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Saturday, July 13, 2024

Heat Waves and Virtual Power Plants

Like many parts of the world, we're having a heat wave; multiple days with highs over 100°F. Luckily we have air conditioning and, during these high temps, it's been running 14+ hours per day. During a heatwave, as you can imagine, there are millions of AC units sucking down kilowatts and pushing cool air into homes and businesses. All of this AC use puts a strain on the grid and there have been some outages. Our neighbors lost power for about an hour while we were visit them for a Sunday cookout. 

Luckily, the utility was able to restore the power quickly. An hour is not too bad; the house didn't get too hot and nothing in the freezer/refrigerator went bad. As you can see in the image below, as I write this, my local utility has over three thousand customers without power. 

It's impressive that, even during this heatwave, they have better that 99.7% service reliability. But, if you're one of the 0.28% without functional electricity for fans and AC, it doesn't feel impressive. Checking the outages the next day and there were fewer than 100 customers affected, so more than 3000 were back online in less than (maybe much less than) 24 hours.

So how do you help reduce the load on the grid and prevent outages when there's a heat wave and everyone wants to run their AC? Our utility has several demand mitigation schemes and they are using them all this week. 

Demand Response 

The three residential programs our utility has are Peak Rebates, Smart Thermostat, and Virtual Power Plant (VPP). They use these programs when demand is expected to be high or what they refer to as an "Energy Rush Hour." 

Peak Rebates

With is program, the utility notifies you the day before and asks you to reduce your energy use during a 3 or 4 hour window the next day. You then receive rebates based on how much your usage is below your typical usage during that period. You get paid for "Negawatts." The rate is $1 per kWh that you don't use compared to your usual load for that time. So if that's when you usually do dishes, laundry, or charge your EV, moving these to other times of the day could give you some payback and reduce grid stress for everyone.

Smart Thermostat Energy Rush Hour

With this program you can let the utility have the ability to tweak your air conditioner settings. They pre-cool your house before the peak hours so your AC doesn't have to run as much during the high energy demand period. For any month that you participate in a Rush Hour event, you earn $25. 

Virtual Power Plant (VPP) 

Last on our list, and the one I want to spend the most time covering, is the VPP. Echoing the Smart Thermostat naming convention, our utility calls this the Smart Battery Program. To participate in this program, you must have an approved residential energy storage battery such as Tesla Powerwalls. When participating, you allow the utility to discharge your battery when the grid needs the energy most. In return, they pay you $1.70 for each kWh dispatched. You can select your participation level at 30, 50, or 80 percent of the nominal storage capacity of your pack. We're participating at the 80% level.

For the recent heat wave, they dispatched our battery 4 times.

Here's one of the dispatches: 

As you can see, the battery is being dispatched at a rate of 10.8 kW. This rate allowed them discharge 80% of the battery capacity during the 3 hour event. During the 4 event they were able to extract a total of 129.6 kWh. At $1.70 per kWh, that's $220. 

As you can see in the chart above, we used 57 kWh and only exported 32 kWh. The point isn't about how much we used but WHEN we used it. As you can see, we charged the battery at off peak times before 6AM and during the Rush Hour event, from 5PM till 8PM, we were exporting solar and battery energy to the grid. 

The Results

Combining the Energy Rush reward and the VPP payment, we earned $245 for our July electricity bill. We'll likely have a negative bill this month. Not bad for our household, but how'd the local grid over all do during these events? 

As you can see in the graph above, grid load was reduced by 109 Megawatts when the Rush Hour started. 

Sunday, July 7, 2024

Tesla Vehicle Production (Q2'24)

We've been anticipating the year Tesla breaks through the two million vehicle annual production mark for some time.

We first asked the question in 2022. At that time, Giga-Austin and Giga-Berlin were newly opened and had a long way to go to ramp their production to high volume, so the answer was clearly 'No' for that year.   

2023 had a chance of being that milestone 2M year. Our estimates for 2023 ranged from 1.86M to 2.18M. Tesla's actual 2023 production was 1,845,985. This was very close to the low-end of our estimate, but again below the big 2M mark. Macro economic, specifically high interest rates, depressed sales in the second half of 2023 and continued to pull-down the first half of 2024. This is still an open issue for the second half of 2024. 

Tesla has reported production and sales for Q2'24, so now we've got the numbers for the 1H'24 and it looks a lot like 2023. 

Production 2023 2024 Y/Y Delta
Q1 440,808 433,371 -2%
Q2 479,700 410,831 -14%

So far, 2024 is not looking like it will be the magic 2M year either; however, it still has a chance. Giga-Berlin is expanding (despite the astroturf protests) and there are signs that interest rates will be reduced. I want to add a little context around this Q2 result. Yes, it is lower than Q2 last year, but Q2 last year was their best quarter ever and this Q2 is their 3rd best sales quarter ever, so it's far from a failure. In fact, it beat the street's estimates and this is one of the reasons the stock has rallied.  

When we initially estimated 2024 production (here), we had a range of 2.0M to 2.7M. The high end of that range is now off the table. If we stick with the Q3 and Q4 estimates that we currently have, that brings the year in at 1.91 million, just 90 thousand shy of the big 2M milestone.

However, our current estimates for Q3 and Q4'24 are now the more conservative 466k and 490k, respectively (shown in the graph below). That brings a total of 1.83M for this year, about flat to the 1.85 of last year. This result of flat to 2023 would be inline with the "between two growth waves" description that Musk used in the Q2 investors call. 

I must admit that I'd be highly disappointed if Tesla produced or delivered fewer vehicles in 2024 compared to 2023 and I think many other investors would be too. So, I expect Tesla to pull a few demand levers in Q4 to make sure they exceed last year's results, coming in at 1.9M for 2024, but I still have my fingers crossed that maybe, just maybe, they hit 2 million.

Friday, June 21, 2024

Summer Solstice 2024

June 20th was the longest day of the year, here in the northern hemisphere. It seems like a good day to look at our solar output.

As you can see in the image above, we had over 15 hours from sunrise to sunset at our Portland, Oregon area home.

Our solar production started just before 6AM and ended just after 8PM for 14 hours of output. Production peaked just after 1PM, aligning with the "solar noon" shown in the first image.

What do the colors mean? This the from the Tesla app. The blue portion is energy that was used to power our home. The green area was charging our Powerwalls. Finally, the grey sections are were we were feeding the grid and running our meter backwards (via 100% net metering). The blue spikes are the AC unit kicking on. It was a hot day. 

Comparing to Previous Years

On this summer solstice day in 2024, we generated 77.6 kWh of electricity. 

I cannot compare this to our 2023 solstice results because we don't have data from last year because the solar panels were off the house while we had our roof replaced. 

In 2022, however, we generated 76.5 kWh. So 2024 performed a little better.

The first summer solstice for our solar panels in their current configuration was 2016. In that year, the longest day of the year yielded 68.6 kWh. So this year was one of our best ever results for a summer solstice. Even though this was the longest day, July usually has a day or two that are over 100 kWh of production. There's less cloud activity in July and the curve of the production output is much smoother. Or maybe it's all the fireworks causing night time production /s

It's nice to see that, even though we've had portions of the system the system since 2007, we are still getting good production from it. I may have to write up a degradation report and compare annual production over the years. Coming soon. Have a great summer!

Wednesday, June 5, 2024

When Will EVs Become Mainstream : 10 Years Later : 2014 Predictions

In June of 2014, we attempted to determine when EVs would become mainstream in the US. At that time, some of my EV-enthusiast friends were convinced that the legacy automakers would switch to 100% EVs any day; while EV detractors said that EVs were just a passing fad or a west coast niche product at best.

Our prediction here at carswithcords.net was between these two extremes. We assumed that EVs would be successful and follow the sigmoid adoption curve that many technologies follow. Although, people do not buy new cars as often as they buy new phones, so the timeline would stretch over half a century. Here's the graph from that 2014 estimate: 

EV Adoption Curve - 2014 Estimate

Now it's 10 years later. How'd our prediction fair? Here's a graph comparing our old estimate to the actual sales in the US.

As you can see in the graph, the actual sales tracked just below our estimate from 2015 through 2020. However, in 2021 things changed. US EV adoption jumped up; 2022 continued this upward trend. Our estimate had this "knee" occurring in 2025. I'm happy to see the upward trend coming sooner than the estimate, but I'm cautiously optimistic that the uptrend will continue. There are factors that may slow adoption in 2024 and bring it back in line with our prediction.

Several black swan events occurred during this time window where we see EV sales exceeding the prediction. The two events most relevant to our discussion are the supply-chain shock and hyperinflation. The pandemic caused supply-chain disruptions for several products. Automobile production was particularly hit hard. Chip supplies from anti-lock brake systems to infotainment units were in short supply. Since EVs are newer designs, they use newer, more abundant chips. This meant that, although impacted, EV production was not hit as hard by the chip shortage and supply chain issues.

Second on our list of things impacting the automotive sector is inflation. Inflation in the US was over 8% in 2022. The high inflation rate was in response to economic stimulus from the pandemic and other factors. To fight inflation, interest rates were increased. High interest rates particularly impacts new car sales since most car purchases are financed. EVs are still generally on the more expensive end of the new vehicle spectrum. Given this current higher price point for EVs, EVs are generally purchased by higher-income households. These households are likely to be less impacted by vehicle interest rates either because they can make higher monthly payments or because these households simply buy the car outright without financing it. So, just as with the chip shortage, EV sales are impacted by this issue, but not as drastically as non-EV car sales. 

We'll find out more about the interest rate impact after inflation returns to a normal 2% rate, interest rates are lowered, and we have published a trailing year's worth of data. So even though we've waited a decade to see how this has progressed, the transition is far from over; in many ways, it is still beginning. The Tesla is over 20 years old and the Nissan Leaf has been on the market for over 13 years, yet the transition to EVs is nascent.

Both of these events worked to give EV sales a relative percentage boost. The supply chain issues were resolved in 2022, while inflation continues to be an issue throughout at least the first half of 2024. These events impacted EV sales volumes, but they suppressed non-EV sales to a greater degree. It is important to note that these are transitory events. I would not extrapolate this growth rate into 2024 and beyond.

EV sales in the US (and globally) are growing and the overall trend is up. However, reality is rarely the smooth curve of predictions. Many factors ebb and flow to make the "actuals" a bumpy ride. Picking the signal out from the noise is the tricky part.

Not Just About The US

For a more complete view, I've added global EV sales and China EV sales to the graph. As you can see the US is a laggard compared to these. However, EV prices are continuing to drop, battery ranges are increasing, recharge times are improving, and the number of places to plug in continues to grow. These will cohere into an EV tipping point by 2026 and the steep acceleration phase will begin (even for the US).    

Thanks for reading my blog.



Sunday, May 19, 2024

Deadfront Blockage - Tesla Mobile Connector Will Not Plug In

Something is stuck in the left side of this NACS connector  

We purchased a Model Y a few months ago. Tesla vehicles no longer come with a Mobile Charging Connector, which is essential equipment to keep in the frunk. Luckily, we had the mobile connector that came with our 2016 Model X. As you can see in the image above, it's a little beat up, but it works fine and I have a bunch of adapters for it, so I'd rather not replace it. 

Well, things didn't work out as expected. 

When we tried to use the 2016 connector with our 2023 Model Y. It would only insert part way. It didn't insert far enough for the locking mechanism to engage. You could hear the lock clicking against the connector over and over. Something was wrong and an error message popped up to confirm this.

Error message when trying to use a 
deadfront blocked charging connector
(our Model Y is named "Sometimes" - get it?)

At first, I thought the old connector was incompatible with newer vehicles. That was not the case. The 2016 mobile connector (aka Universal Mobile Connector) works with all of Tesla's 2012+ (post-original Roadster) vehicles, so it should work fine with our new Model Y. The problem was that there was something lodged down in the connector.

Both sides of the connector looked identical, so I assumed they were fine. They were not. There was something lodged in each side. What was in there? After some investigation, I discovered they were called "deadfronts". Deadfronts are used to insulate the connectors and prevent you from accidentally touching the conductive portion of the receptacle (sounds like a good idea). 

The only problem is that deadfronts are intended to be on the vehicle receptacle rather than the charging connector. So they popped off from the vehicle and were now stuck in the connector. This was a common problem until 2019 when the receptacle was redesigned. These might have popped off years ago, but it was not a problem when I used this mobile connector on the Model X since the deadfront came from that vehicle. When the connector was plugged in, they simply filled the same gap they had vacated.  

So now to the task of removing them. They were challenging to get out. Making sure it was unplugged, I tapped the connector, pounding it on the heel of my hand with no luck. The deadfront would slide forward some, but it would not fall out. I tried tweezers and a small screwdriver with no luck. Getting desperate, I tried a drill with a small drill bit. I used a slow drill so I didn't pierce the deadfront and drill into the connector itself. 

This method worked! I was able to remove both of them. I inspected the connector and nothing appeared damaged.

Deadfront Removal Method

Two removed deadfronts

It might have been smarter to go to the Tesla service center and let them deal with this, but I wanted to fix it myself. And if things did go wrong, this connector is old and we could replace it with a new one.

Now to test it. With these removed, the connector seated properly, and charging worked fine!

Sunday, April 28, 2024

Environmentalist? Technogaianists? Techno-Optimist?

Earth Day was last week. I think it's fair to say, everyone sane wants a world with clean air and clean water. To get there, I want to transition to a world that's powered by renewable energy rather than polluting fossil fuels, but I've never liked being called an "environmentalist."

That label has a stigma, connotation... baggage that I'm not interested in. The saying is Reduce, Reuse, Recycle. How far do you take Reduce? Do you just take it to the point of reducing waste? That seems reasonable. If a little is good, then a lot must be great, right? So do you take reduce to the point of self-deprivation? There it is. The idea that you have to deprive yourself to be a true environmentalist is the part that chafes.

I don't want to wear hemp and only travel on foot. If that's what makes you happy, you do you. I think there's a better way.

If I recoil at the term environmentalist, what term best fits the renewable energy abundance philosophy I hold? Technogaianists? Techno-Optimist? Maybe, let's explore these. 


Technogaianism is the idea that technology can be used to stop the damage that we're doing and even reverse past damages through advancements in technology. So far so good. However, this optimism can be taken to the wrong place. Some people calling themselves Technogaianists say there's no reason to change any of our current behaviors. Taking this idea to an absurd level, they argue that there's no reason to stop (or even reduce) fossil fuel extraction and use. Whatever problems these may cause will be solved by a yet-to-be-discovered technological breakthrough. This head-in-the-sand approach is not the way.
I don't want to gamble the future on the hope that a future technology will be able to undo our damage before it's too late.

My understanding is that the Technogaianism concept includes geoengineering, carbon capture, and the like. These seem more like bad ideas that are funded and promoted to allow us to continue down the status quo fossil fuel path with the promise that some future generation will invent the solution to clean up our mess. I don't want to burden the next generation with our mess. I don't want to gamble the livability of our planet on the hope that some technology will be developed. Wildfires are burning now. Hurricanes are making landfall now. The time to act is now; with the many technologies that we have today.

The time to act is now, with the technologies that we have today.

Let's look at one more term.


In a recent essay “The Techno-Optimism Manifesto,” the author, Marc Andreessen, lays out his vision of how technological advancement leads to to abundance, progress, and human flourishing. I agree with many of these ideas and have even written about how embracing renewable energy leads to a world of abundance. However, Andreessen’s view of techno-optimism is laced with his laissez-faire, no-regulation, market-driven, no-social-responsibility attitude. Portions of Andreessen’s manifesto seem unhinged once you walk down the path of his particular philosophy. 

Much like the Technogaianism philosophy, this brand of Techno-Optimist assumes the needed technologies will be developed when needed and it further assumes that the invisible hand of the market will make them readily available. I do not want to align myself with this kick-the-can brand of techno-optimism. Not that one person gets to define all of the aspects of the term, so Andreessen is not the final arbiter, but he is not the only one with this view of the term.

What's The Answer

Where does that leave me? I want to eliminate fossil fuel use. I want to deploy the renewable technologies that exist today, like solar, wind, battery storage, EVs, heat pumps, induction cooktops... I want to halt the damage we're doing, rather than burdening our children. I don't want to just ignore things and hope that the next generation will 'just figure it out.'  I don't want to count on a techno-miracle or on the "free markets" to save us. There is a role for regulation and environmental protection. 

So how would you label this "renewables now" attitude?

Sunday, April 7, 2024

Solar Panels: What if I need a New Roof?

We installed solar panels in 2007 and we added more panels in 2011. Now, all these years later, it's time to replace our roof and we want to keep our solar panels. Where to start?

I had a lot of questions: 

  • How does that work?
  • How much does it cost?
  • Are the footings for the solar racks removed too? 
  • How are the roof penetrations sealed until the new roof is installed? 

I'll tell you all the answers I found to these questions. You'll see the contractors we used and how our experience went. I hope you find it helpful. 

Eventually, all roofs need work, so if you have solar panels or you're thinking about solar panels, this could be helpful information. 

Don't Bury the Lede

I usually like to tell the story of our experience and how that led to the conclusions. In this case, I'll reverse that. Here's what I learned. If the conclusions make sense to you, then you can stop reading. If you disagree or don't understand, read on to see how we came to these conclusions (then you can disagree while being well-informed).

So let's just answer each of the above questions: 

  • Q:   How does that work?

This process is called a "Removal and Reinstallation" or R&R. Here are the steps: 

1) The solar panels are removed and stored on-site. 

2) The mounting system rails are removed and hauled off. 

3) The feet of the mounting system are left on the roof (to be removed along with the old roof). This is so roof penetrations are not exposed and cause leaks. Depending on the footing materials, they can be removed for recycling on roof removal day.

4) The old roof is removed.

5) The new roof is installed. 

6) The next step is "Wait." This is a step I didn't expect. I learned that the new solar panels are not installed immediately after the new roof is installed. Instead, after the new roof is installed you have to wait for a "curing time*". This can be 14 to 30 days.

7) Finally, the solar panels are reinstalled (along with new footings and a new racking system*). Then the panels are reconnected to the inverter.

* more on these questions below 

  • Q:   How much does it cost?

If your original installation contract included an R&R clause, you'll want to exercise that option because it can save you money. We had two PV systems on our roof. One had this clause and all 36 panels were removed and reinstalled for just $500. The other, our smaller PV system, on the other hand, had no such clause and we received quotes anywhere from $200 to $300 per panel. With the "per panel" portion of those quotes, the costs add up quickly. We had 20 panels in the smaller system, so using the cheapest bid, it was $4000; on top of the roof expense. So, in total (not counting the roof), our R&R was $4500. This is just to get the solar panels that we already have on our roof removed and then put back. Since they were doing all this work, I considered upgrading but decided to just keep the panels that we have.

  • Q:   Are the footings for the solar racks removed too?

Here's another thing that I didn't know. Completely new rack mounting systems are installed as part of the R&R process. Both of our installers did this. There are a couple of reasons: first, rack systems are not that expensive compared to the panels and inverter; second, rack systems have improved significantly over the last decade. Newer systems are quicker to install and less likely to cause roof leaks (I like that).

  • Q:   How are the roof penetrations sealed until the new roof is installed?

The rack footings are left on the roof so leak holes are not exposed while waiting for the roof removal crew. These are removed with the old roof. One of our PV systems had aluminum footings. We recycled those. 

Our Story

We first had solar panels installed in 2007 by a local installer called Mr. Sun Solar and then we had a second system installed in 2011 by SolarCity. Sixteen and twelve years later respectively in the summer of 2023, our roof was old and needed to be replaced.

3 Contractors?

We have two solar PV systems on the roof. The roof under them was pretty bad and many of the plywood sheets needed to be replaced. This meant the entire solar system, mounting rails and all, needed to come off. The three contractors were the roofer (Geek Roofing - they don't deal with solar panels), Tesla (they won't touch the non-Tesla system), and Sun Path (for the Mr. Sun Solar system).

1: Tesla

Our contract with SolarCity/Tesla includes an R&R clause that says they will remove and reinstall the system one time, for the small fee of just $500. They would not touch our other, non-Tesla panels 😞 so we had to find a second solar contractor for that work.

2: Sun Path

The other, older, PV system was installed by Mr. Sun Solar. They are no longer in business, so we had to find someone else to remove and replace these panels. It took a lot of phone calls and emails. We were told over and over by various solar contractors that they would not touch a system they hadn't installed. After calling about 20 solar companies, we finally found 3 companies that would do it. The bids ranged from $200 per panel to $300 per panel. There are 20 panels in this system. That means the cost ranged from $4000 to $6000 to remove and reinstall the system. I understand that it is a lot of work and they need to be paid for it, but in the end, we just have the same PV system that we started with. Compared to the $500 for the Tesla system, $4000+ is hard to swallow. After confirming the contractor license and checking BBB for complaints (and finding no complaints), we selected the cheapest bid, Sun Path Services. I was really happy with their work (more on this later).

3 Geek Roofing

Oh yeah, the point of all of this was to get a new roof. We contacted several roofers and received 4 bids. We were hoping to find a roofer that could also handle the non-Tesla R&R, but had no luck there. Some made referrals, but none would do it themselves or subcontract it.

After looking at all the quotes, unlike the solar remove/reinstall, we didn't select the cheapest bid this time. Roofing materials have improved greatly since our original roof was installed in the mid-1990s. We selected Geek Roofing because they impressed us with their presentation, attention to detail, and advanced materials. The contract included gable vents, a new skylight, and more.

Timeline Scheduling 

We wanted to have the panels off the roof for as short a time as possible. With three contractors to coordinate, this was not easy; here's how it went.

May 26th - Tesla Solar Removal 

7AM: The doorbell chimes! They are here to start the removal of the SolarCity Tesla panels. It's a team, 5 members strong. I snap a couple of before pictures of the roof/panels. They put an empty pallet on the patio and leaned ladders against the house as if storming a castle. Up the ladders they go; our guard dog barks, and Here Comes The Rooster rings out from their boombox as they work; a little revenge on my neighbors for all those early morning leaf blowers and pressure washers😆 An hour or so in, a battery from a portable tool, tumbles off the roof and hits the deck with a loud 'thump'; startling, but no damage to anything or anyone below.

9:30AM: Just two and a half hours later, the panels are stacked up on the patio. The crew is packing up and I snap a couple of after photos. They left several meters of wiring conduit on the roof. I pointed that out and said, "This is still on the roof and needs to be removed so the new roof can be installed there." The Tesla rep assured me that it is no problem for the roofers to slide under those. They also left the mounting pucks/feet on the roof. They said they're left on so they don't expose roof penetrations and cause leaks. They can be removed and disposed of with the old roof. They hop in their truck and van and they are off to another job. It was impressive how fast they were. Cost: $150

Old roof with solar panels removed

Tesla Solar Panels Stacked Up

10:30AM: I sent photos of the conduit to our roofer and asked if this was going to be a problem. I was ready to call Tesla and tell them to come back and finish the job. I didn't want to have our roofing crew show up and then not be able to get started because there was still solar wiring on the roof. To my surprise the roofer said it was 'no problem'; they could work around it. 

June 5th - Mr. Sun / SunPath Removal

1PM: The dog barks and I look out the window to see a truck pulling up. It was Chet from SunPath. He was here right on time to remove the Mr. Sun Solar panels from our roof. Unlike the crew from Tesla, this was a one-man effort. Chet removed the panels and rails and carefully leaned the panels against the fence (these are 16-year-old panels after all). Cost: $1300 

June 9th - Roofing Supplies Arrive 

7:30AM - Doorbell chimes, I was still in bed asleep. Throw on some clothes and open the door. The shingles and other roof supplies were here. This job is scheduled to start in 2 or 3 days and they didn't tell us to expect a delivery before then. I move the car out of the driveway and a giant crane truck moves in. It hoists pallets of roofing materials off the truck and up onto the roof. This seems like a much smarter way to do it than carrying them up a ladder by hand. 20 minutes of pounding supports into place and craning it all up there and they were gone. Some materials were left in the driveway. We moved these to the side of the house so we could go in and out of our garage. 

New Shingles Arrived

June 12th - Roof Removal Day 

A big deuce-and-a-half style truck backed into our driveway at 7:45AM. Tarps went down and ladders went up. The hammering and sawing went on throughout the day as materials rained down and fell in (or at least near) the bed of the truck. 

Old Roof Removal

June 13th - Roof Install Day 

The new roof is going on. Our old roof didn't have air intakes on the roof or an apex vent; the new one will. The new air intakes are generally installed 3 feet from the gutter; however, this area will be covered by our solar panels. So the roofing team decided to install the air intake a little lower on the roof so air flow is less likely to be impeded by the panels. 

New Roof Being Installed

June 14th - Final Roof Day

For the final day, we have a half crew. They were installing the new skylight and cleaning up.

June 15th - Pressure Washing and Haul Away (guess yesterday wasn't the final day)

They ran the nail magnet around the house one more time. Final walk-through. There were a few minor things that were found in our review with them: The flue was supposed to be repainted, the pressure washing job was not complete, and one of the roof anchors was missing.  

June 16th - Pressure Washing Round 2 - Fix the things from the final walk-through

They fixed all the issues from the walk-through and our new roof was looking good.

New Roof Complete
(now it's time to get the panels back up there)

Tip: Magnet Sweep It For Yourself 

A tip I received from a friend was to run a magnet over my lawn before mowing and over the driveway before driving over it. I assured him that they had a big rolling magnet and they ran it over the area twice, so that was unnecessary. He insisted, dug out a magnet wand that he had, handed it to me, and said that he'd buy me a beer if I didn't find a bunch of stuff they missed. With nothing to lose, I couldn't say 'no' to that deal. 

Magnet Pickup Tool

Well, he was right and I didn't get that free beer, but I did avoid a punctured tire and having my lawn mower blade launch a nail at the speed of sound into who-knows-what. Here are the things I found:   

Found After Roof Work

I cannot tell you that all of this is from this job. Some of them are pretty rusted and may have been there for a while, but now they are collected. I also cannot promise to buy you a beer if you don't find anything after your roof work, but I do highly recommend that you use a magnetic pickup tool after any roof work. 

Scheduling the Solar Reinstalls

Now that the roof was complete, I wanted to get both PV systems back to production as quickly as possible; some sunny days were coming.

I text SunPath first. They quickly got back to me and said they could be there on July 5th. That was easy. 

Tesla, on the other hand, was not so simple. Our Tesla energy rep was not returning my emails or calls. I tried to schedule the reinstallation via the app, but we already had an open "Remove and Reinstall," case (and had someone assigned to it) so I didn't want to open another one that was just a reinstall. Eventually, with nowhere left to turn, I called the customer support line, went through the long phone tree, waited out the hold time (thank you for the 'hold for me' feature on my phone), and finally, I talked to someone. They updated our case, flagged it for scheduling, and said that I would be able to schedule the reinstall date in the app in 3 to 5 days.

"Cure Time"

Both SunPath and Tesla require a waiting period after the roof is complete before they will reinstall the solar panels. SunPath required 2 weeks and Tesla required 30 days. I guess this is to make sure there are no problems with the roof before they go up and there. 

Reinstall - SunPath 

July 5th SunPath Reinstall Day

The SunPath crew of three people arrived at 8AM. They laid out all the panels in the grass and cleaned them. The panels were really dirty and desperately needed to be cleaned. The new panels were completely installed and ready to power on before 2PM. 

Power-on unfortunately was not smooth. The old SMA SunnyBoy inverter didn't want to start up. They spent a couple hours on the phone with SMA support before they found the magic settings that would allow the old girl to get going again. Cost: $2700

Reinstall - Tesla Solar

August 11th Tesla Solar Reinstallation Day 

The Tesla crew arrived just before 8AM. All the panels were installed and wired up before 11AM. But there were two problems. One, the panels were really dirty. They have sitting on a pallet under a tree for 6 weeks. You can see how dirty they were in this photo: 

Dirty Solar Panels

I asked them to clean the panels. They said, "No problem," and hosed the panels off. They cleaned up easily. 

The second problem was a grounding wire. It's not easy to see, but if you look left of the house, you can see the wire hanging down in this photo: 
Dangling Ground Wire

It looks like they forgot about it. I asked them to reconnect this. Seems like it might be important. They said they'd take care of it. Great, I went back in the house. I came back out about a half hour later and they were gone. Okay, they could have knocked and said they were done.

I did a walk-through to see how it all looked. I could see things running at the inverter. I could see the solar production in the app. They didn't leave any gear. So far, so good.

Then I got around to the corner of the house with the grounding wire. It was gone. Rather than reconnecting it to the solar panels, they just removed it. When they reinstalled the panels, they didn't put them back exactly where they were the first time. They shifted them about a meter away from this ground wire. Rather than extending the wire, they just *removed* the ground wire completely. If you know anything about electricity, then you know ground connections are an important safety concern. 

I immediately messaged them. I didn't know if it was safe to leave the system operating without this wire connected. I received a reply that simply said that "the grounding wire was not needed" with no additional information.

I was not happy with this terse response. I asked for more information. I explained that before the removal, there was a connected ground wire, so part of reinstallation must include reconnecting this ground wire and that I was not sure that it was safe to keep the system operating without this connected. Again the only response I received was "This wire is not required." Ugh. I insisted that they install the grounding wire. They refused.

This was a removal and reinstallation. No changes to the system were part of the deal. I was not a happy customer.

Are you can see, things were not going well with Tesla. They were failing at communications. I expressed a safety concern and received a condescending "don't worry about it" response. Cost: $350.

SunPath to the Rescue

I remembered the SunPath folks telling me they have done several Tesla R&R jobs. Maybe they know more about the ground wire. So I emailed Chet at SunPath and asked him about it. If it was needed, I was ready to pay him to do what Tesla had refused to do. 

The answer I received from Chet was comprehensive and explained (in detail) that the Oregon electrical code was updated a few years ago and that auxiliary ground wires like this one were no longer required by code. Aux ground wires are no longer part of new solar installations and it is not required for safety. I wish Tesla would have given me this information (at least the second or third time I asked). Cost $0 - priceless peace of mind.

Final Reinstallation

Now that it was all done, Geek Roofing wanted to double-check things and make sure the solar installers had not messed up their roof. They came out in a car, with no ladders. I was wondering how they were going to check the work without getting up on the roof. The answer was a drone. The little thing buzzed up there and landed on the roof near the panels. The camera was low enough that there was a clear view of the roof under the solar panels. The drone hopped from spot to spot as they checked various spots and connections. They gave it a thumbs up and hit the road. I received a copy of the video later that day. 

Lessons Learned

  1. If you are installing a PV system, make sure your contract has an R&R clause in it. This saved us $3500 for the system that had it ($500 compared to $4000). Roof damage and aging can happen and this clause will save you some money at a time that you're already spending for a high-dollar item in a new roof.
  2. Pick a larger solar company. There's no guarantee that they will still be in business 10+ years later, but the odds are a little better and things happen and you may need some service. 
  3. Sweep for nails, clips, staples, etc. even after they have. 
  4. If you want prompt attentive service, pick a local installer. (I know this is at odds with lesson #2)
  5. Your costs associated with solar R&R work might be eligible for tax incentives.

Check For Incentives

If you're considering solar, it's worth looking into the incentives that are out there. In the US, there's a 30% federal incentive. In Oregon, there's a $0.20 per Watt incentive. If you're in the Energy Trust region, there's an additional $400 incentive. If you qualify, these can add up. 


If you're within 50 miles of SunPath's office in Beaverton, Oregon; I recommend getting a quote from them for your solar project. Also (after you have the quote) if you tell them you were referred by Patrick from CarsWithCords.net, you'll get $500 off and I'll receive a referral bonus. 

If you're considering Tesla for your solar project, you can use my referral code (https://ts.la/patrick7819) for $500 off and I'll receive referral points for Tesla merch.

Sunday, March 24, 2024

6 Cent Electricity

The average electricity rate in the U.S. is currently 15.73 cents per kilowatt-hour. Hawaii has the highest average electricity rate of 41.6 cents per kilowatt-hour. While, North Dakota has the lowest average electricity rate of 10.23 cents per kilowatt-hour.

These are averages, so I'm sure there are some electrically co-ops out there that are cheaper. I'm not on one of those. Yet, my electric bill is only 6 cents per kWh. 

To be clear, my utility does not charge 6 cents to everyone; the standard residential rate here is 17.53 cents per kWh. This is just over the national average, yet I'm paying well below the lowest state average (North Dakota's 10.23 cents).

To get the 6 cent rate I had to optimize. This optimization required home energy storage batteries, solar panels, and changing rate plans.

The Plan

We have solar panels, but annually, they do not produce enough to zero-out our electricity bill. However, maybe we can use this energy to not only reduce the amount we purchase from the utility, but also to reduce the price we pay for the electricity that we do buy.

Our plan was to switch from the standard flat rate plan to the time-of-use (TOU) rate schedule that our utility offers. This TOU rate schedule charges more than the flat rate during peak hours (29 cents) and also more during mid-peak at 22 cents, but TOU charges significantly less than the basic rate during off-peak (6 cents). So, our plan was to reduce or eliminate all non-off-peak grid usage by using solar and batteries. As I said, our PV system is not big enough to offset all of our energy needs, but (with batteries) maybe it can eliminate our peak and mid-peak usage. 

A Sunny Day

Here's a graph of our solar production, home usage, battery activity (3 Powerwalls), and grid usage on a cool and sunny spring day.

data was collected via the netzero app

Let's breakdown the more important of these. First, our home's usage. This is where most of the energy goes, so let's start there. You can see in grey, overnight we're using the grid to power our home. This is when the grid has surplus capacity and when we get that nice low 6 cent rate. Increasing usage during these hours means that the infrastructure that's already deployed, is better utilized.

Morning (6AM - 10AM): Once 6AM arrives, the first peak rate window starts, and the battery takes over (shown in green). It will be another hour or so before the sun comes up. As the solar panels wake up, they take over and the battery ramps down.

Mid-day (10AM-5PM): For the bulk of the day solar powers our home, covering the mid-peak and the start of the evening peak window. 

Evening (5PM-10PM): There's a second peak window from 5PM - 8PM; the sun sets during this time and the roles of the battery and solar are reverse from their morning dance. As the sun sets the battery output ramps up, filling in the gaps the dimming light cannot provide. Once the peak rate period ends at 8PM, the battery will use whatever energy is left over above its outage/backup reserve to power our home during the mid-peak from 8PM till 10PM.

Night (10PM - 6AM): We've made it to the off-peak hours. This is when we'll charge up our battery and our electric cars. 

We looked at our home's use, now let's look at the grid activity since that's what will determine the bill.

Morning (6AM - 10AM): When the morning peak rate kicks in, we stop drawing power from the grid. As the solar ramps up and starts producing more than our home needs, the surplus is feed to the grid, running our meter backwards during peak prices. 

Mid-day (10AM-5PM): Once the peak has passed, that surplus solar goes towards recharging our battery rather than the grid, you can see the gap in the solar from 10AM till 11AM. Once the Powerwalls are full, the surplus solar goes again to the grid. By 5PM our surplus solar production has nearly stopped. This was about a week before the spring equinox, so the sunsets will keep getting later over the next few months.

Evening (5PM-10PM): We were effectively off grid for this time during the evening peak rate time. 

Night (10PM - 6AM): You can see the energy use from the grid jump as soon as the off-peak rate started. The green is area is going to charge the batteries and the blue is running our home. 

Wrapping Up

For this day, we our net usage was negative 7.2 kWh. So we could have been off grid for the entire day. Instead, we were active positive participants. We supplied energy to the grid during the peak and mid-peak hours. We didn't import from the grid at all during these times of highest demand and we used the grid at off-peak times when there's surplus supply from the plants that can't just shut-off or the massive wind turbines in the gorge that often spin the hardest during nightly winds. It's nice to be positively contributing, greening the grid, and getting a cheaper electricity rate even on the days that we're not net positive.


If you're considering Tesla for your solar project, you can use my referral code (https://ts.la/patrick7819) for $500 off and I'll receive referral points for Tesla merch.

Saturday, March 2, 2024

Tesla Model Y :: 5000 Mile Report

We just crossed the 5k mile mark in our 2023 Tesla Model Y LR AWD.

In the summer of 2023, we picked up our new Tesla. It's been a lot of fun. In the ~6 months that we've owned the car, we've received 8 software updates. These are little presents from Tesla; they bring bug fixes and new features. One of those updates enabled Full-Self Driving in our Model Y. FSD is a great feature and it makes long drives so much less stressful.

Soon after picking up the car, we ordered and installed the roof rack system. As the weather turned, we installed winter tires.

Road Trips

With over 300 miles of range, we're able to make many trips without even charging while out and about. We made multiple trips from our house in west Portland suburbs to Corvallis. We're able to do this round trip without charging which makes it very convenient. Additionally, there are several Superchargers along this route where we could stop if needed; so there's no range anxiety even if we want to push the range. 

Similarly, we were able to make a long weekend trip to Astoria and back without any on-route charging. To be clear, I'm not against using Superchargers; but, when possible, I'd rather leave the Supercharger stalls available for the people that really need them.

Speaking of Superchargers, I have Supercharged once during these 6 months of ownership. A new Supercharger V4 location opened in Wilsonville and we stopped in to get a little juice. 

Tesla V4 Supercharger stalls in Wilsonville, OR

Speed & Range

Soon after picking up the vehicle, we signed up for TeslaFi. It tracks a lot of data about your vehicle. If you're a data person, this is the service for you. Here's a chart of our Efficiency relative to speed. 

As you can see, if you really want to maximize range, drive in the 25-30 MPH range. However, it's surprising how little the efficiency drops going from 35 to 65. The Model Y is super aerodynamic for its size. It's worth pointing out that most of these drives are during the winter with snow tires, so things will look even better this summer.

Battery Degradation

Long time readers will know that I started tracking battery degradation way back when we had a 2011 Nissan Leaf. I continued this tracking to our Model X and now with the Model Y. Thankfully, the battery longevity performance has improved with each vehicle that we've owned. Maybe a side by side comparison of Year-1 for all three would be a good future story. 

During this 6 months / 5000 miles of ownership, we've had some normal minor degradation. The first 6 month is generally the worst you'll ever see. Degradation rates decrease over time. Here's how our battery health has fared: 

We'll be back for the 1-year report to see if the degradation starts to level out. 

If you'd like to buy a Model Y (or any other Tesla product), you can use my referral code: https://ts.la/patrick7819

Sunday, February 11, 2024

You Cannot Conserve Your Way To Net-Zero

Why a literal (and figurative) power shift is required for a future free from fossil fuels. 

You can turn down your thermostat on your natural gas-powered furnace and drive a hybrid car and these actions will have a minor impact on your CO2 footprint. However, even when used frugally, these are fossil fuel-based energy sources. Even modest use still perpetuates the industries that exploit these resources. No matter how frugal you are with them, you can never have a zero emissions result. 

"But I'll use carbon offsets," I hear some of you proclaim. More than 90% of carbon offsets are scams. Paying someone to not cut down tree A is great, but if that just means tree B is cut down instead, then fundamentally, nothing has changed.

Continuing to use fossil fuels is like the old joke, "Since I Lost One of My Lungs, I’ve Cut My Smoking In Half." Energy deprivation is futile and it reduces quality of life. We need a better answer.

Electrify All The Things

Rather than reduction and deprivation to minimize fossil fuel usage, a new energy system is needed. One that is based on renewable energy. Solar, wind, hydro... these generate energy in the form of electricity; which means, we need the machines that perform our labors to run on electricity rather than liquid fuels. We need cars, trucks, semis, trains, planes, boats... all to be electrically powered. For some of these, we have solutions today, others are emerging, and for some, another score of battery technology advancements will be required, but the transition must occur. Furnaces will transition to heat pumps. Gas stovetops will give way to the superior experience of induction cooktops. 

If we electrify our homes, offices, transportation, and more; and power these devices with renewable energy, then we can lead an energy-abundant lifestyle rather than an energy-deprived lifestyle.

Here's how we should proceed: 

Today, right now, we should deploy the renewable energy technologies that we have. Solar, wind, batteries, EVs, protein fermentation, induction cooktops, heat pumps... There's no need to wait for the next big breakthrough to move the bulk of our energy use to electricity. Wind and solar are complementary and once installed, incremental production is very affordable.

Every sunny rooftop should have solar panels. Every highway on-ramp clover leaf should have a solar field. Every parking lot should have solar canopies. Wind turbines onshore, offshore, running the ridgeline... 

Every substation should have banks of batteries for filling in the intermittent gaps, energy peak shaving and valley filing. Every vehicle on the road should have a big battery and no tailpipe. That big battery can double as home energy storage and demand shifting. 

Protein fermentation allows massive acres used for meat farming, grazing, and feed crops to be reclaimed, allowing more space for wildlife and human expansion.

Turning down the thermostat and getting a little better fuel economy are not enough. We need a better way. It's time for a phase change. We need a literal and figurative power shift. We need to live regeneratively.

Sunday, January 28, 2024

60 Thousand Places To Plug In

January 1st, 2024

I periodically check out the alt-fuel map that the US government maintains. 

You can see in the image above that there are just over 60 thousand places in the US where you can plug in and charge an EV at Level 2 or faster.

Here's the link: https://www.energy.gov/alternative-fueling-station-locator#/find/nearest?country=US&fuel=ELEC&ev_levels=all

March 2023

When I looked at the same map in March of 2023, there were nearly 50 thousand plug-in spots. So more than 10 thousand plug-in stalls were added in less than a year.

Going even further back in time, to one of the first times I looked at this site, there were only 10 thousand public charging spots in the US in 2015 (sorry I didn't grab a screenshot back then).

So EV charging infrastructure is rolling out faster now than it ever has. This is vital to EV adoption. As discussed here, this US infrastructure will change to the North American Charging Standard (NACS) in 2024 and later. 

This move to NACS is important. For EVs to go mainstream, charging has to be easy. You cannot expect people to understand all the various charging options, connectors, AC or DC, and on and on. Once NACS is widely adopted, there will be one connector that "just works." That same connector at home, at work, on road trips... You just plug in and charge up. The Plug-n-Charge standard will make billing easy.

Happy electric motoring in 2024!