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Solar Garage Anyone?

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mikevbf

Active Member
Feb 11, 2012
1,904
4,682
vermont
I have not been able to find a good current thread on this, but maybe there is one? Anyway in the Model S facts section of Tesla's site it says:

"If you’re interested in installing a home solar system to charge your Tesla, we recommend working with a local solar installer to develop and install a system that supports your total daily energy demand. Assume average energy usage per mile is approximately 300Wh/mile (188Wh/km). Multiply 300Wh/mile (188Wh/km) by your daily driving distance to estimate your daily vehicle energy consumption."

Anyone planning on doing this for their Model S? I know some Roadster owners have created solar set ups to charge their car, but many of these systems were done a while ago. Has anyone got a quote for a system like the one described above recently? How much was the quote for? Anyone with experience with these systems want to venture a guess what it might cost on a site with reasonable southern exposure? I guess it would vary a bit depending on latitude. So as to be most useful to everyone reading this thread please include your state and where you generally reside in it i.e. Northern, Central, Southern.
 
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Every house/garage is different and you need a local installer. Some states have incentives, some don't. Everything depends on the amount of sun your roof gets on an average day. etc. etc.

Best advice: figure out your usage and then call a local company for a quote. Don't forget that the electrician may cost extra on top of the PV install.
 
Every house/garage is different and you need a local installer. Some states have incentives, some don't. Everything depends on the amount of sun your roof gets on an average day. etc. etc.

Best advice: figure out your usage and then call a local company for a quote. Don't forget that the electrician may cost extra on top of the PV install.

Yes of course you are right. It still would be useful to get a rough range of the cost to people in different locations, despite the many variables you mention.
 
I'm planning to install at least 8KW of solar on my roof this year. It was actually planned before I reserved my Model S, which is why I say "at least" now.

I'm at 37.3N 122W (SF Bay Area), and will have a 4:12 roof pitch facing due south, which I'm told is excellent.

The quotes I have are about a year old, and my solar contractor tells me that prices have dropped significantly - I'll have a better sense of the cost soon, since they have my final roof plans now and will provide a new quote.

For daily commuting and weekend chores, I'm looking at about 800 miles/month (basically, not all that much). 800*300 = 240KWh.
I don't trust the 8KW number, so I'm figuring my 8KW system will deliver around 6KW on average or 6 hours/day, or 1080KWh/month. So, the car will eat about 1/4 of the total power.

I'm hoping that lower prices will mean I can install more panels.

/Mitch.
 
Every house/garage is different and you need a local installer. Some states have incentives, some don't. Everything depends on the amount of sun your roof gets on an average day. etc. etc.

Best advice: figure out your usage and then call a local company for a quote. Don't forget that the electrician may cost extra on top of the PV install.

NigelM is correct to an extent. I installed a 33 panel array on my home late last year. It produces 11,000 KwH per year. I can't speak for every state, but in MIchigan a local installer will charge about $6.00 per kilowatt hour (which is the full installation, materials, labor, etc.).

Since my installation, I have not paid an electricity bill :smile: Also, there is a 30% Federal Tax credit. And there are state-specific incentives (unfortunately not in Michigan). Some states, such as Michigan, Ohio, New Jersey, Pennsylvania, and others have SRECs market, which is an additional financial incentive.

I can provide more information, but solar installation varies market by market. And since most people in this forum reside in California or Florida, I may not be of much assistance for those state-specific incentives.
 
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MichaganModelS, we too have 33 panels (Sun Power 230 watts each, so about 7.6Kw). We're a little south of you (San Diego), so we make a little more power, about 12,000 KwH/year. Right now we make about 97% of our usage, but once I get my S and my wife gets the Volt she just ordered, it will probably drop down to 90% or so. We'll still be in the tier 1 pricing, so I don't see the need to add more panels, which might also require us to upgrade the inverter.

Pricing on panels dropped significantly a few months after we installed our system in October 2010, but we have no regrets. Everyone talks about time to payback, but the value of your house literally goes up an equal amount of what you pay for the system, so in my mind payback is immediate. For those considering solar, it's a no brainer once you have an electric car. And if you cant afford the initial outlay, then by all means investigate leasing the panels which will lock in your electric rates for years to come.
 
MichaganModelS, we too have 33 panels (Sun Power 230 watts each, so about 7.6Kw). We're a little south of you (San Diego), so we make a little more power, about 12,000 KwH/year. Right now we make about 97% of our usage, but once I get my S and my wife gets the Volt she just ordered, it will probably drop down to 90% or so. We'll still be in the tier 1 pricing, so I don't see the need to add more panels, which might also require us to upgrade the inverter.

Pricing on panels dropped significantly a few months after we installed our system in October 2010, but we have no regrets. Everyone talks about time to payback, but the value of your house literally goes up an equal amount of what you pay for the system, so in my mind payback is immediate. For those considering solar, it's a no brainer once you have an electric car. And if you cant afford the initial outlay, then by all means investigate leasing the panels which will lock in your electric rates for years to come.

I agree with you 100%.

Other than the cash outlay (which can be significant for most), I found it to be a simple decision. I tell people, if 1) you consume electricity and 2) plan on owning a home (for any length of time), you should install solar. The value of a home with a solar array has a higher value because it (depending on the size of the array) has zero electricity expenses. So, whoever purchases my home next may find it attractive that he/she won't have to pay an electricity bill (ever), which clearly has financial value.

mcornwell - my array has 33 - 255 watt panels (the technology is moving so quickly they industry has gone from 230 to 255 in a years time). Also, I have an enphase system. I can view my production on-line (zoom into a region to view an individual house):

Enphase Energy - Enlighten |

My statistics are more detailed than this public view, but you can get the idea. Drill down to an individual home and watch the time lapse and view the Carbon Offset. Cool stuff.
 
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We just went live with our PV solar system on November 1 (San Jose, CA). We started getting quotes in April; finalized bid with Sungevity in May; and they began installation in September. PG&E connected us to the grid on November 1, the start of lower winter rates (coincidence?). With the solar system, we switched to a TOU rate schedule where the system generates energy and is credited at the higher peak rates. An EV will qualify us for a different TOU rate schedule, but we won't be able to switch to that until November (12 months required for current rate schedule), though we're hoping to get delivery of the S in August/September.

We have a 7.4 kw system and paid around $16k for it. We opted for a prepaid 10 year lease. After 10 years we can either renew the lease, buy out system at then FMV, or have them remove the system. We didn't like the idea of having monthly lease payments, but we found that outright ownership of a system requires additional fees for monitoring and maintenance. We also figured that after 10 years, we can see where the technology is. Based upon our usage, payback should be in about 4 years. Production for our system has been 927.8 kWh (Oct), 646.4 kWh (Nov.), 712.1 kWh (Dec.), 673.8 kWh (Jan)...

You can get a free quote from Sungevity by just inputting your home address...no need for an appointment...the quote including panel array set up was extremely accurate.

Good luck!!

DeDe
 
Sun Power also has an online monitor. Here is the public URL for our system:
SunPower Monitoring System


You can see historical data for day, week and month. In the past week or so, with the longer days and position of the sun, as long as it's not too cloudy, we're making more power than we're using now (33.7KwH today), so we sell it back to the utility, SDG&E.
 
Sun Power also has an online monitor. Here is the public URL for our system:
SunPower Monitoring System


You can see historical data for day, week and month. In the past week or so, with the longer days and position of the sun, as long as it's not too cloudy, we're making more power than we're using now (33.7KwH today), so we sell it back to the utility, SDG&E.

I like Sun Power's monitor slightly better than Enphase. Does SDG&E credit your account or do they cut you a check when you over produce / under utilize?

In the next 3 to 5 years, I believe the price of solar will drop significantly, which will be huge for solar city. I'm interested to see if Solar City plans to service the Midwest / East Coast following their IPO.
 
We get a statement every month showing usage/generation, but we only settle up once a year, and make a payment if we owe, or get a check if we produce more than we use. Unless I somehow find a way to use 10% less power, I don't think that's going to happen. As green as we are with solar, a Prius, an upcoming Volt and Tesla, etc, we have too many fridges/freezers (kitchen, wine cooler, outside at BBQ, garage freezer), DVR's/cable boxes that run 24/7, TV's (don't ask, I'm embarrassed to say how many 3 people need), and computers. Add in a 9 year old who is horrible at turning off lights...
 
I would LOVE to install PVs but there are several large pine trees in my neighbor's yard that blot out the sun to my roof for most of the day and he's not at all interested in removing them. It's a major bummer.
 
We get a statement every month showing usage/generation, but we only settle up once a year, and make a payment if we owe, or get a check if we produce more than we use. Unless I somehow find a way to use 10% less power, I don't think that's going to happen. As green as we are with solar, a Prius, an upcoming Volt and Tesla, etc, we have too many fridges/freezers (kitchen, wine cooler, outside at BBQ, garage freezer), DVR's/cable boxes that run 24/7, TV's (don't ask, I'm embarrassed to say how many 3 people need), and computers. Add in a 9 year old who is horrible at turning off lights...

All that refrigeration is definitely killer. Have you thought about putting timers on any of the cable boxes? I had mine set to turn off when everyone in the house is sleeping. :)

I'm pretty interested in solar, I may get a quote this year once Ontario sets the new rates for microFIT. (the past 2 years the rate has been 80.2c/kW! guaranteed for 20 years!)
 
My wife and I put a 4.7kW system on last spring. We went with a 15 year solar lease from SolarCity. Because of the lease and the Oregon and Federal tax rebates and local utility rebates. The system cost us $5850. But we get $6000 in state rebates over 4 years.... plus about 4500 kWH of power per year. We wanted solar panels for sometime, but Oregon just changed the laws last year allowing for a solar lease. It's a pretty sweet deal here. So they should produce enough power for about 15k miles a year in the Tesla.

You can actually seem them on Google Maps : 10588 NW Malia Ln, Portland, OR 97229 - Google Maps
 
mcornwell - my array has 33 - 255 watt panels (the technology is moving so quickly they industry has gone from 230 to 255 in a years time). Also, I have an enphase system. I can view my production on-line (zoom into a region to view an individual house):

Enphase Energy - Enlighten |

My statistics are more detailed than this public view, but you can get the idea. Drill down to an individual home and watch the time lapse and view the Carbon Offset. Cool stuff.

What brand panels do you have? Enphase makes micro-inverters, not panels. I'm curious as to what panels you have that are rated at 255 watts.

My parents put a PV system on their house in 2009. It's a 4.725 kW system. We generated about 5,000 kWh/year, which covers about 55-60% of our electricity.

-Shark2k
 
just did some research here in georgia and what i found out is that it takes about $5/Watt. so for a 5kW system that's about $25000.

here we can sell back to georgia power at $0.17/Watt. it makes about 1200kW per year per Watt installed so a 5kW system makes about 6000kW. It would take about 10 years to recoup costs after the federal rebate of 30% and state rebate here of 35%.

state rebate here is only good until 2014 and they are already using money from the 2013 budgeted year so you might not even get that if you wait to install them.

it is a cool idea to be able to power the car via solar and never have to pay for anything!
 
....it is a cool idea to be able to power the car via solar and never have to pay for anything!

We already do that. There's a bunch of info over here: Tesla coupled with a SolarCity charging station?!

What we thought was going to be a 19-20MWh system actually produced 27MWh, although we had a ridiculously sunny fall and a very quiet storm season last year. The excess energy was mostly used up running the AC more hours and this crazy warm winter (80F today) means we have even been running the AC this season when we normally consume very little energy.