

I had originally calculated it as follows: 43kwh * 0.13=$167 savings per month from solar in summer
$167*6 months=$1006

In the winter. I estimated half the amount of solar production and thus would be saving only $1006/2=$503

This equals approx $1500/year savings due to production by solar.

I spent roughly $7000 in panels, $2000 in inverter, $2000 in batteries, $2000 in charge controllers, $5000 racking, wires and misc. hardware
Total comes to: $18000. Take a 30% tax credit that takes you to : $ 12600

Looking at a saving of $1500/year, it would take me less that 10 years to recoup that $12600 assuming I don't have to replace my batteries.

getravi · July 2014

Re: New user

Wow, I did not know AIMS had such a bad reputation. I started my adventure with solar about 2 years ago on my own by reading a few things, ordering some PWM controllers, upgrading to MPPT controllers, ordering a small AIMS inverter because it was cheap, then upgrading to their 48 volt what they called industrial grade one when it was coming out.

I actually worked for Schneider Electric for 9 years in a previous life, but I avoided their inverter because of expense. Its the experience I gained from Schneider Electric (Groupe Schneider when I worked there) that allowed me to put entire solar project together without blowing anything up or causing a fire.

I tried asking questions, but all I could get was grid tied systems, not what I needed. Are there any alternatives to what I have implemented? I still don't see an alternative out there.

Vic · July 2014

Re: New user

Hi getravi,

It has taken a while for AIMS to have a large enough installed-base for the failures to start to show up. Believe that a large part of their target market was for those who needed an inerter very occasionally. In these cases failures take longer to show up (IMO).

You seem technical, so seems that you have done well on getting quite a lot of the system correct, or close enough.

The sponsor of this site has a store (as you may know), here is their offering of battery-based inverters:
http://www.solar-electric.com/inverters-controllers-accessories/inverters.html

You are holding up well, under some input that many of us would not really want to hear! Later, vic

getravi · July 2014

Re: New user

Thanks. I don't mind any criticism. I have been all alone in this from the begining. I only came upon this forum by talking to the guys at Morningstar. I cannot say if my design is what is normally implemented by the PV professionals out there, but I can tell you this -- I work for a Electric company (Basler Electric - www.basler.com) that has designed and manufactures PV inverters for large power plants (we are talking gigawatts).

Although they don't do small scale residential systems or battery based systems, I did have them do a peer review of my design for any obvious flaws. All wiring, bus bar size etc is of sufficient size.

All voltage, amperage, production yields have been regularly checked for over a year now and meet or exceed theoretical values.

My brother inlaw wants me to implement the same system as mine except 3 times larger for his office. Based on comments I see here, and the fact that he can afford it (he's a doctor), I was thinking of going with 24 - 2volt batteries (high amperage) and a 30KW pv array and definately not AIMS inverter based on what I have heard thus far.

Otherwise, sticking to my design since he too needs to stay off grid -- do you concur? Is this how the professionals design an offgrid system? Mine is solely based on academic experience. I got my EE more than than 25 years ago!

Cariboocoot · July 2014

Re: New user

getravi wrote: »

Yes, it is a hobby and it is also an investment into the future to help shed some of the utility bills and leave behind a green home for the kids.
Here in southern Illinois (close to St.Lous, Missouri) my summer electric bill is usually about $300/month from about April-September and about $200/month in the winter. With my solar installation, I was able to drop that in half.

I had originally calculated it as follows: 43kwh * 0.13=$167 savings per month from solar in summer
$167*6 months=$1006

In the winter. I estimated half the amount of solar production and thus would be saving only $1006/2=$503

This equals approx $1500/year savings due to production by solar.

I spent roughly $7000 in panels, $2000 in inverter, $2000 in batteries, $2000 in charge controllers, $5000 racking, wires and misc. hardware
Total comes to: $18000. Take a 30% tax credit that takes you to : $ 12600

Looking at a saving of $1500/year, it would take me less that 10 years to recoup that $12600 assuming I don't have to replace my batteries.

You should assume you need to replace those batteries in 10 years time. It is rare that a set of batteries will last that long. In 20 years time the whole gig will be up, even if that inverter lasts. So you have 12,600 plus another $6,000 in batteries or $18,600 over 20 years. That's just under $1,000 per year @ $930. For 20 kW hours per day or 7300 kW hours per year. That's $0.127 per kw hour. Against grid electric that costs the same. Saving lots of money, are you? Only when the price of electric rises in the future, providing you don't have to replace that inverter. And keep in mind you are now the electric company; anything that goes wrong/breaks down is entirely on you. Inverter fries tomorrow, it's your problem and your expense.

I would not call this economical.

getravi · July 2014

Re: New user

I agree with you 100%. I look at it as follows: (1) I like to tinker, (2) It is a good learning exercise, (3) I am gambling that in less than 10 years time, this city will finally catch up and allow grid tie systems. Thus, by the time, my inverter and batteries die, I can go grid tied with a new grid tied inverter which will hopefully be reasonably cheap. I am also betting that the cost of electricity will rise!

Please correct me, but as far as I can tell, the only extra cost I have incurred between a grid tie system and my off grid system is $1800 in batteries. A grid tie system would need a grid-tie inverter for a 10KW array which costs around $3500. For me the inverter and MPPT controllers cost a total of $3500, but provide total redundancy down to a failing PV string.

Both systems, use the same PV modules and thus cost the same. All other hardware is the same. Aren't we just talking about the additional $1800 in batteries that I had to use regardless since my city does not allow send power back to the grid? After 10 years, my PV panels should still be in working order for atleast another 10 years providing me free electricity with hopefully a newly acquired grid tie battery less inverter for under $1000.

Please shed the light!

Cariboocoot · July 2014

Re: New user

10kW grid tie inverter $3,100: http://www.solar-electric.com/inverters-controllers-accessories/gridtiesolar/frgrtiein/frigplgrin/frigpl10uni1.html

No charge controllers are used with these because there are no batteries. The up side of that is that 100% of the energy produced is utilized either by the home or the grid. The down side is no grid = no power. Of course with your city not allowing GT (possibly that is not in compliance with law, btw) it is of no value at all.

If you were to compare a full-on 10kW off grid system with a 10kW GT system the costs would differ by quite a lot. For example you do not have 10kW worth of battery storage nor an inverter capable of 10kW output. When you balance them up the GT system is cheaper for fewer components and more efficient in energy production. Again, though, it lack back-up power capacity (unless you buy a hybrid system, and then you add on the expense of charge controllers and batteries again with resultant reduced efficiency).

BTW you could replace that AIMS with a Radian http://www.solar-electric.com/inverters-controllers-accessories/inverters/ouin/rasein/outback-power-radian-series-inverter-gs8048.html and be ready to go grid-tie when allowed while retaining your battery back-up ability. Although the Morningstar charge controllers were not the best choice here either (MidNite Classic; four controllers co-ordinate with the 'Follow Me' function to stay in sync) and you would definitely need more battery capacity. You might want to consider this for your brother-in-law's system.

ButchDeal · July 2014

Re: New user

Outback make several systems that do not SELL to the grid, they call it GRID-Zero.
https://www.youtube.com/watch?v=a33p0jbi1R0
They are still grid-tie systems with battery backup (Hybrid or bimodal). You would just configure it to not sell. It would use the batteries as much as possible and when they get too low and not enough sun, would charge from the grid.
The advantage would be that your bothers business would always have power.

What city is telling you that you can not net-meter?

getravi · July 2014

Re: New user

Yes, I agree. The 10KW grid tie inverter is $3100 and my morningstar system plus inverter is $3500; but, here in Missouri and Southern illinois, we have cities that do not allow us to to put any power back onto the grid. In fact, there is a home owner right around the corner from where I work (Basler Electric) who bought a spec home (All Green --- 3KW PV grid tied system, SMA sunny boy, Geothermal heating and cooling) and he is having problems with the city because he was feeding his power into the grid. The city does not want him to feed into the grid.

So, given the limitation, and the desire to cut down electric cost I saw little option, but the system I devised. I use all I produce, just like a grid tie sytstem, The only extra cost is the batteries ($1800), but the overall cost is still about the same, with the upside being that even if the grid is down, I am not and also, even if multiple controllers go down, I am not down, where as if a single grid tie inverter goes down, I am completely down.

I feel like I am missing something important.

getravi · July 2014

Re: New user

City of Farmington in Missouri (zip code 63640), City of Higland in Illinois (62249), my city doesn't allow net-metering. They wont even let me do wind turbine!!!

ButchDeal · July 2014

Re: New user

getravi wrote: »

City of Farmington in Missouri (zip code 63640), City of Higland in Illinois (62249), my city dont allow net-metering. They wont even let me do wind turbine!!!

Well Missouri has full Net-metering : http://www.dsireusa.org/solar/incentives/incentive.cfm?Incentive_Code=MO07R&re=0&ee=0

Missouri enacted legislation in June 2007 (S.B. 54)* requiring all electric utilities -- investor-owned utilities, municipal utilities and electric cooperatives -- to offer net metering to customers with systems up to 100 kilowatts (kW) in capacity that generate electricity using wind energy, solar-thermal energy, hydroelectric energy, photovoltaics (PV), fuel cells using hydrogen produced by one of the aforementioned resources, and other sources of energy certified as renewable by the Missouri Department of Natural Resources.

Illinois seems to have exceptions for municipal utilities though : http://www.dsireusa.org/solar/incentives/incentive.cfm?Incentive_Code=IL13R&re=0&ee=0

While Illinois's investor-owned utilities and alternative retail electricity suppliers must offer net metering, the state's municipal utilities and electric cooperatives are not required to do so.

getravi · July 2014

Re: New user

There are various cities in Missouri and Illinois and I happen to have hit both of them that buy their own power and sell it its residents. So we are kinda screwd.

Cariboocoot · July 2014

Re: New user

getravi wrote: »

They wont even let me do wind turbine!!!

Well that's one good thing then.

Small wind turbines are a notorious waste of money.

As far as needing back-up power when the grid goes down you have to look at how often that happens, for how long, and what are the consequences of the outage? Most places in the USA and Canada lose power rarely and briefly so no power is not a major concern. In those areas where it is, a generator to keep things going 'til the utility comes back is a far more economical investment than batteries and solar. Consider that one of the major causes of outages is bad weather, and solar panels don't work without sun. It varies a lot from place to place and from person to person, so must be evaluated on a per case basis.

I find it very strange that these locations do not allow grid tie. Not unheard of, but strange. It's allowed here in British Columbia although I can't imagine anyone being foolish enough to go for it: our electricity is cheap and our solar goods are not. In the past seventeen years we've had four outages, each lasting less than four hours. Never even got the gen started for the last one before it came back on!

So why do I have an off-grid system? Because I have a cabin miles away from anywhere and there is not going to be any grid run out to it even if I could pony up the millions to do so. To have electric out here solar is far cheaper than running a generator. Quieter too.

ButchDeal · July 2014

Re: New user

getravi wrote: »

There are various cities in Missouri and Illinois and I happen to have hit both of them that buy their own power and sell it its residents. So we are kinda screwd.

I think you might want to read the Missouri net metering more closely. Municipal utilities are included and have to allow net metering. They just have to approve the plan and going to require a grid-tie or bimodal system with full US certifications.

Missouri enacted legislation in June 2007 (S.B. 54)* requiring all electric utilities -- investor-owned utilities, municipal utilities and electric cooperatives -- to offer net metering to customers with systems up to 100 kilowatts (kW) in capacity

getravi · July 2014

Re: New user

The only reason I went with my PV system is to take the 30% take tax credit while uncle Sam makes it available. Seeing how this investment would pay itself off in 10 years, I figured having a lower utility bill in by retirement years would be nice.

New user

Comments

Categories