Wind is better than solar. Discuss

[noelex 77]

Originally Posted by EngineerRetired

If you are in Norway wind is better, if you are at the equator solar is better. Discussion over. LOL (Lots of truth though)

Solar in Norway is actually very effective for much of the year. The sun angle is not very high, but daylight hours are long.

Wind plus solar can be a great solution, but the shading from the wind generator can diminish the solar output substantially, reducing or even eliminating the value in many cruising grounds.

[Smokeys Kitchen]

Hello,

We have both a wind gen and solar panels on our boat. We are awaiting delivery of another solar panel, but the ones I have (Sun Power from Custom Marine Products) are working well.

The wind gen is a D400. We installed new Victron controllers and a shunt for the wind gen on @ Aug 1. Since we do not have a finished solar panel install, I can't/won't report on what the output is for those, but as of Aug 1 the wind gen has put out 4.6kWh which includes about 6 days of being on a dock plugged in and several day of windless anchoring. This is off the 'history' tab on the shunt app from Victron - it does not have any detail, just a total given at this level of measure.

Figuring 26 days so far, the averaged output is @ 177wh/day or @14.5 ah/day. You would think not much, but the wind gen does tend to fill in a lot when the solar isn't putting out much or any power, and does offset the draw down on the batteries quite a bit when moving. I certainly plan on keeping both even when the other solar panel gets installed.

We are now in Crescent City going down the west coast and the wind gen has worked well. Since I have a little high end hearing loss which could affect my perception of noise as mentioned in several previous responses, I asked the two folks who do not have any hearing loss on the boat - high end or otherwise - if the wind gen is making too much noise for them. They both responded that while they could hear it, it was not a high pitched squeal or whine, just a very small 'woosh' as the wind gen operated.

The pole is @ 9 ft on the aft rail. During some of the night sails we have had, the two good hearing folks are able to have a normal conversation in the cockpit while the wind gen is working a lot.

Just info that I have for others to use or not as they like.

Ron

(waiting for Stu to lampoon me if I did not get the units correct )

[HBrew]

I have a Silentwind (not a pro model) and 1kW of solar on my davits, which I would need in any case for my dinghy.

Based on my real world assessment of amps generated by both, I am lucky if I see 8 amps (@12V) from the wind gen on a really windy day when it’s really buzzing. I get up to 80 amps from the solar. I am sure I could get more output from a better wind gen, but I don’t see how I could run my boat with wind only. In fact, my current setup powers the boat when at anchor but does not provide enough energy when underway, so I am planning on increasing my solar installation. I may at the same time upgrade my wind gen to a better model or get two (currently considering D400s) but I’m not sure about that yet and may just go with extra solar initially to see if that will meet our needs as the noise and vibration when the wind blows hard are not pleasant.


I hope this helps you.

[lordgeoff]

Originally Posted by Na Mara

So I’m still trying to work out what the best power system for Na Mara is. I thought I had it when I decided on a 4kW generator coupled with a big Lithium bank and a fat inverter/charger but then my Dad went and fitted a new silentwind pro onto his boat and now he’s raving about it so I’m having to reconsider. Being a big nerd I decided to crunch some numbers and I thought I’d share this with the community.

To figure out whether a silentwind pro would work for me I closely approximated the output curve with an exponential function. I then found the area and season that I am likely to cruise in that has the lightest winds. That happens to be the Baltic Sea during the summer. The daily average winds there at that time have a mean of 5m/s (10kn) with a single standard deviation of 1m/s (2kn). Assuming that the wind speeds are normally distributed, I then calculated the average output of a silentwind pro by calculating the average value of the output curve for winds between 0 and 15m/s (Integrating the product of the output curve and pdf for the wind distribution between 0 and 15). The result was 36W, which translates to an average daily energy input of 860Wh or 72Ah at 12V. That is just enough to cope with our needs at anchor but no where near enough to cope with them underway. However, two silentwind pros would cover all our needs with a bit of spare capacity even on this worst case scenario.

In this worst case scenario - from a wind power perspective - of being in the Baltic during summer the capacity factor of my wind generators would be less than 9% and the capital cost per daily Wh would be in the region of 3.5€ (silent wind pro plus mast, controller and installation 3000€)

Now compare that with solar. Average monthly solar radiation in the southern Baltic in summer is around 130kWh/m2. Assuming 30 days in a month gives you a daily average of around 4.5kWh/m2. Assuming 20% efficient panels gives you average daily energy input from each meter squared of panels aboard of 900Wh. So as near as makes no difference 1m2 of solar will give me the same energy input as a silentwind pro in this worst case for wind. Again, to meet our needs we would need to double this so we would need about 2m2 of solar. To mount 2m2 of solar - about 350W - on Na Mara I would either need davits or an arch. Either of those plus panels and sundries comes to at least 5000€ installed and so the capital cost per daily Wh is at best 2.8€.

The Baltic in summer is a best case for solar and a worst case for wind. High pressure systems from Siberia tend to move in over the Baltic during the summer and settle there. These together with the high latitude lead to long cloudless days in summer with very little wind. Sailing pretty much anywhere else around these parts, such as Skagerrak or Kattegat or off into the North Atlantic, there will be more cloud and more wind. As output from wind goes up by the cube of wind speed, the above calculation rapidly shifts in the wind turbine’s favour if we sail anywhere else than the Baltic in high summer.

Of course an arch that carries 3m2 of panels isn’t much more expensive than one that carries two, so if Na Mara were a more hungry power consumer, then the calculation above would be more in solar’s favour with a capital cost per daily Wh of a bit less that 2€. However, that extra power would be wasted on Na Mara and the bigger arch would just increase windage, ugliness and capital cost to no practical end.

All in all it would seem that a pair of wind generators charging a very large bank - to smooth out the feast and famine nature of wind energy - would do the trick and for Na Mara better than solar. Basically, unless my calculations are way off, I have to disagree with all the “solar is all you need” crowd on this forum. Modern wind is virtually silent, easy to regulate through Bluetoothed apps, perfectly capable of more than meeting all the energy needs of a moderate cruiser even in relatively low wind zones, and price comparable on a capital cost per energy produced basis (at least this is so for those of us not sailing boats already sporting suitable structures for mounting panels).

One concern with this reasoning is that I, like manus herr, am also wanting to do an Atlantic circuit and everyone keeps saying that the reduction in apparent wind on wind generators makes them borderline useless on such trips. But the trades run at an average of 10m/s with a single standard deviation of 2m/s when yachts do the crossing so even running dead downwind at 6kn (3m/s) the average apparent wind will be 7m/s with 2m/s SSD. That gives an expected average output for the wind genny of about 66W for the crossing producing an average of 1.5kWh a day. That is almost enough to meet my needs on the crossing on its own. Add another wind generator - which I would need in the Baltic anyway to meet my needs summer cruising - and I would luxuriate in over 3kWh a day from the pair. So this concern about wind and power on downwind legs is, according to my calculations, also without foundation.

Why not both……?😳 completely different types of generation.

[Mike OReilly]

Originally Posted by Na Mara

This is particularly true as many wind generator controllers come with inputs for solar as well allowing the two to work in unison optimally. The silent wind can be combined with 200W of solar on the standard controller for example. From my earlier calculations, 200W of unshaded solar should give about a 1kWh per day of energy on average in the Baltic summer. Together they would give nearly 2 kWh, which is way more than I need to keep the lights on underway or on the hook. The question is where to put the 200W of panels where they won't be shaded, won't ruin the lines of my boat, won't be in the way, and won't cost a lot to mount.

Be wary of using the same controller. I nearly killed my batteries using the Silentwind controller to manage the solar. The problem is, the wind controller is basically a voltage cut-off device. It's great for bulk charging, but won't allow you to maintain an absorption or float charge.

Unless they've changed controllers, I strongly suggest getting a quality MPPT for your solar.

[Na Mara]

Originally Posted by Smokeys Kitchen

Figuring 26 days so far, the averaged output is @ 177wh/day or @14.5 ah/day. You would think not much, but the wind gen does tend to fill in a lot when the solar isn't putting out much or any power, and does offset the draw down on the batteries

That’s pretty low. According to my math that’s what a D 400 would do in about 6-8kn mean wind speed. Was that all you had on those 26days?

[waterman46]

Originally Posted by wholybee

Consider mounting them on your lifelines. You could probably fit 4 200W panels, 2 on each side. For a nice install, you could have the upper lifeline replaced with SS tube, and use nice solar panel mounts. Prop them up with some sticks (even works great while sailing) and tie them down for storms. I just used Zip Ties. I used PEX tubing to cover the lifelines, drilled some holes in the solar panel frames, and zip tied them on. They have survived 20k nm of ocean sailing, 45kts sustained of wind, and 5m swells. They (IMHO) look better than panels on an arch, and because they are outside the boat instead of on the centerline, one side will always have good sun without shading.

I had two 75W panels on SS tubes over the lifelines as you described. But in that location, and mine were all the way aft to the pushpit, they got lots of shading compared to mounting on davits or an arch.


Don't understand why does OP not add davits, since they are so useful for the dinghy as well?

[Sailshabby]

<…but I don’t have any use for all that extra energy.>

Until you do…

[wholybee]

Originally Posted by waterman46

I had two 75W panels on SS tubes over the lifelines as you described. But in that location, and mine were all the way aft to the pushpit, they got lots of shading compared to mounting on davits or an arch.


Don't understand why does OP not add davits, since they are so useful for the dinghy as well?

Not sure about the OP. In my case, I have a windvane, so davits is not an option. The cost of a decent arch seems to exceed the cost of the entire rest of the solar system, plus they are ugly, so I passed on that. And, I fold/take down my bimini very often.

I do get very good output with them on the lifelines, but that will depend on what all is on your boat to shade them. (davits, arches, bimini's and all that)

[gezza]

Sounds like OP is preaching rather than asking.
Of all the capital expense I have had on my boat, the only regret I have was a wind generator. Complete waste of money - under 15Kn the output is minimal and in any event when at anchor you are trying to escape the wind. And when it does work it’s noisy - and the ability to Bluetooth turn it off when noisy, seems again to defeat the point of having it.

[kryg]

I find you need both solar and wind generator, I have 720 watts over two solar panels. To keep my AGM batteries 860 amp house banks charged. I don't want a generator, hate the noise. I find you need a wind generator, when it's very overcast and raining, normally it would be windy as well. This keeps my battery bank topped up. Also, to add power on a windy night. Keep in mind, the wind generator can never replace a good solar panel installation. However, I have a D400 from the UK manufacture for 400 watts max input, it is very quiet. I'm very happy with my duel setup of solar and wind power. I run everything off this system 60 litre hr. water maker, fridge computers, lights and so on. Good luck with your projects.

Originally Posted by Na Mara

So I’m still trying to work out what the best power system for Na Mara is. I thought I had it when I decided on a 4kW generator coupled with a big Lithium bank and a fat inverter/charger but then my Dad went and fitted a new silentwind pro onto his boat and now he’s raving about it so I’m having to reconsider. Being a big nerd I decided to crunch some numbers and I thought I’d share this with the community.

To figure out whether a silentwind pro would work for me I closely approximated the output curve with an exponential function. I then found the area and season that I am likely to cruise in that has the lightest winds. That happens to be the Baltic Sea during the summer. The daily average winds there at that time have a mean of 5m/s (10kn) with a single standard deviation of 1m/s (2kn). Assuming that the wind speeds are normally distributed, I then calculated the average output of a silentwind pro by calculating the average value of the output curve for winds between 0 and 15m/s (Integrating the product of the output curve and pdf for the wind distribution between 0 and 15). The result was 36W, which translates to an average daily energy input of 860Wh or 72Ah at 12V. That is just enough to cope with our needs at anchor but no where near enough to cope with them underway. However, two silentwind pros would cover all our needs with a bit of spare capacity even on this worst case scenario.

In this worst case scenario - from a wind power perspective - of being in the Baltic during summer the capacity factor of my wind generators would be less than 9% and the capital cost per daily Wh would be in the region of 3.5€ (silent wind pro plus mast, controller and installation 3000€)

Now compare that with solar. Average monthly solar radiation in the southern Baltic in summer is around 130kWh/m2. Assuming 30 days in a month gives you a daily average of around 4.5kWh/m2. Assuming 20% efficient panels gives you average daily energy input from each meter squared of panels aboard of 900Wh. So as near as makes no difference 1m2 of solar will give me the same energy input as a silentwind pro in this worst case for wind. Again, to meet our needs we would need to double this so we would need about 2m2 of solar. To mount 2m2 of solar - about 350W - on Na Mara I would either need davits or an arch. Either of those plus panels and sundries comes to at least 5000€ installed and so the capital cost per daily Wh is at best 2.8€.

The Baltic in summer is a best case for solar and a worst case for wind. High pressure systems from Siberia tend to move in over the Baltic during the summer and settle there. These together with the high latitude lead to long cloudless days in summer with very little wind. Sailing pretty much anywhere else around these parts, such as Skagerrak or Kattegat or off into the North Atlantic, there will be more cloud and more wind. As output from wind goes up by the cube of wind speed, the above calculation rapidly shifts in the wind turbine’s favour if we sail anywhere else than the Baltic in high summer.

Of course an arch that carries 3m2 of panels isn’t much more expensive than one that carries two, so if Na Mara were a more hungry power consumer, then the calculation above would be more in solar’s favour with a capital cost per daily Wh of a bit less that 2€. However, that extra power would be wasted on Na Mara and the bigger arch would just increase windage, ugliness and capital cost to no practical end.

All in all it would seem that a pair of wind generators charging a very large bank - to smooth out the feast and famine nature of wind energy - would do the trick and for Na Mara better than solar. Basically, unless my calculations are way off, I have to disagree with all the “solar is all you need” crowd on this forum. Modern wind is virtually silent, easy to regulate through Bluetoothed apps, perfectly capable of more than meeting all the energy needs of a moderate cruiser even in relatively low wind zones, and price comparable on a capital cost per energy produced basis (at least this is so for those of us not sailing boats already sporting suitable structures for mounting panels).

One concern with this reasoning is that I, like manus herr, am also wanting to do an Atlantic circuit and everyone keeps saying that the reduction in apparent wind on wind generators makes them borderline useless on such trips. But the trades run at an average of 10m/s with a single standard deviation of 2m/s when yachts do the crossing so even running dead downwind at 6kn (3m/s) the average apparent wind will be 7m/s with 2m/s SSD. That gives an expected average output for the wind genny of about 66W for the crossing producing an average of 1.5kWh a day. That is almost enough to meet my needs on the crossing on its own. Add another wind generator - which I would need in the Baltic anyway to meet my needs summer cruising - and I would luxuriate in over 3kWh a day from the pair. So this concern about wind and power on downwind legs is, according to my calculations, also without foundation.

[Na Mara]

kryg,

The reason i initially settled on a generator was as follows:
1. I have space in the engine bay for one and that bay is well insulated for sound. The noise should be significantly less than my engine and my engine noise is fine for short periods.
2. I planned to have about 8kWh of lithium batteries. At anchor, I should only have to run the generator for 1-2 hrs every 4-5 days. Underway it would be once every 2-3days. I figured I would appreciate the hot water for showering about then and could live with the noise if it is that infrequent, quiet and short.
3. Due to having a perfect spare space in the engine bay right in the middle of the boat, the impact of a generator aboard on other boat functions would be basically zero.
4. I am concerned that no matter what renewables source I have, that I am going to have to run some kind of ICE for juice regularly anyway. My engine is so inefficient at this (big engine, tiny dumb hitachi alternator), that I will need to do something here anyway. A new second high-power alternator rig is going to cost 3000 euro done right, and even then the efficiency wont be great (1.7l/kWh) compared with a proper generator (0.4l/kWh). As a renewables package plus alternator upgrade is going to be in the ball park of 10000 euro anyway, and as the generator isn't much more than that installed, it seemed better just to do the generator and forget everything else (or add it later).

What got me rethinking this was reports from my Dad and others here on how little they run their ICEs for power with their solar and wind set ups.

[rslifkin]

Maybe start with the generator and whatever solar you can install cheaply, see where that gets you and then add more solar or wind later? The generator may prove useful even if you've got enough solar / wind to cover 95% of days, particularly if you want to consider electric cooking without a rather large solar / battery setup.

[jmschmidt]

Wind generators are fine when you are anchored or in a slip but underway (power or sail) they simply extract the same or even a slightly more energy from your motor or sails that they produce.
Solar is fine in daylight and does not extract energy from you motor or sales while anchored or underway.
Many on this forum don't believe that there is no free lunch in physics.

[Caleb_Grey]

If you can fill your battery bank everday on wind alone you need a bigger battery bank.