Finally installed our PowerWalls Part 1… The build-up to the actual installation…

I will be posting the installation article a few days from now, but first, I wanted to catch my readers up on what led us to this point and provide you with a little tease…

Some History

On April 30, 2015, we were introduced to Tesla’s PowerWall.  We had a great time at the party.  We were supporting some of our friends in the EV media (namely Teslarati and Transport Evolved) by providing some coverage on social media.  I never did get to do a full write-up of the event as we departed for our epic Here, There, and EVerywhere roadtrip from Southern California to Maine and back the next day.

I did a bunch of tweets during the original Tesla Energy, PowerWall and PowerPack launch event from April 30, 2015…

(Here’s a link to the Flickr album from the Tesla Energy event.)

Some selected tweets from the original Tesla Energy Event:

 

 

However, a few things happened at that party.

  1. We grasped the applications we can use the PowerWalls for and were intrigued.
  2. We signed up to be “on the list” to buy several PowerWalls.
  3. And on a completely different note, we volunteered to help Beta Test and provide content to the Teslarati Mobile App which needed help fine-tuning and more importantly content for Tesla locations ex. California.

The @TeslaMotors Home Battery solution in a nice red! #TEatTesla

Back to the PowerWall.  As you can see above, PowerWall 1 is aesthetically pleasing.  It looks like modern art and looks great hanging on a wall.

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One can order it in many colors, and, more importantly, many sizes.

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Your correspondents for @Teslarati @danielsparks on left @dennis_p on right #TeslaLive

(Here I am pictured with @DanielSparks with the nice blue finish PowerWall.)

However, the original PowerWall was limited in its applications and at the time of the original party, the customer had to decide whether to buy the product for daily use OR for backup purposes.  Additionally, the PW1 was more expensive, required purchasers to install their own DC-AC inverters, and had half the storage, between 7-10 kWh of battery storage, depending on which application people purchased the PowerWall for.

Regardless of the application, we thought that it would be a great add to our home and we spent many a conversation on our our epic Here, There, and EVerywhere roadtrip from Southern California to Maine discussing what we would use our PowerWall for.

I was hoping to adapt the system to eventually be the storage for our excess solar production, in the future.  However, what I wanted to use the PowerWall for was to charge the batteries during our cheapest rate which is overnight and discharge it for our use during the peak (so we can maximize the solar energy that we send out to the grid and use the off-set as greater savings).  The original PowerWalls were strictly DC and required an external inverter.   We figured to “get in line” and wait until we get the call from our first night’s reservation to make that eventual decision.

Then…  NOTHING HAPPENED.  Tesla sold and installed a bunch of these PowerWall 1 systems in Australia and Germany, but very few in the US.  I was in the “right” state to possibly qualify for Tesla to install a PowerWall 1 into, we never got the call.  In fact, I know several who made reservations for PowerWall 1 that never heard from Tesla.  To be fair, the PowerWall 1 reservations was just a form to show intent.  No money changed hands at the reservations, unlike other Tesla reservations.

Tesla Solar and PowerWall 2 Event

On October 28, 2016, we attended the Tesla Solar event at Universal City.  We gladly covered the event for our friends at Teslarati under their Twitter handle for this party as some of the regular folks had personal commitments and conflicts.  So much more details of THAT event on a proper article on the blog, so you can read more about that event in the link.

We put a reservation AND a deposit down for three PowerWalls at the event and waited.  The PowerWall 2 is a dramatic improvement over PowerWall 1 in everything but its appearance.  I prefer the aesthetics of the original PowerWall, but loved everything else about the PowerWall 2.  With an integrated DC-AC inverter, the PowerWall 2 was more flexible than the PowerWall 1 and can be used to charge off ANY source.   I emphasize this as this was the categorization from many Tesla Energy folks that I spoke to.  Of course, Elon and crew focused the ability to recharge the batteries off renewable sources, specifically the Tesla Solar Roof that was the focus of that October night’s event, but there was nothing technically about the PowerWall 2 that precluded it from taking a charge from the electrical grid.  So, typical Tesla.  Order placed, and now the wait…

Some seemingly random Contact Points throughout the process.

I get my first phone call several weeks (months) after the initial deposit, the agent was nice enough, but no information.

Several months later, on February 1 and 2, I get a phone call AND an email and had some conversations with some Tesla Energy employees.

The first one left me an email

Hello Dennis,

Thank you for your interest in the Tesla Powerwall 2. My name is [removed to protect the innocent] and I just tried to reach you by phone to respond to your request for information about the product.

I’m happy to answer any questions you have about Tesla’s Energy products, including Powerwall 2, and our solar energy options.

Please feel free to respond via email, or give me a call on my direct line at 725-XXX-YYWZ.                                         

I look forward to speaking to you at your convenience. 

He signed the email and his title was Inside Energy Advisor, Solar City.

I responded via email

I returned your call today.
I will be available to speak tomorrow after 10AM tomorrow.
Please call me back.  I have registered my interest in PW since PW1 and paid a deposit for 3 PW2s…
I am looking to use the unit for charging on AC during Super Off Peak (overnight) and use the PW during Peak (when my solar is also feeding into the grid)
We have net metering in California and I want to knock out all my Peak needs and get more credit for it during the day.
(until Net Metering is done, then I’ll charge from the panels.)  I have Solar through Real Goods Solar (on a PPA (fully prepaid))

And followed up with a phone call and got the following as a response from the person that I spoke to on the phone.

Hi Dennis,

Thanks again for taking some time for me to talk about your interest in Powerwall 2. As I mentioned on the phone, we expect to schedule your site survey for you by the middle of the year. I’ll send you another email when I have more information of Time of Use load shifting and the state of net metering in California. Feel free to consider me your point of contact here. I am available to answer any questions you have, and address any concerns about your home’s ideal energy solution.

The person I spoke to had the title Referral Energy Advisor | SolarCity.

So, it would seem that SolarCity (now Tesla Energy) has been integrated into the delayed gratification ways of Tesla.  But, they were at least setting expectations in February that this won’t be happening for a few more months.  The Site Survey wasn’t even on the radar until mid 2017.

Exceeded expectations – Site Survey

Wow.  Even though Tesla’s communications in February was that the Site Survey wouldn’t be until mid 2017, we actually were contacted in March and got our Site Survey scheduled and completed on March 22, 2017.  The guy who came out from Tesla was friendly and accommodating.  He took measurements of the house, photographs of some parts and and we discussed various locations of placement for the PowerWall 2.  At the time, he was looking at spreading the PowerWalls side, by side, by side, akin to how the PowerWall 1 was configured and wall mounting the unit.

Apparently in March, Tesla was unsure how to take care of the middle units of a stacked configuration, should failure occur in the field.  I explained to the gentleman that we saw the stacked configuration and understand that Tesla was going to deliver on that configuration as well, so we would like to design the one to the house in that manner.  He capitulated.

The next challenge with regard to the initial location discussions was the Tesla representative wanted to place the units (stacked or unstacked) in a heavily trafficked location of our home.  Our gardeners and others walk by that section all the time.  Additionally, there is not much room to walk by there, so we identified a location that he felt was controversial because of its exposure to sunlight.  Nevertheless, he took notes to bring the whole solution back to the engineers to approve of any of the plans in our configuration.  It would take weeks before we heard back regarding this information.

Self Generation Incentive Program

The second week of April 2017, I started sending some documents that Tesla required for the project, utility bills and the like.  I assume this was to get my utility account information so that Tesla can work with SCE to get the installation approved, etc.  Furthermore, I was interested in the Self Generation Incentive Program (SGIP) and filled out the paperwork in April since the application program from the state was re-opening on May 1, 2017. One thing I learned in this process, because I was ordering three PowerWall 2, that kicked OUR order into the Commercial and not Residential traunch for the SGIP.  Needless to say, it didn’t look good to get the help from California, and this was later confirmed that we “missed” qualifying for Step 1 or 2 of the program and hopeful for Step 3.  As opposed to other incentives for Tesla Purchasers, this California program is filed on the customer’s behalf by Tesla (or whoever you’re purchasing your battery storage from.)

It was also around this same time that the design was getting tightened and our contract with Tesla was getting finalized.  The engineering drawings arrived with the proposed PowerWall 2 location in the wrong spot.  It wasn’t even on any of the spots that I discussed with the site engineer.  A bunch of emails and phone calls later, we clarified and agreed on the location that we wanted to install the product in.  Throughout this time, we understood that we would be getting the AC PowerWall 2 as we have micro-inverters from our Real Goods Power setup. Additionally, we continue to be interested in charging the PowerWalls during the Super Off Peak time of 10pm to 8am.  The same times that we charge our EVs.

On April 28, 2017, we executed our Agreement and the wait to install started.

Install Scheduling and Specifications Call

On Sunday, July 9, I received a call while we were on a roadtrip to the Bay Area and had a great conversation with a very knowledgeable Scheduling Specialist who was able to answer and confirm all of our requirements.  As I had indicated since the beginning, with the AC PowerWalls, we continue to be interested in recharging the units using the grid and using our Super Off Peak while Net Metering and those tariffs were still available.  He mentioned to us that current projections from Tesla in July was that the Off Peak scheduled charging that I expected the system to do was being finalized and expected to be released in approximately four weeks.  With that, we identified our installation date for Monday and Tuesday August 7 and 8.  We were told that we should expect to have power off for at least half the day for both days (four hours for each day.)

Concrete Pad pre-installation

After the scheduling call, one of the items on the contract that was still unsettled was the concrete pad that I wanted installed to floor mount the three PowerWall 2 units on. I did not want to have the units stacked and tear the wall off, so, I asked Tesla about those. On our original contract, it showed a $0 value for the work and it was listed as additional and optional. After further discussion, it turns out to be another $500 that Tesla was going to charge for the concrete work.

To prepare for the PowerWall 2, we needed an old planter removed and replaced.

Here it is before:

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And we wanted the concrete pad to be an inch taller than our airconditioner.

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Instead of having Tesla do the work, we got a local concrete guy to take care of it for less than $200.

It took a little while to get specifications from Tesla and they started off with a 48×48 inch concrete pad. I said that sounded excessive, and they finally said 36×36 inch pad. That still seemed big to me, but decided to ask our concrete guy to do a 37×37 inch pad.

So, a few weeks prior to Tesla’s installation, on July 22nd. We had our concrete pad completed.

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We asked him to raise the pad an inch above the airconditioner, so it is a 4 inch rise, and not a 3 inch one.

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Here it is dry and waiting for the installers.

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Waiting for Godot, err… Tesla

Having completed our concrete pad…  we waited…  Being a long-time Tesla owner is like being in Samuel Beckett’s play…  Except, it’s not Godot that we wait for.

And, as I mentioned earlier in this article…  I wanted you, dear reader, to experience our Tesla PowerWall installation as a tease.  Your wait will NOT be as long as ours, but definitely a good tease, because Tesla was on-time on August 7 and 8 and we have pictures…

…on the next article…  However, I don’t have that written yet, and I intend to publish…

…Soon.

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In the meantime, a recap of some Tweets I’ve sent out (and some responses) recently…

@vdivanov corrected me and said CONDUITS, ’cause it’s not liquids going through that!

Lots more to come, in another article… SOON!

Solar Panels and Inverters, Our First Solar Repair Experience.

In 2012, shortly after moving to electric with our BMW Active E, it became apparent to us that installing a solar array on our roof was going to be beneficial for us to lower the cost of our transportation fuel as well as our consumption of energy at home.  Producing our own fuel coupled with net metering and time of use would provide us with efficiency that would provide for a rather quick payback.

As I understand it, Net Metering allows utility customers with the ability to export the power generated by their devices (in our case, our solar panels) to the utility at the retail rate of energy as a credit against our overall consumption.  Time of Use is a program that provides differing pricing for electricity depending on the time of day and week that energy is consumed by a utility customer.  When we first started on this program, our peak times for energy mapped perfectly with the hours of sunlight.  That is to say, the peak energy times were from Monday to Friday from 10am to 6pm.  This meant that during the the times that we were not at home, our solar panels would produce enough credit to be offset during our primary usage, which is after 6pm and before 10am (in SCE territory, since we installed our panels, this peak time has changed and shifted to 2pm to 8pm).  Under our original assumptions, and armed with a single EV that was capable of an 80-100 mile range, we figured our break-even for this project to be in the approximately six to seven years.  As many long-time readers have found out, it was soon after getting into our BMW Active E that we dedicated ourselves to a primarily EV existence that we went from one EV to three EVs and back down to two EVs.  With the amount of driving that both my wife and I did, this break-even point was reached sometime last year (around the three and a half to four year mark.)

When we first bid out our homes’ solar PV, we shopped it around and ended up with Solar City.  As I’ve documented before, because there was a snag in the age of our roof, we had the opportunity to re-open this to others and ended up with Real Goods Solar (RGS Energy).  We documented all this in some articles on this blog.  I did a follow up that covered the installation.  Because of how things worked out for us, we opted to pre-pay our power purchase agreement with Real Goods Solar for the 20 years of service that we signed up for, if we do this again now, we would buy the system instead, but I didn’t want to have to worry about maintenance and the like.

Which brings us to the subject of inverters.  As I understand it, the inverter is the device that converts the Direct Current (DC) produced by our solar panels into AC (Alternating Current) energy that our appliances and other domestic household devices uses. Every solar company that I spoke to during the bid process basically said that the main thing that would break in a solar installation is the inverter.   Under original solar installation designs, solar installations would have ONE or TWO inverters that connect the whole system to the home and electrical grid. This means that if the inverter failed, the energy produced by the solar panels would not be converted to AC power and be effectively out of service for the whole system until it gets repaired.  We picked Real Goods Solar primarily for financial reasons.  However, at the time, they pitched an interesting system using micro-inverters.  Instead of one (or a primary and backup) inverter situation for the house, each solar panel has its own inverter that converts the energy produced by each panel to AC.  This configuration spread the risk of outage from the whole system to just a single panel at a time.  Being a systems guy and understanding single points of failure versus minimizing this, I appreciated the pitch, but money savings really drove the decision.

One of the technical benefits we got from having the micro-inverter solution is we are able to see the production of our solar system down to the panel level.

So, on a normal day, we can see the panel production on either the website on a browser:

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Or on the mobile app.

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A few months ago, we experienced our first repair under this program.  On the weeks prior to failure, I started receiving alerts regarding AC voltage being out of range and on March 8, I noticed that one of the panels had a hard failure.

This is a screenshot of the email that I received to show the errors in one of the micro-inverters that started to occur.

Enphase Alert Screenshot

It looked minor at first, but as you can see in the graphic of our system, one of the panels is grey.  And this is a good indication of the failure AND the location of the failure in our system.

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I reported this to Real Goods Energy and received a trouble ticket on March 9th. They remotely diagnosed the problem and required me to contact the owners of the system.  Since I am on a Power Purchase Agreement (PPA), I don’t actually own the system on my roof, I effectively buy power from those that do at a predetermined rate when I signed my contract.  Traditional PPA purchasers do this on a monthly basis that have riders that increase the cost per kWh over the years, but we decided to prepay the entire contract at the time that we finalized our deal and therefore fixed our cost per kWh soon after the installation was complete.  Therefore, technically, we don’t own the system on top of our roof.  The owner to the system provided approval and we waited for the repair to be completed.

It took about a month for the full repair to be completed and I estimate that we lost about 40kWh of production from having one panel out that entire month.  To put this into perspective, the whole system produces 40kWh on a Summer day, so even though the panels were missing one of the 28 panels on the roof from producing, my outage was only equivalent to one day’s outage with a more traditional set up.

So, what does a micro-inverter look like?  Well.  Here are a few photos.

Here is the broken one getting put back in the box.

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Here it is on the roof.

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And here it is installed and in-place.

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In writing this article, I was looking for pictures of larger inverters and came across this picture of a commercial solar installation from Brightergy.com.

Solar Inverters at Cross Midwest’s solar-power installation

The picture is from an article “How Solar Inverters Work” from February 6, 2013 on the brightergy website. It also covers inverters.

Here is the picture of a more common inverter from Wikipedia’s article on Solar Inverters.

Solar Inverter from Wikipedia
Solar Inverter from Wikipedia

Why would I not want to use micro-inverters. In moderate climate, like California, it works great. However, someone in Arizona has mentioned to me that it is too hot in their climate. I don’t know if this is true, but it has been reported by one person to me.

Consider going solar, use our referral code here.   If you wish to have a longer discussion, I have access to other installers as well.  Send me a tweet and we can get that process started interactively.

Minimizing gas use…

So, about a month ago I was inspired by an article, on Plugincars.com regarding BMW’s plan to allow i3 drivers the ability to rent a traditional gas (internal combustion engine/ICE) BMW when they need it, to figure out how often my family uses ICE vs. EV.

Seeing that there are two of us who use vehicles in the family, I figured to count the FAMILY’s usage of Gas vs. Electric.

So, I decided to log my mileage of use for the period between March 6 and April 5, 2013. It was a rather interesting log. We travelled a total of 2,948 miles in this period of which we did 2,499 miles Electric vs. 449 miles on gasoline. I anticipated a heavier gasoline use this past month as we were going to help our nephew move. Ended up not using the X5 for this and he only needed a few items which fit our ActiveE, so, score 1 for the EV use.

However, as things do tend to go to the mean, the 328i ended up with a recall. Of all things, in the electric wiring of the vehicle. As a result, had to do almost 100 of those miles gasoline and 22 of the approximately 100 miles was using a 5 series loaner.

Good thing the BMW ActiveE folks were not planning on the Morro Bay FB meetup until tomorrow, otherwise, I would be adding another 460 miles on gas as I’m not crazy enough to wait the hours needed to charge the Active E on the drive north and south to the meet.

Hats off to some of my fellow electronauts who live a fully electric life, I’m not sure if I can quite do that yet.

These brave souls all live fully electric, or at least nearly so – check out the blogs of Todd Crook, Peter Norby, and Pamela Thwaite

Todd is impressive because the whole family uses the ActiveE, solely! Peter has both an ActiveE and a Honda Fit EV, and Pamela Thwaite‘s family has 3 Electric cars. A Tesla (roadster, I believe), Active E, and a Mitsubishi iMiev for the kids.

Still, at 85% electric vs. 15% gasoline. I think I’m doing well… Saving a lot of money and enjoying the ride!  Figuring that my 2499 electric miles is closer to $21.64 and my 449 miles of gasoline is closer to $85 (using an inflated approximate $0.19 per mile as I do not have the cost per mile for the 5 series vs. my $0.17 per mile calculated convertible 328i cost.)  If I were to extend $0.17 per mile to the 2499 electric miles, I’m saving about $400 on not buying gas.  (not even factoring in $100/hour per the currently controversial articles on Tesla’s leasing program.)

When we get a Tesla Model S (unless BMW comes out with a more aesthetically pleasing i3 or cheaper i8 BEV, not hybrid) and with that range, we would probably not need to drive as much gas as we do now.

Some significant mileage… 25,000 Miles and counting…

ActiveE by dennis_p
ActiveE, a photo by dennis_p on Flickr.

Reached 25,000 Miles a few days ago… Seeing that my one year anniversary will be in a few weeks I figure to write more about my experience then.In the meantime.

25,000 miles all electric. Using a blended 1.5 cents per mile figure (just estimating here since it’s closer to 0.8 cents per mile since I’ve gotten solar at home) nets me a $375.00 energy cost for the 25,000 miles. Comparing this with an estimated 15 cents per mile for gasoline (rounding down ’cause it’s easier to do the math…) puts the estimated mileage cost to $3,750.

So looks like we’ve at least saved $3,375 this past year on the miles that we used electricity vs. gasoline.

The savings are compelling.

Real Goods Solar installation

A picture is worth a 1000 words… So,here are some pictures…

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This is what the front of the house looks like. One of the good things about our house is the fact that the south facing roof (the one with the most power generating capability) is not on the front of the house. This fact made it easier to sell Solar Power to the better half on the aesthetics of the solution.

More front of the house shots. Closer to the roof –

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My new roof looks great, but you’re here for the Solar pictures…

So, the next picture is from the backyard looking up.

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That doesn’t really give you a good shot of it, so… Even though I have a fear of the sudden stop after a fall… (i.e. it’s not really the heights that scare me or kill you.) I decided to get on the roof to take some pictures.

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Here is a nice shot of the conduit runs for the electrical cable.

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Here’s the ActiveE peeking out from the roof.

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Closer shot…

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Here’s a shot of the junction from the South Facing and the West Facing roof… The conduit still looks good.

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Better shot of the junction

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Panoramic of my most productive panels

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Panoramic by the chimney. The shading really wrecks havoc on my production for three of the panels.

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Some of the nice warning signs

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Another shot of the ActiveE from the roof…

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Meter is going backward! Success!

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One of the things you get with Real Goods Solar under this plan is TWO monitoring systems. This one is a closed system mounted by your panel and it is for the finance company to ensure that they’re producing what they committed to.

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Here’s the one from Enphase that allows the user to see what the system is producing. It connects to the panel via Ethernet over Power and then you need to have a port on your router to connect to the Internet.

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Here’s the ports on the box –

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Here is the sub-panel for the whole system –

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These are the breakers for each of the 3 sets –

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Here’s the disconnect for the whole system –

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Lastly, the installation was very clean, here is where they ran the power to the main breaker as well as the Ethernet for the monitoring.

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The conduit on the left side (on the wall of the house) is where the power comes from the solar panels to the main panel.

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I asked them to run two Ethernet runs from the monitoring to the wall so that there’s one spare in case of failure in the future. This sucker is supposed to last 20 years.

That’s it. Several THOUSAND WORDS worth of pictures.

Interested in going solar? Get a quote from my solar vendor – Real Goods Solar.

More Napkin math, OR – Real Goods Solar and BMW’s program is a REAL GOOD deal!

Saving money while saving the environment is an addictive process.  It’s crack for good Karma!  I feel like Michael Corleone in the Godfather III, I try to get away from it, but they keep dragging me back in!

As I had indicated on my Ping! post, I got “unofficial” Permission to Operate (PTO) on August 17, 2012 and finally received official PTO ten days later on August 27, 2012.

So, we’re now running our car on Solar Power…  or are we?  Unless your house is completely disconnected from the electric grid, what you are really doing is netting out generated power from the solar panels on the roof with consumed power from the electric grid.  So, if you’re overproducing power from your solar panels than what you’re consuming, you get money back, otherwise you’re really just netting out what you’ve made with what you’ve used.  As I have published previously, the rate to charge depends a lot on what tariff you’ve chosen.

In my first napkin math post, I charged on the SCE Domestic rate which effectively got me charged at $0.31 per kWh as my usage of electricity had already pushed me to Tier 5 for most of the billing periods.  In order to normalize and compare ICE vs Electric, I calculated that the cost under the first plan was 1.714¢ per mile

By my third napkin math post, I attempt to alleviate that $0.31 per kWh charge by opting for the whole house SCE Electric TOU Tiered rate structure, this pretty much reduced my rate to charge to $0.13 per kWh for my car charging needs (as well as my pool pump as I switched the time of use for that from mid-day to mid-night to 6 am).  As we noted on that post, my cost per mile dropped to about 1.412¢ per mile.

So, the big question is what is my cost per mile under the Real Goods Solar and BMW ActiveE program deal.

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Before I took advantage of this deal, I would like to tell you about my search to save our energy costs further.  Not necessarily the environment, but that’s always a fun side-effect with this accidental environmentalism that I’ve stumbled across.  After signing up for the Active E, I figured to become educated on what my solar options were.  To that end I requested quotes from three solar companies in the Los Angeles County area: Peak Power Solutions (Sunpower reseller), Solar City, and Verengo Solar.  Each solution had its strengths and weaknesses and around the third week of March (between three to four weeks of receiving my ActiveE), I decided to sign a power purchase agreement with Solar City.

A power purchase agreement is basically the right to buy a guaranteed amount of power from a provider for twenty years.  I don’t own the solar array on my roof, someone else does (a finance company) and I agree to pay them a fee for this.  This means at the end of twenty years I get the option to keep buying from them, buy the equipment outright, or have them remove the array from my roof.

So, how did I compare the suppliers.  Ultimately, economics.  So, at the end the Solar City deal that I had originally signed was approximately $0.10344 per kWh.  How did I calculate this?  All the suppliers with the power purchase agreements have a guaranteed rate of production for the 20 years that the system will be produced, so I divided the total guaranteed kWh by the the total prepaid lease amount, and that’s how I got to the $0.10344 per kWh.

So, I thought that was it.  I signed up with Solar City, got a rate that I felt was fair and waited to get installed.  Solar City’s installation process was methodological and professional.  They provided a website to track the progress of the installation and was quite impressive.  However, their process proved to be the opportunity for Real Goods Solar and BMW’s deal to come in and make my costs even less.  Around the beginning of May, during the design and survey process, Solar City notified me that in order to proceed with the installation of the system that I signed in the third week of March (about five to six weeks earlier) my roof would have to be replaced.  This change provided me with an out-clause from completing the agreement that I signed with Solar City.

As I was mulling through a roof quote and setting up more roofers to see what this replacement roof would cost me, Real Goods Solar and the BMW Active E program announced their program.  So, I figured, why not ask them to see what the solution would cost me.  I contacted Real Goods and they had a sales agent contact me within the day.  Their initial quote was 12% less than the Solar City quote and agreement that I went with.  However, I had to bundle in the cost of the replacement roof and needed to get the total project cost to figure out which deal I was going to take.

Figuring that both solar companies would probably be able to get a reliable, professional, licensed roofer at a lower cost than I would have on my own, I went back to both providers to find out what the roof was going to cost from them and go from there.  My assumption was not exactly correct as my independent roofer quote was actually $500 to $1000 cheaper than the lowest quote from either solar provider.  I was at an inflection point.  I was already saving quite a bit on gasoline with the TOU tariff and this would have been the time to quit or cut bait.  I approached both providers to see if there was anything they can do to their quote to make the entire project less expensive (replacement roof and solar).

The dilemma is how do I adequately calculate my cost per kWh based on the various scenarios.  I figured the most conservative thing to do would be to subtract the lowest roofing quote from my total project cost and use that figure to divide my cost per kWh over the guaranteed generation over the life of the system.  Granted, this methodology would provide me with an understatement of cost as the guaranteed rate of production is typically rather conservative of the suppliers, but it IS what they guarantee, that is why I went with that methodology.  When the system has really sunny days it will outperform this guarantee and my actual cost per kWh is less than what I calculated.

With the total system cost, I figure that my cost per kWh is $0.10250, however, if I subtract the roof cost my cost per kWh drops to $0.07970 based on guaranteed power.  Seeing that my energy cost is a 38.7% reduction, mathematically speaking, my cost per mile is approximately .8657¢ per mile ($0.008657) or 73.58 cents per day based on the 85 mile day that I had in the last post on this matter.  Not bad at all.  Of course, the system is currently overproducing and with time of use I actually am paid a rate for the energy I am sending back to the grid during the day and most of my charging occurs between midnight and 6 am, so this is, like my other estimates “napkin math”, so I am certain my actual costs are lower, but the numbers work for me.  Remember, my original calculation of a comparable vehicle costs were approximately 17 cents per mile, so my 0.8657 cents per mile cost is quite a bit less than driving my ICE 328i convertible.

So, there you have it.  My energy costs are a heck of a lot less than it has been.

Want to see what my system is producing, check out the sidebar production information courtesy of Ken Clifton‘s plugin for WordPress or directly from Enlighten’s website.

In a few days, I will follow up this Napkin Math article with pictures and my opinion on the installation from Real Goods.  Let me just say, I recommend them and if you give my name, I get a referral on your system, so contact me if you’re serious and I will recommend them.

Interested in going solar? Get a quote from my solar vendor – Real Goods Solar.

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Ping…

Yes,  I’m still here.

I’ve been busy with our ActiveE and have been on vacation on top of that…  I promise at least two more ChargeIt! articles for two really great food AND charging facilities (here’s one of them – Gjelina at Electric Avenue in Venice). [Here’s the other Church and State – Mateo Street Charger, now caught up for the Great Food series.]  However, trying to decide on whether to do the next article on joining the Solar powered movement.

Still haven’t received my “official” PTO, but I did notice an off-cycle close to my SCE account this past Friday (August 17) (when I logged in to my SCE account on Saturday) and followed up with a call to SCE on Saturday morning.  According to the telephone representative my permission to operate (PTO) letter went out last week and I am now generating my own energy via the Solar Panels on the roof of the house.

Thanks to BMW and its partnership with Real Goods Solar, I was able to get a system at a bigger discount than I had originally negotiated with Solar City.  But that will have to be the subject of a subsequent post.  As well as updates to my Back of the Napkin Math series (1) and (2).

As those that have followed this blog, I’m not an “environmentalist”, I just like to save money.  As long as one has a “long” view, the money savings will follow those that do things that are “environmental.”