AP Climate Solutions


Solar Equipment and Installation Basics

Just put your phone number into a Internet Solar Inquiry and "they" descend on you like yellow jackets at a picnic.

After being held captive in the living room through three presentations, waiting 4 months to be refunded the $500 "upfront, refundable starter, assessment" fee, I called an electrician we knew who had given us prior sterling service.  I asked him for a price to install solar panels with battery storage.  He said he couldn't beat the price Tesla Energy charged, and I should go with them.  

Tesla Energy had never called us during the yellow jacket swarm, so I called them.  After paying a $500 refundable assessment fee, they made one site visit to evaluate the roof.  Everything else was done over the phone, engineering, docu-signing the contract, and payment.  Upper management seemed somewhat disorganized and busy having a fire-drill, but the individual workers were superb.   The sales person was flexible.  I told her how much I wanted to spend and she designed a system that accommodated my budget.  It was OK to own, not lease, and to pay in cash.  Amazingly, other companies pushed back on these simple requests. 

Unfortunately, it did take 6 months to get the solar system in service, because they messed up on the re-roofing, which Tesla paid most of and my partner the rest.  Because of this delay I split my 2 principle payments between 2 tax years.  But that should be fine with the new Section 48 on Form 3468 allowing the deduction to begin in the year when the construction starts.  


During my research I determined 4 comparisons to make when evaluating the panels.

Efficiency The higher the percentage the better.

Energy Temperature Co-efficient / degrees F   The closer to zero the better.

Warranty: 10 year for material is normal, but 12, 15, and even 25 is available.  

Cost:  As of 2019 Mid-range was $3.30-3.67/watt

I found Tesla compared better on all these elements.  They were not the ones who told me to look for these comparisons.


How to determined the number of panels

First, I told Tesla the amount of money I had to spend and they designed a system with the number of panels plus 1 PowerWall for that amount.  The other 3 solar installers I interviewed argued immediately about the amount and would not consider designing a system for less than what they wanted to sell.  To me this was heavy handed and an immediate red-flag.

On my friend's current PGE bill, heating is with gas, and electric includes charging for an EV [electric vehicle].  His monthly average is 818 kWh for electricity.  The system Tesla suggested with the amount of money I gave them to spend would only produce 42% or 345 kWh per month with their panels which produced 325 w/hr.  They told me the roof could accommodate more panels though, and they could optimize our system to give 66% of the amount of electricity currently being used.  This was a more cooperative sales approach for me, and I authorized another 8.5K to allow more solar power be produced.  (vary the w/hr in the equation according to your chosen panel)

To figure out how many panels you should consider:     ((1 panel @ 325 watt / hour) X (6 hours sunshine / day X 30.5 days / month)) = 59.4 kWh / panel 

The final system installed contains:                                  (13  panels X 59.4 kWh / panel) = 773,173 kWh / month

or 94% possible net metering under perfect conditions.   Tesla factored in shade and weather/seasons lowering their output guarantee to 66%.  

Net Metering

The first home owners who installed solar were just as grid dependent as people without any.  The only benefit solar owners got was net metering.  The value of net metering depended on whether or not you were able to use all your energy credit before your utility company zeroed out your account each year.  Net metering returns were also dependent on the retail verses the wholesale price of a kWh, because solar arrays owners had to sell their kWh to their only customer, their utility company, and buy kWh from their only supplier, their utility company.  Yes, the electric company ruled.

That all changed with...

 The Battery.

Now solar array owners are not mercilessly tethered to their utility company, and most importantly enjoyed continued power when their neighbors are in the dark. 

I bought the Tesla Powerwall because it was guaranteed to withstand loading and discharging everyday in order to send its full load (or what we determine) of electric charge to the grid thereby maximizing net metering benefits.  Alkaloid and golf cart batteries may not be capable or guaranteed for this use and should be evaluated carefully.  I also bought the Tesla Powerwall because it was simply more aesthetically pleasing to look at than a stack of alkaloid or golf cart batteries.  Finally a Tesla app to download onto a cell phone allows grid discharge scheduling changes when necessary, and can be done even away from the house.

In California, where we live, if you have an EV, the utility company PG&E has different kWh rates dependent on the demand for electricity.  This arrangement allows us to maximize net metering benefits by sending electricity during peak time, 2-9 PM, when we earn .47 per kWh in the Summer, and use grid power not battery power during the night, when it cost only .13 per kWh.   During our now regular fire season when outages were more likely we can change this schedule so the battery would always be fully charged and available for an mandatory outage . 


The Electric Quantity Guarantee

I do not know if all solar companies give the solar generation quantity guarantee for their installation.  But during our evaluation phase Tesla determined 66% of our usage would be met by the number of panels, their arrangement on the roof, and amount of sunshine expected to shine on them.  If we do not realize their estimate they write an annual check to compensate.