Guest essay by Eric Worrall
The Solar Impulse 2 has finally completed completed the latest leg of its round the world flight. In engineering terms, a round the world flight using solar power is a remarkable achievement. But the difficulty of achieving this feat showcases why solar energy will never be a viable replacement for fossil fuels.
An experimental plane flying around the world without a single drop of fuel landed in California after a two-and-a-half day flight across the Pacific.
Piloted by Swiss explorer and psychiatrist Bertrand Piccard, Solar Impulse 2 touched down in Mountain View just before midnight (3 a.m. ET).
“It’s a new era. It’s not science fiction. It’s today,” Piccard told CNN from California after his successful voyage. “It exists and clean technologies can do the impossible.”
Images of the elegant solar aircraft, which has the wingspan of a Boeing 747 but only weighs about as much as an SUV, flying over the Golden Gate Bridge into San Francisco Bay mark a significant achievement. The team has seen the project beset with problems and setbacks during its pioneering airborne circumnavigation.
…
“I’m very happy that everything works extremely well and the airplane is functioning as it should,” Piccard’s business partner and the plane’s other pilot, Swiss engineer Andre Borschberg, told CNN by phone from California just ahead of the successful, on-schedule landing.
“It’s a demonstration that the tech is reliable.”
The plane took off from Hawaii on Thursday, resuming a journey that had stalled on the island of Oahu for almost 10 months.
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Read more: http://edition.cnn.com/2016/04/24/travel/solar-impulse-2-plane-california/
Solar planes can’t carry meaningful amounts of cargo. They can barely carry passengers.
I am not disrespecting the talent of the engineers who achieved this feat. Flying a solar plane around the world is a remarkable achievement. But this achievement does not demonstrate the technology is viable. What it demonstrates is that solar is a ridiculously poor source of power. A solar collector the size of a 747 just managed to collect enough electricity, to keep an incredibly lightweight plane aloft.
Just like solar panels, solar planes might find some niche uses, such as long life high altitude robotic observation platforms, or even as mobile telephone repeater stations – solar planes are not restricted by fuel payload, and can reach very high altitudes, because they don’t depend on burning fuel with oxygen for their power.
Solar planes will never replace fossil fuel powered planes, for ferrying people and high value cargoes across vast distances.
Update (EW): h/t etudiant – the flight is not yet complete…
We tend to call ’em satellites when they get that high. Nothing new under the sun.
Gee, and I thought planes fly because they get lift from the air (mostly Nitrogen and Oxygen with trace CO2) passing above and below the wings carefully designed to produce lift? No lift needed?
It is a lovely piece of work that has about as much relevance to the future of practical transport as the man-powered aeroplane. If you truly want renewable powered long distance transport, sailing ships are far more practical. You can even carry passengers. Some of my ancestors got here that way.
What is wrong is not with renewables but with the soda-straw view, absolutist, critical thought free spins such as this article. If the impracticality of a solar powered cargo plane is a metaphor for what is wrong with renewables, it is also a metaphor for what is wrong with coal, since a coal powered plane would be even less practical. Trying to make a point about renewables in general using this example is simply ludicrous.
Consider that solar powered drones for surveillance and dirigibles for short haul cargo movement are eminently practical.
Ahh, but if I process that coal into a liquified gaseous form and put it into the jet engines I can fly a 777 on it (with some engine and fuel system modification). I can’t do that with solar.
Is it practical? No, but if liquid fuels are unobtainable and coal is cheap and plentiful, that is what I would do!
Ahh, the frustration of the true believer. It’s the perfect way to start the morning.
Nobody is proposing that we build a coal powered plane, so your analogy is ludicrous on it’s face.
Much like yourself.
On the other hand, the backers of this project are the ones who are claiming that it can replace fossil fuel powered planes, and by that they mean petroleum products.
I love the angst of the warmista, it smells like victory.
true, being the guy that stands on the wings in mach .8 at approx 35K ft trying to shovel coal into the fan bypass ducts in a manner that gets it into the compressor stages would truly suck….
I’ve seen this sort of head fake with cars.
The tech here is with the PLANE, not the solar. Solar still sux.
So what happens when this plane encounters a strong head wind?
Goes into reverse……….
Westerly winds they could never go back just west to east around and around.
Tumbleweed.
Just wondering whether Bertrand Piccard is related to the twins Auguste Piccard and Jean Piccard, 19th century balloonists…
I was wondering if he is related to Jean Luc Piccard.
He is indeed a member of the famous Piccard family:
Grandfather Auguste Piccard was the first to reach the high stratosphere with a balloon and father Jacques Piccard was an underwater explorer into the lowest depths of the oceans.
Bertrand Piccard and Brian Jones did perform the first around the world non-stop balloon flight.
The airplane flight is performed with the help of a meteorologist in my country, David Dehenau, to find the best wind directions at different heights, who also helped them with their balloon flight and also Steve Fosset with his first ever solo balloon flight non-stop around the world… The Piccard/Jones balloon flight was completed in 19 days, 21 hours and 47 minutes, Steve Fosset even faster: 13 days, 12 hours and 16 minutes. Compare that to the plane, which needs about a year…
You guys are all the same people who said 100 years ago that aeroplanes would never replace the reliable dirigible. Have fun in the shadow of the adoption curve.
False equivalence there, Jeremy. Fun to Believe, though, huh?
Enjoy your ignorance.
If you look back to the 1920’s and 1930’s then you will see that an equally large group of people believed that airships were the future of air-travel. They were wrong.
And frankly, giant airships were of far more practical use than this concept will ever be – with regard to transportation of passengers and goods.
You are simply proposing that we are equivalent to the people who failed to see that the future was rigid aircraft. But we are the people proposing that the future is the continuation of this proven tech.
We are clearly equivalent to those people, since we are saying the same thing.
Why are you not suspecting that it will be you who has fun in the shadows?
This solar powered glider technology will never transport significant quantities of people or goods.
Not unless somebody can find a way to increase the brightness of sunlight by several powers.
It may be useful for other purposes.
So far, it is just good at drawing attention and wasting massive amounts of energy and money.
No problem, Jeremy. We’ll just destroy a few 7×7’s in spectacular accidents; then we’ll be all set to replace them with an immature technology that would have (literally) crashed and burned if it hadn’t had a government monopoly to fall back on. That’ll show ’em!
Engineering is a dreadful field. It keeps having to deal with the practical limitations of technology.
At the altitudes this flies, there is probably about 1000watts/square meter possible to collect at high noon. Solar cells are what, about 40% efficient at the best? This gives 400 watts/square meter maximum collected.
A 777 engine at takeoff produces about 117MW. To produce this much power, would require 292,500 square meters of solar cells per engine!
Now if we give solar technology the chance to break the laws of thermodynamics and achieve 100% efficiency that is only 117,000 Square meters per engine at noon to create the thrust of a 777 at takeoff.
For comparison, the wing area of a 777 is 427.8 square meters. In other words you would need the surface area in a perfect solar cell case of 546 Boeing 777 wings per engine to fly a modern airliner.
A soccer pitch is approximately 7140 square meters so the engineering challenge is to make a plane with enough flat surface area to encompass 16 soccer pitches light enough to actually fly on one 777 engine’s worth of thrust. (provided we can break the laws of thermodynamics and produce 10% efficient solar cells). This is the reason people here scoff at this idea.
oops 100% in that last parenthesis.
Owen.
Thanks.
You saved me from having to work out these obvious details (at least obvious to a competent engineer) and post them here.
Your post is exactly why a solar airplane will never be practical.
And these details are exactly why the liberal ignoranti, who took philosophy or economics instead of hard science, will never understand.
Instead, they will wave their arms and say the equivalent of “because unicorns.”
Thank you for this patient explanation.
Albeit a “back of an envelope” analysis.
And what we discover from the back of the envelope is that this kind of vehicle is doomed to always have a very small envelope.
In a sense, the huge amount of money squandered on this silly stunt project, may serve to highlight the deficiencies which are immediately clear to people familiar with the existing fundamental limits.
Perhaps if we were situated near to the binary star and massive energy source Cygnus X-1, then we could more successfully harness the planet-bound radiation to create an experimental solar craft that could break the sound barrier. We could call it, Experimental Craft One. Or maybe X-1 for short.
This idea is brilliant.
Where is my X-prize?
(Apologies for indulging in yet more silliness.)
You are obviously unaware that airplanes got where they are today with the use of a compact lightweight energy source – Jet A-1.
Solar is a diffuse energy source with a heavyweight concentration device which even if it was 100% efficient would still not compete with kerosene.
Have fun watching solar fail to be adopted (without subsidy).
Why didn’t they simply add a windmill to the front and back of the plane to capture the power of the wind? Then that thing could have stayed aloft for ever and flown around the world in a matter of minutes and the power grew exponentially as it gained speed!
Your idea is being sidelined already.
Quite possibly due to the conspir&cy by “Big Oil” to deny people access to exponentially self-increasing power sources.
I can’t tell if you are being sarcastic or not.
If you aren’t, please look up the second law of thermodynamics.
If you are, that joke stopped being funny when people were seriously recommending it.
Really good posting.
The solar plan did one thing that airplanes can do – fly a man through the air and it did that one thing to s large extreme – all around the world. It can not do a lot of things that planes typically do, carry significant cargo, deal with adverse weather, travel at a high speed, maneuver… The one thing it does well kind of misses really does not embrace the “value” that planes can provide. Similarly producing kwh is a singular value that does not encompass the widespread benefits available from more conventional generation technology. Adding up the applications and kwh produced will not mean that renewables can replace conventional generation.
A useful thought-experiment is to imagine that the anti-carbon mass delusion hadn’t happened. Would a stunt like this have ever gotten funding? Doubtful. And if it had, what they’ve “achieved” would mostly be deservedly laughed at and derided. To call this an “accomplishment” makes a mockery of true accomplishments like that of the Wright Brothers.
[snip] ‘Duh!’ Like it’s supposed to replace a real 747 or any other fossil fuel plane.
“Solar planes will never replace fossil fuel powered planes”
true … because in reality “fossil fuel” does not exist.
A 10 month gap in the trip? How come? Did they need to recharge it for 10 months?
A fried battery apparently. Very expensive to replace. And the trip is only halfway done.
Every year, there is a “news” article that shows how students at the [insert name of local university] are getting great mileage out of their solar-powered car. Every. Year.
I guess its a step up from all Kardashians, all the time, but barely.
Strap Al Gore to it for a flight and it will capture a lot more viewers.
At Algore’s weight it won’t leave the ground.
Of course if we get all the hot air and BS removed he can pilot the “model” planes.
Definite sarcasm. Right?
I fail to see how this is any more meaningful than had they circumnavigated the globe with a peddle power plane. It’s nifty, but so what.
“But the difficulty of achieving this feat showcases why solar energy will never be a viable replacement for fossil fuels.” A very comprehensive statement, not supported by the valid argument made here about solar power for AIRPLANES. Solar power , stored in batteries, can certainly power automobiles – all of
Tesla Motors supercharger charging sttaions get most (or perhaps all)of their power from solar panels, which charge large master batteries used to charge customer vehicles either when there is no sun, or when there are no cars hooked up that need to be charged. Of course, the simple fact that this can be done (using massive govt subsidies, by the way) doesn’t mean that it makes sense to do so, even in the context of reducing carbon emissions. Nuclear power, in the form of advanced reactors, such as the molten salt reactors, which not even the most biased anti-nuke greenies can object to (at least not logically)
will be the solution to carbon free power that is cheaper than fossil fuel power, even coal power. Solar
power, or any unreliable power source, requires massive supporting back up capacity (usually fossil fuel
powered) that renders it both uneccessarily complicated, but a lot more expensive than simply the cost of the solar apparatus.
The Tesla charging station at Harris Ranch, CA (about halfway between Sacramento and Los Angeles) is, or used to be, powered by DIESEL generators.
Thank you for flying Sunny Airlines.
Please notice the “fasten your seatbelts” light has been activated. Unfortunately, we have been slowed by running under a cloud bank, and the sun will set soon, so we’ll have to ditch in the ocean. Review your emergency pamphlets and prepare to take the position. Your seat cushions will act as flotation devices.
Thank you for flying Sunny Airlines, and have a nice day!
There’s your problem right there.
The power needed to light the “fasten your seatbelts” signs took too much energy away from the motors, and we are going to crash. Sorry about that. Now fasten your seat belts.
And the pamphlets weigh too much. 🙂
The underlying airframe technology is more useful for traditionally powered air launched rocket platforms.
Balloons are way more reliable.
“The first Pacific crossing was achieved 3 years later in 1981. The Double Eagle V launched from Japan on November 10th and landed 84 hours later in Mendocino National Forest, California. The 4 pilots set a new distance record at 5,678 miles.”
http://www.eballoon.org/history/history-of-ballooning.html
Japan’s Secret WWII Weapon: Balloon Bombs
news.nationalgeographic.com/…/130527-map-video-balloon-bomb-wwii…
May 27, 2013 – Balloon bombs launched from Japan were intended for the United … Experts estimate it took between 30 and 60 hours for a balloon bomb to reach … When the balloons made landfall, there were no obvious clues as to where …
http://blog.cleveland.com/metro/2008/07/japanese_balloons_brought_deat.html
“On May 5, 1945, Rev. Archie Mitchell and his wife took a group of five children from their church on a tragic outing in the woods near Bly, Oregon.
Something strange — a large deflated balloon — dangled from a tree. One of the group grabbed hold and pulled it, setting off a fragmentation bomb, killing everyone except the pastor.
They became the only casualties of a Japanese attack on the U.S. mainland during World War II; their gravestones noting: “Killed by enemy balloon bomb.”
From November, 1944, to April, 1945, more than 9,000 balloons were launched by the Japanese into high-altitude westerly winds, carrying anti-personnel or incendiary bombs over the North Pacific Ocean to land in the U.S. “
Solar makes perfect sense where there is no grid availability. Was reading a story out of TX a week or so ago about a fellow who lost over 80 solar panels in a hail storm. It is fragile power and I fear that the next time we get a major hurricane strike, a lot of people are going to be out a lot of money for solar and wind power generation capacity. Insurance companies are going to get tired of paying out for damaged solar/wind at some point.
” a fellow who lost over 80 solar panels in a hail storm”.
Yeah, and yet it’s so easy to avoid hail damage.
All you have to do is bury the panels in concrete.
No darned hail stones are gonna get through all that.
http://dailysignal.com/2013/02/26/bankrupt-abound-solar-to-bury-unused-solar-panels/
“10 months on the ground in Oahu.” Letting the sun recharge its batteries?
Laying out in the sun certainly recharges my batteries.
if it had few hundred lbs more carry capacity it could be a useful sensor platform.
as is thats about it.
didn’t see breakdown anywhere but I wonder what avionics draws were.
Probably none. That’s what the chase plane was for.
would had to have been something, radios could have been handheld but speed indicator and altitude would have needed some sort of heated pitot system right?
I’d be surprised if it was heated.
wikipedia (yeah I know) shows legs of the journey at 14K feet lowest and 28K+ in some spots. if using pitot system would need to be heated.
I forget what power draw on the common pitot heaters is, possible the solar cells themselves were more than enough for that
The first planes that did burn fossil fuels were far worse than these early solar planes. Give it time. And if the future planes aren’t electric they will be hydrogen or biofuel powered – certainly won’t be from the petro we use in them today.
Hydrogen? You sure are a funny guy.
What makes you think that we won’t be using petro 100 years from now?
We certainly aren’t going to be running out before then.
WWI was only about a decade or so after the first flight of fossil fuel powered planes.
By WWII, those same planes were going well over [3000] miles and could fly from England deep into Germany carrying thousands of pounds of bombs.
Anyone who thinks that solar powered planes are going to make similar progress must be smoking some of that wacky tobacky.
[By 1948, only 40 years after their 1908 flights from a pasture, the B-36 could take off with a almost a 1/2 million pound total weight, and fly over 12,000 miles. .mod]
Give it time? Give it time to what? It won’t get any better.