Solar panels built into sails... good idea or bad?

[Nostrodamus]

I saw somewhere the other day in passing that a sail company was researching the use of very flexible solar panels that are built into sails.

Initially it sounded sensible and a good idea until I thought about it further.

You would need panels on both sides of the sails.
Sails would probably be less efficient
They are not at the correct angle to the sun usually
It would mean a boat full of batteries and what would the power be used for?
When you are at anchor and need the power the sails are away.

So what initially sounded like a good idea now seems less so.

I am all for boat manufactures going even greener and producing boats with built in solar panels. I have seen them hung on the hulls of boats and built into the deck. Again sounded good but would they be very slippery in the wet.

So are solar panels in sails a good idea, would you like manufacturers to look at building them into boats and where would you put them.

I must admit we need more solar power and would like a go faster racing wing at the back with panels on but what we would like and what we can afford may be different.

 

[CPD]

I think you need to seperate solar panels as we know them now, and solar technology. I can see the day when solar technology enables different materials etc to generate power in the same way that fixed panels do now. I have always been full of ideas. It is the implementation of them that has always let me down !!

 

[JumbleDuck]

I think you need to seperate solar panels as we know them now, and solar technology. I can see the day when solar technology enables different materials etc to generate power in the same way that fixed panels do now. I have always been full of ideas. It is the implementation of them that has always let me down !!

There was some very neat work going on in optical rectennas, which are basically nanoscale antenna arrays which receive optical frequency EM radiation in lots of little aerials and produce electrical power as a result. All very experimental and IR only at the moment (longer wavelengths mean bigger antennas), and it seems to have gone a bit quiet, but I wouldn't be surprised if conventional PV panels were pushed aside by something like that over the next 10 - 20 years.

Meanwhile I think Nostrodamus is absolutely right about solar panels on sails. It might have some benefits in very specific applications - long distance ocean crossing, maybe - but I can't see it working for 99% of leisure sailors.

 

[[70521]]

I saw somewhere the other day...

Careful now I might get very, very geeky and start about energy harvesting and such like.

 

[Sgeir]

This is something I've been wondering about for a while and I'm pleased that it seems to be taking off. These are early days yet and I'm confident that the materials technology will improve and costs will reduce. Eventually.

The concept is really good, IMHO. Solar panels are fine for keeping batteries topped up but not so great when under sail for extended periods. If costs come down sufficiently I'd suggest that it will be taken up by cruisers.

In a decent season on the west coast for example, we normally try to only ever use the engine for coming into, or out of, anchorages and harbours. We use the battery for gps, radio, Navtex, auto helm, computer and iPad for email etc, internal lighting, navigation lights, masthead anchor light, fresh water pump (already fitted on boat when purchased, would prefer manual pump though). With most nights spent at anchor we are always careful with battery use and use oil lamps down below, and LEDs at the masthead. Leccy from the sails would be useful IMHO.

 

[photodog]

Not convinced...

You can already get leccy from sails... Via a towed generator.
You can already get leccy from the sun... Via normal solar panels.

So are we just substituting systems already in place? There are issues with multiple systems from one device... Single point of failure will deny you both leccy and propulsion...

Unless the cost is considerably lower than the two existing systems... Can't see it taking off.

 

[Seajet]

There was some very neat work going on in optical rectennas, which are basically nanoscale antenna arrays which receive optical frequency EM radiation in lots of little aerials and produce electrical power as a result. All very experimental and IR only at the moment (longer wavelengths mean bigger antennas), and it seems to have gone a bit quiet, but I wouldn't be surprised if conventional PV panels were pushed aside by something like that over the next 10 - 20 years.

Meanwhile I think Nostrodamus is absolutely right about solar panels on sails. It might have some benefits in very specific applications - long distance ocean crossing, maybe - but I can't see it working for 99% of leisure sailors.

Thinking back it's not so long ago when RDF seemed a wizard wheeze for some wicked people ( actually a WWII German idea ) with a perverted sense of humour to inflict on us yotties, now in the 21st Century we have GPS; we haven't got jet cars, silver suits, robot housemaids and a base on the moon yet but I reckon we can look forward to some technology such as fuel cells, not to mention ' solar sails ' - the idea of which was to propel solar powered racing yachts in space - as proposed by Arthur C Clarke in the 1970's.

 

[JumbleDuck]

With most nights spent at anchor we are always careful with battery use and use oil lamps down below, and LEDs at the masthead. Leccy from the sails would be useful IMHO.

I think I'd be more interested in a solar sail I could hoist during lazy days at anchor.

 

[Seajet]

I think I'd be more interested in a solar sail I could hoist during lazy days at anchor.

Jumbleduck,

doesn't that equate to a solar panel then ?

 

[Blueboatman]

A wing mast has useful area to exploit, all the time.

A roll away flat cockpit awning would work too, easily doubling most cruisers' solar array capacity.

In the UK? Perhaps a tide driven generator when at anchor, along with smaller, more powerful and silent ( ha!) wind generators seem as valid a pathway to more leccy. Along with 100% dischargeable, USEABLE domestic batteries.

At least, that is mine own current thinking/wish list...

But, just think of all that loverly area of mainsail turned into MWs of electricity for more, state-of-the-art, modern inconveniences: Microwaves, 72inch plasma tellies and satellite comms, watermakers, waterHEATERS, cooking hobs, washing machines, dishwashers ...silent propulsion...
One thing ' chust' leads to the other eh?

 

[mjcoon]

There was some very neat work going on in optical rectennas, which are basically nanoscale antenna arrays which receive optical frequency EM radiation in lots of little aerials and produce electrical power as a result. All very experimental and IR only at the moment (longer wavelengths mean bigger antennas), and it seems to have gone a bit quiet, but I wouldn't be surprised if conventional PV panels were pushed aside by something like that over the next 10 - 20 years.

I should like a reference to that if you can find one. I don't recollect hearing of it despite reading every New Scientist for decades. But then my memory has the "decayed" problem, too...

Even IR has an incredibly high frequency; optical even worse. I don't see how a nano-scale antenna can arrange to rectify it because of the problem of reacting to that alternating frequency. And even if feasible, the rectification would have to be linked in series or parallel to do anything useful with the electricity. (After all, just producing heat does not require technology beyond an absorbing surface!)

Mike (ancient BSc)

 

[JumbleDuck]

Jumbleduck,

doesn't that equate to a solar panel then ?

I was thinking of something much bigger than a panel; a few square metres.

 

[JumbleDuck]

I should like a reference to that if you can find one. I don't recollect hearing of it despite reading every New Scientist for decades. But then my memory has the "decayed" problem, too...

Sure. Have a shufti at http://munews.missouri.edu/news-rel...r-technology-could-break-photovoltaic-limits/. Googling "Missouri nantenna" brings up a bit more, but it all seems to have been a bit quiet since 2011. There was a piece about it in one of the early episodes of "Bang Goes The Theory" on BBC1 - the chap from Missouri brought a prototype nantenna across and showed it producing a little bit of power from background IR on a cloudy day. Rather low conversion efficiency, I think, but I do think it shows promise for the future.

 

[Cardo]

Along with 100% dischargeable, USEABLE domestic batteries.

I'm still wondering why Lithium Ion batteries haven't become more popular. Apparently can be discharged to 0, much quicker to charge and much lighter than lead acids Ah for Ah.

A forum member (don't think he posts anymore) had such a setup on his cat and 600Ah (I think that's what it was) worth of Li ion was relatively small and lightweight compared to our 500Ah of lead acids...

 

[Bru]

But, just think of all that loverly area of mainsail turned into MWs of electricity for more, state-of-the-art, modern inconveniences: Microwaves, 72inch plasma tellies and satellite comms, watermakers, waterHEATERS, cooking hobs, washing machines, dishwashers ...silent propulsion...
One thing ' chust' leads to the other eh?

Or possibly MWs of electricity stored in keel cells that double as ballast hooked up to electric auxiliary propulsion

I know the technology isn't good enough right now but in another generation or two I venture to predict that the ultra-modern yacht will not rely heavily, if at all, on fossil fueled power sources and a solar sailcloth would be a key part of such a system

 

[JumbleDuck]

I'm still wondering why Lithium Ion batteries haven't become more popular. Apparently can be discharged to 0, much quicker to charge and much lighter than lead acids Ah for Ah.

A forum member (don't think he posts anymore) had such a setup on his cat and 600Ah (I think that's what it was) worth of Li ion was relatively small and lightweight compared to our 500Ah of lead acids...

Have a look at the Mastervolt MLI Ultra 12/5000. That's 12V, 5kWh, so ~420Ah, which, since it can be discharged to flat, is probably the equivalent of about 2,000Ah of lead-acid. I can't find a UK price, but they seem to be €4399 across Europe, which may explain why they haven't quite taken over the market yet ...

http://www.mastervolt.com/marine/products/li-ion/mli-ultra-12-5000/

 

[Cardo]

Have a look at the Mastervolt MLI Ultra 12/5000. That's 12V, 5kWh, so ~420Ah, which, since it can be discharged to flat, is probably the equivalent of about 2,000Ah of lead-acid. I can't find a UK price, but they seem to be €4399 across Europe, which may explain why they haven't quite taken over the market yet ...

http://www.mastervolt.com/marine/products/li-ion/mli-ultra-12-5000/

Now that's what I'm talking about. Pity about the eye watering price tag, though. Let's hope the prices drop a bit!

 

[Nostrodamus]

I should like a reference to that if you can find one. I don't recollect hearing of it despite reading every New Scientist for decades. But then my memory has the "decayed" problem, too...

Even IR has an incredibly high frequency; optical even worse. I don't see how a nano-scale antenna can arrange to rectify it because of the problem of reacting to that alternating frequency. And even if feasible, the rectification would have to be linked in series or parallel to do anything useful with the electricity. (After all, just producing heat does not require technology beyond an absorbing surface!)

Mike (ancient BSc)

Mike...
Absolutly 100% totally agree. Now what the hell are you talking about?????????????
Can you wire a plug for me

 

[Nostrodamus]

I have also seen a lot of boats in the med with Panels in pockets in the Bimimi which makes more sense and seems to work well.

 

[Cardo]

I have also seen a lot of boats in the med with Panels in pockets in the Bimimi which makes more sense and seems to work well.

Until you want to roll away the bimini!
But yeah, it's great having a panel there.