One Finite Planet

Solar Electric Vehicles: What you can, and can’t do with solar power.

Table of Contents

There are solar boats and even a plane already, yet the EVs we are most familiar with are cars, and despite all the models on sale, none so far is solar powered.

However, that is set to set to change with at least 3 solar powered cars nearing production, and of course the solar does not have to built into the car to enable solar powered travel. I decided to publish a page as a place where I can continue to add updates as progress occurs.

The economics: Solar power reduces economic activity.

Yes, solar power reduces economic activity. In fact if enough people are able to install solar power in one quarter, and then installs stop for the next two quarters, unless growth in the economy elsewhere offset people having lower power bills, it would produce two quarters of negative growth, which is officially a recession.

This is problem for governments. If solar cells last long enough to save more than they cost, the result is a reduction in consumer spending, and a key economic indicator is consumer spending. Solar is also the economists nightmare, as there is no corporation providing the solar energy, so it is almost as bad as us all making our own coffees instead of buying them, which would result cafés losing revenues.

Its clear, if we all moved to solar power, the total value of companies on the stock exchange would fall, as the revenue for electricity providers would fall, and as a result, so would their shares. This could mean some governments may have mixed emotions, and interests, with regard to solar power.

Solar Cars: Technology.

The limitations of Solar Cars: Range added per day.

There is the expression “the sun does not always shine”, and clearly, cars need to be driven not only when clouds block the sun, but also at night. For this reason, real world solar powered cars use the sun to charge the batteries, and use battery power when being driven. With today’s technology, solar power only provides enough power to sustain daily commutes of 50-70 km per day (approximately 30-40 miles per day). When you need to drive further, you will either need to consume several days worth of solar charging, or have charged/recharged from normal electric vehicle chargers to boost energy.

There is research that private cars spend over 90% of their time parked, so as long as a car is charging while parked, there is usually ample time to store up far more power from the sun than what would be available during the drive. However, as explained in the video ‘why solar powered cars don’t exist‘ (see below) just taking a Tesla, covering it with current solar cells, parking in random location (and considering at the poles to be same probability as at the equator), will not give enough range per day for the typical driver. Which is why solar cars on this page (below), are not just Teslas with solar cells added.

The world solar challenge: The impracticality of instant solar.

Actually they do exist, but the case against instant solar is well explained, and as he in the end concludes, solar can work.

There has, for many years, been a challenge in a remote area of Australia where solar powered cars without batteries race for glory, and travel at average speeds of over 100 km/h (60 mph) on solar power alone.

The event promotes research that finds its way into production, but the vehicles in the race are far from practical in the real world. So far these vehicles demonstrate that for a real world vehicle, instant solar power, as opposed to using solar to charge the battery, is impractical.

For the real world, you do need a battery. And you need the car to be parked in the sun for more hours than it will be driven.

In addition to the engineering explained video “why don’t solar powered cars exist”, there are other pages and videos on solar EVs, but they such as quite this derivative one, tend to repeat the same mistakes, and also be derivative of the video from engineering explained or another source, but add mistakes and use out of date information, and sometimes increase the not necessarily accurate in the real world assumptions of their source data.

Jennifer Sensiba from Cleantechnica does a great job of summing up the problems and making sense of it all in her page: Why Automotive Outlets Keep Butchering Solar Vehicles (& Why They’re Wrong) Hopefully this information on this page also helps show, as engineering explained did concluded despite his starting assumptions, solar powered cars are already viable, and could play an increasing role going forward.

Home Solar.

For those with home solar, or the potential for home solar, any electric vehicle can be charged from the sun. A big advantage of home solar, is the car can be under cover of a carport or garage, which has a much larger area than the surface of the car, making solar charging of even a large SUV or a pick-up viable, provided it spends enough hours parked at home. If those hours parked at home are only overnight, then the home/garage will also need enough battery storage to store the power from the sun during the day, and then transfer some to the car overnight.

Portable Solar.

Another possibility for using solar power, is the use of portable solar. This can be used to charge charge an ’emergency’ range extending battery which does not need the solar cells to be on the car, or perhaps more usefully, if a car is to be used on a lengthy wilderness/camping trip where there will be long periods at fixed locations, portable solar can also be used to directly charge a car. Even a slow road trip, as described below, can be possible:

The journey will take place across 84 days, and begin in Newcastle in September. The team will rely on 18, 17.98 m solar panels that can be rolled out alongside the car to capture the Sun’s energy. The panels are made from PET, which is the same plastic used to make water bottles, and are printed with “water-based solar paint” on a printer that used to print wine labels.

Round Australia journey powered by rollable solar panels.

An example of a commercial portable solar is described below.

The Cars: 2023 and beyond.

Well, Reality in 2023? 3 Very different market segments.

There are three vehicles that are headed for production I am aware of, and they all are schedule to come to market before the end of 2023.

As will be covered when discussing each vehicle below, they each address totally different market segments, from low cost to prestige, from 2 to 5 seats, and from ‘go anywhere’ to more a city car. The common theme is that each of the three is produced by a small boutique operation, dedicated only to the production of, at this stage, one single solar vehicle and each of these three is targeting its own distinct market niches.

So why no mainstream manufacturer? It seems the mainstream view is that at this time, solar vehicles only address small market niches. However, as seen with the Mercedes EQXX and cars from Hyundai, Toyota, Tesla, (below) solar is at least now on the radar of many established brands.

Technical comparison of vehicles as different in their uses as a Bentley and Vespa.

I even found one video providing technical data for all three of the upcoming cars, which highlights the common technical points of any solar vehicle, and the very different nature of these three cars.

I only just found this video, and at first though maybe I no longer needed had a separate section for each car, but watching the video emphasises how many aspects of these three vehicles need considering separately.

Beyond the specs in the video, all three also not only have rather generic mainstream supplier batteries, but with all three having been in development for some time, they rely on the rapidly going out of fashion, nickel cobalt style of lithium ion batteries.

Aptera: The Wingless one?

A-ptera, from the latin ‘a’ meaning ‘no’ and ‘ptera’ meaning ‘wing’: so ‘no wing’. The car does look a little like a wingless bird. Scheduled to begin deliveries in 2023, the Aptera is a 3 wheeled, extremely efficient, two-seater car with 1,000 miles (1,600 km) of maximum range when fully charged, that can be charged at around 70km per day in reasonably sunny locations, or alternatively at regular EV chargers.

As a two seater, the Aptera fits two niches:

  • that of a second car for those who only occasionally all travel together.
    • or
  • an only car for singles, or couples, who can live with having only two seats.

Apart from the number of seats, the room including luggage space, is generous. The car performs, unlike the other two cars here, like a sports car.

Sono Scion.

A regular small hatchback, the Sono Scion is can be a pure solar “city car”, where daily commutes are short, but does not solar enough range for those with longer daily commutes. The average distance that can be driven per day on solar power is below average driving distance per day for those in many areas.

Despite the distance per day limitation, the Sono may be the perfect car for a large groups of people: mainly those city dwellers who can only park on street.

Parking on the street goes with suburban living, which can very often require a daily mixture of short distance commute and shop trips, together with far less frequent ‘road trips’. On the road trips, you are, like most others with EVs, using the more expensive electricity from fast chargers, but you may be able to eliminate or at least minimise the need for anything beyond solar charging when not on road trips.

The Sono Scion is not an exciting car as it has leisurely acceleration and conservative looks. But it could be the most practical car possible, for those who need to park on the street, and cannot live with a more radical car like the very wide, and two seat only, Aptera.

Lightyear One.

The luxury option among solar cars so far, is the Lightyear one. The Lightyear delivers ‘ultra green’ luxury motoring for those willing to pay for the privilege.

With the solar range, and close to the same efficiency as the smaller Aptera, but 5 seats and a luxury interior, the Lightyear does it all. Well, except fit in a short parking space. Lightyear still thinks of themselves as the first long range electric vehicle, but once in production, they will only hold that title for a short time, if at all, as the Aptera is not far behind.

In fact, one of Lightyears’ assumptions, that batteries are so expensive that Lightyear can compete on price with other long range vehicles, is at risk of getting out of date as battery prices fall.

While the longest range Tesla does not match the Lightyear One 725 WLTP range, even a lower model Lucid air with the range of 649 km using the stricter EPA standard would match the range of Lightyear One (725 km WLTP) offer substantially higher performance, and a significantly lower price. Although there is appeal in the lower energy use, Lightyear needs to avoid further delays and bring the car to market.

Fringe? Custom and other vehicles available now.

Solarolla: A solar vehicle production company in Oregon

Further in the future.

Eindhoven University Solar Camper: Stella Vita.

Forget the 70 km, or around 40 miles, per day added range of the vehicles so far, how about a camper that can add 200 km (125 miles) of range per day?

A fully campervan with a total range of 600km, fully rechargeable by simply parking for 2-3 days. The vehicle also travelled 3,000 km around Europe as a demonstration, while also proving power for accommodation and cooking for the drivers, while only needing two fast charges during the entire trip.

The vehicle was designed by students from the World Solar challenge teams from Eindoven University in Holland. The team has only won the challenge four years in a row in the past, it has also trained the students that went on to create the Lightyear One (above). Now their students have also created the Stella Vita: Self-sustaining House On Wheels.

The bad news is that, at this time, there is no production version planned. Yet anyway.

Mercedes Vision EQXX

The Mercedes design study “Vision EQXX“, incorporates a solar roof that adds 25 km (15 miles) per day. Not at the level of range of a car designed from the outset to be a solar car, but would many people who own a high end Mercedes, need to park on the street? A test for the technology, but maybe not a solution to areal need at this time.

Tesla Cybertruck.

The often delayed Tesla Cybertruck will, it has been said, have an option of a solar cover which can, in theory, add between 15 and 19 miles (24-30 km) of range per day. How much range depends on the information source so the specification may have changed over time, and there will be a further option of extendable ‘wings’ that can, it has been suggested, could increase the range added to 40 miles (64 km) per day.

At this stage, the idea is there, but a reality of a date for production does not seem to be available yet.

Fisker Ocean with Solar Roof.

The Fisker Ocean solar roof adds in theory 1,600 km per year (1,000 miles), so it contributes to saving power, but unless your typical day when based at home requires only 4.3 km (2.7 miles), it is not going to replace charging.

Solar Powered Drive Toyota Prius.

Toyota, mostly known as an ‘ev denier’, has produced prototypes of a Solar Powered Drive Prius using high efficiency solar cells from Sharp, enabling adding 44.5 km (27 miles) or range per day. As a hybrid with small battery and and internal combustion engine for long range, it is not like you can charge up several days for a much longer trip either. Not sure with this one goes, but at least they are working on the technology and I have added it for completeness.

Boats.

Overview.

Electric boats are also a thing, and there is quite a lot happening in the the world of electric boats. This is somewhat surprising to me, as emission free boats are not exactly new. If you want a zero pollution boat, why not a sail boat? In reality, even sail boats larger than those people can lift, also have internal combustion motors. Tankers, ocean liners and superyachts, with vary rare exception, are all powered by internal combustion engines.

The simplest classes of boat to transition from internal combustion to electric power, it seems to me seem would logically be:

  1. Privately owned motor boats which spend almost all time moored or anchored.
  2. Tenders and outboards which travel short distances.

For group 1, and some private craft of group 2, solar charging of batteries seems just a natural fit, as there usually spend long periods of time between use in the sun. Yet, perhaps because moving to electric itself is new, commercial applications of electric boats such as ferries are more common.

Solar cars, can be practical in part because privately owned cars spend most of time parked, and privately owned boats spend an even greater percentage of time parked. For most private boats, even when the boat is in use, much of the time people are on the boat, it will be at anchor. Plus, the boat is normally out in the sun!

The solar boats I have found so far all incorporate range extender diesel motors, also called generators, and do not bother to move from gas to induction cooktops etc.. Nor do these boats incorporate high capacity batteries that can really leverage the long times available for charging. This is likely in part because the boats use older, more expensive nickel cobalt batteries, rather than most cost effective LFP batteries. If space for batteries would increased by eliminating the diesel motors and fuel tanks, and the latest lower cost per kWh sodium batteries are introduced, solar boats could move to a whole new level.

Sunlight Yachts Silent Series.

Sunlight yachts seem to be one of the pioneers with their silent series, but despite the ‘silent’ label, these non-sail yachts all incorporate diesel generators, revealing current limitations of solar power.

Personally, to me, even an emergency mast and sail would have more appeal. However, obviously they know what their market wants, and they do have quite a number of models on offer. Once Sunlight can get their hands on newer battery technology, things could improve even further. The biggest drawback is likely to be price.

Herley Boats, New Zealand.

The electric catamaran from from Herley yachts appears closer to the price range of normal people, but with far less solar cells and a relatively smaller battery, the range extender/generator would likely play and even more significant role. Still, this does reveal where things are headed, and be more and better solar cells, plus new lower cost battery technology that a boat can have the room to house, things could get even better.

Azura Marine Aquanima

Following their first craft, the 40 foot model, it is hard to know how things progressed for this even more affordable solar option. There are reports of manufacture in Spain and Bali, but it could also be that Covid-19 created to big a problem to overcome. I will look for updates.

Planes.

While there are applications where electric planes are already in operation, such as flying instruction, seaplanes, and other short flights, and these planes could easily be charged from hangar top solar, the applications of true solar planes are even more specialised. In fact, perhaps they are drones.

The Future? (this section to follow)

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