off grid tied in grid

Martin · July 2014

Hello newbie solar wannabe here

Looking to install a solar generator at the house
I want to be grid connected but not delivering back to the grid
Reason is the the new electronic meter only run forward
If I deliver back to the grid I pay double
The only option that will work that I figured out for now is an off grid system connected to the grid (is this correct?)
Also don't want none or very little battery's
I know that's a loss of energy not used
when I install more panels thinking about 2-4 kW then I can still supply enough energy to run a AC unit during a sunny day
What compensate for no battery's
But what happens with the energy generated by the panels when not all is used?
any thought an or advise is more than welcome

Thanks
Martin

Cariboocoot · July 2014

Re: off grid tied in grid

Welcome to the forum Martin.

You're wasting your time, and possibly your money.

If you've got grid it's going to be cheaper than solar.
Next best bet: grid-tie solar. But if they (the utility) don't allow sell-back then that's a no go.
Then there are battery-based systems. For example hybrid inverters that can sell to the grid but also be set not to sell to the grid. You can activate grid sell back when the utility comes to its senses. There are also off-grid system which can not sell to the grid, ever, but could use the grid as a "generator" input when needed.

At this point you are looking at costs in the $1 per kW hour neighbourhood, which is likely far higher than what your utility charges. So whereas you would save money on the electric bill you would in fact not be saving any money.

This brings up the question of why you want to put in a solar power system of any kind? A seemingly odd question for a solar forum, but we like to maintain a practical approach here.

Minimizing batteries can be done, but it is not easy or cheap and has risks. You're looking at complex AC coupled systems, complete with limitations (no full power when the sun does not shine).

When panels have nothing connected to them they do not produce any power. The only down side to that is potential power not realized which is a waste of money.

Photowhit · July 2014

Re: off grid tied in grid

There is a 'solar air conditioner' out there that draws much of the energy needed from solar while running, though it needs the grid to run and crank things up. It too is an expensive undertaking. As I recall $2000 and then you still have to provide 6-800watts of panels for a 6-8000btu A/C.

There is currently a thread about someone doing something similar to what you want to do. New user in the Off the grid section. You might read through it and see if that answers some of your questions.

bill von novak · July 2014

Re: off grid tied in grid

Martin wrote: »

Hello newbie solar wannabe here

Looking to install a solar generator at the house
I want to be grid connected but not delivering back to the grid
Reason is the the new electronic meter only run forward
If I deliver back to the grid I pay double
The only option that will work that I figured out for now is an off grid system connected to the grid (is this correct?)
Also don't want none or very little battery's
I know that's a loss of energy not used
when I install more panels thinking about 2-4 kW then I can still supply enough energy to run a AC unit during a sunny day
What compensate for no battery's
But what happens with the energy generated by the panels when not all is used?
any thought an or advise is more than welcome

There are two mistakes in your plan. One is that you can somehow "keep the electricity out of the grid." There is no effective way to do that. Second is "just want to run A/C." A/C is the toughest solar load to run, due to its intermittent nature, high startup loads and high overall energy usage.

My advice would be:

1) Find out what it would take to do it right - do a real grid tied installation with new meter etc.
2) Invest in a mini-split air conditioner. Every $1 you spend on efficiency saves you $5-$10 on a solar power system.

ButchDeal · July 2014

Re: off grid tied in grid

Martin wrote: »

Hello newbie solar wannabe here

Looking to install a solar generator at the house
I want to be grid connected but not delivering back to the grid
Reason is the the new electronic meter only run forward
If I deliver back to the grid I pay double
The only option that will work that I figured out for now is an off grid system connected to the grid (is this correct?)
Also don't want none or very little battery's
I know that's a loss of energy not used
when I install more panels thinking about 2-4 kW then I can still supply enough energy to run a AC unit during a sunny day
What compensate for no battery's
But what happens with the energy generated by the panels when not all is used?
any thought an or advise is more than welcome

Thanks
Martin

What your talking about is OutBack's Flexpower 1 or Flexpower 2 system in "Net Zero" configuration. In this way the outback will not feed power back to the grid, will use batteries more like an offgrid configuration, and use grid power to supplement solar/battery.
I have the Flexpower 1 with a step up transformer to get 220V for our well pump. You could do something similar, or go up to the larger 220V Flexpower 2.

What area do you live in that does not have net metering though?

Martin · July 2014

Re: off grid tied in grid

Thanks all for the replies

First I'm in the Bahamas and power can run up to $0.40 kW depends how much you use and it aint getting cheaper soon
I ordered a better efficient AC seer 20 that's the best my wallet could carry
So now I'm looking at a way to see if I can reduce my poco usage a little more or get more comfort for the same $
normally we run the AC in the evenings during the day to work
My thought was if I run my AC during the day with solar assist then I have only to maintain the temperature in the night
Talk to the poco is of no use they don't want you to deliver back one reason they give they want there lines man save I think they want my money
If I make a quick calculation out of my head then I think I can get even in 5-7 years with my investment

Rgds
Martin

Blackcherry04 · July 2014

Re: off grid tied in grid

Martin wrote: »

Thanks all for the replies

First I'm in the Bahamas and power can run up to $0.40 kW depends how much you use and it aint getting cheaper soon
I ordered a better efficient AC seer 20 that's the best my wallet could carry
So now I'm looking at a way to see if I can reduce my poco usage a little more or get more comfort for the same $
normally we run the AC in the evenings during the day to work
My thought was if I run my AC during the day with solar assist then I have only to maintain the temperature in the night
Talk to the poco is of no use they don't want you to deliver back one reason they give they want there lines man save I think they want my money
If I make a quick calculation out of my head then I think I can get even in 5-7 years with my investment

Rgds
Martin

Truthfully, your probably better off letting the A/C remain on the Grid and see if off-setting the rest of your use with Solar is best. A/C is a challenge for Solar. It's not hard to split off the circuits from your main panel to a Inverter powered panel. How do you Heat water ?? This way you don't have way oversize the Solar for the A/C, I don't know how many months you use the Air. If your running it during the evenings, there is no sun, so your using stored energy and thats not cheap to do. Even @ $.40 the grid is cheaper than solar and a generator and battery storage.

Photowhit · July 2014

Re: off grid tied in grid

Martin wrote: »

If I make a quick calculation out of my head then I think I can get even in 5-7 years with my investment

If you don't know what you need, how can you make estimates?

Did you read through the thread I sent you a link for?

Do you understand that you would need batteries and a good sized inverter for any of the options that don't back feed the grid(as far as I know)? You might get by with a minimal battery bank since the system would revert to the grid, but it's a good bit of money... I don't know if I see a return. At 40 cents a Kwh you might be able to go off grid, but higher costs of transporting to an island likely make that a no win situation and still the pay back period would be 20 years out if any. I think in the states I could setup a system at around 25 cents a kwh and a lot of labor! and even then it would have to be for the right person in the right place and time. One bad mistake and you fry your battery and you loose, No more 240v appliances, shut things down to run others not the 'normal' on grid life.

ButchDeal · July 2014

Re: off grid tied in grid

Martin wrote: »

Thanks all for the replies

First I'm in the Bahamas and power can run up to $0.40 kW depends how much you use and it aint getting cheaper soon
I ordered a better efficient AC seer 20 that's the best my wallet could carry
So now I'm looking at a way to see if I can reduce my poco usage a little more or get more comfort for the same $
normally we run the AC in the evenings during the day to work
My thought was if I run my AC during the day with solar assist then I have only to maintain the temperature in the night
Talk to the poco is of no use they don't want you to deliver back one reason they give they want there lines man save I think they want my money
If I make a quick calculation out of my head then I think I can get even in 5-7 years with my investment

Rgds
Martin

it looks like they are working on the rules to allow feed in power: http://www.tribune242.com/news/2013/jan/25/bec-backs-net-billing-over-metering/

The Outback net zero option would work well for you and at some point if they allow feed in, you can just change the settings.
You would also have some limited backup power and could put more than just the A/C unit on the solar to allow better balancing.

Martin · July 2014

Re: off grid tied in grid

ButchDeal wrote: »

it looks like they are working on the rules to allow feed in power: http://www.tribune242.com/news/2013/jan/25/bec-backs-net-billing-over-metering/

The Outback net zero option would work well for you and at some point if they allow feed in, you can just change the settings.
You would also have some limited backup power and could put more than just the A/C unit on the solar to allow better balancing.

Yes if this was the company where I get my power from my power company is a different one
This net zero I want to look into

Martin · July 2014

Re: off grid tied in grid

Photowhit wrote: »

If you don't know what you need, how can you make estimates?

Did you read through the thread I sent you a link for?

Do you understand that you would need batteries and a good sized inverter for any of the options that don't back feed the grid(as far as I know)? You might get by with a minimal battery bank since the system would revert to the grid, but it's a good bit of money... I don't know if I see a return. At 40 cents a Kwh you might be able to go off grid, but higher costs of transporting to an island likely make that a no win situation and still the pay back period would be 20 years out if any. I think in the states I could setup a system at around 25 cents a kwh and a lot of labor! and even then it would have to be for the right person in the right place and time. One bad mistake and you fry your battery and you loose, No more 240v appliances, shut things down to run others not the 'normal' on grid life.

Yes I went half way true the link thanks for that
Save the other halve for tomorrow
bed time for now

ButchDeal · July 2014

Re: off grid tied in grid

Martin wrote: »

Yes if this was the company where I get my power from my power company is a different one
This net zero I want to look into

Sorry, OutBack refers to it as GridZero
here is a link http://www.outbackpower.com/downloads/documents/APP_NOTE_RADIAN_GridZero_ABC_2-18-14.pdf
or two : https://www.youtube.com/watch?v=a33p0jbi1R0
Although they often mention it with the higher end Radian, it is available on the FlexPower series.

Martin · July 2014

Re: off grid tied in grid

ButchDeal wrote: »

Sorry, OutBack refers to it as GridZero
here is a link http://www.outbackpower.com/downloads/documents/APP_NOTE_RADIAN_GridZero_ABC_2-18-14.pdf
or two : https://www.youtube.com/watch?v=a33p0jbi1R0
Although they often mention it with the higher end Radian, it is available on the FlexPower series.

Yes you correct
Thanks for the links

off grid tied in grid

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