I can't go Green, and this is why:

[RonMar]

Well the power was off at night so the PV's were not going to work. But the next morning they would have. Since watts is watts, why would the PV's not power the freezer? If there is 6,000 watts going into the house that is enough to power the fridge. We do have a grid disconnect already for the generator.

Later,
Dan

Because of the varying input from a solar panel, an inverter needs something to stabilize it's power source. In a competely disconnected off-grid system, this would be a battery to carry it over short duration light interruptions as clouds pass over(or the sun sets), and to absorb the excess energy when the load is less than the PV supply to provide power for the low/no sun situations.

In a grid tied system, the grid performs the duties that the battery normally would, particularly the absorbing the excess energy. No grid power available, the inverter purposely shuts down to:
1. Avoid the inevitable power fluxes caused by varying power from the PV panels. What this would seem like is standing at your main panel breaker and randomly flipping it on and off. Your equipment would love that, as would the inverter having to deal with repeated startup surge loads
2. To prevent the inverter from backfeeding the now dead grid while lineman are attempting to work on it...

Now if you disconnected the grid and substuted a generator to provide that input to the inverter, the inverter could probably be made to mix the two sources, as it does with grid power, and you could use some of that solar energy when available. But the grid tied inverter is designed to direct it's excess to the grid, and the generator might not take too kindly to that. Also running a generator lightly loaded is not very economical.

For purely backup power needs, a generator is the best bang for the buck IMO...

 

[RonMar]

Moss, it's not leaking....evaporating. It's in the middle of a 5ac pasture that is almost flat, so it gets no rainwater unless it's a frog choker. When I dug it I knew it would need help during the dry season.

I just got off the phone with Robinson Solar Systems in OK. They build their own brushless solar water pumps(YES, made in the USA), and have a complete system w/solar panel in the $1700 range that would do about 1100 gallons a day. This is more in line with the farm budget.

Here is their link:
Solar pump and solar pumps for solar water pumping from wells ponds and creeks

RD

Here is a link to some spiral pump info. I think it could be done for far less than $1700, and have $0 operating costs...

The Spiral Pump: A High Lift, Slow Turning Pump

 

[MossRoad]

Moss, it's not leaking....evaporating. It's in the middle of a 5ac pasture that is almost flat, so it gets no rainwater unless it's a frog choker. When I dug it I knew it would need help during the dry season.

I just got off the phone with Robinson Solar Systems in OK. They build their own brushless solar water pumps(YES, made in the USA), and have a complete system w/solar panel in the $1700 range that would do about 1100 gallons a day. This is more in line with the farm budget.

Here is their link:
Solar pump and solar pumps for solar water pumping from wells ponds and creeks

RD

I've got a 24' swimming pool that is only 42" deep. It is 12,000 gallons. It would take that pump 10-11 days to fill that little pool provided there was no other losses. How big is your pond?

 

[Tororider]

Because of the varying input from a solar panel, an inverter needs something to stabilize it's power source. In a competely disconnected off-grid system, this would be a battery to carry it over short duration light interruptions as clouds pass over(or the sun sets), and to absorb the excess energy when the load is less than the PV supply to provide power for the low/no sun situations.

In a grid tied system, the grid performs the duties that the battery normally would, particularly the absorbing the excess energy. No grid power available, the inverter purposely shuts down to:
1. Avoid the inevitable power fluxes caused by varying power from the PV panels. What this would seem like is standing at your main panel breaker and randomly flipping it on and off. Your equipment would love that, as would the inverter having to deal with repeated startup surge loads
2. To prevent the inverter from backfeeding the now dead grid while lineman are attempting to work on it...

Now if you disconnected the grid and substuted a generator to provide that input to the inverter, the inverter could probably be made to mix the two sources, as it does with grid power, and you could use some of that solar energy when available. But the grid tied inverter is designed to direct it's excess to the grid, and the generator might not take too kindly to that. Also running a generator lightly loaded is not very economical.

For purely backup power needs, a generator is the best bang for the buck IMO...

Just to be clear, if you had a grid tied system with batteries, you could still use the power as the inverter wouldn't shut you off right?

 

[RonMar]

Just to be clear, if you had a grid tied system with batteries, you could still use the power as the inverter wouldn't shut you off right?

That would be correct. The inverter used in a grid tied system with batteries has different programmed operating modes to deal with backfeeding the grid, charging the batteries, feeding the load ect. It is set up for just that purpose. Unfortunatly, with the expense of the different inverter, additional wiring, setup and most especially batteries, not many people go this route just for backup power as the grid is typically pretty reliable...

 

[Tororider]

That would be correct. The inverter used in a grid tied system with batteries has different programmed operating modes to deal with backfeeding the grid, charging the batteries, feeding the load ect. It is set up for just that purpose. Unfortunatly, with the expense of the different inverter, additional wiring, setup and most especially batteries, not many people go this route just for backup power as the grid is typically pretty reliable...

That makes sense. I had originally thought about, when I build, going with a grid tied plus batteries. But you bring up a good point. If the grid is 99%+ reliable, why not just go with the grid tied, with a generator backup.

 

[MotorSeven]

Ron, very interesting pump, but it looks like it would take some time to build. Are there commercial ones available?
Moss, even if empty, once filled, a solar pump would keep it topped off indefinatly whenever the sun is out.

RD

 

[QRTRHRS]

Over the last year or so the Wall Street Journal has had a couple of articles about the price of PV getting cheaper. One article quite a while ago said the some very big companies were getting into PVs and that the price per watt would bet $1. The $1 per watt would be some sort of Holy Grail price point.

A month or so ago there was another article that said the price was down to $2 per watt.

We had a storm about that time that left us without power for 6-8 hours. So I went out and started looking at the cost of a 6,000 watt system tied to the grid. Just enough power to keep the fridge and freezers cold. A few lights. An run the well.

Long story short turnkey systems were $8-9 per watt!

6,000 watts times $8 = $48,000

Hmmmmm.... I don't think so.

There are a lot of hot air blowers in state capitals, Washington DC and Environmentalists Salons...

Later,
Dan

Your post has me thinking back to my twenty years in semi-conductor manufacturing, fourteen of which were in silicon materials, ie; crystal growth and wafer fab.

Having had an interest in alternate lifestyles and all that even before the seventies "fuel shortages", I somewhat followed the PV cells stories. As I understand it, the wafers are a major cost.

I can understand that as the infrastructure to build a production facility is not cheap. The supply of high purity silicon is quite finite.

Anyway, during that time, we used to dump wafers that fell out of spec into cardboard totes and they were sold off to someone perhaps to be used in steel making or something. I never thought to ask if those fallout wafers would be marketable to the PV industry.

 

[RonMar]

Ron, very interesting pump, but it looks like it would take some time to build. Are there commercial ones available?

RD

I have never seen a commercial one.

 

[tommu56]

Here is a link to some spiral pump info. I think it could be done for far less than $1700, and have $0 operating costs...

The Spiral Pump: A High Lift, Slow Turning Pump

With the spiral pump if you wanted or need more flow with this just up size the pipe or put 2 spirals on the same frame.

tom