Average solar calculations

[ROMAD]

Interesting. I used my house location halfway between Phoenix and Flagstaff to get these results:

[george-hughes]

This is great information about the relative generation based on the location of state capitols.

That said, the notion of a solar electric car is so new and different that we really need to think about how to maximize the power generation regardless of location.

I’m going to suggest this can be accomplished with an custom app that includes the instant generation readout. This would give you instant readings of input which, if you’re trying to keep the vehicle under 80% SOC, could tell you which lane you’re traversing generates more power (or less).

Now factor in the temp, date (position of the sun by season) and also the images from around the vehicle showing obstructions like buildings, trees, etc. as well as the orientation of the vehicle as well as hourly forecasts as to cloud cover, etc.

The combination of this varied data should allow for a relatively accurate estimate of the remaining potential charge from a particular point for the remainder of the day from any particular point on earth based on current conditions.

You could argue such an app is not needed but I disagree, particularly in more established (older) communities with long-term growth (trees and buildings.)

The understanding is you could have two Aptera parked within 100 ft of each other and one might generate 2-3kw in a day whereas the other might only generate .8kw because of shading and orientation to the path of the sun.

Indeed, the algorithm’s key data point revolves around predicting the path of the sun in relation to shade obstructions that might impact a vehicle.

I imagine a graphic with the car parked in the center with an overall view of the surroundings. This data is already there from the cameras. Plot the path of the sun, (based on time of day, vehicle orientation to north, etc.) and you plot a 2-3-4-5-6-7-8-10-12 hour time span going forward with the sun’s position and projected generation on a graph through time.

Of course these specific displays would be called from the main screen which is simply reading the power generated instantly.

It would take some time to simplify the settings and display to meet typical drivers needs who will need some ‘assistance’ in determining the best place to park.

The point is that in the instant, we all know whether the sun is projected on a spot of real estate (parking spot) in real time and while common sense can get you into the zone in probably 60 percent of the instances, a tool to aid you either maximize or minimize the charge over the next 12 hours is needed because such extrapolation over time is infinitely more difficult.

The real value, however, may be the data that could be collected to further enhance and refine the predictive powers of the solar maximization application.

I’ll close with this imagery: It is December 20th, 2026 and you’re driving into San Diego and you need to visit Aptera’s HQ. As you drive up, there are ten possible parking spots. Because people with the app have parked there before, the app highlights the parking spots in terms of solar generation and suggests the top five spots for generating juice.

Heck, let’s assume you don’t want to maximize the solar charge. What if you’re in for a day at a business and don’t want to maximize your charge so you choose a shaded spot not realizing that in five minutes, considering the path of the sun, this becomes the sunniest spot in the lot as a lone building four blocks away, only shades this spot for fifteen minutes.

Bottom line, we need a tool to help choose the best parking spot anywhere for solar generation, Doing so requires more information to make an informed decision and that information is not easily discernable by most drivers intuitively and they need a tool to fill in the information gaps.

[Mike-Mars]

<div>Struggling with the new version of the solar calculator https://aptera.us/savings-calculator/ – I’m in what was Zone 2 on the old map, how does that tie into the new options?</div>

> What is your average local solar exposure?

> Little to No Exposure

> Low Exposure

> Medium Exposure

> High Exposure

> Very High Exposure

• This reply was modified 4 months, 1 week ago by  Michael Marsden.
• This reply was modified 4 months ago by  Gabriel Kemeny.

[JRWiley]

More specifically, how does one estimate their sun exposure?

[jonah-jorgenson]

Just noticed this change. Thanks for the alert!

Good question! Much more nebulous than the original version. Hard to tell if it refers to a full solar Aptera, just an Aptera with roof and dashboard, or something in between to include full solar. Meaningless with out additional information.

The configurator still has the same “Miles” for different solar configurations

Roof and Dash – 16mi

+ Hood – 22 mi

+Rear Hatch – 34 mi

Full Solar – 40 mi

I drive a Tesla model 3 that gets about 4.17 miles/kWh. I ran the model with 40 miles a day driving distance, Electric car, 4.2 mi/kWh for “High Exposure” and got these key results:

Only 28 free miles per day (Not 40)

Charges needed in a year 11

This is considerably different (Not as good) as when I did the calculations with the previous map/table. Seems like Aptera is baking away from the “40 mile per day” for full solar in a San Diego like area.

I suspect this change is a result of current solar testing and perhaps solar testing on a vehicle which is producing less than anticipated capacity. Not unexpected because real world results often differ from engineering estimates derived from simulations early in development.

Hopefully, Aptera will reconcile all of the calculators, data, etc. when all testing is done so there is no discrepancy between results using different pages on the site.

[joshua-rosen]

The comparison doesn’t work for EVs. They ask you howmany miles per KWh your EV gets but it maxes at 1 mile, that’s a Hummer which hardly anyone owns, a Tesla is 4 but you can’t put that in.

[Russell]

I tried using .2 since I get a little more than 5 miles per kilowatt. It delivered a more reasonable answer. It must be calculating kwh per mile rather than miles per kwh.

[joshua-rosen]

That makes sense. However they don’t include the cost per KWh which varies widely across the country.

• This reply was modified 4 months, 1 week ago by  Joshua Rosen.

[leo-shapiro]

Going very high. Got 30.

Question….are these numbers legit or more guesswork from simulated lab tests and software?

[Mike-Mars]

No idea, but in theory they are finally able to get some real-world figures from Gamma.

The problem I have is that I don’t know their assumptions for the calculator (which zone relates to which sun exposure, the battery size, whether it is 2WD or 3WD, winter day length, offroad package, etc). If you don’t know which sun exposure to select, then the results are meaningless.

When the calculator was originally released there was a lot more info – it would show an estimate for each month. The month-by-month forecast went away (I think during 2021?), then with this new version you can’t even tell what you should be entering in the first place.

• This reply was modified 4 months, 1 week ago by  Michael Marsden.

[Riley]

I am happy with the new design and the results still meet my needs.

Screenshot_20221110-031534_Samsung-Internet.jpg 276 KB Image File - Click to view

• Copy Download Link

[Mike-Mars]

Cross-correlating with the old-old map, 10,950 miles is zone 10 (Peru, Southern Africa, the Sahara desert, and Ayres Rock).

Of course we have no idea if that is still the same estimate or not, since we don’t know the exact assumptions for either any of the maps. Maybe it takes into account the extra solar cells on the hatch, or maybe zone 10 equates to the same local solar exposure setting which you selected.

[NetworkRick]

Only 28 miles/day ? Now that’s a deal breaker for me unless it’s for the base model !

[Mike-Mars]

Depends what zone Riley is in. For example, I’m zone 2, with average light levels somewhere between Alaska and Washington. 28 miles would be amazing given that it’s only light for 8 hours daily in winter lol, whereas 28 miles would be disappointing for Arizona.

[NetworkRick]

Was referring to my results. Central Italy, with medium to high exposure it gave me 28 miles a day.
If this is a real value they have to specify in what config. I.E. If they calculate full solar to get 28 miles it isn’t worth bothering.

[ROMAD]

Michael, maybe this map will help.

I’d say that the lowest would be less than 2200 hours followed by 2201 – 2600, 2601 – 2800, 2801 – 3200, and last above 3201

• This reply was modified 4 months, 1 week ago by  Dennis Swaney. Reason: Added possible conversion of map data to Aptera's 5 groups

[JRWiley]

SC is in a 2600 – 2800 average annual days of sunshine zone. So, do I plug in “medium” or “high” exposure into their calculator? Do I plug in both and take the average? I personally think this calculator is pretty useless. On the other hand, the solar cells will gain me something. As long as the break even period on the optional solar packages is under 10 years I will be happy.

[Russell]

@John Wiley, I live in SC. I have a solar array at my house. Its annual production, averaged out over a year, works out to 4 hours of full rated power per day. If the Aptera solar is rated at 700 watts then it should average out to 28 miles per day.

Using the new calculator, Medium Exposure yields 26 miles per day and High Exposure shows 30 miles per day.

• This reply was modified 4 months, 1 week ago by  Russell Fauver.
• This reply was modified 4 months, 1 week ago by  Gabriel Kemeny.

[jonah-jorgenson]

My cousin came over last night. He is an avid fan of Prius and drives one getting 52 – 54 MPG. He likes it because he can travel with it without having “Arduous” task of planning charging stops. He wanted to use the Aptera savings calculator so we put his information in (High exposure – central FL, 40 mi per day driving distance – should result in 40 free miles based on Aptera claims, Gas car, gas price $3.49/gallon- current at Wawa where he fills up) when wee ran the model the results were:

Free miles 28

Number of charges required 11

I have to agree with John Wiley. Calculator is useless as is and misleading without more explanation/information/data.

This in addition to Mr. Rosen’s discovery that you can only put in up to “1” mile if you select EV as the type of car for miles per kWh.

[kevin-bradbury]

Watched a panel discussion video on Aptera owners Club that Chris Anthony was a part of. He stated in that video, that you can gain 30 miles of solar range per day instead of the 40 miles he used to say and what is stated on the configure page if you opt for the full solar package. Is this a misstatement, or has Gamma testing revealed that now only 30 miles per day is possible, even with the extra cells they squeezed in?

[ROMAD]

I used the Wayback Machine (https://web.archive.org) to find the previous chart.

Using it: Little or No: 0; Low: 1 & 2; Medium: 4 & 6; High: 8 & maybe 10; Very High: 10 & 12

• This reply was modified 4 months, 1 week ago by  Dennis Swaney.
• This reply was modified 4 months, 1 week ago by  Gabriel Kemeny.

[Mike-Mars]

Here’s the even older one

https://cleantechnica.com/2020/12/12/aptera-reveals-solar-calculator/

For example, for zone 8, it includes the midsummer (40), midwinter (16) and average (28) estimates. Whereas the new one only seems to give the average without the seasonal data.

Interestingly I’m zone 1 on the old-old map (this one), but zone 2 on the old map (your one).

• This reply was modified 4 months, 1 week ago by  Michael Marsden.
• This reply was modified 4 months, 1 week ago by  Michael Marsden.
• This reply was modified 4 months, 1 week ago by  Michael Marsden.

[JRWiley]

It sounded to me like he said 40 miles per day.

[jonah-jorgenson]

Good catch and thanks for passing this on!

The 30 “Free” miles seem to fit with the new Calculate My Savings function on the Vehicle menu for the Very High Exposure category. It appears that the High Exposure category will provide a max of 28 miles. I have not gone through the calculations for the other categories yet. Although not stated, I assume that is for the full solar package.

Disappointing again to get this information second hand from a CEO in a public forum and not on the Aptera site after the claim of “Openness” by that same CEO on the public forum.

Also disappointing that the configurator still has to 40 free miles for full solar.

Certainly wish Aptera could get their story strait and publish the correct information to everyone at the same time. No excuse for the difference between the configurator and the Calculate My Savings calculator. Just sloppy.

[kevin-bradbury]

@John Wiley – Thanks, my bad. Re-watched with volume UP and Closed Captioning On. Getting old is a breeding female canine.

@Jonah Jorgenson – My bad😬. Please see above reply to John Wiley.

[benjamin-dreidel]

I think the 30 miles per day average for calculating long term savings is probably consistent with the ‘up to 40 miles per day’ of the configurator. Over the long term, you will have cloudy / rainy / short days that will bring your average down. But if you have a bright sunny day all day in June you can get 4 kwh of energy out of the solar panels. A December cloudy day, more like 0.5 – 1.5 kwh.

We’ll have to wait and see.

[Mike-Mars]

On the original solar calculator (2020 – 2021 era), it used to show 40.3 miles in midsummer, and 28.4 miles averaged over the year, for zone 8 (San Diego). 16.5 midwinter.

• This reply was modified 4 months, 1 week ago by  Michael Marsden.

[steven-g-bueche]

So, let’s throw this out there; If the full solar package would only get you 30 miles a day in the best situation, would it be justified at $900? How would this effect your purchase? Would you still buy the full solar package or reduce your solar? Is $900 a fair price for 30 miles a day?

For me I’d say no. It’s cheaper to plug in and get more miles per cost of a charge. The real benefit would be if the grid went down for any reason. I’ll still get the full solar because I still think it’s a cool feather to brag about.

Your thoughts?

[Mike-Mars]

To some extent, it depends on your personal circumstances. For example, I can’t charge at home (nor can 40% of the population), and in my part of the world, public charger prices are in the region of $0.80/kWh (and are expected to rise significantly during 2023). The panels will pay for themselves fairly quickly for me, even though we get a lot less sun than San Diego.

[joshua-rosen]

I think it’s more of a styling choice rather than a practical one. If you like the look then get it else not. The place where there is a big tradeoff are the panels on the rear hatch because it’s a choice between having a rear window or extra solar panels. I live in New England where summers aren’t particularly hot, I’d much rather have a rear window than solar panels which will be of minimal benefit to me. If I lived in Arizona I would make the opposite choice, not having a rear window (i.e. not having more greenhouse glass) is in itself a benefit and having more solar is just the cherry on top.

MY original choice was minimal solar. When I watched videos of the alphas my reaction was that the solar panels looked really good so I added the hood panels because they were so cheap. The alpha panels were just mockups, the real panels on the gammas look like crap so I’ll probably delete them and go back to minimal. I’ll make the final decision after I’ve seen the vehicle in person. If I like the looks of the hood panels I’ll get them, if I don’t I’ll go back to minimal.

[george-hughes]

This so-called solar calculator is flawed, first off, as its adjustable bar computes a figure that makes no sense as it can only calculate the savings of a EV that requires 200 watts to travel a mile. Given the slider only goes from .20 kwh to 1.0 kwh and is base set at 0.32.

But even that is not the problem; the problem is no calculator will do any more than the most gross estimate of generation.

In another topic I suggested a real ‘calculator’ that literally combines information from the exact location you are planning to park, its orientation to north, weather predictions from the Internet, photos of the surrounding area, a plot of the sun’s travel through the visible sky at the point in time and place can all be used to predict with fair precision, whether you need to park where you are or do you need to look elsewhere?

Developing that real-time application is the real opportunity.

Let me simplify:

As an Aptera owner:

1. I want to generate the most miles I can from my solar powered car because, what else is the point?

2. I know that the power generated may vary by +/- 80percent (or more!) depending on where the sun in the sky is. (I.e. a spot in the sun right now but shaded 80 percent of the time of the ‘park’ is less productive than a shaded parking spot that has clear sun 70 percent of the time.

3. Sometimes, if I haven’t driven a few days, I may want to park in places with less sun but how do I quickly and easily determine the complex relationships between the path of the sun and obstructions, time of year and the impact on a small patch of earth?

I dare say the variations that solar EV drivers will experience between locations in their local environs will be as great and greater than those ‘estimates’ based on gross geography.

There is a reason that modern EVs, and especially SOLAR EVs, need some good computing. I know Chris and Steve know this and I’m guessing there is a lot of wow left to be revealed when it comes to the UI.

Edited to add:

And for those concerned about miles, this onboard Aptera accessory/app can report its result in kwh of energy. If the reading is 2.3 kwh for an 8hr park at point A, I can do the math and see I’d get about 23 miles in that instance – assuming I’m using the 10mi/kw usage.

But the point is the only ‘solar calculator’ that is more than a sales tool, will have to be in the car using real time information.

• This reply was modified 4 months, 1 week ago by  George Hughes. Reason: add final observation

[Greek]

Aside from how much energy you will receive from your local area, I know I will not get the miles that are envisioned. Having a heavy foot, I know I will not get the benefit to what ever the numbers are computed. So when APTERA tells me 40 miles of range a day, it won’t apply to me and I’m sure many others. I plan on having as much fun as possible since it will be replacing my Zero sr/f and my i3.

[jonah-jorgenson]

I developed and ran a simple Monte Carlo simulation to determine the max (I guess we think yearly daily average??) “Free” miles per day for each of the exposure categories independent of savings calculations. Also included in the simulation output was the number of times a customer would have to plug in for a charge in the same yearly period. I ran it for one million reps. These are the numbers it converged on for daily average “Free Miles” and “Number of “Plug in times” for each exposure category:

Little Exposure – 22mi/12 plug ins

Low Exposure – 24 miles/10 plug ins

Medium Exposure – 26 miles/8 plug ins

High Exposure – 28 mi/6 plug ins

Very High Exposure – 30 mi/5 plug ins

Assumptions were:

Full solar, Sea level standard day meteorological conditions (No affects of weather or altitude), flat terrain, Aptera’s claim of 10 miles for kWh.

Of course this is not a realistic representation of the variance of one driver from another or the variance of terrain or weather conditions.

Conclusions:

It appears that Aptera used deterministic calculations in their calculator (No compensation for the the variability over a range of values for the factors in the model)

It appears that driver behavior affecting miles per kilowatt hour were not incorporated in their model

The results would appear to match the new 30 mile max figure for a full solar configuration(We believe) and represents a daily average (We believe) over a one year period

Aptera’s model does not accurately represent real world miles from solar or number of plug ins needed in a year

There are no definitions of the categories with reference to geographical locations

The model results do not reconcile with the current solar configuration/miles in the reservation function solar configuration.

There is no disclaimer in the reservation solar configuration function for this discrepancy

Most importantly, the model is only a very rough estimator of savings and should not be used as an authoritative source of savings

[joshua-rosen]

Driver behavior is never included in any range calculation because it’s an unknown variable. The purpose of any range estimate, be it EPA, WLTP or Aptera’s solar calculator is to provide an apples to apples metric, individuals can then provide their own derating factor based on their own driving style.

What I would prefer to single numbers are graphs that show a wide range of conditions. Instead of a EPA/WLTP numbers that makes assumptions about the mix of speeds I’d rather see a graph from 30MPH to 90MPH. With the current system you get two different numbers for the same car because EPA and WLTP use different speed mixes in their calculations, a graph would eliminate those differences. For Aptera’s solar calculator I’d like to see a graph over the course of the year. The amount of sunlight that you get in January is much less than what you get in June, a graph makes that clear. The amount that you travel also matters on the time of the year. And just as you would apply your own weighting based on how you drive to a speed vs range graph you would also apply your own weighting to a range vs month graph depending on which months you travel and which months you don’t. I live in New England, most of my miles are put on in the spring, summer and fall, we don’t go anywhere in the winter so winter range doesn’t matter nearly as much. If I lived in Arizona or Florida I suspect my pattern would be the opposite, I wouldn’t want to leave my air conditioned house in the summer and would do most of my traveling in the milder winter months.

[trevor-anderson]

The old solar calculators had the following for Zone 4 (CT region)

OG website: ~24 miles/day

Previous (2021-mid 2022): ~22 miles/day

Current 11/22+ (low exposure zone): 24 miles/day

If that can be believed, I am thrilled because it could be a combination of:

1) Solar testing has yielded better results over the curved surface than estimated.

2) They are factoring in the modest increase in number solar panels since the pre-production models (several tubers talked about it, ~10% increase in panels).

3) The Aptera is more aerodynamic than originally estimated.

4) The production motors are more efficient than the pre-production model.

5) Power conversion equipment is more efficient than original estimates.

6) Weight savings due to carbon frame

However for my 15,000 mile/year commute the difference of 24 vs 22 miles/day solar gain equates to $159 vs $179 per year for electricity; or a $20 difference. I have estimated my savings to be around 900-1200 compared to the hybrid I am driving now…I cant be more excited.

I have preordered the tri-motor version, it would be cool if they could do some software black magic and increase efficiency by swapping to RWD when cruising to reduce power conversion losses by only feeding one wheel or in lieu of three.

[Mike-Mars]

Hopefully 🙂

There’s also 7) maybe the zone 4 and ‘low exposure’ don’t map onto each other. But I’m hoping the extra panels and aero efficiency are the true reasons.

[Scott]

The full solar package is a good thing and a good option for some personal preferences. I personally look at the rear window as the preferred option since I value exterior unimpeded field of view (which is why I dislike the side windows’ view-blocking frames 😊 ). I have selected the front hood solar option since that is over an opaque body panel like the standard roof, yet I like to be able to look over my shoulder too and therefore do not want the solar rear hatch. And I made that decision before my Subaru’s rear view backup camera stopped working recently (and that vehicle of course has a reflective center rear view mirror). I like options on visibility. I also don’t want to feel like I am driving in a dark enclosed box down the road.

I also have solar panels on my home that intentionally produce more than my entire home’s annual energy usage so that excess can go to an EV. Then add in that I intend to have the vehicle garage kept, especially with the “solar-phobic” wraps being discussed, and the rear solar hatch has little value to my use case, especially with the other two panels in place that are producing some power anyhow when out and about.

I of course very much hope that the Aptera company lasts for a century+. Nonetheless, I also account for risk factors of potentially needing to jury rig replacement video cameras and displays in the future for a “collectible” car that may not have direct parts suppliers if the company happens to close shop after initial production. I could always just insert a standard, inexpensive, commonly available reflective rear view mirror if ever needed or desired (assuming there is some decent rear facing line of sight, TBD).

Lots to think about. All panel option choices are certainly valid and good based on your preferences and use case.

[mark-salyzyn]

I have also seen various sources of information about the Aptera moving from 100Wh/mile to 129Wh/mile, which would jibe with a drop from 40 to 30 miles/day of solar range. Ruthless efficiency is extremely fragile in the face of engineering realities, available parts streams and the real world. I urge all to manage their expectations, this vehicle will be wonderful, the best, just let the pennies and nickels fall where they may.

I am expecting the near 3 times more efficient than nearest competitors drop to a solid 2 by the time we take delivery.

[Greek]

Good point Mark. Just as Curtis has calculated that the APTERA is so efficient that the slightest difference in with weight or speed can have a greater effect on all around performance.

I know not to be so disappointed. I will still be driving/riding the most efficient vehicle known to man. I have a heavy foot to begin with but I can’t wait for some of the early deliveries who’s owners will try to hyper mile the vehicle and see what if any gains they can make to beat projected range estimates.

[curtis-cibinel]

As an extremely light vehicle Aptera will do amazingly well at low speed. My physics calculations (with some estimates on constants that are likely inaccurate by a reasonable margin) at 30 mph has the Aptera 45 kwh at 51 wh/m and model 3 at 125 wh/m. At Aptera’s top speed of 110 mph Aptera uses 264 wh/m, model 3 will use that same energy at only 74 mph or 466 at 110 mph. At low speeds Aptera has ludicrous range potential but as the speed goes up despite extreme efficiency the Aptera will lose more relative rated range due to its comparatively small battery and efficiency at mid speeds (48.5 mph average) used in the EPA cycle. Aptera 45 kwh uses 41% the energy of model 3 at 30 mph or 56% at 110 mph.

If you want to play with the numbers please make a copy: https://docs.google.com/spreadsheets/d/1Tuu7avKH2dS_JPk7aiP2av09a1f1WE0OvvNH6fdHpiQ/edit#gid=2123689303

[Mike-Mars]

Is there a source for the Wh/mile figure?

The 40/d miles was only ever the midsummer figure for zone 8. The average for the year was 28/d, as per this https://cleantechnica.com/2020/12/12/aptera-reveals-solar-calculator/

Personally I don’t think there has been a change. It’s ‘up to’ 40 versus ‘average’ 30, it’s consistent with what they said back in 2020.

• This reply was modified 4 months ago by  Michael Marsden.
• This reply was modified 4 months ago by  Michael Marsden.

[john-belmonte]

From a recent Sono article:

The solar cells generate from 70 miles (in typical weather) to 152 miles per week (in optimal, always sunny) environs

If Aptera were to quote similarly, it would be “210 miles per week in typical weather” (based on recent guidance of 30 miles average per day).

I’m not saying Aptera should quote weekly range only because a competitor is, but there are several reasons why this makes sense:

• in most regions (especially U.S.), a typical week has a mix of sun and clouds, so the use of averaging is more tangible
• most cars enjoy a day or two per week of recuperation from the normal commute, and mentally it’s straightforward to apply the benefit of that to a weekly range
• the numbers are bigger !!!

• This reply was modified 3 months, 2 weeks ago by  bbelcamino.
• This reply was modified 3 months, 2 weeks ago by  Gabriel Kemeny.

[seth]

I think they should bring back the old style solar calculators that showed average for different months, and annually. Preferably if you put in your zipcode and it would just grab your solar zone instead of guessing. It would also be nice to get highway vs city vs mixed driving miles.

[jesthorbjorn]

Gotta admit that one of the first things I did when I discovered Aptera was compare the 280 miles I drive commuting to work each week against the coincidently equal 280 miles worth of solar gain I might accumulate per week under ideal conditions. Sure, I would fall short during the work week, but then potentially completely recover during the weekend.

Note that I am a PV system owner of many years already so I have no illusions about how often I am liable to see “ideal conditions”. I also know how disproportionately satisfying it is for those rare days or weeks when the PV system really kicks ass!

So, yeah. There’s good sense to the notion of weekly gain rather than daily.

[BigSky]

Potayto/Potahto

😉

[kerbe2705]

I tend to agree with @BigSky Country : The difference is just “spin”. I remember when, years back, a woman’s size 4 dress became a size 0 almost overnight so that people could pretend they were smaller because the numerals used to describe their sizes were lower…

Chris Anthony said (in the “Now You Know” interview) that the best solar information could be found here: https://www.nrel.gov/gis/solar-resource-maps.html