Solar cell economics

Aptera Community Aptera Discussions Solar cell economics

Aptera Community Aptera Discussions Solar cell economics

  • Solar cell economics

     Fanfare 100 updated 2 weeks, 3 days ago 16 Members · 27 Posts
  • Michael Kahlow

    June 16, 2022 at 8:30 am

    I’ll start by confessing that the solar aspect of Aptera is, for me, one of the least useful aspects of the concept, and maybe a bit of a marketing hype. I’m here for the design and the efficiency.

    Getting 40 miles per day (mpd?) from solar sounds like a lot. At current gas prices, that’s nearly $5/day for my Prius, or $10/day for some gawdawful biga** boytoy truck.

    But on time of day metering, it’s less than $1/day for my Bolt.

    It gets more complex. The claim is 40 mpd of charging with the full solar cell set, 16 mpd with the base set. I live in the Cold North, in a house with a fairly shaded lot and driveway. Even if I were able to park the car in a fully exposed area, I have an average of about 4 hours of peak sun per day. This means I’m going to get about 15 mpd with full solar cell coverage – on average.

    Given a projected efficiency of about 10 miles per kW-hr for the Aptera, this means that charging the Aptera that same distance courtesy of my local municipal utility will cost me a grand total of 10 cents per day, or $40/year (I’m rounding).

    Comparing solar panel coverage – it costs $900 to increase the solar charging from maximum 16 mpd to 40 mpd. Given my sun exposure, this extra 24 mpd maximum (40 – 16) will net me about 8 mpd on average. That’s a savings of approximately a nickel a day, or about $20/year. For comparison, if I invest the $900 and get a 2% rate of return, I get the same savings.

    I realize that a lot of this rests on the assumptions Aptera makes in their 40 mpd estimate, but even if I’m off by a factor of two, the opportunity cost for spending that $900 on extra solar panels is real.

    This assumes my car is parked where it gets the maximum average amount of sun for my area, when in reality it is likely to spend at least half of its time in the garage, saving it from hail, snow, tree sap, bird poop, and, oddly enough, the sun, because that body finish wrap won’t last forever.

    Now that I’ve invited all of you to turn on your flamethowers 😉, let me know if I’ve made a dramatic mistake. Some factor of 10 that I missed, and I’ll call mea culpa. Otherwise, I’m considering editing my order to change to the base solar panel, and if they want to give me a discounted one without any panels, I’m there.

    Of course, depending on your location, usage, commute, where you park your Aptera, and electrical rates, literally YMMV.

    • This discussion was modified 2 weeks, 6 days ago by  Michael Kahlow.
    • This discussion was modified 2 weeks, 6 days ago by  Michael Kahlow. Reason: clarity
  • Jonah Jorgenson

    June 16, 2022 at 8:53 am

    Everybody’s use case is different. For me, in a condo, in FL, the 40 miles is the second most important feature. It will cover all of my weekly commuting to work and errands. Of course, not trips outside of the local area.

    Most of my close family have solar homes, some in less then sunny climes. (Western Oregon) They, as would I in a house, will charge their Aptera with their solar so the charge cost is $0.

    Sounds like even with out the Solar you see value enough in the Aptera to pursue purchasing one

    • Michael Kahlow

      June 16, 2022 at 10:04 am

      “Sounds like even with out the Solar you see value enough in the Aptera to pursue purchasing one”

      Yup. I’m a sucker for efficiency, conservation, and sustainability. I started my career working for a guy who was testifying before Congress in the early 1980s that combustion of fossil fuels was going to lead to increased global temperatures. (Thought he was crazy at the time… )

      If Aptera comes to market, and if it fits me, my dream is to take that car on my occasional solo western road trips. Just me and the road, 700+ miles/day. Being able to recharge only once a day is a plus.

      Of course, even with the 600 mi Aptera, no more trips to the Badlands until SD gets their **** together and puts in a few charging stations…

      • Jonah Jorgenson

        June 16, 2022 at 10:06 am

        hmmmmm……. not “Sucker” good judgement!

  • Joshua Rosen

    June 16, 2022 at 9:21 am

    I’m in complete agreement with you, I’m interested in the range not the solar energy. I have home charging and a shaded driveway so there is no benefit from the solar panels for me. I might add on the solar hood just because it’s only $300 and it looks cool, I’d never get the solar rear hatch cells because I’m much rather have a rear window. People who live in the south with short commutes and no home charging might get a real benefit assuming that they don’t mind their car becoming an oven because it’s sitting in full sun.

    • Jonah Jorgenson

      June 16, 2022 at 9:43 am

      I am sure you know this, but any car, sitting in the sun in Florida, becomes an oven and most parking is open, unshaded lots. Parking at NASA consists of acres and acres of outside parking. An Aptera without solar on the big glass hatch would be worse. Aptera with the solar powered ventilation and glass hatch covered with solar to maintain ambient temps would be an improvement over my Model 3.

      Unlike you, I can not charge at home. Not available in the Condo. Perhaps If I move into a house that will be possible.

      • Joshua Rosen

        June 16, 2022 at 10:37 am

        My experience with sunnier places is pretty much limited to Silicon Valley, in pre Internet days I’d spend a month a year there. My observation was that the parking spaces in apartment complexes were covered, I assumed the purpose was to shade the car to keep it cooler. You live in the Sunshine State, if I were you I’d be just as excited about the solar panels as you are. Given that your car spends the day in an open parking lot I agree that the Aptera is an ideal choice, not only will you get free electricity the fact that it has no sun roof or rear window, assuming full solar, will reduce the internal temperature.

        BTW doesn’t NASA have chargers available in their parking lots? Charging is becoming a fairly common perk at private companies. Workplace EVSEs are an important piece of the puzzle for solving the EV charging problem.

        • Jonah Jorgenson

          June 16, 2022 at 10:40 am

          Ha Ha. No. The check is in the mail regarding the availability of chargers for personal vehicles here for employees. Maybe with the current funding of charging networks we will get some more. Chargers are available at the visitors center for visitors. There are some legal issues with providing chargers for personal vehicles for the rest of the center. Goddard is taking the lead on coming up with a process using some models from other government agencies that provide charging stations.

          • This reply was modified 2 weeks, 6 days ago by  Jonah Jorgenson. Reason: added elaboration
          • Dennis Swaney

            June 16, 2022 at 10:59 am

            Maybe NASA could license franchises for EV charging?

            • This reply was modified 2 weeks, 6 days ago by  Dennis Swaney.
    • kerbe2705

      June 16, 2022 at 6:49 pm

      @Joshua Rosen – I made that same aesthetic choice: I like the idea of having a matching blue roof and hood. I was also thinking about the day when my Aptera requires a new wrap: Maybe matching the blue of the solar cells…

  • Richard Palmisano

    June 16, 2022 at 9:40 am

    Michael, no flame thrower…I don’t own one 😎 … Your use case likely isn’t ideal for a full solar integration.

    I live in the Sunshine State (NE Florida) and the full solar option ($900) appears to make more sense. That said…the full option at $900 is literally 2.2% of my configuration. I assume that I would have the ability to charge while at work. (Assuming the full configuration will deliver the amount of energy to the battery as stated).

    Boring math time:

    I would expect to get 35 mpd for 237 days (total sun days in my region) or 8295 miles.

    My daily commute is 80 miles (round trip) and factoring working 5 days a week, that’s 260 days x 80 = 21k miles +/-.

    The total solar package would cover 1/3ish (21K miles annually / 8295 miles of production) of my commute alone.

    Based on 1kw per 10 miles as stated, I’m not sure that efficiency is real world yet (Full solar 700w x 5 hrs = 3500w, 3.5 kw or 35 miles), annually I would expect to recoup $110+/- (8295 mi/10 mi/kw = 830 kw * $0.135/kw = $112) from the full configuration alone (vs. my residential electric rates).

    $900 / $112 = 8 year return on investment…

    Maybe…you are on to something…🙄…or I need to get solar on the roof of my house and some batteries…

    • Michael Kahlow

      June 16, 2022 at 10:17 am

      “Maybe…you are on to something…”

      Yeah, that old rate-of-return. Even under optimal conditions, it’s going to take a long time to earn back the $$ for the cells. Under optimal conditions, solar is competitive with fossil fuel generated electricity, but the rate of return is fairly long. That’s not a problem for a utility which plans 40+ years out and can locate their panels in the best possible location. But if conditions are less than optimal, and/or you’re looking at a shorter time window, then maybe you’re better off plugging the car into the grid (which is hopefully powered by solar and wind). (Edit – or, as you say, putting solar panels on the roof of your house, where they’re presumably better located and have a longer useful lifetime.)

      OTOH, at the 10,000 miles per year that I drive (and $4/gallon gasoline), my Prius costs me $1000 for fuel (and let’s not forget 2-3 oil changes), the Aptera would cost $66 for time-of-day charging at home (!!!).

      I do see the convenience if you’re driving, say, a 15 mile commute and you’re parking in an open lot. You might never need to charge, or, at most, run an extension cord out to the car in the driveway every few days.

  • EVservices .us

    June 16, 2022 at 10:16 am

    This kind of calculation goes back over 20 years when folks were trying to figure out if the extra up front cost of a hybrid or diesel version of a gas car could be recouped in the typical ownership period – the great majority of the time the answer was no. Maybe only very recently, with gas well over $5 (and diesel even higher), do some of them make sense, financially.

    If the ownership period is long enough and/or the cost of a kwh is high enough, the extra solar panel up front cost could make sense – for many, the math could be like the OP. This doesn’t factor in things like inability to charge and you need the most solar possible.

  • Graham Smith

    June 16, 2022 at 11:04 am


    If you expect 15 mpd then you’re generating 1.5kwh per day, if that costs you $0.10 your utility only charges $0.066 / kwh, is that correct?

    In California PGE now charges $0.37 / kwh. Thankfully we are generally sunny and my home solar makes ~ 6660 kwh / year which is an average of 18.2 kwh / day. On a peak day I get ~ 26 kwh/day, therefore an average day is 18.2/26 = ~70% of peak.

    If we apply this to Aptera with the full solar pack we should get 40 * 0.70 = 28 miles per day on average which is equivalent to 2.8 kwh from the grid. At PGE prices that is 2.8 * 0.37 = $1.04 saved per day and the full solar roof would pay for itself in $900/$1.04 = 868 day (2.4 years) and that is a great ROI to me.

    Also safe to assume that PGE and others will increase rates over time, so I expect an even better ROI.

    • Michael Kahlow

      June 16, 2022 at 11:28 am

      Good point. At $0.37 per kW-hr and a sunnier clime, the economics are different!

      My off peak electrical is $0.066 per kW-hr. I haven’t signed up for that rate structure yet, I’m waiting until I get the 240V line to my garage for Level 2 for my Bolt. If I stick with the “standard” rate structure I’m at $0.111 per kW-hr.

      We have a local municipal utility (Yay to socialism! 🤣 ) which has built a local solar farm, funded by “investors” among the ratepayers. (They asked which of us would be willing to pay $300 or so to help construction; of course I ponied up.) So far it’s been an economic success.

  • Benjamin Dreidel

    June 16, 2022 at 4:57 pm

    Your math works pretty well, I think. I’m going full solar even though I live in upstate NY. My current car (2008 Prius) already gets left in the sun all day and I tend to drive my cars into the dirt (again, 2008 Prius). I’m going for the solar to displace electricity from the grid, not in financial self interest.

    Even with the great efficiency, I’m not sure the Aptera is better than a Chevy Bolt EV on a purely financial basis. But I don’t care to do the numbers because pure financial benefit isn’t my goal.

    • Michael Kahlow

      June 16, 2022 at 6:21 pm

      LOL. 2008 Prius here, currently with 240k miles. That was Prius #2; Prius #1 was a 2007 which was still running – with 330k miles – when we got the Bolt.

    • Dennis Swaney

      June 17, 2022 at 4:38 pm

      My ’04 Prius died a few weeks ago at 18 years and 161,600 miles. Not cost effective to repair for me. Toyota wanted $6,000 to replace the Inverter and the traction battery is on back order. So I sold it to a service writer at the dealer. He plans on fixing it and using it to replace his Suburban. It served us well for almost 18 years.

  • kerbe2705

    June 16, 2022 at 6:53 pm

    @Michael Kahlow I recall a time when all automotive advertising on television and radio ended with the disclaimer, “Your mileage may vary.”

  • Jon_J

    June 16, 2022 at 10:51 pm

    Having the solar cells “pay” for themselves really wouldn’t be my motivation for getting them and I don’t think it need be anyone’s reasoning for getting them. I wouldn’t try to argue with the base economics at all. The numbers are hard to dispute.

    The reason I would pay $900 for the solar cells would be the same reason I paid ~$900 for the navigational system in my current vehicle. Sure, I have GPS in my phone and I can use that, but having the navigational system built into the vehicle (not associated with my phone) provides numerous conveniences and benefits. If my phone is in use as my navigational device, the phone is challenging to use for other purposes when I am driving and this sort of issue pops up more frequently than one might like to admit. The navigational system is integrated into my vehicle’s display and console display and both are helpful.

    Similarly, the convenience of the solar cells is that they can meaningfully reduce the need to plug in. The benefit of this can be far ranging and can be hard to put a dollar value on. Consider needing to route to a charging station when you have just 10 miles left to get home. Wouldn’t it have been far better if your vehicle already had the 10 extra miles because it soaked up the sun in the parking lot from which you departed? What if instead of being 10 miles from home, you were 10 miles from the hospital trying to get a critically injured family member there? Now instead of avoiding an inconvenience, you are saving a life. Can’t put a dollar value on that. Maybe you think you’ll plan around these possibilities like always charging to 80% each night, but this is inconvenient and unexpected things do happen (life happens).

    So, like the navigational device, the solar cells are convenient as they are located at the point of use. They charge up the battery regardless of where your car is located (unless its not receiving sunshine, of course). The solar cells on your home don’t provide that same benefit to the battery in your vehicle as they don’t follow you around everywhere, continually plugged in.

    Furthermore, some users may find the solar cells more handy than others depending upon the availability of locations at which to charge. BEVs are most convenient for people who park their cars in a garage at night, but this is likely less than half of the US population. The solar cells on the Aptera make BEVs much more accessible to people in various living situations. If not for your own convenience, it might make sense to get the full solar simply because the vehicle may be easier to sell if you ever do so.

    I also like that the rear hatch solar panels block the primary view of what is in the trunk area. I like to keep prying eyes off of the junk in my trunk. 🙂

  • Dan Kerpe

    June 17, 2022 at 11:46 am

    What I like about the way Aptera is doing this, is that you don’t have to pay for the extra solar panels if they aren’t a benefit to your use/case scenario. I can totally understand if they’re not for you. In my case, they’re a huge benefit and basically make the math work for me.

    Disclaimer, my math is probably incorrect, but I’m basing it off the most common numbers getting tossed around so far. I’m now leaning towards the 600 mile battery with AWD. If the AWD takes off 10% of range, that drops it to 540 miles. Now, if I only use 80% of the battery, I’m down to 432 miles. Between my daily commute and after work driving, I’ve found I average about 85 miles a day. On battery alone, this theoretically means I could make it the whole work week without charging, but with just a few miles to spare. So it’s possible, but not smart. This is where the solar benefit kicks in for me. If the panels give me a safety net of 10-40 miles a day, this makes it possible for me to only have to charge once a week during a typical week, winter excluded. Most weekends I only drive 5-10 miles a day, so solar would cover those. My apartment currently doesn’t have any home charging options, so this is a big deal for me. In my case, I don’t really care what the cost numbers are, it’s the ability to go electric and still have the convenience. I fully understand that there’ll be plenty of weeks this won’t work, but for the majority that it does, it’ll be awesome. So for me it’s all about the economy of convenience, if that makes any sense.

    • Curtis Cibinel

      June 17, 2022 at 5:15 pm

      Fingers crossed for lfp eventually so the “only have 80% usable battery” justification can go away. When they started work lfp wasn’t what it is now; it is advancing by leaps and bound. 180 wh/kg is very readily available now, 210 is the bleeding edge and 230 will be in production this year; any of these would be plenty for the 400 mile to be viable. Changing technologies will take time and likely millions in rework but could also be thousands saved per vehicle. As an investor this would really help profitability given the aggressiveness of the pricing.

  • David Marlow

    June 17, 2022 at 5:30 pm

    I’m not sure about the economics, however driving a real solar vehicle and the other unique features of Aptera makes it very special to me. I would very much like to be part of leading the way to a next generation of transportation.

  • Tim Dean

    June 17, 2022 at 6:28 pm

    The Aptera is so efficient, The solar economics blur into personal preferences. I think the solar hatch is cool and I like the idea of rear cameras which are better than mirrors so I don’t need a rear window a plus is the solar hatch keeping people from seeing the items in my trunk. I’d also like a curtain between the front cabin and “trunk” area.

  • M T

    June 17, 2022 at 7:01 pm

    I like the solar aspect, even though the efficiency/range is what really sold me. I think of it as getting up to 10% of my energy draw on the highway from the solar cells. Or never being truly stranded with a dead battery in the daytime… I also can park in the sun both at work and at home.

    I picked everything BUT the solar hood on my options list, I had fears with the inevitable impacts it will be the first area to show problems with the cells being disabled/shorting out. Hopefully the truly aerodynamic shape keeps impact energy to a minimum for those with that option.

  • Fanfare 100

    June 18, 2022 at 10:35 pm

    I look forward to the solar aspect because that will mean that I will be able to drive 190 miles to the headquarters of the company I work for, park it in the sun and have more than enough to drive back in two to three days and not worry about having to look for a place to plug in the whole time. I travel like this about 1ce a month and despite that I would still not have to plug it in almost never if at all. The Aptera is like the self-licking ice-cream cone. lol …just keeps going and going and going. Makes things very worry free.

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