Pond Fountain

[artbuc]

Hello, this is my first post. I have a technical background but a pure novice re solar. I am on our HOA Facilities Committee. This morning I was asked to research this question. This looks like a great place to get started.

We have a pond fountain which operates from sunup to sundown 6 month per year, May through October. It has a 5hp, 220v, 3 phase motor. This fountain along with a minor LED street light load has its own meter. We live in SE PA about 30 miles west of Philadelphia. The fountain uses about 2100 kWh per month during the operating season, less than $1900 per year.

Would it make sense to install a stand alone solar system to power this pump? My gut says no but I do not know for sure. Some questions I have:

1. Stand alone means we need storage for early morning, late afternoons and cloudy days, right? Storage investment and maintenance may be showstoppers. Alternatively we could tie into the utility meter and view our system as supplemental.

2. If a stand alone is not practical and we tie in to the utility, then it seems we should install as many panels as we have room for since a bigger system would have a faster payback, right?

3. How would we handle the 3-5x peak motor startup current?

Thanks for helping me get started. If we had no infrastructure in place, I can see the possibility of a solar solution. But we already have everything in place and spend less than $1900 per year in electricity. This provides little incentive for investment. Also, an agricultural pumping system can pump during peak solar and store water. In our fountain scenario, we will have to store electricity or tie into utility.

 

[sunshine_eggo]

2100kWh/day = 70kWh/day - this is over 2X the average U.S. household power consumption.

1. Off the top of my head - about $30-40K DIY.
2. Even then, you're looking at about 20000W of solar, and Net Metering is becoming less favorable with the power company buying your power at cost and selling it back to you at standard rates. DIY grid-tie is more challenging with widely varying local policy/allowances.
3. Three beefy inverters paralleled to supply 3 phase, or a big beefy inverter with a VFD drive on the pump for soft-start and feeding 3 phase with single phase.

 

[artbuc]

2100kWh/day = 70kWh/day - this is over 2X the average U.S. household power consumption.

1. Off the top of my head - about $30-40K DIY.
2. Even then, you're looking at about 20000W of solar, and Net Metering is becoming less favorable with the power company buying your power at cost and selling it back to you at standard rates. DIY grid-tie is more challenging with widely varying local policy/allowances.
3. Three beefy inverters paralleled to supply 3 phase, or a big beefy inverter with a VFD drive on the pump for soft-start and feeding 3 phase with single phase.

Thanks. Is your estimate for a stand alone system with sufficient storage for 12 hour/day operation rain or shine? Or, does it assume grid connected? What about 3-4x motor start-up peak load? Finally, how much more would it cost if we hired a contractor? Thanks.

 

[svetz]

Welcome to the forums!

That fountain is a power hog. Are you sure it's worth it? If you're doing it for the visual esthetic, won't having panels spoil that? As @sunshine_eggo says, that's enough panels to cover two roof-tops. It'll be pricey (of course, if grid-tied you can just add panels and microinverters as you like as few as one at a time to reduce opex, since the fountain and sun work during the daytime the net-metering agreement isn't really important until you start producing more than the fountain can consume, about 6KW of panels).

If the HOA is "sensitive" you might want to get ahead of it with some out-of-the-box thinking. It won't take too much longer before people realize that they're paying $1900 per year to increase global warming and then you'll be back to square 1.

 

[artbuc]

Welcome to the forums!

That fountain is a power hog. Are you sure it's worth it? If you're doing it for the visual esthetic, won't having panels spoil that? As @sunshine_eggo says, that's enough panels to cover two roof-tops. It'll be pricey (of course, if grid-tied you can just add panels and microinverters as you like as few as one at a time to reduce opex, since the fountain and sun work during the daytime the net-metering agreement isn't really important until you start producing more than the fountain can consume, about 6KW of panels).

If the HOA is "sensitive" you might want to get ahead of it with some out-of-the-box thinking. It won't take too much longer before people realize that they're paying $1900 per year to increase global warming and then you'll be back to square 1.

I am not sure it is worth it. That is what I am trying to determine. Not sure what your last paragraph means? Our HOA is concerned about aesthetics. They have banned solar panels on roofs. Individuals can reduce their carbon footprint by selecting a supplier who offers green electricity. We have electric supplier choice in PA. A ground panel system was suggested a few years ago to supply HOA common areas but this was also rejected. The current idea to install a solar system for the pond fountain did not come from the HOA Board.

Here is what I don’t understand. How do I know how big the system needs to be? The panels will be generating much less power at 7 am and 7 pm then they will at 1 pm. But the fountain consumes the same power all day, about 6kw.

 

[curiouscarbon]

hi! welcome to forum

i think your project idea is cool and admirable

the pump uses quite a bit of electricity energy!

can the panels be built in a circle around the pond? probably not but it popped into my head.

if completion is important, given the constraints, skipping storage and just offsetting grid use seems like a possible win.

total autonomous systems often require so much more upfront cost.. good lucky to you! shine on

 

[sunshine_eggo]

If you're going to have to hire a contractor, start there. Bring those estimates here, and we can sanity check them.

 

[artbuc]

If you're going to have to hire a contractor, start there. Bring those estimates here, and we can sanity check them.

Will do.

 

[svetz]

...They have banned solar panels on roofs....

If it's in the U.S.A. an HOA can't ban solar panels as there are federal laws to prevent that; at best they can add annoying restrictions. They will act like they can ban them and you do need their permission...but they have to grant it. (oops.. turns out I'm wrong on this, see #12)

...Not sure what your last paragraph means? ...

It means if the constituents of your HOA are worried about global warming (I'm assuming they are as someone asked you to look into solar powering the pond and I believe that sort of sentiment is rapidly growing) you'd be better off ditching the power-hog pump and thinking of something as attractive/fun that didn't add to the problem. Possibly something kinetic (e.g., pond yachts)?

Here is what I don’t understand. How do I know how big the system needs to be?

Your pump is pulling 70 kWh per day, assuming it runs for 12 hours a day that's a 6 kW pump as you said. It'll pull a lot more during startup, but if grid-tied the grid can provide the extra power to get it going.

You can look up your insolation from a calculator, probably around 4 if you switch operation to April-to-September. An insolation of 4 means a 17.5 kW PV array will provide (17.5x4) 70 kWh/d. At noon that array would make 17.5/6 kW of power, a lot more than you need (e.g., 6); but it'll net enough power over the rest of the day when you're making less than 6 kW to even out. Any solar added reduces the overall power costs.

If you have a good net-metering agreement in your area the power company can act as your "battery", but if you don't adding your own battery will make the project crazy expensive. You could reduce that by shortening operating hours to a few hours after dawn to a few hours before dusk.

Hope that helps!

 

[artbuc]

If it's in the U.S.A. an HOA can't ban solar panels as there are federal laws to prevent that; at best they can add annoying restrictions. They will act like they can ban them and you do need their permission...but they have to grant it.


It means if the constituents of your HOA are worried about global warming (I'm assuming they are as someone asked you to look into solar powering the pond and I believe that sort of sentiment is rapidly growing) you'd be better off ditching the power-hog pump and thinking of something as attractive/fun that didn't add to the problem. Possibly something kinetic (e.g., pond yachts)?


Your pump is pulling 70 kWh per day, assuming it runs for 12 hours a day that's a 6 kW pump as you said. It'll pull a lot more during startup, but if grid-tied the grid can provide the extra power to get it going.

You can look up your insolation from a calculator, probably around 4 if you switch operation to April-to-September. An insolation of 4 means a 17.5 kW PV array will provide (17.5x4) 70 kWh/d. At noon that array would make 17.5/6 kW of power, a lot more than you need (e.g., 6); but it'll net enough power over the rest of the day when you're making less than 6 kW to even out. Any solar added reduces the overall power costs.

If you have a good net-metering agreement in your area the power company can act as your "battery", but if you don't adding your own battery will make the project crazy expensive. You could reduce that by shortening operating hours to a few hours after dawn to a few hours before dusk.

Hope that helps!

Yes, that helps a great deal. Not sure about the noon production. Where does 17.5/6 kW come from? Also, what is “crazy” expensive for an off grid battery storage system for our conditions, ie May through October and 7am through 7pm. I am guessing it is a totally ridiculous scenario.

 

[sunshine_eggo]

If it's in the U.S.A. an HOA can't ban solar panels as there are federal laws to prevent that; at best they can add annoying restrictions. They will act like they can ban them and you do need their permission...but they have to grant it.

My understanding is that this is determined by state law, not federal, and Google yields results to that effect. Can you cite the specific Fed Law that forces it?

 

[svetz]

My understanding is that this is determined by state law, not federal, and Google yields results to that effect. Can you cite the specific Fed Law that forces it?

I thought it was H.R.2454 - American Clean Energy and Security Act of 2009, but I see despite being passed in the house it didn't in fact become law. My bad! Thanks for the correction that it was left to the states!

Sorry @artbuc, looks like PA is one of the 16 states that hasn't yet adopted solar access laws. It has one waiting to be voted on (826), so the best you could do is contact your state legislators about it.

 

[artbuc]

I thought it was H.R.2454 - American Clean Energy and Security Act of 2009, but I see despite being passed in the house it didn't in fact become law. My bad! Thanks for the correction that it was left to the states!

Sorry @artbuc, looks like PA is one of the 16 states that hasn't yet adopted solar access laws. It has one waiting to be voted on (826), so the best you could do is contact your state legislators about it.

Thx for that. Another head wind comes from fact we can not use Federal tax credit since our HOA pays essentially no federal tax. On the other hand, PA has a fantastic net metering arrangement. I also learned to use the PV calculator which a answered all of my questions regarding peak vs average output. Need to get contractor confirmation but looks like a 6kW ground system will be at least $25k considering underground cable requirements. Looks like 20-25 year payback which will never fly.

 

[sunshine_eggo]

Thx for that. Another head wind comes from fact we can not use Federal tax credit since our HOA pays essentially no federal tax. On the other hand, PA has a fantastic net metering arrangement. I also learned to use the PV calculator which a answered all of my questions regarding peak vs average output. Need to get contractor confirmation but looks like a 6kW ground system will be at least $25k considering underground cable requirements. Looks like 20-25 year payback which will never fly.

6kW wouldn't cover it. The array needs to generate 70kWh/day. With great solar, the 6kW would likely only produce about 24-30kWh/day. You'd need about 15-20kW worth of solar panels to produce 70kWh/day.

kW is power - the rate of energy consumption.
kWh is the quantity of energy.

 

[artbuc]

6kW wouldn't cover it. The array needs to generate 70kWh/day. With great solar, the 6kW would likely only produce about 24-30kWh/day. You'd need about 15-20kW worth of solar panels to produce 70kWh/day.

kW is power - the rate of energy consumption.
kWh is the quantity of energy.

Right, I understand all of that. We could use a 12kW system which we could never sell due to its size and $40-50k price tag. Would not think of going above 12kW since utility credits drop dramatically. A 12kW system will produce annually our total needs. Our utility will pay us retail for that amount. When we generate above that, credit is based on supply/demand which is currently about 25% of retail. Incremental ROI would be ridiculously low. Payback is already 20+ years.

 

[sunshine_eggo]

12kW won't cut it when you factor in inefficiencies and weather.

Simulated 12kW array in Coatsville, PA with panels tilted at 20° facing South:



As you can see, no month produces 2100kWh, so at best, a 12kW array might replace 75% of the pump energy which further worsens the ROI.

You can simulate this for your exact location at https://pvwatts.nrel.gov/pvwatts.php

 

[artbuc]

12kW won't cut it when you factor in inefficiencies and weather.

Simulated 12kW array in Coatsville, PA with panels tilted at 20° facing South:

View attachment 76496

As you can see, no month produces 2100kWh, so at best, a 12kW array might replace 75% of the pump energy which further worsens the ROI.

You can simulate this for your exact location at https://pvwatts.nrel.gov/pvwatts.php

Guess I am not communicating very well. I used the same tool you did. I am not trying to produce enough electricity on an hourly or daily basis to power the fountain or produce 3-5x starting current. A system that large would be DOA. Our utility manages credits on an annual basis and pays full retail as long as we do not generate more than we consume on an annual basis which is about 15000kwh. Generate more than that and credits become variable and low. That is why we would never go higher than 12kW. However, as I said, a system that big would be DOA. I might be able to sell a 6kW system but payback is too long. Remember we get no benefit from the Federal tax credit.

 

[sunshine_eggo]

Guess I am not communicating very well. I used the same tool you did. I am not trying to produce enough electricity on an hourly or daily basis to power the fountain or produce 3-5x starting current. A system that large would be DOA. Our utility manages credits on an annual basis and pays full retail as long as we do not generate more than we consume on an annual basis which is about 15000kwh. Generate more than that and credits become variable and low. That is why we would never go higher than 12kW. However, as I said, a system that big would be DOA. I might be able to sell a 6kW system but payback is too long. Remember we get no benefit from the Federal tax credit.

I completely understand the limitations, but you said:

Right, I understand all of that. We could use a 12kW system which we could never sell due to its size and $40-50k price tag. Would not think of going above 12kW since utility credits drop dramatically. A 12kW system will produce annually our total needs. Our utility will pay us retail for that amount. When we generate above that, credit is based on supply/demand which is currently about 25% of retail. Incremental ROI would be ridiculously low. Payback is already 20+ years.

Which is somewhat ambiguous. The 12kW system will produce about 75% of your total pump needs and hit the annual limit, but it is valid to look at it over an annual pay-off.

Solar is often a loser if you're just looking at ROI. ROI of less than 10 years is tough. It's almost impossible if you're not willing to DIY. I didn't go grid tie primarily because of unfavorable local policy. A system that produces 70% of my annual needs would only save me 30% on my bill. Even with used panels and full DIY, my payback was 8+ years. Not worth it. It would be more advantageous to install an off-grid system with peak time offsets where I just use less during peak periods. More out of pocket up front, but the ROI was shorter. Of course I still didn't do it... up front cost and DIY labor made it a no-go.

 

[Browneye]

Perhaps a smaller pump would do, with re-arranged fountains or heads, somewhat reduced flow.
Then adapt some solar power to make it run.

 

[artbuc]

Not sure what assumptions you are making about fountain operating hours. Believe it or not, this particular system averages about 15000 kW per year, some years more, some years less depending on when we start and shut down the fountain. The fountain consumes about 12.3kW and the rest is street lighting and pond bubblers (air pumps).