Grid-tied solar

[ultrarunner]

Interesting application with the power diverter... I was thinking along these lines of the possibility of maybe a dual fuel water heater or adding a heat coil to the gas heater.

 

[Kyle_in_Tex]

The bolded is our goal. How we get there is a work in progress. We're still pushing ahead with the solar for the house. We are researching whether we should replace the air handler and coils, replace the entire system, or go to mini split. Waiting on bids from the HVAC contractors.

Sounds to me that you folks have acclimated or climatized yourselves to a great extent. I you had solar and mini splits, would you run it to get some humidity out of the air?

 

[sseelhoff]

Sounds to me that you folks have acclimated or climatized yourselves to a great extent. I you had solar and mini splits, would you run it to get some humidity out of the air?

Likely be used more for dehumidification than cooling. We never turn the A/C below 83. Mostly at 85. At night we shut it down and open the windows. A 75 degree morning feels cool to me.

We are going ahead with the solar project. The contractor has started the paperwork with the utility. 9100 kwh system. They are estimating 92% of our electrical needs will be served by the system, using the .77 factor they are required to use. If the system outperforms the required factor, the 92% will increase. He expects that to happen, but cannot sell it that way. Also got the quotes back on the AC repair. $1400 for a new Carrier coil. $1726 for a new air handler with coil. Kind of a no brainer. I would like to get the mini-split, but not sure we can get competitive quotes. We were expecting $3000-$4000 grand to repair the system. Our condensor is fine (for now).

 

[dave1949]

The July, 2014 results.

Above the model this month and reasonably consistent with July 2013.

Month--NREL Model (AC kWh)-----2012 Actual-----2013 Actual-----2104 Actual

Jan.----388----------------------NA--------------440-------------360
Feb.----412----------------------NA--------------375-------------446
Mar.----509----------------------NA--------------462-------------577
Apr.----374----------------------NA--------------487-------------525
May----353----------------------NA--------------375-------------361
Jun.----308----------------------NA--------------379-------------390
Jul.-----341----------------------NA--------------377-------------395
Aug.----383----------------------461-------------470
Sep.----394----------------------481-------------476
Oct.----369----------------------378-------------453
Nov.----283----------------------400-------------414
Dec.----331----------------------297-------------278

For anyone curious about adding AC mini-splits in a similar climate, 1600 sq ft well insulated house, below is how our electric usage is changing since adding AC. Our large amount of south-facing glass for passive solar adds more of a heat load in late summer than would be typical of a house this size. All else being roughly equal, a larger house with fewer south windows would probably see similar results.

This July our usage is 590 kWh compared to 415 kWh July '12, and 441 kWh July '13. That is a 162 kWh average increase that is attributable to running the min-split units give or take. We have used them about every day this month. They are usually turned off overnight.

 

[dave1949]

For anyone looking at jobs in the Maine-New Hampshire area this is a great outfit and a growing solar company:

Jobs in Solar New Hampshire - Maine Renewable Energy Career Opportunities

Installers, sales, investor relations, licensed electrician, marketing.

They installed my system and I was very impressed from start to finish. No affiliation.

 

[dave1949]

Solar cells from recycled lead batteries.

Recycling old car batteries into solar cells: Environmental twofer could recycle lead batteries to make solar cells -- ScienceDaily

 

[Redneck in training]

My system just hit 60 MWh produced over past 20 months.

 

[dave1949]

The August, 2014 results.

Above the model but below August in the last two years.

Month--NREL Model (AC kWh)--2012 Actual---2013 Actual---2104 Actual

Jan.----388----------------------NA--------------440-------------360
Feb.----412----------------------NA--------------375-------------446
Mar.----509----------------------NA--------------462-------------577
Apr.----374----------------------NA--------------487-------------525
May----353----------------------NA--------------375-------------361
Jun.----308----------------------NA--------------379-------------390
Jul.-----341----------------------NA--------------377-------------395
Aug.----383----------------------461-------------470------------453
Sep.----394----------------------481-------------476
Oct.----369----------------------378-------------453
Nov.----283----------------------400-------------414
Dec.----331----------------------297-------------278

 

[Carl_NH]

Third quote received today. About $12K net for a 9100 KWh system. German panels, U.S. inverter. Roof mounted.

Hi Scott,

You have an amazing deal $12K net for 9.1KW which is $1.31 a watt installed after local and federal rebates.

Can you outline the panels and system they are installing and rebates to attain this very low number?

For reference, (and thanks to Dave) we are installing a 10KW system from Revision Energy here in NH. At the end of the day it is $2/Watt after all rebates and incentives - $32K total less $13K Incentives.

This is a roof mounted 36-270 W LG Mono panels, 36 Solar Edge Power Optimizers, and Solar Edge 10KW Inverter.

Estimated installed cost after rebate is @ $2.00KWH / $.165 KWH so ROI is 12 Years at present rates.

I appreciate DIY installation can achieve $1 a watt installed after rebates, but can you provide a breakdown on how you achieved $1.31 a watt installed?


Thanks

Carl

 

[sseelhoff]

Hi Scott,

You have an amazing deal $12K net for 9.1KW which is $1.31 a watt installed after local and federal rebates.

Can you outline the panels and system they are installing and rebates to attain this very low number?

For reference, (and thanks to Dave) we are installing a 10KW system from Revision Energy here in NH. At the end of the day it is $2/Watt after all rebates and incentives - $32K total less $13K Incentives.

This is a roof mounted 36-270 W LG Mono panels, 36 Solar Edge Power Optimizers, and Solar Edge 10KW Inverter.

Estimated installed cost after rebate is @ $2.00KWH / $.165 KWH so ROI is 12 Years at present rates.

I appreciate DIY installation can achieve $1 a watt installed after rebates, but can you provide a breakdown on how you achieved $1.31 a watt installed?


Thanks

Carl

This is not the best quote. Here are the numbers from the best quote:

Gross Price: $18,246
Contractor Incentive: ($7,200)
Total Contract: $11,046

Federal credit (30%) ($3,314)

Total out of pocket: $7,732

Panels: Axitec, model AC250p.156-60S
Inverter: Samil Power Co., Ltd. Model: SolarRiver 6000TL-US

 

[Carl_NH]

This is not the best quote. Here are the numbers from the best quote:

Gross Price: $18,246
Contractor Incentive: ($7,200)
Total Contract: $11,046

Federal credit (30%) ($3,314)

Total out of pocket: $7,732

Panels: Axitec, model AC250p.156-60S
Inverter: Samil Power Co., Ltd. Model: SolarRiver 6000TL-US

So, it appears you will get 36 250W panels for 9KW of production with a 6KW inverter installed for $11K with a $3K federal rebate - net cost to you of $8K?

Have you signed the contract for installation? Something doesn't add up as this is too good to be true IMHO.

 

[farmer2009]

Can someone explain why you would have a 6kw inverter with a 9kw system. Wouldn't you want the inverter to be able to handle the entire system. Just my thoughts.

 

[Kyle_in_Tex]

This is not the best quote. Here are the numbers from the best quote:

Gross Price: $18,246
Contractor Incentive: ($7,200)
Total Contract: $11,046

Federal credit (30%) ($3,314)

Total out of pocket: $7,732

Panels: Axitec, model AC250p.156-60S
Inverter: Samil Power Co., Ltd. Model: SolarRiver 6000TL-US

Who's your electric provider mind I ask?

 

[lockhaven]

would someone actually with a working system that has had it for a reasonable amount of time please give a cost break down. Do they ever really pay for themselves? How much maintenance? Battery disposal? Hazardous material disposal? What happens with the house roof, except for slate roofs need replacing from time to time. I do not trust those installing the systems to be totally accurate, and as far as the government zero trust

 

[ultrarunner]

My retired Telco engineer neighbor installed his own system 5 years ago and has not paid for a single kW of utility power...

He is grid tied with no batteries.

Only has ground pole mounted arrays with a sunny boy invertor...

Has tile roof to roof mounting was not considered.

Every 6 weeks or so if it does not rain he gives them a squirt of water to wash off dust.

Twice a year he pulls a pin to change the angle... take 10 minutes to do all 3 arrays... only does it to improve efficiency.

Counting only materials and nothing for his labor... he is on track with an 11 year pay off at present rates and less if rates go up... also panels are less expensive now and he said he would probably go the micro invertor if doing it today... this lets a panel drop out for whatever reason and the rest keep working at full power.

 

[fordmantpw]

Can someone explain why you would have a 6kw inverter with a 9kw system. Wouldn't you want the inverter to be able to handle the entire system. Just my thoughts.

The solar panels are not 100% efficient, so you wouldn't need a converter for the entire 9kW. I would think it would need to be closer to 7.5kW than 6kW though.

 

[buickanddeere]

Likely be used more for dehumidification than cooling. We never turn the A/C below 83. Mostly at 85. At night we shut it down and open the windows. A 75 degree morning feels cool to me.

We are going ahead with the solar project. The contractor has started the paperwork with the utility. 9100 kwh system. They are estimating 92% of our electrical needs will be served by the system, using the .77 factor they are required to use. If the system outperforms the required factor, the 92% will increase. He expects that to happen, but cannot sell it that way. Also got the quotes back on the AC repair. $1400 for a new Carrier coil. $1726 for a new air handler with coil. Kind of a no brainer. I would like to get the mini-split, but not sure we can get competitive quotes. We were expecting $3000-$4000 grand to repair the system. Our condensor is fine (for now).

Why do you use all that power to dehumidify the house the turn around and open the windows which lets the humidity back in?

 

[dave1949]

The solar panels are not 100% efficient, so you wouldn't need a converter for the entire 9kW. I would think it would need to be closer to 7.5kW than 6kW though.

The solar panels will, if honestly rated by the manufacturer, produce 100% of their rated output when ideal conditions exist. Mine do, mostly in March when the conditions are: cool air, clear sky, and the sun angle is optimal for my system. I'm probably benefiting from a little snow reflection too.

It is more accurate to say solar panels do not operate under ideal conditions 100% of the time. A decent inverter should pass 90%-93% of the DC watts in to AC watts out.

I don't know if it is a more or less standard inverter feature, but my inverter will "derate" when the panel DC watts exceeds the inverter maximum rating. I'm not sure what is going on electrically inside the inverter to do the derating function.

 

[fordmantpw]

Thanks for the clarification dave! I'm hoping to add solar next year some time, so I want to learn as much as I can before then.

 

[dave1949]

Thanks for the clarification dave! I'm hoping to add solar next year some time, so I want to learn as much as I can before then.

I hope you put in a system. Your new home is in an open setting, are you thinking about a ground mount system? They have some advantages. No roof penetrations nor need to get on the roof to repair something. No need to worry about life of the shingles/roofing versus life of the solar system. Easy to make them seasonally angle adjustable, and easy to do the adjustment as UltraRunner mentioned. You aren't in deep snow country IIRC.

If your house and the garage under construction are on the same electric meter service, you can tie the system into the garage or house panel and the result will be the same. For the inverter to panel connection you would usually need one 220v double breaker slot, or one double slot per inverter for a larger system with multiple inverters.