Author Topic: Solar Challenge: Net Zero  (Read 3035 times)

Livethedream

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Solar Challenge: Net Zero
« on: February 18, 2018, 10:02:34 AM »
Wondering if any other solar nerds out there would like to have a solar challenge to keep your electricity bill at $0 or negative!

Post a picture of your system, talk about your experience, system size, how your power usage has changed since solar.

2600 sqft House + 1000sqft shop
All electric everything
House built 2015 2x6 TONS of insulation
Northern CA HOTTTT summers peak at 110.
Mild winters

This is our second year of solar with true up due in July. We are on pace to be negative this year. Our balance last year was $40. We have adjusted our thermostat a bit, that has been the biggest electricity saver for us.

24 Panels
7.2kw
DIY install
4.5 year estimated repayment time


« Last Edit: February 18, 2018, 11:23:55 AM by Livethedream »

Slow&Steady

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Re: Solar Challenge: Net Zero
« Reply #1 on: February 19, 2018, 09:48:14 AM »
I am temped to join this challenge but we had our system specifically designed to only cover 8-9 months out of the year.  We have extremely high energy usage in the winter and low solar abilities, to size our system to cover our winter months would mean that it was 2-3 times more than we would need for the rest of the year and our electric company only buys back at wholesale rates (read very NON-cost effective).  Below is our set up though.

2700 sqft house
1 full electric vehicle (average 25k-30k miles/year)
All electric house
Geothermal heat/air (great for summer, not so great under freezing temps)
House built in early 2000's (NEEDS a lot of insulation)
Partially underground house with lots of shade (great for summers)

Solar turned on in July 2017, 12kW system.


Slow&Steady

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Re: Solar Challenge: Net Zero
« Reply #2 on: February 19, 2018, 09:51:31 AM »
I am temped to join this challenge but we had our system specifically designed to only cover 8-9 months out of the year.  We have extremely high energy usage in the winter and low solar abilities, to size our system to cover our winter months would mean that it was 2-3 times more than we would need for the rest of the year and our electric company only buys back at wholesale rates (read very NON-cost effective).  Below is our set up though.

2700 sqft house
1 full electric vehicle (average 25k-30k miles/year)
All electric house
Geothermal heat/air (great for summer, not so great under freezing temps)
House built in early 2000's (NEEDS a lot of insulation)
Partially underground house with lots of shade (great for summers)

Solar turned on in July 2017, 12kW system.

I will add that it is on my goals for 2018 to try to winter proof the house.  Add more attic insulation and see about adding insulation to the exterior walls, plus redo caulking around windows/doors.

Livethedream

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Re: Solar Challenge: Net Zero
« Reply #3 on: February 19, 2018, 08:48:10 PM »
I am temped to join this challenge but we had our system specifically designed to only cover 8-9 months out of the year.  We have extremely high energy usage in the winter and low solar abilities, to size our system to cover our winter months would mean that it was 2-3 times more than we would need for the rest of the year and our electric company only buys back at wholesale rates (read very NON-cost effective).  Below is our set up though.

2700 sqft house
1 full electric vehicle (average 25k-30k miles/year)
All electric house
Geothermal heat/air (great for summer, not so great under freezing temps)
House built in early 2000's (NEEDS a lot of insulation)
Partially underground house with lots of shade (great for summers)

Solar turned on in July 2017, 12kW system.

You must be involved in some kind of Ag? That is quite a bit of power that system is producing.

CowboyAndIndian

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Re: Solar Challenge: Net Zero
« Reply #4 on: February 20, 2018, 06:06:09 AM »
PTF. I do not have solar on my house since I am going to leave it for a condo next year.
But I always wanted to be completely free from the utilities.

Slow&Steady

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Re: Solar Challenge: Net Zero
« Reply #5 on: February 20, 2018, 08:23:15 AM »
I am temped to join this challenge but we had our system specifically designed to only cover 8-9 months out of the year.  We have extremely high energy usage in the winter and low solar abilities, to size our system to cover our winter months would mean that it was 2-3 times more than we would need for the rest of the year and our electric company only buys back at wholesale rates (read very NON-cost effective).  Below is our set up though.

2700 sqft house
1 full electric vehicle (average 25k-30k miles/year)
All electric house
Geothermal heat/air (great for summer, not so great under freezing temps)
House built in early 2000's (NEEDS a lot of insulation)
Partially underground house with lots of shade (great for summers)

Solar turned on in July 2017, 12kW system.

You must be involved in some kind of Ag? That is quite a bit of power that system is producing.

Electric cars use a lot of energy to travel 90-100 miles a day, they use even more when it is cold outside.  Batteries do not like cold.  During the summer both my electric and my car "fuel" bill should be $0 (except the connection fee that I get charged for every month).  Adding the capacity to handle the car really bumped up the system. 

However, a huge draw on our electric is keeping humans warm (really need to add insulation) and animals and their water from freezing in the winter.  I also struggle year around with teenagers that don't understand that the light, tv, ceiling fan, and floor fan do not need to be turned on if there is nobody in that room.  The teenagers also think it is unfair that I refuse to turn the thermostat up in the winter when they complain that it is cold but they have a fan blowing in their face all night long. 

MaybeBabyMustache

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Re: Solar Challenge: Net Zero
« Reply #6 on: February 20, 2018, 03:31:02 PM »
We recently installed solar panels on our house. There is a month long wait for our power company to start "processing" the solar. Amazingly, they still get to receive the power, just not credit our account. They are "working on it". So, should know more soon! I'm super excited to see how close we can get. Our heat runs on gas, however, so we are hoping to have enough solar to cover all of our power needs, but will still need to pay for gas.

We also have an electric car, but no charger at home. We charge for free at work.
« Last Edit: February 20, 2018, 04:00:53 PM by MaybeBabyMustache »

BrandNewPapa

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Re: Solar Challenge: Net Zero
« Reply #7 on: April 09, 2018, 07:51:02 AM »
I'm hoping to DIY a 7-9kw system this year, depending on my financials. I just had a new roof installed with a lifetime warranty, and I plan to be in this house for at least 30 years, so now is the time to do it. I was hoping to have already ordered panels, but the roof costs 2x what I had budgeted, so I need to save up more money before I pull the trigger.

I live in central Ohio, so payback period would be 7-10 years depending on final installed cost and system size. It should cover 75-80% of my electric usage. I have a Chevy Volt, electric water heater, and electric dryer (formally all electric house).

My roof exposure is not ideal. I have a small south facing section where I can fit 3 or 4 panels and the rest of my roof is east/west. I'll probably do two west facing sections of 10 panels, and one south facing of 4 panels.

The only hurdle I have right now is permitting through my county. They require plans drawn up by a certified architect or professional engineer...I need to find someone that will do it at a reasonable cost. Guess I should have gotten my PE license! d'oh!

MaybeBabyMustache

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Re: Solar Challenge: Net Zero
« Reply #8 on: April 10, 2018, 07:58:22 PM »
We recently installed solar panels on our house. There is a month long wait for our power company to start "processing" the solar. Amazingly, they still get to receive the power, just not credit our account. They are "working on it". So, should know more soon! I'm super excited to see how close we can get. Our heat runs on gas, however, so we are hoping to have enough solar to cover all of our power needs, but will still need to pay for gas.

We also have an electric car, but no charger at home. We charge for free at work.

Bitter because the power company still hasn't started to credit us for our solar. We received our "permission to operate" the first week of March, but they are still processing it & are unsure what's taking so long. Hopefully I'll have an update soon.

Livethedream

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Re: Solar Challenge: Net Zero
« Reply #9 on: April 13, 2018, 07:59:57 AM »
Thatís a bummer, hopefully they get it done soon. We have been having a rainy April, might bust our chances of hitting $0 for the year.

Another Reader

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Re: Solar Challenge: Net Zero
« Reply #10 on: April 13, 2018, 08:21:20 AM »
Wondering if any other solar nerds out there would like to have a solar challenge to keep your electricity bill at $0 or negative!

Post a picture of your system, talk about your experience, system size, how your power usage has changed since solar.

2600 sqft House + 1000sqft shop
All electric everything
House built 2015 2x6 TONS of insulation
Northern CA HOTTTT summers peak at 110.
Mild winters

This is our second year of solar with true up due in July. We are on pace to be negative this year. Our balance last year was $40. We have adjusted our thermostat a bit, that has been the biggest electricity saver for us.

24 Panels
7.2kw
DIY install
4.5 year estimated repayment time

Haven't made the leap yet.  Cost is too high in the Bay Area, roof orientation is marginal.

Some questions, though.

Cost per kW, DIY installed? 
Sacramento or Redding or somewhere else (how cold/foggy in the winter)?
PG&E or SMUD?

Thanks!

Livethedream

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Re: Solar Challenge: Net Zero
« Reply #11 on: April 13, 2018, 10:01:15 AM »
Wondering if any other solar nerds out there would like to have a solar challenge to keep your electricity bill at $0 or negative!

Post a picture of your system, talk about your experience, system size, how your power usage has changed since solar.

2600 sqft House + 1000sqft shop
All electric everything
House built 2015 2x6 TONS of insulation
Northern CA HOTTTT summers peak at 110.
Mild winters

This is our second year of solar with true up due in July. We are on pace to be negative this year. Our balance last year was $40. We have adjusted our thermostat a bit, that has been the biggest electricity saver for us.

24 Panels
7.2kw
DIY install
4.5 year estimated repayment time

Haven't made the leap yet.  Cost is too high in the Bay Area, roof orientation is marginal.

Some questions, though.

Cost per kW, DIY installed? 
Sacramento or Redding or somewhere else (how cold/foggy in the winter)?
PG&E or SMUD?

Thanks!

Iím at about $1.15 a kw installed DIY, paying for some help with install.
Im inbetween Redding and Sacramento, PG&E. We donít get fog here, temperature unless close to freezing wonít really be an issue in winter, we have a bigger impact from temperature in the summer when 100+ for weeks.

Another Reader

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Re: Solar Challenge: Net Zero
« Reply #12 on: April 13, 2018, 10:31:09 AM »
It's $3.25 per kW and up installed here in Silly Valley.  With mostly east/west roof surface at this house, it's harder to make it pencil out even if the price came down.

My neighbor was an early adopter with just under 10 KW.  I think he paid around $40k and got a large rebate.  He has a tri-level with a lot of roof facing about 10 degrees south of mine. He switched everything except the furnace to electric.

Recently he had to replace the 80 gallon electric hot water heater and the solar inverter.  The inverter installation was pricey.  His electric bill is close to zero, but he is paying for natural gas.  His wife is home all day and the two A/C units run constantly in the summer, so he is generating a lot of power.  He is under the old TOU plan from 10 or 15 years ago, which is more favorable to the customer than the current options.

If you are above the fog line, your winter production must be pretty good.  I think we will see a lot more DIY installs like yours and Mr. MM's, which might put some downward pressure on prices.

Cadman

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Re: Solar Challenge: Net Zero
« Reply #13 on: April 13, 2018, 01:05:36 PM »
S&S, nice setup! Reminds me of our 10kw system.  http://www.linearlook.com/solar/solar.html

With cold winters, overcast skies and electric heat, winter bills can be a little unpleasant, but we do go negative during the summer months. It's crossed my mind that once we go FIRE, it may actually be cheaper to boondock out west for a couple months and let the panels work for us.

Abe

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Re: Solar Challenge: Net Zero
« Reply #14 on: April 14, 2018, 10:06:38 PM »
Those of you in California, any advice on what aspects can be DIY and what you need a licensed contractor/electrician to do? I have a portable system that powers my computer since we're renting, but am interested in upgrading once we buy a house in 1-2 years. We'll probably aim for a 5kW system based on our current energy usage.

Joel

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Re: Solar Challenge: Net Zero
« Reply #15 on: April 14, 2018, 10:20:42 PM »
Posting to follow. Could you guys point me to some good guidance for DIY solar?


Slow&Steady

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Re: Solar Challenge: Net Zero
« Reply #16 on: June 07, 2018, 10:24:47 AM »
I am temped to join this challenge but we had our system specifically designed to only cover 8-9 months out of the year.  We have extremely high energy usage in the winter and low solar abilities, to size our system to cover our winter months would mean that it was 2-3 times more than we would need for the rest of the year and our electric company only buys back at wholesale rates (read very NON-cost effective).  Below is our set up though.

2700 sqft house
1 full electric vehicle (average 25k-30k miles/year)
All electric house
Geothermal heat/air (great for summer, not so great under freezing temps)
House built in early 2000's (NEEDS a lot of insulation)
Partially underground house with lots of shade (great for summers)

Solar turned on in July 2017, 12kW system.

I am thinking that I want to actually track this.

Month  -  Usage  -  Generated  -  Net
Jan  -  5.64MWh  -  1.01MWh  -  (4.63MWh)
Feb  -  5.08MWh  -  923kWh  -  (4.16MWh)
Mar  -  3.31MWh  -  1.33MWh  -  (1.98MWh)
April  -  2.98MWh  -  1.68MWh  -  (1.30MWh)
May  -  1.67MWh  -  1.91MWh  -  242kWh

Yes I am fully aware that is a ridiculous amount of energy in the winter.  I am taking steps to reduce that but it will probably always be ridiculous.  Also I know my previous post said that the system was supposed to cover 8-9 months of usage but March and April were both stupid cold this year. 

Slow&Steady

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Re: Solar Challenge: Net Zero
« Reply #17 on: June 07, 2018, 01:36:29 PM »
I am temped to join this challenge but we had our system specifically designed to only cover 8-9 months out of the year.  We have extremely high energy usage in the winter and low solar abilities, to size our system to cover our winter months would mean that it was 2-3 times more than we would need for the rest of the year and our electric company only buys back at wholesale rates (read very NON-cost effective).  Below is our set up though.

2700 sqft house
1 full electric vehicle (average 25k-30k miles/year)
All electric house
Geothermal heat/air (great for summer, not so great under freezing temps)
House built in early 2000's (NEEDS a lot of insulation)
Partially underground house with lots of shade (great for summers)

Solar turned on in July 2017, 12kW system.

I am thinking that I want to actually track this.

Month  -  Usage  -  Generated  -  Net
Jan  -  5.64MWh  -  1.01MWh  -  (4.63MWh)
Feb  -  5.08MWh  -  923kWh  -  (4.16MWh)
Mar  -  3.31MWh  -  1.33MWh  -  (1.98MWh)
April  -  2.98MWh  -  1.68MWh  -  (1.30MWh)
May  -  1.67MWh  -  1.91MWh  -  242kWh

Yes I am fully aware that is a ridiculous amount of energy in the winter.  I am taking steps to reduce that but it will probably always be ridiculous.  Also I know my previous post said that the system was supposed to cover 8-9 months of usage but March and April were both stupid cold this year.

Somebody showed me how to do a table!!

MonthUsageGenerated  Net
Jan-185.64MWh1.01MWh-4.63MWh
Feb-185.08MWh923kWh-4.16MWh
Mar-183.31MWh1.33MWh-1.98MWh
Apr-182.98MWh1.68MWh-1.30MWh
May-181.67MWh1.91MWh242kWh
Jun-18------

CowboyAndIndian

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Re: Solar Challenge: Net Zero
« Reply #18 on: June 08, 2018, 08:58:20 AM »

MonthUsageGenerated  Net
Jan-185.64MWh1.01MWh-4.63MWh
Feb-185.08MWh923kWh-4.16MWh
Mar-183.31MWh1.33MWh-1.98MWh
Apr-182.98MWh1.68MWh-1.30MWh
May-181.67MWh1.91MWh242kWh
Jun-18------

Are you sure that is MWh (Mega Watt Hour)? Must be the grow lights ;-)

Slow&Steady

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Re: Solar Challenge: Net Zero
« Reply #19 on: June 08, 2018, 11:08:23 AM »

MonthUsageGenerated  Net
Jan-185.64MWh1.01MWh-4.63MWh
Feb-185.08MWh923kWh-4.16MWh
Mar-183.31MWh1.33MWh-1.98MWh
Apr-182.98MWh1.68MWh-1.30MWh
May-181.67MWh1.91MWh242kWh
Jun-18------

Are you sure that is MWh (Mega Watt Hour)? Must be the grow lights ;-)

Yes, I am sure.  See up thread about fully electric really inefficient winter usage and a high usage electric car.  It is a work in progress to get these numbers down, it will probably continue until I can convince SO to move.

sisto

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Re: Solar Challenge: Net Zero
« Reply #20 on: June 08, 2018, 12:56:53 PM »
Curious about your 7.2KW system, is that the AC or DC rating of the system? It makes a difference. I have a 24 panel system as well, but it's only been rated at 4KW AC, but also guaranteed to support that for 25 years so in reality it generates more than 4KW regularly. I've had it for a few years now and have not been able to achieve net zero, but it's pretty close not including the $20/mo just to be connected to service. Sad since when I first got solar that amount was $12. The following year it went to $16, then $18, and now $20 plus change.

Mrs. PoP

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Re: Solar Challenge: Net Zero
« Reply #21 on: June 08, 2018, 06:02:00 PM »
Challenge accepted! 

We got our system installed in April 2015, and with the exception of last year (due to being offline pending repairs for about 2 months post hurricane damage), we have been producing more kWh than we use on a yearly basis.  I love it. 

Our system is 28 panels, and I think 7.6Kw.  Net cost to us after utility and tax rebates was <$6K installed, so about a 5 year payback since our power bill was averaging close to $100/mo before installing solar.   

I love our panels and think it's great that some of our neighbors have followed suit with natural power sources since we installed it, with several adding solar pool heating panels and one considering solar integrated into his new roof! 

Plina

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Re: Solar Challenge: Net Zero
« Reply #22 on: June 08, 2018, 11:21:45 PM »
Challenge accepted! 

We got our system installed in April 2015, and with the exception of last year (due to being offline pending repairs for about 2 months post hurricane damage), we have been producing more kWh than we use on a yearly basis.  I love it. 

Our system is 28 panels, and I think 7.6Kw.  Net cost to us after utility and tax rebates was <$6K installed, so about a 5 year payback since our power bill was averaging close to $100/mo before installing solar.   

I love our panels and think it's great that some of our neighbors have followed suit with natural power sources since we installed it, with several adding solar pool heating panels and one considering solar integrated into his new roof!

It is so nice that you can be an inspiration to your neighbours!

Phryne

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Re: Solar Challenge: Net Zero
« Reply #23 on: June 19, 2018, 06:07:25 AM »
Posting to follow!

Our panels are being installed next week, southern Australia (yup, itís winter....)

Cost is ~$5k for 12 panels, all facing west (north is best but not possible for us) just over 3kw I believe. Weíre all electric but also wood heating. Payoff is estimated at 4.5 to 6 years. Winter will see us produce about 40% of our needs, summer about 2.5 times. Feed in tariffs arenít great here, so weíll be adjusting our usage to focus on the solar.

I see this as another optimisation game, looking forward to it!!

Slow&Steady

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Re: Solar Challenge: Net Zero
« Reply #24 on: July 02, 2018, 10:59:35 AM »
I am temped to join this challenge but we had our system specifically designed to only cover 8-9 months out of the year.  We have extremely high energy usage in the winter and low solar abilities, to size our system to cover our winter months would mean that it was 2-3 times more than we would need for the rest of the year and our electric company only buys back at wholesale rates (read very NON-cost effective).  Below is our set up though.

2700 sqft house
1 full electric vehicle (average 25k-30k miles/year)
All electric house
Geothermal heat/air (great for summer, not so great under freezing temps)
House built in early 2000's (NEEDS a lot of insulation)
Partially underground house with lots of shade (great for summers)

Solar turned on in July 2017, 12kW system.

Yes I am fully aware that is a ridiculous amount of energy in the winter.  I am taking steps to reduce that but it will probably always be ridiculous.  Also I know my previous post said that the system was supposed to cover 8-9 months of usage but March and April were both stupid cold this year.

MonthUsageGenerated  Net
Jan-185.64MWh1.01MWh-4.63MWh
Feb-185.08MWh923kWh-4.16MWh
Mar-183.31MWh1.33MWh-1.98MWh
Apr-182.98MWh1.68MWh-1.30MWh
May-181.67MWh1.91MWh242kWh
Jun-182.35MWh1.93MWh-416kWh

CCCA

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Re: Solar Challenge: Net Zero
« Reply #25 on: July 03, 2018, 10:20:13 AM »
We have a 2.4kW system (10 panels with microinverters) in the SF bay area.  We've got great sun and no shading on the system.  We produce about 3900 kWh/yr.
No A/C is a big mitigating factor for our electric system.  It covers more than 100% of our electrical needs, so we sell back to PG&E.  But they only give us wholesale prices (~2c/kWh) for any excess electricity that gets us below zero for the year.  We do have NG based heating/water heating/cooking, so we're not really net zero. 

Just checked our annual summary and we are at 577 kWh exported to the grid for the year.  This is about 2 months of gross electricity usage for us (~ 300 kwh/month though it fluctuates depending on season). 
« Last Edit: July 03, 2018, 10:44:57 AM by CCCA »

sisto

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Re: Solar Challenge: Net Zero
« Reply #26 on: July 09, 2018, 09:36:56 AM »
I'm sitting at a $95 credit right now. My yearly bill closes in October, but I doubt I will make it net zero. What usually happens is that production is less in September, but I still have to use A/C and pool pump. I also usually end up having to use more A/C in August too which dips into the excess a bit. We've really been trying to save by signing up for Time Of Use Rates which gives us a lower rate during off peak, but also heavily dings us in the summer during Super Summer Peak hours with the A/C operation. I'll check back in with an update next month.

Livethedream

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Re: Solar Challenge: Net Zero
« Reply #27 on: July 09, 2018, 01:09:50 PM »
Just closed out the year and had a $15 credit! Added a baby and chest freezer over the last year but weíre able to drop consumption a bit.

MaybeBabyMustache

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Re: Solar Challenge: Net Zero
« Reply #28 on: July 09, 2018, 01:20:15 PM »
Through June, we generated 4,185 kWh, and used 2,776 kWh, so definitely sending energy back to the grid. We didn't get our system fulling up & running until April.

Joel

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Re: Solar Challenge: Net Zero
« Reply #29 on: July 09, 2018, 06:51:10 PM »
If you guys are net zero, doesnít that mean you spent too much / purchased too many panels?
Here in California, most solar setups are targeted at 85% of usage.

Livethedream

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Re: Solar Challenge: Net Zero
« Reply #30 on: July 09, 2018, 08:17:18 PM »
If you guys are net zero, doesnít that mean you spent too much / purchased too many panels?
Here in California, most solar setups are targeted at 85% of usage.

Nothing wrong with 85%, I just preferred to cover 100%. If I have a $15 credit each year that would save me much more then being 85% over the course of my system. The big thing is you donít want to push much past 100% because then you are waiting money on extra panels.

California title 24 zero net energy, they are pushing for all residential buildings to meet this standard by 2020.
http://www.cpuc.ca.gov/ZNE/

MaybeBabyMustache

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Re: Solar Challenge: Net Zero
« Reply #31 on: July 10, 2018, 07:37:30 AM »
If you guys are net zero, doesnít that mean you spent too much / purchased too many panels?
Here in California, most solar setups are targeted at 85% of usage.

Nothing wrong with 85%, I just preferred to cover 100%. If I have a $15 credit each year that would save me much more then being 85% over the course of my system. The big thing is you donít want to push much past 100% because then you are waiting money on extra panels.

California title 24 zero net energy, they are pushing for all residential buildings to meet this standard by 2020.
http://www.cpuc.ca.gov/ZNE/

We had our panels put in spring, and budgeted for air conditioning. We are having air conditioning installed this week. We'll know soon whether we had the right number of panels put in. Also, we generate a lot more in the summer than the winter, so I expect things to even out later in the year. We haven't had our panels for a full year yet to get a good handle on the winter production

Cadman

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Re: Solar Challenge: Net Zero
« Reply #32 on: July 14, 2018, 07:07:20 PM »
If you guys are net zero, doesnít that mean you spent too much / purchased too many panels?
Here in California, most solar setups are targeted at 85% of usage.

Nothing wrong with 85%, I just preferred to cover 100%. If I have a $15 credit each year that would save me much more then being 85% over the course of my system. The big thing is you donít want to push much past 100% because then you are waiting money on extra panels.

California title 24 zero net energy, they are pushing for all residential buildings to meet this standard by 2020.
http://www.cpuc.ca.gov/ZNE/

There are too many variables to shoot for an exact %. In the midwest, our utility provider also offers internet, water, sewer, etc., so any additional power generated offsets those charges. And while we get lots of sun during the summer, it's also 90F+, where efficiency drops off with temperature. A few sunny winter days at 10 or 20 degrees and we can hit the max instantaneous power point of our inverter; but with electric heat, we don't see much in the way of surplus at that time of year. Since rebates and tax incentives help decrease system cost, it can make financial sense to oversize, especially if you have roof or ground mount space.

monarda

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Re: Solar Challenge: Net Zero
« Reply #33 on: July 14, 2018, 08:20:30 PM »
Just saw this thread.

We have a 1.92 kW system on our rental property, 8 panels facing south. (Our primary res. is too shady for any panels)

We installed in 2012 and have generated 16.5 MWh since installation.

We plan to add 8 or 9 more panels someday. Every couple of years we get an estimate, but we have a lot of other expenses to deal with first.

CCCA

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Re: Solar Challenge: Net Zero
« Reply #34 on: July 15, 2018, 01:22:14 PM »
I wrote previously that we generate abou 120% of our electricity needs from solar. I forgot to mention that we are in a time of use rate as well. So solar generates when the costs are high and we consume when costs are low.

Overall we generate a surplus because this. However we can’t make money on this time of use rate but if we could we’d make about $200-300/yr. therefore if we use $200-300 more* in electricity each year we’d actually pay zero for this.

So I’ve been trying to find some productive uses for electricity like a plug-in car or converting some heating over to heat pump.  But I haven’t done anything yet.

Slow&Steady

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Re: Solar Challenge: Net Zero
« Reply #35 on: August 03, 2018, 10:22:29 AM »
I am temped to join this challenge but we had our system specifically designed to only cover 8-9 months out of the year.  We have extremely high energy usage in the winter and low solar abilities, to size our system to cover our winter months would mean that it was 2-3 times more than we would need for the rest of the year and our electric company only buys back at wholesale rates (read very NON-cost effective).  Below is our set up though.

2700 sqft house
1 full electric vehicle (average 25k-30k miles/year)
All electric house
Geothermal heat/air (great for summer, not so great under freezing temps)
House built in early 2000's (NEEDS a lot of insulation)
Partially underground house with lots of shade (great for summers)

Solar turned on in July 2017, 12kW system.

Yes I am fully aware that is a ridiculous amount of energy in the winter.  I am taking steps to reduce that but it will probably always be ridiculous.  Also I know my previous post said that the system was supposed to cover 8-9 months of usage but March and April were both stupid cold this year.

MonthUsageGenerated  Net
Jan-185.64MWh1.01MWh-4.63MWh
Feb-185.08MWh923kWh-4.16MWh
Mar-183.31MWh1.33MWh-1.98MWh
Apr-182.98MWh1.68MWh-1.30MWh
May-181.67MWh1.91MWh242kWh
Jun-182.35MWh1.93MWh-416kWh
Jul-182.79MWh1.98MWh-808kWh

My SO pointed out to me that we put up a pool this year for the kids/us to enjoy without having to drive.  Turns out that the electricity used by the pool pump is for the last 2 months is more than the negative net.  I guess I have discovered why we are not generating a surplus this summer.  I did put that pump on a timer after he mentioned that because neither of us seem to remember to turn it on/off.

We live on 18 acres and half of that is wood, I am thinking about installing an outdoor wood boiler/furnace to hopefully make a big impact on my winter electric usage.

sol

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Re: Solar Challenge: Net Zero
« Reply #36 on: August 03, 2018, 11:03:24 AM »
My family of five lives in a 2300 sqft two story detached SFR. We put up 7500W of solar panels in 2014.  In the first 12 month period they generated about 10,000 kWh, which was roughly double our annual household usage.  A surplus of about 5k kWh per year.

Then we bought a 100% electric car.  Our power bills went up by about $25/mo, but our gasoline bills dropped by far more than that.  The solar panels still generated a net surplus over the following year of about 1000 kWh.

Then we replaced our gas furnace with an electric heat pump, which is also an air conditioner.  Our natural gas bill dropped about $300/yr, all of it the winter.  Our power consumption is up enough that I don't think we are electricity neutral anymore, but our costs are way down and our carbon emissions are way down.

Our regional electricity generation is mostly hydropower anyway, so any opportunity to replace fossil fuel burning with local electricity is a net positive, whether that electricity comes from your roof or from the grid.  Cost wise, my family profits more by using ALL of our rooftop generation to displace gasoline or natural gas instead of selling any net surplus back to the grid at 7.5 cents/kWh, so the optimal solution for us is to be just barely net negative on household usage.  We're pretty close.

CCCA

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Re: Solar Challenge: Net Zero
« Reply #37 on: August 03, 2018, 01:38:25 PM »
My family of five lives in a 2300 sqft two story detached SFR. We put up 7500W of solar panels in 2014.  In the first 12 month period they generated about 10,000 kWh, which was roughly double our annual household usage.  A surplus of about 5k kWh per year.

Then we bought a 100% electric car.  Our power bills went up by about $25/mo, but our gasoline bills dropped by far more than that.  The solar panels still generated a net surplus over the following year of about 1000 kWh.

Then we replaced our gas furnace with an electric heat pump, which is also an air conditioner.  Our natural gas bill dropped about $300/yr, all of it the winter.  Our power consumption is up enough that I don't think we are electricity neutral anymore, but our costs are way down and our carbon emissions are way down.

Our regional electricity generation is mostly hydropower anyway, so any opportunity to replace fossil fuel burning with local electricity is a net positive, whether that electricity comes from your roof or from the grid.  Cost wise, my family profits more by using ALL of our rooftop generation to displace gasoline or natural gas instead of selling any net surplus back to the grid at 7.5 cents/kWh, so the optimal solution for us is to be just barely net negative on household usage.  We're pretty close.


I was trying to decide whether it makes sense to try to convert our heating from NG to electric minisplit heat-pump.  Since our high-efficiency NG furnace works fine now and will for awhile it's probably it's easier and cheaper to just to buy a plug-in car.  From a GHG perspective, replacing gasoline with clean electricity is probably better than replacing NG with clean electricity.  However, right now our excess solar is helping to displace NG fired generation when we sell back to the grid in California.
« Last Edit: August 06, 2018, 11:17:03 AM by CCCA »

MaybeBabyMustache

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Re: Solar Challenge: Net Zero
« Reply #38 on: August 04, 2018, 12:35:15 PM »
We've had our a/c installed for a few weeks now, and are just figuring out how it will impact our solar. We installed enough solar panels to theoretically absorb the cost of a/c, but the solar installation came before the a/c installation. Now we have both & are trying to see if we can be net neutral. On the hottest days (we're in the Bay Area, so think like 90+), if there are multiple hot days in a row, we need to run the a/c enough that we are pulling from the grid. But, that's been outweighed by cooler days, and effectively using screens & fans earlier in the day & keeping the house cool enough that our a/c usage is minimal.

Net/net, I think we installed the right amount, and/or will have maybe a small surplus when we do our gross up at the end of the year.

Another Reader

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Re: Solar Challenge: Net Zero
« Reply #39 on: August 04, 2018, 03:19:30 PM »
We've had our a/c installed for a few weeks now, and are just figuring out how it will impact our solar. We installed enough solar panels to theoretically absorb the cost of a/c, but the solar installation came before the a/c installation. Now we have both & are trying to see if we can be net neutral. On the hottest days (we're in the Bay Area, so think like 90+), if there are multiple hot days in a row, we need to run the a/c enough that we are pulling from the grid. But, that's been outweighed by cooler days, and effectively using screens & fans earlier in the day & keeping the house cool enough that our a/c usage is minimal.

Net/net, I think we installed the right amount, and/or will have maybe a small surplus when we do our gross up at the end of the year.

How much per watt did you pay?

I run A/C from 2 to 7 on days like today.  Lots of west facing glass and roof.  I would install solar if I could make the numbers work.  Most companies just ask how much you use and suggest a percentage of that.  My take is that roof orientation, the TOU plan you are on, and how hot it gets need to be considered.

MaybeBabyMustache

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Re: Solar Challenge: Net Zero
« Reply #40 on: August 04, 2018, 04:12:01 PM »
We've had our a/c installed for a few weeks now, and are just figuring out how it will impact our solar. We installed enough solar panels to theoretically absorb the cost of a/c, but the solar installation came before the a/c installation. Now we have both & are trying to see if we can be net neutral. On the hottest days (we're in the Bay Area, so think like 90+), if there are multiple hot days in a row, we need to run the a/c enough that we are pulling from the grid. But, that's been outweighed by cooler days, and effectively using screens & fans earlier in the day & keeping the house cool enough that our a/c usage is minimal.

Net/net, I think we installed the right amount, and/or will have maybe a small surplus when we do our gross up at the end of the year.

How much per watt did you pay?

I run A/C from 2 to 7 on days like today.  Lots of west facing glass and roof.  I would install solar if I could make the numbers work.  Most companies just ask how much you use and suggest a percentage of that.  My take is that roof orientation, the TOU plan you are on, and how hot it gets need to be considered.

@Another Reader - I'm not sure how much the per watt cost was? We have 14 panels, and also get a ton of sun. We have rented in this neighborhood before in a house with a/c & forgot we had it/rarely used it. This house gets a tremendous amount of sun due to orientation. Last week we generated 260 kWH, as an example. We paid just under $28K, but had to upgrade an exceptionally old electric panel in order to support the solar, so there was some additional work in there. We are about ~4 months in, and at 3% of our payback.

Another Reader

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Re: Solar Challenge: Net Zero
« Reply #41 on: August 04, 2018, 05:06:50 PM »
Sorry I was not clear.  How much per watt of potential generation did the system cost?  For example, one of my neighbors got a 7.1 kw system.  The cost was $3.25 per watt, or around $23,000, before the tax credit.  He used a no-name installer and Chinese panels.  The lowest I was quoted two years ago for American made products was $3.75 per watt.  I think the cost has risen since then.

sol

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Re: Solar Challenge: Net Zero
« Reply #42 on: August 04, 2018, 05:35:11 PM »
The cost was $3.25 per watt, or around $23,000, before the tax credit. 

Why do you want to know the cost before the tax credit?  Are you cash poor?

For example, my system cost about $32,000 up front, but then I got over $9k in tax refund the following April, and the state cuts me a check for $5k every year for the first six years.  My net cost was sort of negative, before accounting for the free power, unless you time-amortize the cost because I fronted the cash and then made money back in the future.  I certainly would have made more money investing $32k in the stock market in 2014 and paying my full utility bills since then.

Another Reader

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Re: Solar Challenge: Net Zero
« Reply #43 on: August 04, 2018, 06:17:22 PM »
The cost was $3.25 per watt, or around $23,000, before the tax credit. 

Why do you want to know the cost before the tax credit?  Are you cash poor?

For example, my system cost about $32,000 up front, but then I got over $9k in tax refund the following April, and the state cuts me a check for $5k every year for the first six years.  My net cost was sort of negative, before accounting for the free power, unless you time-amortize the cost because I fronted the cash and then made money back in the future.  I certainly would have made more money investing $32k in the stock market in 2014 and paying my full utility bills since then.

I do this because I want to bring the cost back to reality.  If I have the roof under the panels replaced, I can get the cost out of the salesman in about 5 minutes,  Not so with solar.  I was in Costco last week and I asked the solar sales guy how much per watt installed?  He had no idea,  Tons of hand waving about rebates but literally he could not tell me how much it cost to install a typical system. 

I understand the tax credits go away after 2019.  If that's correct, the prices are going to have to drop as well, as the government will no longer be subsidizing the solar contractors.  If it is not feasible to install without subsidies, then the solar party for individuals is likely over.

Roots&Wings

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Re: Solar Challenge: Net Zero
« Reply #44 on: August 06, 2018, 06:45:32 AM »
I'm in! Here in FL, average price per watt is $2.50 installed (or $1.75 post tax credit).


Hope to join you all and install a system designed for net zero in the next few months! Energysage.com has been really helpful with getting quotes.

CCCA

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Re: Solar Challenge: Net Zero
« Reply #45 on: August 06, 2018, 11:32:30 AM »
I'm in! Here in FL, average price per watt is $2.50 installed (or $1.75 post tax credit).


Hope to join you all and install a system designed for net zero in the next few months! Energysage.com has been really helpful with getting quotes.

Interesting graph.  When we had ours installed in 2012 our price per installed watt was close to $6/watt in CA.  However, the size of the system has a big impact I would think.  We had a very small installation (around 2.25kW) so there are a number of fixed costs and the installer indicated that our system was the minimum they would install.  Presumably if we'd installed a 7kW system instead we might have gotten a better price per watt.


I understand the tax credits go away after 2019.  If that's correct, the prices are going to have to drop as well, as the government will no longer be subsidizing the solar contractors.  If it is not feasible to install without subsidies, then the solar party for individuals is likely over.

In California, we have tiered pricing, which means that the more electricity you use, the more your average price will be.  It's a progressive system like taxes:


As a result, solar makes alot of sense to displace electricity usage in these highest tiers (> 30c/kWh). And oftentimes in CA, people don't try to displace 100% of their electricity needs, just the most expensive part, to push you back into a lower tier.  So even without subsidies, this portion of solar installation will still exist. 

Another note is the size of the tiers (i.e. number of kWh in the baseline) changes based upon climate in your part of CA.  In the cooler coastal areas, the amount of electricity usage that will get you to the highest tier is smaller than if you live in the hotter central valley.  This of course is to encourage conservation, but not penalize those who have to have AC.  And electric vehicles owners are given another set of baseline levels so as not to discourage EV purchase and usage.
« Last Edit: August 06, 2018, 11:34:19 AM by CCCA »

sol

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Re: Solar Challenge: Net Zero
« Reply #46 on: August 06, 2018, 11:42:13 AM »
Those rates are insane.  We pay 7.5 cents per kWh including the delivery charge (but not the monthly hookup fee) and our power is already 97.5% carbon free.  Why do people still live in California?

edit:  I just looked it up and SCE only charges about $10/month for the connection fee (which they call the "minimum charge") and then charges up to 32 cents/kWh but that includes the minimum charge.  That makes it really hard to compare the cost of power, because we're using fundamentally different pricing schemes.  I'd have to build a spreadsheet to show costs for various levels of usage, and I'm guessing there might even be some (very low) usage levels at which SCE is cheaper than my local utility.  Unless they handle the tax credits and solar credits differnetly, which seems likely too.
« Last Edit: August 06, 2018, 11:46:33 AM by sol »

Slow&Steady

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Re: Solar Challenge: Net Zero
« Reply #47 on: August 06, 2018, 12:41:55 PM »
The cost to install my 12 kW system in 2017 after the tax rebate was $1.70 per watt.  It was $2.42 per watt before the rebate.

CCCA

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Re: Solar Challenge: Net Zero
« Reply #48 on: August 06, 2018, 02:29:45 PM »
Those rates are insane.  We pay 7.5 cents per kWh including the delivery charge (but not the monthly hookup fee) and our power is already 97.5% carbon free.  Why do people still live in California?

edit:  I just looked it up and SCE only charges about $10/month for the connection fee (which they call the "minimum charge") and then charges up to 32 cents/kWh but that includes the minimum charge.  That makes it really hard to compare the cost of power, because we're using fundamentally different pricing schemes.  I'd have to build a spreadsheet to show costs for various levels of usage, and I'm guessing there might even be some (very low) usage levels at which SCE is cheaper than my local utility.  Unless they handle the tax credits and solar credits differnetly, which seems likely too.

yes it's hard to compare since we have different fixed and marginal costs.  Up until a few years ago we didn't have any fixed costs (solar changed that because lots of people were literally paying $0 per month while still being connected to the grid, and we were one of them). 

However, given our electricity usage rates before we went solar, our bills ranged from $20-75/month. It didn't make alot of sense for us to spend ~$10k on a solar system, but we did.  We are a fairly efficient household, but the cost of electricity is not a big reason to not live in CA (I know you were probably being somewhat facetious).  It's like water.  I'm sure in the PNW you can just leave your taps on all the time and not worry about it.  In CA, water conservation is expected, but honestly we still pay ridiculously low rates for water.

Syonyk

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Re: Solar Challenge: Net Zero
« Reply #49 on: August 06, 2018, 03:12:36 PM »
I do this because I want to bring the cost back to reality.  If I have the roof under the panels replaced, I can get the cost out of the salesman in about 5 minutes,  Not so with solar.  I was in Costco last week and I asked the solar sales guy how much per watt installed?  He had no idea,  Tons of hand waving about rebates but literally he could not tell me how much it cost to install a typical system.

Sounds about right.  But, man, they'll talk your ear off about how amazing their innovative financing is! Now, what's your monthly power bill...?

Hint: The prices are obscene compared to materials and labor costs.

Quote
I understand the tax credits go away after 2019.  If that's correct, the prices are going to have to drop as well, as the government will no longer be subsidizing the solar contractors.  If it is not feasible to install without subsidies, then the solar party for individuals is likely over.

Not quite true.  Yes, 2019 is the last year of the 30% credit.  Then you get, for 2020, 26%.  Then, 2021, 22%.  Then it drops to zero for residential (remains at 10% for commercial).

Hopefully the installed prices come down, because for what the installers want for a basic grid tie roof mount system around here, I can install my own ground mount, significantly larger, DC coupled system with battery backup.  Which is next year's big project.