Solar electric

Now that everybody's power consumption is going to go up by 300 KWh every month (approximate consumption for 1000 miles), has anybody considered getting solar electric?
When Solar City gave me the estimate for installing the Nema they also gave me a quote for installing solar panels. I can't make up my mind if this additional investment (on top of the already big ticket item of the Model S) is something I should pursue.

@Nwdiver93 -- yeah , but doesn't sound way better to have someone else do it for free and only have to worry about paying a cheaper bill? Solarcity's way takes out all the hassle it seems like. At the end of the day, that counts for a lot for most everyday people that just want to see their utility cost go down...

My guaranteed output is fixed, and is about 63% of my past usage including an estimate for charging the S. My cost however is reduced by 84%. The reason they would not configure the system at 100% of usage, has to do with the time of use rate structure. Under this rate structure the cost is very high ($.50 per kWh) during daytime peak and then low ($.05 per kWh) at off peak hours. The solar electricity is generated during peak daytime rates. and can benefit you at the very high rates. If they configured the system larger to generate more electricity, the benefit deducted on your bill will be at lower rates resulting in a longer payback for a more costly system.

Yeah, my system definitely doesn't cover 100% of my usage (probably 80%), but anything more would be a waste because my bill is already reduced to 0. PGE is buying electricity from me at high rates during the day, and most of my usage is in the evening (no air-con needed here).

My Solar City panels were installed today. For me, it was a no-brainier. I'm surprised to hear others have looked at it and found it lacking. Have you looked at it recently? Panel costs (from China) have dropped dramatically. That's what caused Solyndra to go bankrupt.

I expect to save about $50k over the 20 year contract. That pays for part of my Tesla! I recommend talking to a Solar City salesperson to go through the math. In a tiered system where you pay more the more you use, the idea is just to get out of the higher tiers. So the sweet spot is to have you solar cover a good percentage of your usage, and have your remaining usage from the power company all in tier 1. The cost of the additional panels to cover the remaining tier 1 usage becomes uncompetitive.

I could have done the $0 down and started saving $80/mo average right out of the gate. That's why i say it's a no-brainer. But I chose the per-pay option others mentioned, so for $11k I'll save even more.

Yes, I agree if my typical electricity usage takes me to tier-3 or above, then switching to SolarCity makes sense. That why I'm going to wait a couple months to see if charging my S will take me to the next tier. If so, I'll re-visit SolarCity at that time. Thanks for the inputs.

If you can "pay" for it, The math works. If its leased, that company gets the tax incentives. Dig deep, the end results Are in the first sentence. Ask a lot of questions. Then put it All in front of your accountant.

We live in Seattle and already have a medium sized solar array of 5625 Watts. We made 6.2 Megawatts in 2012, so we can drive 21,900 miles this year completely on solar. We only average 10K miles a year so the rest of the power will offsets the house.

I love my solar array. Even when you have a crappy day at the office you can come home and see that your house has been working hard all day collecting power. I tell people I have two jobs, a Software Engineer and Solar Farmer. This year we had a good crop. :D

If your looking for a good solar system I recommend the Enphase micro-inverters. They have a awesome UI tool that is on par with Tesla's UI. We have Sanyo 225 panels because we don't have a lot of roof space so we need watt/inch to be high.

That 300kWh/mo for the car may be a bit low. 400kWh would be a safer bet, I think.

Hey Stark

Who's did you contract to install / contract the solar panels to? I'm in Toronto.

I'm curious about this. I have a low-slope south-facing roof on a hill in sunny Los angeles. However, I don't even have central A/C. Pre-tesla, my electric use is around 370kwh/mo. - which I doubt is a lot compared to most of you. My bill is around $65-$70/mo for electric. The Tesla should roughly double that, at 12k miles a year. My wife works for a general contractor, so I may have her ask her solar guy to take a look at our house - but I don't think that you can sell electricity back to LADWP right now - they have no feed in tariff program, and especially since we're at work with no A/C during the high-sun time (with very little electrical usage) I don't know if solar makes sense for us - most of our power use is between 6-8 a.m. and 7-11 p.m. - when we're home and awake.

Hmmm, doing some quick calculations here:

If I will use 8160 kwh over a year with the Tesla, in LA (5.62 solar hours/day), I need a 4.7 kWh array to cover 90% of my electricity needs. That would be roughly 17 of these panels: - which would cost $3740 - plus install and whatever else you need to hook up the panels to your home (no idea what that stuff costs). Also not sure how federal/state rebates work for something like that. Hmmm...

solarcity is not the best offering out there.
Look at pre-paid lease instead, and keep the electricity you generate to yourself.
The panels from China maybe cheap, but they are less efficient than what's being made here by Sunpower (up to 20%).
Especially if your roof space is limited, it's definitely worth considering.

archibaldcrane - I'm pretty much in the same boat as you in terms of kWh usage, so I'll be really curious to see what you ended up deciding. I don't know if LADWP uses the tier-based system, but here in N. Cal, I had never exceeded tier-3. When I punched in some numbers, SolarCity leasing just didn't add up for me. Besides, starting this Spring, PG&E is implementing a time-of-use system exclusively for EV homeowners (must own a EV vehicle), so I'll see how that goes first. Please keep us posted.

It only makes sense with a separate meter, that will cost $$ to install.

Yeah, for LADWP EV electricity breaks you have to be on TOU also, which I currently am not (but considering my power use patterns probably should already be). It just seems crazy that the cost of the panels alone to get a 5ish kwh system is just under 5k, but installers are in the 20-25k range to install a system of that size.

I had a 10KW solar system installed this fall in preparation for the model-s. I didn't use SolarCity, I just used a local contractor. This is one of the worst months for solar energy, but here is a link to my solar system

Actually, for time-of-use (TOU) system, there is no need for two meters. It is purely based on when the power is being used during the day. So it's perfect for family with both parents having day jobs, when no one is home during the day. For PG&E, this is what their TOU rate is (note that there is a separate table for weekends and holidays too):

Peak: 2pm to 9pm @ 26.7 cents
Part-Peak: 7am to 2pm & 9pm to 11pm @ 16.5 cents
Off-Peak: 11pm to 7am @ 9.9 cents

So for charging the car will cost 9.9 cents/kWh if I set the timer for charging after midnight. Since SolarCity is charging me 19 cents/kWh (the zero down option), I will only save on the Peak usages.

For LADWP you can't get the 2c/kwh rate reduction unless you get a second meter just for the garage charger plug. But yeah if that's not part of it, no need for 2 meters.

tcunning - that is a really cool monitoring system!

I installed solar on a rental I own in Bremerton, Wa. According to most solar resource maps it's one of the worst places in the lower 48. Still... even in Bremerton, Wa... I'm producing ~10000kWh per year with an 8.4 kW array. It will pay for itself in 7 years.

Solar tech is improving every year but it's one step at a time. There really aren't any "breakthroughs", although no doubt the media will call them that. The Headline "Marginal improvements in cell performance" doesn't get as much traffic as "Astounding new discovery promises free energy".


that's an impressive setup, 44 panels with microinverters.
17kWh a day this time of year is pretty darn good.

I live in Georgia and have had my 10kWh array of panels up for a couple of months. Just awaiting the arrival of my Tesla!

Yup! I just bought a system from Solar City last month! The tax credit (30% off) is just too good to pass up! Never mind, my currently utility bills have been skyrocketing since they passed 'power deregulation' back in the late 1990's. So the system actually starts to pay for itself in under 5 to seven years (with the MS, likely 4 years).

Also, where I live, our nuclear power plant has been off-line for over a years + now, and might never go back on-line, because they have found so man issues with it (including possible sabotage). Thus, part of my current utility bill goes toward paying to maintain a completely defunct nuclear plant, that cost millions of dollars every year, just to maintain, though it is producing ZERO kWh!

I have a strange feeling that in order to maintain the power grid where I live, solar might eventually become mandatory, just to keep our area from brown and blackouts.

If you have a home based business, you can currently deduct the deprecation on the system every year (as well as my MS). So the investment makes even more sense.

PGE has two time of use schedules for residential with Low emission vehicles. The E-9A is for a single meter application and the E-9B is for applications where the EV is on a separate meter. The E-9B has a lower rate but because of the added cost of installing a separate meter may or may not be a good economic decision. In my case it is not, and I will be happy to be on the 9A schedule. If you are getting a proposal from anyone, make sure they compare your cost as though you are converted to the 9A rate schedule to the cost with the addition of solar. In my first presentation they assumed I was on the standard rate schedule and charging the Model S when in fact I can switch to the 9A schedule and get some benefit without having solar.

Another gotcha - your rate change will stay in effect for at least 6 months, meaning if you don't like it you can't change it for 6 months.
With PGE offpeak being late at night, I'd rather wait for Tesla to add scheduled charging before switching.

I have had solar PV since 201. It's very cool to be carbon neutral.... But not as cool as a Model S.

Here in the Northeast we have Solar Renewable Energy credits (S-RECs). It's a market based carbon offset purchase program (but don't call it cap & trade). Check out for info. They pay me to produce electricity... and I get to keep the electricity. I sell my S-RECs to Washington DC. I am currently getting paid about 30 cents for every Kwh I produce.

Please read that as "I have had solar PV since 2010".

Woohoo! Looks like LADWP just approved launch of their feed-in tariff program (FiT) - they'll buy excess solar energy for 17 cents/kwh!

Didn't realize that scheduled charging is not yet available in S. Does anyone know if there is some sort of a timer that I can attach to the Nema 14-50 outlet in the meantime? Otherwise, I'll just need to remember to plug in the cord after 11pm every night to take advantage of the lowest TOU rate.

I currently have two LEAF's using about $40 per month per car of electricity. I had Southern California Edison (SCE) put in a second meter which drives my charging price down to $0.11 per KWH from 9pm to noon the next day. It cost about $800 for the electrician and the parts to put in the second meter box next to my box. SCE people came out and connected it to the grid for free. A very quick pay back.

I am hoping when I get my Sunset Red Tesla sometime in the March - June timeframe that the built in timer on the Tesla will be working although it isn't a major issue to plug in at 9pm

We put a SolarCity system in about 6 months ago and have been extremely happy. We went with their PPA lease program which gave us the option to pay nothing and immediately reduce our SCE bill by about 20%, or pre-pay for blocks of power to lock in lower rates. The cost to pre-buy 20 years of power was less than actually buying the system outright and they own all the equipment so we basically have a 20 year warranty with guaranteed annual output. We put down about 6 years of our average electrical bills (for 20 years of electricity).

I still can't see the down side. System is fantastic and I love the on line monitoring. SolarCity was easy to deal with and respectful of family and neighbors during the install. They have everything turned on about 3 months after my original call to them. Bottom's worth giving them a call and having them come out to do the free assessment..they lay all the options out for you and we didn't get a hard sell in any way.

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