question about grid and non grid panels

[glennxx1]

i was browsing through some panels and noticed some of the lower wattage panels kept stating "for off grid use" why would you not be able to put a particular panel in a grid tied system?

[ChrisOlson]

i was browsing through some panels and noticed some of the lower wattage panels kept stating "for off grid use" why would you not be able to put a particular panel in a grid tied system?

Because they're not UL Listed.
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Chris

[glennxx1]

UL listed?

[Ungrounded Lightning Rod]

UL listed?

Tested and approved by Underwriters Laboratories.

UL is an organization, started by insurance companies, that inspects and rates various products for safety.  In the US its approval of the component devices is one of the things that is required for an electrical installation to comply with the typical jurisdictions' electrical code, not just for improved insurance rates.  And electrical code inspection and approval, in turn, is required for any installation - house or what-have-you - that is connected to the grid.

Its approval is not required to sell the devices and getting it is costly: designing stuff that will pass, paying the labs to test it, and providing sample equipment for them to test - which they destroy in the testing process.  So if you're off-grid (and not worried about your fire insurance) you can use the cheaper, non-approved, products, but you need the approved products for a grid-connected system.

There's a similar organization in Europe for equipment used there, though I forget its name at the moment...

[glennxx1]

so lets say you get some UL approved panels, if you want to tie to the grid for a battery-free operation would you have to have a professional installation? Does the power company install a separate meter?

[ChrisOlson]

so lets say you get some UL approved panels, if you want to tie to the grid for a battery-free operation would you have to have a professional installation? Does the power company install a separate meter?

It has to be inspected by a Licensed Master Electrician (usually from the utility), if that's what you're wondering.  And it has to meet all requirements for disconnection from the grid if the grid goes down.

Most power companies these days install a separate meter so they can screw you with your eyes open.  Very few use the Net Metering method of running the meter backwards anymore.  You would have to check with your utility to see what their policy is, and what your state laws are.  And you have to check to see what their payment policy is.  Here in Wisconsin they got a law requiring investor-owned and municipal utilities to allow Net Metering and pay retail rate by crediting your bill.  But they never send you a check.  They just apply a credit and if you supply more than you use you can only keep the credit for up to twelve months.  They force you to use more power than you supply to the grid - or you never get paid for it.  Plus they charge you $7 a month, plus tax,  just to be connected to the grid even if you don't use any power.

But it doesn't apply to Cooperatives.  So the local utility, being a Cooperative, don't credit your bill every month, but instead keep a running tally of the power you supply to the grid and pay you once a year with a credit on your December bill - with no interest accumulated - at less than half retail rate for anything you supplied to the grid.

We don't have grid power and I wouldn't hook to the grid if they gave me the power for free, paid me double retail rate for my renewable Net Metered power I generate, plus sent my wife and I Christmas presents every year.  My place is the only place around for miles that's lit when the grid goes down and that's worth way more to me than getting a bogus credit on a utility bill.
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Chris

[ruddycrazy]

On the news the other day was an article on the power costs annually around Oz and SA came in at just over 2K a year for the average home. Now our RE setup 7 years ago cost 17K and going on that figure allowing for lesser annual figures in the past I reckon in 3 years our RE setup will be paid off. In 3 years time I reckon a new set of batteries will be needed as we do have a couple of young girls growing up will cost around 10K and the way power prices are going up and don't forget that carbon tax coming soon, that 10K spent will be square in a heap less time than my original RE purchase.

Comparing RE to paying electricity bills might seem out of vague to grid dwellers but eh it works for me and when it's 46C in the shade and the townies are sweating it out as the power got cut my RE array will be making that much power I'll have no choice but to run the aircon.

By the way I do have 'so called' grid panels here and they are hooked up to a FM60 outback for off grid use. In overcast weather they still provide a decent charge where my mono's don't output anything.....

Cheers Bryan

[ChrisOlson]

Comparing RE to paying electricity bills might seem out of vague to grid dwellers but eh it works for me and when it's 46C in the shade and the townies are sweating it out as the power got cut my RE array will be making that much power I'll have no choice but to run the aircon.

It's just my opinion, but I can't see the value of hooking to the grid.  If you put in solar or wind I figure use the power to run your own place and forget everybody else.  If you make more power than you use, there's usually no problem figuring out a way to use it up, such as heating water with electricity on high production days.  I have never seen yet where a grid connected RE system paid off in a reasonable amount of time, and it appears the main reason a lot of people do it is so they don't have to have a battery bank.
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Chris

[GaryGary]

so lets say you get some UL approved panels, if you want to tie to the grid for a battery-free operation would you have to have a professional installation? Does the power company install a separate meter?

I think that this varies from state to state and even city to city.

Here in MT, you can put in your own grid-tie system.
You have to get an electrical permit ($40) and it has to be inspected as part of the permit.

Once you have finished installing the system and have the permit signed off, you call the utility (Northwestern Energy in our case), and they come and install a net meter.

We did this, and it all went very smoothly.  The system install is pretty easy these days as long as you do a little homework beforehand and have a little wiring experience.  The inspector and NW power people were all very cooperative and very prompt.

The way net metering works here, the meter runs "backward" when you are generating more power than you use, and "forwards" when the grid is supplying you power.  You pay a regular utility bill (same rates as anyone else) for the NET power you use.
If we generated more power over a full year than we used, the utility zeros out the account and does not pay for the excess power we generated.  Because of this, we sized our system so that it comes fairly close to giving us a net zero for the year, but will never go below zero.

All the details on planning, installing, living with our system:
http://www.builditsolar.com/Projects/PV/EnphasePV/Main.htm


I understand the appeal of being fully off grid -- its an appealing lifestyle thing.  But, its not without its down sides  -- much more expensive system, much higher system maintenance due to the batteries, lower system efficiency due to the batteries, high battery replacement cost, having to cover all of your power needs with your own system rather than having the grid for backup.  Its all stuff you should consider carefully -- a grid-tie system is essentially an install it and forget it system -- with a off grid system, you are the power company and you have to take on all the responsibilities that go with that -- this is appealing to some people, but not for everyone.
From an economic point of view, grid-tie systems in most areas have a low but positive return (ours earns about 5% on the money we invested).  I think its unlikely that when you include high initial costs and battery replacement costs that a off grid system will ever earn a positive return --the benefits are more along the lines of the off-grid system allowing you to live where you want to and to be independent of the utility folks.

From an economic point of view the best deal is conservation and efficiency.  For us, when we added up the numbers for the bunch of conservation projects we did and compared it to the savings and cost for the PV system, the conservation projects were 10 times more cost effective than an inexpensive, self installed PV system!

Gary

[ChrisOlson]

If we generated more power over a full year than we used, the utility zeros out the account and does not pay for the excess power we generated.  Because of this, we sized our system so that it comes fairly close to giving us a net zero for the year, but will never go below zero.

What Gary said here.  The setup where the meter runs backwards, in my opinion, is the best because you technically get retail rate for the power you generate with renewable sources.  But almost all of them have it arranged so you will never get paid for any excess power you generate.
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Chris

[ghurd]

Getting credit at retail sounds like a good deal to me.

Is there any other company that generally pays wholesale for their product, but will buy the same product from elsewhere at full retail, then deliver it to somewhere else for the same price they paid for it?
G-

[ChrisOlson]

Is there any other company that generally pays wholesale for their product, but will buy the same product from elsewhere at full retail, then deliver it to somewhere else for the same price they paid for it?

I think you've been listening to to many of them political ads on the radio   

Seriously, I know of no power companies that do that.  On Net Metering they'll credit you for what you make that you use yourself.  But if you make any more than what you can use they'll gladly take it - for free, because you won't get paid for it - then deliver it someplace else over their wires.  I have never really heard of a Net Metering scheme that's  "good deal".
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Chris

[DamonHD]

In the UK you get paid about three times the retail rate for every grid-tied kWh you generate, and then you either don't import it saving you other retail kWh, or you export it for a nominal 3p/kWh (roughly wholesale rate).

It's madness for anyone with capital and a roof *not* to put up PV at the moment IMHO.

Rgds

Damon

[ChrisOlson]

In the UK you get paid about three times the retail rate for every grid-tied kWh you generate

Well, I should revise my post to say I've never seen a Net Metering scheme in the US that's a "good deal".

If people could get paid for the excess power they generate, even at the wholesale rate, it wouldn't be that bad.  But that's not what happens in most cases.  Every state has different laws here but I've yet to see one that actually requires the utility to send you a check for excess power you provide to them.  There's no way they'd let you use power off them, settle up at the end of the year, then write part the bill off for whatever reason.  But that's what they require you to do after spending several thousand dollars on a grid-tied system that you'd like to see a payback on in a reasonable amount of time.
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Chris

[ghurd]

Is there any other company that generally pays wholesale for their product, but will buy the same product from elsewhere at full retail, then deliver it to somewhere else for the same price they paid for it?

I think you've been listening to to many of them political ads on the radio   

Seriously, I know of no power companies that do that.  On Net Metering they'll credit you for what you make that you use yourself.  But if you make any more than what you can use they'll gladly take it - for free, because you won't get paid for it - then deliver it someplace else over their wires.  I have never really heard of a Net Metering scheme that's  "good deal".
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Chris

I still say it is a good deal.
For one thing, what percentage of the population has the remote possibility to even make enough to break even.
It sounds like a far worse deal getting paid wholesale for one direction, and retail for the other direction. Especially if it was calculated instantaneously.

You are a rancher, right?
A few liberties...
That means beef.
That means planting grain that is not harvested.
And sometimes that means you need to buy grain.
And sometimes you have plenty left over in the field at the end of the season.
Call the company that brought you the grain last year.
Tell them you want them to come get this years surplus out on the range.
Then tell them you want paid the same price they sell it for. 
G-

[ChrisOlson]

You are a rancher, right?
A few liberties...
That means beef.
That means planting grain that is not harvested.
And sometimes that means you need to buy grain.
And sometimes you have plenty left over in the field at the end of the season.
Call the company that brought you the grain last year.
Tell them you want them to come get this years surplus out on the range.
Then tell them you want paid the same price they sell it for. 

I'm going to have to take a few moments to fully absorb this analysis of the situation.

But my initial reaction is that you definitely have been listening to them political ads on the radio too much.  After several weeks it causes irrational thought patterns in even the best of us   
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Chris

[kitestrings]

Greetings,

A couple thoughts for what there worth:

I initially interpretted Glenn's original question slightly differently - though this is grest discussion - regarding panel compatibility.  Just to pont out, that many panels now are in fact made primarily for grid-connection, and with an off-grid system there are some panels, and string configurations that simply don't work.  You have to make sure you are both under the maximum voltage (Voc) of the controller (in cold temp design case), but also above the battery voltage during warm/hot design temperatures likely to be encoutered for the location.  A typical 12V nominal system for example might have 18V panels, some of the grid-tied panels are considerably higher, but under the nominal voltage of say a 48V bank.

We've been happily off-grid since 1984 - before net metering - so I can relate to a lot of what Chris has descrided in terms of independence, autonomy, satisfaction.  I also know that living with a finite amount of power does alot for improving ones awareness of energy usage, efficiency, lighting and aplliance choices.

I also work for a Cooperative (eek I hear the readers grimace) so I've seen both sides of the issue.  Here in VT, a net meter 'member' gets full retail credit for the energy they produce, can carry credits up to 12-mos. from when they are generated, can apply as 'groups', qualify for State incentive and Federal tax incentives, and if components are bought in-state are sales tax exempt.  There is one IOU paying $.06/kWh for excess, and I know this is being considered here (the concept, not necessarily at that rate).  With rolling average, a system can be sized to pretty much 'net' out the entire annual use.  In some cases 'Group' are selling excess to neighbors, there local school, etc.

On the down-side, you have to file an (all-be-it streamlined) application for a Certificate of Public Good (CPG) - which would infuriate most DIY's here, including me.  Though not scientific, I've also observed that many who opt for net metering are far from frugal with there use.  In the rare case it rises to "look at how big my array is" - another toy in the yard.

Still for some, they may not be able to climb the roof, let alone a wind tower or service an off-grid system.  Net metering allows many more folks to potentially have at least some say in where their kWh's come from - and offers the security of relatively reliable service.

~kitestrings

[ChrisOlson]

Though not scientific, I've also observed that many who opt for net metering are far from frugal with there use.  In the rare case it rises to "look at how big my array is" - another toy in the yard.

This is very true I think.  You'll find a basic difference in energy lifestyle of people who live totally off-grid vs those who don't, can't or don't want to.  For us, our little 1 kW solar array is secondary because our primary power is supplied by wind turbines.  The solar just fills in so we got a few kWh when the wind doesn't blow.  But we don't have a lot of the luxuries of modern living like air conditioning, dish washing machine, or outdoor security lighting because we don't make enough power to run that stuff day in and day out.  We even unplug our DSL modem when we're not using the internet because we can't afford the 15 watts it draws when it's not being used.

But we also live in an area where grid power is not exceedingly reliable, and our off-grid power system has never failed us or left us in the dark.  Our neighbors who rely on grid power have their whole life come to a grinding halt when the grid goes down.  Around here you can't even buy a carton of milk or a loaf of bread when the grid goes down because they lock the doors to the store in town.  Their credit card machines, cash registers - nothing works.  During the last major outage one of our neighbors even called to find out if they could bring their meat to our place and put it in our freezer so it wouldn't spoil.  So to my way of thinking, a little independence is not a bad thing and storing the power in batteries is the better option as compared to tying the system to a house-of-cards grid power system
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Chris

[Ungrounded Lightning Rod]

Getting credit at retail sounds like a good deal to me.

Is there any other company that generally pays wholesale for their product, but will buy the same product from elsewhere at full retail, then deliver it to somewhere else for the same price they paid for it?

Solar and wind tend to generate power during peak consumption times and/or when demand is higher.  Wind tends to have a peak during the late part of the afternoon/evening peak due to "lake effect" winds.  Higher winds also mean building insulation is less effective so HVAC loads are higher.  Solar peaks in the daytime, including the early part of the afternoon/evening peak, and is higher on sunny days, when AC loads are higher.

Power costs the company more during the peak and less during the off times.  Consumers get a flat rate because it's so much cheaper to meter it that way - or was before "smart meters".  Selling the power company power when it's expensive to them and buying it back at the same rate when it's cheap for them - and doing this at small distributed sites so they don't lose much shipping it around - is a good deal for them (until/unless SO many people are doing it that the peak/offpeak times are reversed and their peak generation time becomes the time the RE systems don't generate).

[Ungrounded Lightning Rod]

In the UK you get paid about three times the retail rate for every grid-tied kWh you generate

Well, I should revise my post to say I've never seen a Net Metering scheme in the US that's a "good deal".

Don't forget to include this in your calculations:

Some power companies are under government mandates to put in renewable energy generation and/or generate a certain percentage of their power from renewable resources.  Having/helping/paying-for customers to put in their own RE systems counts toward that requirement.  So you may earn "renewable energy credits" for the power generated by the operation of your system if it's grid connected, which the power company will buy from you (or for which there may be a general market so other power companies can bid) - possibly at much more than the market rate for the power - in order to meet this requirement and/or reduce their penalties for a miss by making the miss smaller.

[ChrisOlson]

So you may earn "renewable energy credits" for the power generated by the operation of your system if it's grid connected

There's some that do that, and that's a good deal.  But not here.  Our local electric cooperative will credit you $750 on your bill for having a bogus** wind site assessment done for a wind turbine installation.  That's it - end of story on renewable incentives.  But they do have a nifty program where if you replace your gas heat with electric they'll credit you on your bill for 10% of the cost of the electric heating equipment.

**This bogus wind site assessment costs about $1,500 and consists of this guy from Superior that studies a wind map  - never comes to your place - and sends you a report of what the wind map says.  For $1,500 he don't fly a anemometer, put up a MET pole, have a clue what your place looks like, nothing.  After flying wind turbines for five years I got way more data on local wind conditions than what that $1,500 "wind site assessment" will tell you.

Our local cooperative buys their power from We Energies, who in turn buys renewables from some wind farms in southern Wisconsin and Minnesota to meet their 20% renewable mandate.  They could give a hoot less about residential turbines or solar installations.  I, in turn, could give a hoot less about whether or not the electric cooperative even exists.
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Chris