Solar electric

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.

GoTeslaChicago | January 10, 2013

If you're in California where electric rates are high, it is probably a good investment. In other parts of the country, the return investment dollar wise is probably not that good, but the environmental benefit is still there.

I live in Chicago, and hope to go ahead this summer, finances permitting. Solar panels plus time of use pricing will allow me to produce power when the cost is high, and charge my car at night when the electricity cost is low.

Stark | January 10, 2013

For the me, the up front capital costs for a solar system were too high, and as noted by GoTeslaChicago, my rates are pretty low (Ontario Canada - $0.063 cents per kWh off peak), so the return on investment was too long. What I opted to do is lease my roof to a solar company. They install, maintain and insure the solar system and pay me to lease my roof. They have a 20 year fixed rate contact with my power company, so I'll get a constant source of income over the next 20 years. Once their contract with the power company expires, I buy the system for a penny. Seems like a pretty good deal, and costs me zero out of pocket. Install is scheduled for summer.

sidney_wang | January 10, 2013

"Buy low and sell high" - that was the sells pitch SolarCity gave me on their proposal. Does it really work this way in California with PG&E? In other words, during the day my solar system will produce some Y units of credits to the grid, and during the night when I charge my Tesla, I'll have more than 2 or 3 times the Y units of credits to burn (because the rate at night is approx 2 or 3 times lower)? Does anyone know if this is how it works? I'm also contemplating solar panel leasing.

archibaldcrane | January 10, 2013

Not even all California electric rates are high. If I get a separate meter installed by LADWP, my charging will cost a whopping 7-9 cents per kwh - so like $24/mo for 300kwh. That being said, it would be nearly impossible to make solar panel installation make sense for me.

sidney_wang | January 10, 2013

@archibaldcrane Would you mind revealing the investment cost for a second meter? That's also one option I'm considering.

jk2014 | January 10, 2013

Doesn't solar city take on all the costs of installation and maintenance? All you have to worry about is paying your monthly electric bill (which is guaranteed to be lower then traditional utility company)?

rlpm | January 10, 2013

I'm lucky to be in NM, where we have lots of sunlight, good tax incentives on PV systems (e.g. no sales (actually gross receipts) tax), $0.04 Renewable Energy Credit per kWh produced (whether you use it or not, but only for the next 8 years) and net metering. We have much higher usage in the late summer: compressed air to combat the high temperatures. Nevertheless, because of the REC, you can get paid each month by the power company, including during the summer, and run the meter backwards during the other months to net zero. Depending on usage and size of PV system, ROI (after tax credits) can be fewer than 10 years at current tiered electric rates. And since rates are just about guaranteed to go up, it's even better than that.

sidney_wang | January 10, 2013

There is no guarantee from SolarCity that your total electric bill will be lower than what you are paying now. True, there is a fixed amount that you pay SolarCity every month, but there is no guarantee that your future PG&E bill will be near zero.

ckanuga | January 10, 2013

I am in California and get the electricity from PG&E. Their tier 1 & 2 (~400 unit) is 0.13c.
But once you use up the first 400 units the subsequent ones costs 0.34$.
For the zero initial cost Solar City sells each unit for 0.23$ - so saving of 9c. Not too appealing.
But for the pre-pay or the purchase option the initial investment is over 20K and then each unit costs 0.11$. Good 0.23$ saving but a hefty upfront investment.

jk2014 | January 10, 2013

ckanuga -- are you saying its not worth doing the zero initial cost?

DonS | January 10, 2013

In CA, PGE tiered rates for normal users are such that you need to be using a lot of electricity in the highest tier to make solar ever payoff. This means larger homes with central A/C, pool pumps and often electric dryers. If you have a low energy footprint, forget it.

I haven't redone my calculations yet for the EV rates, which include time of day metering. By selling electricity during the day and charging your car at night, solar has to have a better financial picture than with the regular rate plan. I'm still not sure yet if it is good enough to warrant up front costs. It takes a lot of guesses about when you will be using electricity.

GLarwill | January 10, 2013

I have an appointment with a solar panel rep tomorrow at around noon. This car would NOT be possible with out it. Here in the SF Bay Area, I'm paying through the NOSE for electricity. Over $0.30 per kWh on my last bill... even now in the winter when there is no AirCond and electricity usage is low. This is due to the "baselining" noted in posts above.

My hope for solar are that I can get my generating cost down to about $0.10 per kWh over 10 years, and lower if you amortize out further. Remaining question for me, 'Do I have enough roof space?" As others have noted, doing this in other locations where electricity rates are actually reasonable may not make $ense.

On the lease vs buy side of things, I'm leaning more towards the BUY as the value of your home is increased with the presence of solar as well. Even if I move before my ROI for the power us reached, there will be some value for the solar.

Time-of-Day billing for night-time charging and solar generation during the day (when costs are highest) seem like the sweet spot for Do-It-Yourself power. I expect/hope my Solar Rep will have these answers for me tomorrow.

FYI, you can go to and for some idea of the actual prices of the hardware. I had one quote that indicated 75% of the cost was "installation" when I compared it to a Lowes purchase.

More data when I have it if you are interested...

jk2014 | January 10, 2013

I'm curious, if all you have to do is pay a monthly bill (which is guaranteed to be lower then what you pay in utilities right now), without having to pay for the panels, the set up, or the maintenance... Isn't this a no brainier great f-inge deal from solarcity or am I missing something?

Sounds like you don't have to worry about sh*t except paying a lower monthly utility bill...

sidney_wang | January 10, 2013

Thank you for these valuable information as I'll be revisiting them again in six months. For now, I'll just go with PG&E's EV plan which charges 10 cents for after midnight charging and see how it'll impact my overall electricity bill. That way I'll have a baseline to compare against SolarCity's proposal.

sidney_wang | January 10, 2013

@jk2014 - You must have missed my earlier post (5 before yours)? Even with SolarCity's lease, you will still be getting a monthly bill from your utility company and there is *no* guarantee that your total bill (SolarCity + your utility bill) will be lower than what you are paying today. Hope that makes sense?

archibaldcrane | January 10, 2013

@sidney_wang - I don't know exactly what it costs to get a second meter installed by LADWP - however, they do provide a rebate up to $2000 for the costs associated with installing an EV charger in your garage, so it could very well be rolled into that.

schumonster | January 10, 2013

I did solar a few years back. I happen to have a big flat south facing roof in the Valley in LA, so my house was optimal for a solar installation. That said, LADWP will only permit the size of your system to what they consider a net 0 based on the previous 4 year history of your electrical usage. I had plenty more roof space for additional panels but LADWP doesn't want to owe me money. I find that the net yearly energy cost is currently slightly less than when I was buying straight from the DWP. I leased with no money up front, so I am saving a small amount of money and reducing my carbon footprint, but that's about it. Someday when the depreciation curve for the panels makes sense I will buy them out and reduce my cost significantly, but for now it has been a painless and marginally cash positive experience. The costs of my lease are fixed and have been rising slower than those from the DWP so the long term payoff might increase slightly.

jk2014 | January 10, 2013

Sidney -- thanks for info... I was under the assumption solarcity would guarantee a lower electric bill even if you exceed your average usage. They eat the difference.

sidney_wang | January 10, 2013

@jk2014 - if that's the case, I would sign up in a heartbeat! The only guarantee SolarCity will make is the total kWh the system will produce in a given year (they do take into account the year-to-year degradation of the panels). For some reason SolarCity is proposing a system that can only produce approx 75% of my annual kWh usage. So not knowing who is covering the other 25% of my kWh usage, I declined their offer. They tried to convince me that I'll end up with a "net 0" (ie. paying nothing to my utility company) at the end of the year, but it's hard for me believe...

jk2014 | January 10, 2013

Sidney -- thanks again for the info... Just curious, If you pay less per month with solarcity than just grid power alone, why not take the deal?

sidney_wang | January 10, 2013

@jk2014 - The problem is that I don't know if I'll be paying less per month with SolarCity *until* after I sign the 20 years commitment *and* see the first total bill from SolarCity and PG&E together. If it turns out to be more, then I'm screwed for the next 20 years!

peahl | January 10, 2013

ckanuga, I am pretty sure that it makes sense to install Solar if you live in an area with a high number of sunny days.
I had my solar panels installed already 5 years ago and I had additional panels installed just before I got my BMW ActiveE one year ago. I do not pay anything for electicity to SDG&E just natural gas for the water heater and I have also a pool pump running. I will break even in one year, because of a lot of incentives from federal and state government.
And considering that CA will produce his electricity in the future with a great part of renewables (Solar, Wind) we all do a lot good to our environment.

jk2014 | January 10, 2013

If that turns out to be the case, solarcity gonna be out of business real fast. The whole point is saving money on electricity.

mika_ | January 10, 2013

I think how good of a deal you get from SolarCity is going to vary a lot depending on your electrical usage, how sunny your roof is, and what your rates are in your area. I got a proposal from them recently and for me it might work out to be a pretty good deal. In a "normal" month of electrical usage, I'm using more than double my PG&E baseline - in my neighborhood (marin) the tiers look like this:

Baseline = 6.6 cents per kWh
100-130% of baseline = 8.4 cents
131-200% = 23.3 cents
201%+ = 27.3 cents

According to the SolarCity proposal I received, they could build me a system that would provide enough juice to keep my monthly non-solar usage under 130% baseline pretty much year round, which makes a significant difference due to how quickly PG&E's rate jumps when you exceed that. If they're wrong and it under-produces, they pay me for the juice is failed to deliver.

They presented three different options to me for paying for the solar part of my bill. Option 1 is no up front cost, and they sell the solar juice to me for 19 cents/kWh. Not a huge savings over PG&E's 23-27, but an improvement. Option 2 is basically buying five years worth of panel output in advance, but you lock in a 16 cent/kWh rate. Option 3 is buy the expected output of the panels for the next 20 years in advance, but at just under 11 cents/kWh, and at that point you pay nothing each month to SC. The up-front cost of option 3 was just over 11k for the system they proposed for me.

I'm still thinking about if I want to go through with it, and which option seems like the best deal.

mika_ | January 10, 2013

Forgot to add the generation component to those above tiers... curse you, missing edit feature! :)

Basically add another 6.9 cents to each of those PG&E tiers. So yea, solar is likely a considerably better deal for me.

sidney_wang | January 10, 2013

mika - I think what you stated reconfirms what my understanding is with SolarCity's proposal. Please correct me if I'm wrong. Since PG&E's baseline and tier-2 rate is less than SolarCity's 19 cents per kWh rate, they would like you to maximize the allowable quota given in those two tiers, and then the rest of your usages will be covered by the solar panels at 19 cents. Does this sound right? If so, then if you pick Option 1, your PG&E will not be near zero, is that right?

BTW, you guys have pretty PG&E rate there. Mine is:

Baseline = 12.8 cents per kWh
100-130% of baseline = 14.6 cents
131-200% = 29.5 cents
201%+ = don't know since I'm not over that

DJay | January 10, 2013

I got my proposal from Solar City just today. For me the best option is the 20 year prepaid Lease and not a purchase or the monthly lease option which has the potential to escalate over the life of the lease. The reason the prepaid lease works is Solar City passes on some of the tax benefit of the rapid tax depreciation as well as the other tax benefits. I'm in California and use PG&E. The simple payback was 7 years and Solar City will guarantee the output from the solar system or pay you for the shortfall. It's worth looking at if you're a PG&E customer.

sidney_wang | January 10, 2013

jayhicks - Do you know if the guarantee output will 100% cover your typical annual kWh usage? In my proposal the guarantee output only covers approx 75% of my annual kWh usage. I don't know why they couldn't just configure a larger size system to cover 100%?

nwdiver93 | January 10, 2013

I've installed solar on all three homes I've lived in over the last four years. I'm not an electrician but I did most of the work myself, contracting an electrician for the work required by code. Installing solar is not hard to DIY and you can save thousands if not tens of thousands of dollars. My favorite sources are and Use an SMA inverter and you can't go wrong... those things are bulletproof.

bsimoes | January 10, 2013

Where I live, it seems like only one day in ten is sunny. I've been following solar developments for years now. It sounds like scientists are on the cusp of some major breakthroughs coming to market. For example, they are finding ways to gain power from all light at all angles, not just direct sunlight--great for cloudy locations like the northeast in winter! They are also more than doubling solar capacity (87% more power)while using materials that are much more common and therefore far less expensive and are finding viable storage solutions--imagine cost effective night time power from solar. When this all comes together, then I will invest. Right now, it seems like covering my roof in panels would only allow me to use a few lightbulbs--and then, only on every tenth day!

jk2014 | January 10, 2013

@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...

DJay | January 10, 2013

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.

gregv64 | January 10, 2013

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).

Mtlord | January 10, 2013

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.

sidney_wang | January 10, 2013

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.

TINO F | January 10, 2013

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.

HClark | January 11, 2013

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.

Brian H | January 11, 2013

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

dstiavnicky | January 11, 2013

Hey Stark

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

archibaldcrane | January 11, 2013

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...

sergiyz | January 11, 2013

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.

sidney_wang | January 11, 2013

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.

sergiyz | January 11, 2013

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

archibaldcrane | January 11, 2013

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.

tcunning | January 11, 2013

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

sidney_wang | January 11, 2013

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.

archibaldcrane | January 11, 2013

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.

sidney_wang | January 11, 2013

tcunning - that is a really cool monitoring system!

nwdiver93 | January 11, 2013

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".

sergiyz | January 11, 2013


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