Thinkin' of goin' solar..

The Tesla battery;
The math works out that one battery will supply up to 17amps at 120 volts for 1 hour at a cost of $3,500.  (That's 2kw)  I don't see what the recovery/recharge rate is though. 

Theoretically, you COULD charge it during non-peak times at 5 cents a kWh and sell it back at peak times at 35 cents a kWh. 

Power storage is the missing link in energy design. 

I have solar, and one important thing to know ( at least for me ) when buying a solar system If you can't have full sun all of the time. You should buy a system that has a micro inverter for each panel. If you have a common Inverter when shade hits one Panel it will shut the whole system off. Best investment is a balancing situation. You do not want to buy a system so big that you do not knock off the lower tier. As that tier price is actually lower than PG&E can produce the power. Mine face in a driection, not the optimal way. So I added one more than recommended Panel and happy I did. I knew where I wanted my system on the house, The first company I called came in and had their guy on the roof. He said the system would work fine. When I got the second quote from company B. I told the salesman the same information. With out checking with their tool he said I needed a large unsightly rack system, his guy came out, He said he wouldn't check the area I wanted it in as it wasn't on the work order. So informed Company A that Company B said it would not work there. He sent his man  back to make sure, and Guaranteed it would work where I wanted it. So I went with Company A. And told Company B why I didn't consider them. One reason it takes less than 10 mins to use the tool to measure the area and The Man From Company B wouldn't check it as it wasn't on the order.

At work we have to deal with the demand charge that comes with our rate schedule. Our max demand is around 400-500kW and the charge during the summer is $30-35/kW, roughly 40% of the energy bill ends up being demand charge. We will never produce enough to sell back but we can save quite a bit of a 30K/mo energy bill, and with storage we can charge on off peak and use on peak. I haven't spoken to our PGE rep but am wondering if I will have to change rate schedules because I won't hit 500kW anymore to qualify for the rate. These are what the storage units we are looking look like, 90kW and 200kW.

We are even looking at doing a storage system that would be quite advantageous since we are on a TOU billing rate.

I've worked out the calcs for TOU billing and optimizing the solar panels for azimuth and tilt.  For my lat anyways, of 38 degrees north.  I bet you are within a degree of that.

So, instead of 180 degree azimuth and 22 degree tilt for best annual generation,  I calculated that at latitude 38 degrees north, the most economical orientation is to face 37 degrees west of south, and tilt 31 degrees from horizontal.  You will generate the most power when PG&E charges the highest rates AND you will sell back excess power to PG&E also at the highest rates. 

 In California, Pacific Gas and Electric is required to buy electricity from small generators at the same rate at which they sell it. If you have a solar electric system connected to their grid, then rather than maximizing the amount of energy you produce, you may be interested in maximizing the amount of money you can be paid for generating electricity (or equivalently, the amount of money you can save by not buying their energy).

From noon to 6 pm between May 1st and November 1st, PG&E will buy or sell electricity at 35 cents per kwh. During all other times, they will buy or sell electricity at 5 cents per kwh on TOU.  I think those are still the TOU figures.

I think the key word there is buy. Whatever you decide you need to buy the panels not rent them.

My $0.02

You should buy a system that has a micro inverter for each panel. If you have a common Inverter when shade hits one Panel it will shut the whole system off. Best investment is a balancing situation. You do not want to buy a system so big that you do not knock off the lower tier. As that tier price is actually lower than PG&E can produce the power.

I agree that isolation between panels is important.  Also, a microinverter will be sending AC power to the house panel, not DC to a co-located inverter near the panel.  DC has higher line losses and at their lower voltages, have a higher current that also causes losses.  Having the inverter right at the panel mitigates most of that loss, making the panel's over all efficiency more like 97% compared to the old-school method of 84%. 

Your comprehension of tier structure is true for now, but not for long.  Electric companies will no longer be able to charge a high tier rate that isn't the actual cost to make that electricity.  So high tier users won't be subsidizing lower tiers for long.  Court rulings have determined that utilities can not charge more than actual costs to generate, they can not tack on a premium simply because one customer uses more power.  If that extra power comes from a costlier source, and the utility can demonstrate that, fine.  But not otherwise. 
That will be a BIG game changer for utilities.  Not just electric, but water as well for example.  Tier structuring will have to be redesigned and it's not gonna go over well by rate payers soon. 

O.K., I'm pretty much narrowing it down to what system I'm considering.  A company called GreenNRG that uses SolarWorld panels and Enphase microinverters.  The panels are 275 watts each and I'll have 18 of them to a rated output of 4.95kW of power.  (In a perfect world of course...)The installed price is $2.94 per watt after 30% Federal Tax Credit, installed including permits, PG&E rate structuring, etc.  I have nothing to do but pay the man.  I pay at stages of the project; Engineering, beginning of installation, completion of installation and county final inspection. I can pay via credit card with no penalties or other fees, maximizing my credit card's cash-back, air miles, or any other program they might have. 

This system is a 95% offset design, meaning it should cover 95% of my historical usage.  I could optimize the output by adjusting the panels twice a year for the winter/summer tilt and realize an additional 4% efficiency.  That's up to me to do. 

This system's panels are solely built in the USA.  Oregon.  From the silicon to the final product, it's all USA, no parts shipped in from China and assembled here.  I could get a cheaper system at $2.50 a watt, but I would prefer to support our own US economy. Also, these components are guaranteed to a minimum output rating higher than the Chinese ones and warranty is for 25 years, not 20 like the Chinese stuff. 
It will break even at 8 years based on a utility rate increase of 3% annually.  If rates increase more than that, I break even sooner.  Over the life of the warranty, I save over $41,000. 

For comparison, I would have to put the cost of this system, $14,500, in a guaranteed growth of 4.5% for the same 25 years to have paid for the same power without the solar plant.   CD's don't even pay 1% these days, and the system will probably last 40 years. 

Personally, I'll be 85 in 25 years and won't really care.  It would be nice to build the system with a payback period shorter, like 4 years or so, but I'm just not that big a user.  I could downsize the plant, but my bet is that energy costs are going to rise faster than inflation due to mandates to convert to renewable sources rather quickly. 

I'm still not dead set on this for a couple reasons; it ties up the liquidity of $14,500 for the surity of eliminating my electric bill for at least 25 years and probably a lot more than that.  I imagine it's value will not depreciate over time, and the solar value will be recovered if I ever sell the place. 

Lots to consider.  It's risky, trying to anticipate future energy costs, but I figure it's a safe investment.  Now I've got to check with my home owner insurance policy to see what a solar plant like this might do to my policy cost. 

A lot of thought went into that Jerry.  Keep us posted.

Thanks DG.  One other option is to buy this system as a 'kit' and assemble it myself.  Some sites will put together a package and sell that to you, with a cost of around 60% of a turn key system.  That's a lot of savings.  I'm capable of assembling the system, it's the sort of thing I did working for SMUD; taking engineering packages and building them in the field.  And they were a lot more technical than just a solar project of this size. The issue is when there's a problem.  No support team to fall back on.  I deal with the manufacturer for any warranty issues.  I'm responsible for getting the county permits and such.  I'd probably pay someone to give me a design drawing that meets the county codes as well so I don't end up making a bone headed mistake. 

That drops the cost to the $9,000 range and a per-watt price of $1.81

Also not sure how I would have to demonstrate on the tax filing that I am qualified for the tax credit. 

You've done a great write up on this, Jerry.  I was recently lightly researching this issue also.  Your questions and analysis are better than other specific overviews of home solar I could find on the internet.  Thanks!

I've done some more number crunching on my electric bills.  I use Quicken and have quite a historical log of electric use and cost.  My electric rate has gone up an average of 7% a year for the past 4 years.  That is much higher than I realized and had calculated a return on my solar investment based on 3% inflation rate.  With 7%, my return on investment isn't reduced much, maybe 6 months or so.  However, over the life of the solar warranty, 25 years, I save over $40,000 MORE than I anticipated with a 3% growth compared to a 7% growth in electric utility increases. 

That is huge. 

This is a no-brainer folks; if you are planning to stay in your home for more than 10 years, it is without a doubt, a significant advantage to install solar.  Even if you don't stay in your house, the tax credit makes it worth while as a selling point when the credit goes away after 2016.  I don't see how you can loose money and I don't see how you can invest the capital outlay in anything with minimal risk that could pay back anywhere near what the long term solar savings will. 

NEXT;
Technologies;
I'm considering two technologies for my solar system;
a microinverter solution where the DC to AC inverter is attached to each solar panel individually.  This allows for easy expansion since the panel now outputs AC power, not DC.  Cable sizes are smaller, no single point of failure with a central inverter, efficiencies are 15% better than conventional systems.
Then there is a Power Optimizer system where the DC to DC converter is at the solar panel, optimizing the solar voltage down to as low as 5 volts and making the panel very efficient in low light, shade and overcast conditions.  The inverter is centrally located and allows for a battery back up if desired.  It's also less expensive as well as more efficient.  I need to work on how much less cost and how much more efficient.
I do like that the microinverter is just a plug-n-play for expansion.  Just add more panels and micro inverters to your string and it's done.  Anyone wanting to start out small and grow as budget allows, this is the way to go.

I am also convinced the micro inverter is highly reliable as it's a 4th generation technology and is proven.  I'm not so sure yet about the Power Optimizer, have more to study about that.

We keep "thinking" about solar around our house too but a bit scared to pull the trigger with soo many choices/options out there.  I would, ideally, like to have a solar field vs. panels on the roof top.  That's one thing to consider ... the age of your roof.  Depending on the age/condition of your roof shingles, you might consider replacement BEFORE you go roof top with the panels or else, say 10 years down the road, you are now left having to remove all the solar to replace the shingles.  We just did our roof ~5 years ago.  Boy does time FLY!

Our front acreage has great view of the sun, not being used for anything & MORE than enough room for a good field of panels.

Hey Jerry,
Thank you for posting this. I'm just starting the research process. You gave me a great jump start!
Cheers, Lloyd

I see you guys use the terms But vs Rent.  Is "renting" referring to companies like 'SolarCity' that install/maintain the panels & you get a lower rate from them vs. PG&E ...  I'm always dodging the people in Home Depot who are there to pitch the solar stuff but that (very limited I might add) is what I understand happens.  I asked them about solar fields but they said they won't do it unless you offer up something like 10+ acres for them to do it on.

We keep "thinking" about solar around our house too but a bit scared to pull the trigger with soo many choices/options out there.  I would, ideally, like to have a solar field vs. panels on the roof top.  That's one thing to consider ... the age of your roof.  Depending on the age/condition of your roof shingles, you might consider replacement BEFORE you go roof top with the panels or else, say 10 years down the road, you are now left having to remove all the solar to replace the shingles.  We just did our roof ~5 years ago.  Boy does time FLY!

Our front acreage has great view of the sun, not being used for anything & MORE than enough room for a good field of panels.

Some things to consider with solar placement;
1. shading.  You want as unobstructed a view of the Southern sky as possible.  For our latitude of 38 degrees, that is due South at 22 degree tilt.
2. location.  As you stated, roof condition should be as near perfect as you can get it.  Plan on the panels lasting 30 years, maybe even 40. 
3. mounting. New mounting allows for very little penetration of your roof for things like leaks and such.  They have come a long ways with how to mount a panel.  Panels are smaller, thinner, lighter, and don't need as much air circulation and can be mounted closer to the roof than ever before.
4. logistic placement.  Most solar designs have things in common; the output of a solar panel is DC and relatively low voltage.  That means heavy losses with longer runs of wire to get this back to your meter.  Placing solar panels off-roof and in a field is going to make for long wire runs, and much efficiency lost.  One way around that is to have the inverter at the panels so you are running AC power back to the meter. 

I have 5 acres and a great West Southwest exposure.  I priced out putting the panels out there.  It just wasn't cost effective unless I did a self-install.  I would except I'd rather go fishing and just as likely to never finish the project to get it past county code and a final permit in order to collect my 30% tax rebate.  Ha!!  However, if you are going to place panels off-roof, consider a tracking system.  Panel efficiency can go from 75% to 99% by having the panels track the sun on both the azimuth and the elevation.  You could offset that cost with a smaller design with that much efficiency.  Again, I would have to design my own in order to make it worth the effort.  (Meaning the pay-back is way too long to make it worth my investment)  A tracking motor is no big deal; imagine an electric gate opener ram arm that rotates the shaft that is being extended and retracted.  The extension / retraction is the elevation adjustment, the rotation is the azimuth adjustment.  Of course, these change day by day, every day of the year, but....  Oh well, not worth the effort.  Just throw on an extra panel or two and call it good.  Ha!

I see you guys use the terms But vs Rent.  Is "renting" referring to companies like 'SolarCity' that install/maintain the panels & you get a lower rate from them vs. PG&E ...  I'm always dodging the people in Home Depot who are there to pitch the solar stuff but that (very limited I might add) is what I understand happens.  I asked them about solar fields but they said they won't do it unless you offer up something like 10+ acres for them to do it on.

That's correct; purchase over leasing are the terms, not so much buy over rent. 

Leasing is tricky.  You pay for all the generation of THEIR solar panels.  If the system is over built, you pay for more electricity than you needed.  This screams for a deliberate under design of the system so there will always be a utility bill from your electric company of some amount.  The good thing is that it's kept in the tier 1 rate and not getting into the high tier 2, 3 and even 4 rates. 

With a lease system, you do not have any capital outlay.  Costs you nothing out of pocket to get set up.  You 'freeze' your electric costs, but not really.  They SAY your rates are locked in, but read the contract.  They usually have some sort of adjustment or floating rate structure based on the prevailing rates of the local utility company. 

I just got off the phone with Solar City.  They are big.  They are much higher in cost for a bid on my job for a self-owned system.  Their claim for the higher cost is their size, reputation and 30 year warranty in an industry that is usually 20 to 25 years.  They do make a point; most solar companies will die off when the 30% Federal tax credit goes away.  Then what's your warranty worth?  Many manufacturers will also either go away, or are Chinese and how you gonna exercise a warranty that way? 

Now to get 'political'.  The chinese just hacked our government.  A cyber attack needs to be considered an act of war in this technological age.  Are YOU wanting to fund their actions?  I'm not.  My solar design is using materials made in USA.  It's a little more expensive, but not a lot.  The fact my dollars fund American jobs and not the chinese, could not be happier. 

Now for my rant;
We know down to the building where the hack originated.  In order to protect the American citizens who personal information was stolen and the government information as well, a cruise missile should have taken out that building. 
I worked for the electric company.  Our systems were under cyber attack all the time by the chinese.  Imagine they hack the grid, shut off our power, THEN launch a strike??!!  This isn't a game, like the cold war with Russia.  This is not going to end well.... 

Makes me kind of reconsider Hillary Clinton's private server for her e-mails.  While illegal, guess who's e-mail and personal information WASN'T attacked by the chinese?