# A solar hybrid ro ro ship.....

Discussion in 'Boat Design' started by saurabh11july, Dec 6, 2012.

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### saurabh11julyNew Member

m a B.tech final year student and in my project i have decided to make a solar hybrid ship..... same as MV Emerald Ace....

plz any one can help me in deciding on the capacity of the battery and panels that i must use to maximise my efficiency....

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### SpartanJunior Member

At best you have 150w per square meter.

Maybe 1200 hours a year in 'full' output on a yearly basis.

You need 4000kw to power 15,000 ton ship at 12kt every hour.

On a 20x120 meter ship you have at best 70% coverage.

Do the math.

You need 30 divers to recover the panels from the bottom of the ocean after a storm.

Get sails.

Don't worry about batteries.

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### kvsgkvngSenior Member

Could 1 hp electric engine power a special light boat?

I am not sure about my estimate, but having 150 W/m² means that an area of 7m² (75 ft²) could provide something close to a one horse power.

One horse power is theoretically close to a maximum output of a human power and it could theoretically power a light seaworsy vessel, even without batteries.

75ft² may be translated into something 10ft x 8ft flat enough to accept the solar cells. 10ft x 8ft would probably fit into category of a catboat proportions, say 8.5' by(16~18)' plan or a light catamaran.

If it is light enough, then this one horse power could move this light boat at a steady speed durig the entire daylight period.

If additonal sail is added, plus a simple 2~3hp combustion engine, then this platform may make a "something" capable of extensive cruising.

Is this scenario possible? I would like to know your opinion please. Thank you.

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### daiquiriEngineering and Design

Around 150 W/sq.m is the maximum you can expect to have from PV panels with 14-15% mean efficiency at mid latitudes (45°), in mid summer.
In winter it will be something like 50 W/sq.m, and in spring/autumn around 110 W/sq.m .
These values refer to optimum conditions, on a bright sunny day. Put some clouds on the sky or a particularily humid day, and the numbers fall down like Felix Baumgartner.

The calculations have to take these reduction factors into account.

Cheers

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### SpartanJunior Member

Everything is "theoretically" possible. But not practical.

Solar panels maximum output is when they are facing the sun otherwise their output is on a bell curve. To keep them facing the sun you need to put them on a two axis mounts/swivel. At that point, they are acting as a sail. The sun and the wind will not cooperate most of the time.

Then you have the issue of panel storage in order to get at the sails.

Then there is the issue of the mast. Solar panels don't produce energy when they are shadowed.

Ship and solar don't mix. Period. Other then a weird experiment or a publicity stunt, it wont be practical.

Solar panels are so hyped by the sky falling community and manufacturers that it's not funny. If is a relatively weak source of energy that at the very best, at it's most "look at us and how we can greenwash for publicity" is okay for a minor secondary source of power on SHIPS. Think about this, a large cargo ship can cost 50 million dollars and bunker oil is running at \$700 per ton. You need 60 tons of bunker a day so its \$42k per day in fuel. The people who own them would think nothing of spending a million dollars to get "free power", yet, almost none do. Even on my fantasy small ultra high tech cargo ship plying the Med, it would only supply 1/10 of the energy needs.

Stick to sails.

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### SpartanJunior Member

Ergo 1200 hours a year of "full rated power".

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### kvsgkvngSenior Member

Thanx, I appreciate your realistic answers. Now I have my brain gears spinning. With 3x times the area, approx 200 ft² or 10'x20' I still would be able to get close to 1hp. This should be enough to move something like 800# at a steady pace in calm water. Now I wonder if it would be a realistic idea to have one person's craft squeezed within 400# including panels, small outboard and sails. I can see not other alternative but a lightweight foam core catamaran. *This* does sound tough...
Anyways -- thanks again.

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### SpartanJunior Member

If you want to experiment with the concept, knock yourself out. I know a lot about solar because I am involved on a investment/commercial level. I will give you whatever info/guidance you need.

Know this, wind is far more available and more powerful and more mature resource. At best with solar, you will have a moving experiment. Plus wear rubber underwear, you're dealing with electricity on water. On a small craft. By yourself.

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### alan craigSenior Member

I think the solar ro-ro hybrid ship might be feasible for short repeated trips. If the ship is a catamaran it might have room for, I guess, 50% more solar panels than a mono of the same payload. Then, if it is used on short routes where it spends as much time loading as moving, the batteries will still be charging while it is docked. And as it is a hybrid it will have a generator installed producing maybe a quarter of the power required when moving, and it will be generating continuously. Surely this is starting to sound feasible?

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### alan craigSenior Member

full electric ro-ro ferry

See my post above then take a look at this:
http://www.shiptonorway.no/SitePages/NewsDetail.aspx?nid=11&t=Battery-powered car ferry!
This full electric ferry will apparently be fully recharged in 10 minutes at each docking, with shore mounted batteries to assist the local grid recharging. Power and CO2 numbers for the diesel ferry it will replace are given, although no numbers for CO2 from grid supplied power.
At 80M x 20.8M it has enough surface area to be a completely solar ferry in theory.

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### SamSamSenior Member

Alan Craig, you have got to develop your cynicism. You have to recognize that a commercial puff piece is hardly any different than an armed robbery. I'm too tired to elaborate now, maybe tomorrow.

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### alan craigSenior Member

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### LucklessSenior Member

Direct solar is, as people have pointed out already, going to be a pain to do. Solar is not well suited to mobile applications, and you would be far better off building a collection plant at either end of the boat's regular run to gather and store energy for a hot-swap or quick charge battery, or maybe hydrogen fuel cells. I've also seen some interesting research into "Solar Enhanced Gas", using large biological reactors to produce a hydrocarbon gas (Which scrubs CO2 from the air to get its carbon, so carbon neutral), then using a solar plant to convert the collected gas into a more powerful fuel. Similar things are done using natural gas instead of produced fuel.

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### groperSenior Member

everything is doable, its just a question of cost really. Most gubments are offereing subsidies for "green technology" in order to offset the increased capitol costs of implementing this type of thing...

We havnt seen mass produced electric cars until now with tesla taking the lead. The same goes for boats etc due to the cost of high energy density batteries making the cost prohibitive. Until now that is... Lifepo4 batteries have come down in price and made the tesla car possible, we will see similar trends in boats now the batteries arent so expensive. This trend will continue as the battery prices keep falling.

In this lifetime, its not so hard to imagine, that the majority of cars on the road will be electric. In 20 years, i predict this to be the case. So the same goes for boats...

Solar is another story tho, producing enough electricity from the available realestate on a boat is almost impossible - if you still want any notable payload or function that is. In a ferry, i also concur that a better solution would be to have shorebased solar power station to generate the power, and fast charge a battery bank on board the vessel during unloading/loading periods. Would work well, only reasons we dont see more of it, is that its still too expensive for commercial interest, but this is slowly changing remember, in future we will see it happening more and more...

15. ### Number4Previous Member

If everything that requires any sort of power is to be run on electricity, and this electricity is to be produced renewably, then the whole planet will have to become one big wind farm, with the spaces in between the towers filled with solar panels, and every river dammed for hydro.
Scotland is now a giant wind farm.
The Scottish ferries do not use 20% less energy. They use 20% less diesel. They definitely use more energy, as there are huge loses in transmission and storage of electricity.
200 years ago we grew our own ships and sailed them around the world, and now we are all scratching our heads and coming up with b@llocks like solar powered ships.
Banque Populaire V, aka "The Blue Beast", went around the world in 45 days on wind power alone. Earthrace took 61 days, guzzling thousands of litres of juice, and some how claimed to be a green machine. The solar powered Turanor took 584 days!

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