Solar Panel Degradation

As regular readers know, I have tracked the battery degradation of my EVs since purchasing a Nissan Leaf in 2011. Recently, Mark from The Tesla Life asked me how much my solar panels have degraded. I said, they are still producing and I haven't noticed any degradation, but that's not a very analytical answer.

We have production data on both of our solar PV systems going back to the day they were installed. So let's dig into the data and see what it shows.

Our older PV system was installed in 2007 and our newer one in 2015. But how do we go about comparing the results from then to now? Any given day can have weather, cloud shading, wildfire smoke, or other impacts; maybe the panels were dirty, pollen-covered, etc. 

To smooth over some of this, we'll be looking at annual solar production numbers and I'll note any special circumstances that apply to that year. 

Here's the chart of production for our two systems. You can see that production is generally flat for both of them until 2022.

Generally speaking, solar panels degrade about 0.5% per year. Using this rule-of-thumb, our 2007 panels production should be about 92% of their original capacity.

Let's look at the Mr. Sun system since it's older and the degradation is more likely to be visible. 2008 was our first full year of production. We'll use this as our baseline. The 2009 and 2010 years are lower. This could be the degradation we're looking for. I cleaned the panels in the spring of 2012 and production quickly returned to 2008 levels. So that was not degradation.

2016 has a similar dip and then 2017 returns to normal production. 

2021 was surprising in that it was our best production year ever. I would expect some degradation in a 14-year-old system that would prevent it from having its best year ever at that age.  

In 2022, there were more than a dozen wildfires in Oregon. This had a noticeable impact on our solar production. 

In 2023, our production was even lower than 2022 because the solar panels were offline during June and July while we had a new roof was installed.

So there you have it. The degradation signal is lost in the noise of production interference. I guess that's good news since the degradation is not large and obvious. Hopefully, 2024 will be a year where we keep the panels on the roof, no inverters go down, and the sky is not darkened for weeks by wildfires.

Hot Summer 2024 and Virtual Power Plant Activity

We love Virtual Power Plants (VPPs) here at CwC. We've written about them several times. 

In short, a VPP is when the electric utility company can pull energy from hundreds or thousands of residential battery systems when the grid needs extra juice such as a hot summer evening when nearly every air conditioner in the region is running full out. 

Our local utility, Portland General Electric, has had 7 VPP events (and counting) this summer. Six VPP events showed up as credits on our most recent bill. We have 3 Powerwall 2s configured to allow the utility to extract up to 80% of the charge from our batteries. That means the utility can extract about 32 kWh for each event. At $1.70 per kWh that the utility pays during a VPP, we earn about $50 for participating in a VPP event.

You can see how much we earned for each event here: 

July and August are usually months that have big electricity bills because of all of the AC use. However, now with VPP events, we have a couple hundred dollars in credit on our account. 

If you want Powerwalls for your house to join a VPP in your region, you can use my referral code and we'll both get perks (https://ts.la/patrick7819).

Ω

Tesla Model Y - 1 Year Review, Battery Degradation

In the summer of 2023, we purchased a Tesla Model Y Long Range. This is our third Tesla and our fifth EV. For context, we've owned a Model X, Model 3, and now a Model Y. Now that we'd had the Y for a year, let's see how it's gone. How's it working out? What issues has it had? How's the range... We'll cover all this and more.

Our Model Y after a Shower with its Winter Tires

Why Long Range

We opted for the long-range, all-wheel drive variant with the free paint color, midnight silver metallic. The long range allows us to keep the battery at a medium state of charge most days. With a fuller charge, the LR variant allows us to drive from our Portland suburb home to the Mount Hood ski areas or the Oregon coast and back without stopping to charge. Roadside charging while on a trek is not too bad, but nothing is as convenient as charging up in your own garage while you sleep. If you can afford it, the extra range is a luxury all on its own. 

Accessories

We installed a roof rack system on our Y, it didn't have a notable impact on the range.

 

We also bought snow tires for the winter months.

Trip Stats

During this first year of ownership, we put almost 9,000 miles on the odometer. 

Our road trips included a 170 mile round trip to Astoria, Oregon; several 180 mile round trips to Corvallis, Oregon; 150 mile round trip to Cannon Beach, and several 160 miles round trips to Mount Hood ski areas. 

On one of our road trips we made it home with a 5% charge left in the battery. The trip planner was accurate and we arrived with a state-of-charge just as it predicted. There was no anxiety because there were multiple places we could have stopped if the energy meter was dipping too low.  

 

We generally stop every hundred miles or so to refresh our caffeinated beverages and stretch our legs. Our longest single leg was 2 hours 3 min, it was 89 miles and used 20.51 kWh. That's 230 Wh/Mile or 91% efficiency.

In November of 2023 we drove in 33°F and in July of 2024 (last month) we drove in 112°F with the cabin at a comfortable temp in both cases.

 
Our highest elevation was 4,648 feet on Mount Hood and our lowest elevation was just 4 feet above sea level in Astoria.

Firmware and FSD

During this year, we received 16 firmware updates including several FSD updates, culminating in firmware v2024.21.5. The updates are fun; they add games, new features, and bug fixes to the vehicle. The new UI with a large view of the vehicle when parked was a nice improvement.

 

We transferred full self-driving (FSD) from our 2018 Model 3 to our Model Y. Our Model Y was among the first to have FSD HW4. When we took delivery, the FSD software didn't support HW4 yet. However, one of our first firmware updates enabled FSD. 

 

Many of the 16 firmware updates came along with FSD updates too. We started with FSD v11.3.6, then multiple v11.4 builds, then we jumped to v12.3 flavors and now we're on v12.5.1.1.  FSD is getting good enough that I can see, with continued iteration (and, initially at least, remote human support), how it will be possible to have eyes-off, hands-off driving and/or Robotaxis by our predicted timeline of August 2027.

 

Charging

During this 1 year of ownership, we've charged our Model Y 200 times. All but 2 of these charges were at home in our garage. The first of the not-at-home charges was at my in-laws house to test our old mobile charger on their RV outlet (NEMA 14-50) with our new vehicle to see if they were compatible. We had a couple of glitches, but eventually got it to work. If you're considering buying a used mobile connectors, you'll want to read this. 

The second of our not-at-home charging sessions was at the (then) newly opened V4 Supercharger installation in Wilsonville, OR. There are 8 V4 stalls there and I wanted to, one, confirm that Supercharging worked on our vehicle, and two, see how fast the V4 stations were. This was the first V4 location in my region. Apparently, I was not the only one that wanted to try out the new V4, there was a line of cars. It would have been easy to continue south and charge up in Woodburn, OR instead, but we were 3rd in the queue and the line moved quickly. We stayed and soon, we were charging. The charging session was 39 minutes and we charged from 31% to 80% SoC. Looking at it in MPH of range added, we averaged 250 MPH and had a max of 403 MPH.

V3 and V4 Superchargers can charge at a rate 250kW. We topped out at 99kW and averaged 66kW. I was expecting a V4 station to charge faster than this, but it was a warm day and, as I said, there was a line of cars, so the system was not getting a chance to cool off between sessions. Or maybe they were still waiting for permits to go over 100kW. I may try another session now that the novelty of this location has faded.

Battery Degradation

Okay, saving the best for last, here's the reason you came here, the battery degradation data. Soon after purchasing our Y we signed up for TeslaFi to track our vehicle statistics. One of the things it tracks is the range degradation / battery health. Generally, the first 2 or 3 years are the worst degradation for Li-ion batteries, after that the degradation slows. 

 

As you can see in the graph above, we've had a small amount (1.9%) of degradation. That's good news since the first year is expected to be the worst. This is a rate of 0.22% per thousand miles traveled. For comparison, in the first year of ownership of our 2016 Model X, it had a battery degradation of 2.7%.

If you have a newish EV, share your battery degradation. I'd like to see how it compares.

Referrals 

If you're interested in a Model Y, you can use my referral code and we'll both get perks (https://ts.la/patrick7819).

If you want to know what your Tesla's highest elevation was, you can use my TeslaFi referral to get all kinds of cool stats. If you use a referral, you get an extra month free and so do I.  

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. 

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.

End Dependence Day: July 4th

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!

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.

References:

https://en.wikipedia.org/wiki/Electric_car_use_by_country

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!

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. 

Technogaianists

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.

Techno-Optimist

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?